O ISI W OD V LA U N K D U S M CLEAN ENERGY Adaptable Accessible Clean Reliable Environmentally Friendly and Sustainable
A Resource Book for Secondary School Environment Clubs
CONTENTS
Acknowledgements ...... ii Abbreviations ...... iii Preamble ...... iv Foreword ...... v Problem statement ...... vi Clean Energy Workshop Objectives ...... vi
1 Energy ...... 1 1.1 What is energy?...... 2 1.2 Sources of energy...... 3 1.3 Zimbabwe Energy supply situation ...... 3 2 Types of energy ...... 4 2.1 Biomass ...... 4 2.2 Fossil Fuels ...... 4 2.3 Electricity...... 5 2.3.1 How is electricity generated from water? ...... 5 2.3.2 General Energy Strategy ...... 6 2.4 Important Laws and Regulations and polices...... 6 2.5 Electricity Market ...... 7 2.6 Key problems of the Energy Sector...... 7 3 Energy Conservation...... 9 3.1 Energy saving tips ...... 9 3.1.1 Electricity saving in cooking ...... 9 3.1.2 Electricity saving on water heating ...... 10 3.1.3 Electricity saving on lighting ...... 10 3.2 Safety in the home ...... 10 4 Climate Change Response: The need to Cope, Adapt and Mitigate ...... 11 4.1 Climate Change ...... 11 4.2 Global Warming ...... 11 4.3 Greenhouse gases and greenhouse effect ...... 12 4.4 The Ozone Layer Depletion...... 13 4.5 Impacts of Climate Change ...... 14 4.5.1 Children’s fi ndings on Climate Change ...... 15 4.6 Adaptation and Mitigation ...... 15 5 Renewable Clean Energy...... 16 5.1 Why must we go for Clean Energy? ...... 16 5.2 Energy For all Options and Sources of Renewable and Clean Energy ...... 17 5.2.1 Solar Energy ...... 17 5.2.2 Wind Energy ...... 23 5.2.3 Geothermal Energy ...... 23 5.2.4 Micro-hydropower (Using water power to generate energy)...... 23 5.2.5 Biogas ...... 24 5.2.6 Fireless cooker ...... 28 5.3 Cookstoves ...... 31 5.3.1 Open fi re cooking...... 32 5.3.2 Rocket Stove ...... 34 5.4 What can we do as an Eco Schools environment club? ...... 36 6 The Eco Schools Programme ...... 37 6.1 Becoming an Eco School ...... 38 6.2 Membership ...... 38 6.3 Information and Registration ...... 38 Glossary...... 39 References ...... 41 ACKNOWLEDGEMENTS
Compiled by: Mukuvisi Woodlands. Editing by: ACTION Institute for Environment Health and Development Communication (Action IEHDC). Researchers: Gibson Nhokwara, Eunice Moyo, Pyke Chari. Photography: Green Studio, Brighton Nyachega. Design and Layout: Casmia Nyamuba. Artwork: Munyaradzi Tsodzo.
Mukuvisi Woodlands would like to thank the experts from the participating organisations for their contribution in this book. Every effort has been made to ensure the accuracy of the information within this book. This book could not have been produced without the editorial skills of Action Institute for Environment Health and Development Communication (Action IEHDC). This book has been produced with fi nancial support from UNICEF and technical assistance from colleagues at the UNICEF Harare Climate Offi ce, Amy Wickham, Jeremiah Mushosho and Jackie Magwenzi.
Consent for use of pictures and information in this book was granted by the presenters and resource persons at the three workshops for school environment club leaders. These have been acknowledged as Blessing Jonga (BJ), Lewis Makurumure (LM), Chiedza Mazaiwana (CM), Jeremiah Mushosho (JM), Amy Wickham (AW), Brighton Nyachega (BN), Green studio, Practical Action, Ministry of Energy and Power Development, Rural Electrifi cation Agency (REA), Econet Zimbabwe, Zimbabwe Energy Regulatory Authority (ZERA) and Mr. Ndiweni from Fort Rixon in Matabeleland South Province who allowed the Clean Energy workshop participants to use his homestead for practical activities where they witnessed biogas in use (see back cover picture). The information has been used for educational purposes rather than for commercial reasons as this book is not for sale but intended to be a handbook for environment club members who are interested in clean energy projects.
Thank you to all the children, teachers and the schools that helped in the pre-testing of the booklet. Testing was done with Grades 4, 5, 6 and 7 pupils from Louis Mount Batten Primary School and their environment club teacher patrons, Mrs. Manyonga, Miss Sibanda and Mrs. Saungweme the Deputy Head. Pre-testing was also done with the environment club members in Forms 1, 2, 3 and Upper 6 at Mufakose 1 High School together with their teacher patrons Mrs. Veronica Muchawa, Mrs. Chitsa and the Head of Department (HOD) Geography, Mr. Matavire.
Second Print
Clean Energy for School Environment Clubs ii ABBREVIATIONS
IPCC Intergovernmental Panel on Climate Change NocZim National Oil Company of Zimbabwe REA Rural Electrifi cation Agency UNICEF United Nations Children’s Fund ZERA Zimbabwe Energy Regulatory Authority ZESA Zimbabwe Electricity Supply Authority ZETDC Zimbabwe Electricity Transmission and Distribution Company Zim Asset Zimbabwe Agenda for Sustainable Socio Economic Transformation SPV Solar Photovoltaic system PVP Photo Voltaic Products GWh Gigawatt hour(s) mW Megawatt(s) kWh Kilowatt-hour(s) kW Kilowatt(s) W Watts HEP Hydroelectric Power ZPC Zimbabwe Power Company LED Light-emitting diode
iii Clean Energy for School Environment Clubs PREAMBLE
This booklet comes as a result of a series of Clean Energy Programme (CEP) workshops for school environment club leaders which introduced the participants to clean energy also known as renewable energy. The workshops were coordinated by the Mukuvisi Woodlands Eco Schools Environmental Education Programme in partnership with Action IEHDC with the assistance of resource persons from Ministry of Energy and Power Development, REA and Practical Action Zimbabwe. Renewable Energy is an energy option for a cleaner and more sustainable environment. The main focus is to enable the creation of climate smart schools through the formation of environmental clubs, to upscale and broaden scope for Science Exhibitions as children make gadgets, models and or tools for climate change education. Renewable energy for cities and communities is a strategy for climate change adaptation and hence schools environmental clubs must advocate for a clean and green environment.
The book includes an overview of the current energy situation in the country and various sources of alternative renewable energy. It gives tips on safe and effi cient use of energy e.g. electricity aimed at effecting behavioral change from the current wasteful practices.
Clean Energy for School Environment Clubs iv FOREWORD
Our environment is threatened by all sorts of dangers much of which are linked to human activity which is referred to as anthropogenic. Man is a think tank bestowed with indigenous knowledge systems which are typical of different cultural practices. The major problem with indigenous knowledge is the absence of a handover between generations thus there is no sustainability plan. It is therefore important that the elders share their vast knowledge with their children as a way of ensuring that there is no gap of knowledge when those who have the knowledge are no longer available to offer such knowledge. The youth environmental education programme therefore seeks to involve youths at every stage. Mukuvisi Woodlands would like to thank UNICEF for supporting such initiatives that involve children.
v Clean Energy for School Environment Clubs PROBLEM STATEMENT
Zimbabwe faces an energy crisis like most of the countries in the world. Reliance on non-renewable energy forms is unsustainable especially in the light of the changing climate. Researchers indicate that climate change is one of the biggest challenges faced by humankind today and while its impacts are bad for everyone, they are worse for the vulnerable groups in society, particularly children and women. Current energy production and consumption methods in Zimbabwe and the neighbouring countries contribute to climate change. Non- renewable energy sources, especially fossil fuels used in industry, emit greenhouse gases which promote climate change. Energy consumption practices in domestic cooking, tobacco curing, brick making and in other industrial activities affect the environment negatively, which in turn has adverse impacts on the school going child who uses energy for lighting to read and for heat to prepare food. A study conducted by UNICEF and the University of Zimbabwe Institute of Environmental Studies (IES) where youths were consulted revealed that 50% of children in rural areas and 40% of their urban counterparts assist their parents to collect fi re wood. Females (both girls and women) dominate in the performance of this task and generally carry fi rewood by the head, while males (boys and men) normally use the wheelbarrow or animal drawn cart. The same study reports incidences where some children were forced to skip school in order to go and collect fi rewood for the family, “The situation will force you not to go to school as there will be no fi rewood and you want food when you come back from school”, lamented one child from the study area. Such reports prompted the Eco Schools Programme to challenge the affected youths to come up with possible solutions to this energy crisis.
CLEAN ENERGY WORKSHOP OBJECTIVES
Major hopes were pinned on the assumptions that school environment clubs will be able to: 1. Educate environment clubs on clean and renewable energy. This is a key climate change adaptation strategy for cities and communities. 2. Cultivate a culture of using energy effi ciently and practice conservation among the young generation so that they grow up to be responsible energy consumers. 3. Cultivate innovativeness, energy effi ciency and conservation culture among the young generation. 4. Encourage environment clubs to develop practical skills that will help alleviate the energy crisis in the future. 5. Create awareness among the young generation on the available renewable energy alternative sources of energy for sustainable economic and social development. 6. Educate learners about programmes that are being implemented by the Government of Zimbabwe and non-governmental organisations which are running various programmes on energy conservation and renewable energy in different communities in the country.
Clean Energy for School Environment Clubs vi 1 ENERGY
Schools Clean Energy Workshops 2015 Edition Motto The Clean Energy workshops for schools environment club leaders’ motto was: “Clean energy is Adaptable, Accessible, Clean, Reliable, Environmentally Friendly and Sustainable!”. Can you justify the following statements: a. It is Clean because its production and usage does not pollute the environment b. It is Environmentally Friendly to use since there are minimum health and safety risks c. It is Sustainable because ….. d. It is Reliable because …… e. It is Accessible because ….. f. It is Adaptable because…
vity Acti Discussion. Find out how much you know about clean energy. 1. What are the sources of energy for our homes and schools? 2. How are we using energy in our home and school communities? 3. What do we need if we wanted to have electricity / lights and heat energy for domestic use in our homes or schools? 4. What can we do to have safe energy at home? 5. Is the energy we use at home and in the country enough for everyone? Why? 6. Do you think this source that we are using at home is going to last? Why? 7. What are the possible dangers that may arise from using this energy source? Why? 8. Why are we not having clean energy for all in Zimbabwe? Explain.
1 Clean Energy for School Environment Clubs 1.1 What is Energy Energy is the capacity to do work. It causes things to happen and therefore it is needed for movement and life. These are some of its characteristics: • Energy can be converted from one form to another and this is called an energy chain. • Energy can never be destroyed and in the same manner it cannot be created. • Energy is involved whenever things move and wherever there is a change. Energy is seen in animals moving, vehicles moving, growing plants, rocks falling, a stone thrown etc. • The sun is the main source of energy. Green plants convert this energy into food and pass it on to animals. • Moving objects produce kinetic energy while every object that is not moving has stored and ready for use energy called potential energy. Some objects can store energy like in batteries, fuel, food and this is called chemical energy.
vity Acti In the diagram below, can you identify and describe the types and or sources of energy that you can see?
Figure 1: Energy crossword puzzle
Adapted from www.dreamstime.com
Clean Energy for School Environment Clubs 2 1.2 Sources of Energy: The main source of all energy is the sun. The source can be renewable or non-renewable. Renewable sources include solar, wind, water, wood and other biomass while non-renewable sources include petroleum (oil, paraffi n, diesel, petrol, kerosene, jet fuel), nuclear and coal. These are used only once and they get depleted or exhausted such that they cannot be used again. Renewable energy is made from resources that mother nature will replace such as wind, water and sunshine. Renewable energy is also referred to as “clean energy” or “green power” because it doesn’t pollute the air or the water. Renewable energy technologies are clean sources of energy with a much lower environmental impact than conventional energy technologies. They do not emit any greenhouse gases thus they keep the world cleaner and safer.
Non renewable energy is energy from resources which can be depleted or exhausted and thus called non-renewable. Thermal electricity is generated from non-renewable sources like coal and petroleum. Such energy has disadvantages in that it produces smoke which pollutes the air. Burning of fuel sources (that contain carbon, hydrogen and oxygen) produces carbon dioxide, carbon monoxide, soot and sulphur dioxide which pollute the air. 1.3 Zimbabwe energy supply situation Zimbabwe is a landlocked country located in Southern Africa, between the Zambezi and Limpopo rivers. Zimbabwe mainly relies on hydroelectric power (HEP). In rural parts of the country, 80 to 90% of the people depend on wood fuel and kerosene for cooking and lighting. Food processing tasks like milling grain are usually carried out with diesel powered systems. Total electricity generation in 2009 was 7,900 gigawatt hours (Gwh) of which 53% of this was produced from renewable sources. The energy supply options in Zimbabwe have a mixture of hydroelectricity, coal and renewable sources. Much of Zimbabwe’s electricity is produced at the Kariba Dam Hydroelectric Power Station with an installed capacity of 750mW, at Hwange Thermal Power Station which has an installed capacity of 920 mW and at three small coal powered thermal stations (National Energy Policy, 2009). Apart from the Kariba Dam Hydroelectric Power Station, there is still quite a lot of hydropower potential especially along the Zambezi River. Solar power has enormous potential both on small and large scale. Wind and biogas energy are other possibilities.
Figure 2: Facts and Information about Zimbabwe related to energy
Zimbabwe’s position in Africa Did you know that Zimbabwe is in Southern Africa and its capital city is Harare? It is located on 17.8333 degrees South and 31.0500 degrees East? It has a total land area of 390,760 square kilometers (39 million hectares)? It has a population of 14 million people (14,599,399) as of 2014 census. Of these, 67% live in rural areas? 40% of the people in Zimbabwe have access to electricity energy. 7% of the total energy used is imported and 28.29 % of our electrical energy is made from fossil fuels? Total primary energy supply as in 2009: Electricity imports = 5%, petroleum products = 6%, coal = 19%, biomass = 66% and hydro = 4%?
Adapted from World Bank./ Zimbabwe, Ministry of Energy and Power Development, Energy Balance, 2009. Ministry of Energy and Power Development. National Energy Policy
3 Clean Energy for School Environment Clubs 2 TYPES OF ENERGY
2.1 Biomass Biomass fuels come from natural material things that once lived, for example wood, dried vegetables and crop residues, most commonly used by the poor communities. Biomass accounts for about 66% of the energy use. Wood fuel is the most important domestic fuel in the country especially used in the rural areas. It is the major source of energy for cooking, lighting and heating for over 80% of the population mainly in the rural and peri-urban areas. The potential of bagasse (the dry pulpy residue left after the extraction of juice from sugar cane) or co-generation in Zimbabwe, particularly from sugarcane and or from wood waste generated from the timber industry with over 70 000 tonnes of biomass waste each year. More than 200 biogas plants have been installed in Zimbabwe, mainly by government, Non Governmental Organisations and other private players. There is also great potential for generating electricity using biogas from animal waste due to the large population of livestock in Zimbabwe. In the south of Zimbabwe there are 2 sugarcane-crushing mills that use more than 1 300 000 tonnes of bagasse for electricity generation for the sugar factories. Zimbabwe had a targeted plan of substituting 15% of its fuel requirements by 2015 through bio-fuels by expanding sugar cane growth for ethanol production and expanding jatropha growth (by planting 122 000 hectares). Additionally, a 35 000 000 litres per annum biodiesel production facility is already in place in Zimbabwe at Mount Hampden. 2.2 Fossil Fuels Fossil fuels are fuels that were formed under the earth’s surface from the fossilized remains of plants and animals that lived millions of years ago, examples include coal, oil, gas and coal. Zimbabwe has 30 billion tonnes of coal in 21 known deposits that could last for over 100 years. Hwange Colliery Company (HCC) is the major coal company in Zimbabwe with 38% owned by the government. HCC has large deposits of coal but does not have the fi nancial resources to signifi cantly boost output. HCC provides coal to the Hwange Thermal Power Plant, the largest thermal facility in Zimbabwe that has a capacity of about 920 mW. Zimbabwe does not have any indigenous sources of oil and natural gas and thus depends on imports for liquid fuel. The majority of Zimbabwe’s refi ned petroleum and diesel oil are imported via a pipeline from the port of Beira in Mozambique to Mutare district in Manicaland province. Petroleum and diesel are also imported from South Africa. Oil fuel imports cost the country a lot of foreign currency (US$ 454 million in 2009) or 15.7% of total import expenditure. A project is underway to produce 20% of the country’s liquid fuel as ethanol from sugar cane in Chipinge district, Manicaland province.
Clean Energy for School Environment Clubs 4 2.3 Electricity Electricity is a form of energy resulting from the existence of charged particles (such as electrons or protons) either statically as an accumulation of charge or dynamically as a current. Electricity is all around us powering technology like our cell phones, lighting up homes and cooking our food. Electricity is generated from various sources which can be renewable or non-renewable. Figure 3: Generating electricity from coal
Stack Coal supply Electricity
Conveyer Steam
Boiler Steam turbine Generator
Pulveriser/Mill Sub-station Transformer
Condenser Ash systems Water purifi cation Adapted from Focus on Science Rainbow Resource Books
2.3.1 How is electricity generated from water? Electricity generated from water is called Hydroelectric Power or simply HEP. Water is drawn from the water intakes in the lake through penstocks. The water is used to turn a turbine which is coupled to a generator. After turning the turbine, the water is discharged through a spiral casing into the lake. Water is trapped at a height from the dam and directed to the turbine blades to turn the turbine shaft. The shaft turns the generator rotor which is coupled to the turbine to produce electricity. See the diagram below. Figure 4
Resevoir Powerhouse Long Distant Intake Power Lines Generator
Penstock Turbine River
Hydro-Electric
Source: zera.co.zw Source: Ministry of Energy and Power development website Zimbabwe has a hydropower potential of 18,500 GWh a year, of which 17,500 GWh is technically feasible. To date about 19% of the technically feasible potential has already been exploited. Rusitu Hydro, a mini hydro plant of 750 kW operating privately sells power to the state-owned company, Zimbabwe Electricity Supply Authority (ZESA). About 8 small-hydro plants are currently installed in Zimbabwe, ranging from 3 kW to over 700 kW. The total potential of small-hydro in Zimbabwe is estimated at 120 mW.
5 Clean Energy for School Environment Clubs vity Acti Answer all questions below: 1. What is electricity? 2. Which is the largest hydropower station in Zimbabwe? 3. Using whatever resources you can fi nd around you, make a model to demonstrate how hydroelectricity is generated from water. You can look at fi gure 3 page 11 for assistance. 4. Make another model to demonstrate how electricity is generated using coal. 5. Describe and explain how electricity is transmitted and distributed to homes and schools. 6. Discuss and debate on how the generation of electricity impacts the environment.
2.3.2 General Energy Strategy The Zimbabwean Government has plans to boost the electrifi cation rate from 34.3% to 85% by 2020. To achieve this target, the Zimbabwe Electricity Supply Authority announced the following plans: • Build another coal-fi red power plant with a capacity of 1,400 mW. • Expand capacity at Hwange Power Station by 600 mW. • Add 300 mW to the Kariba Dam Hydroelectric Power Station. 2.4 Important Laws, Regulations and Policies The legislation that governs the electricity supply industry in Zimbabwe is the Electricity Act (Chapter 13:19) and the Rural Electrifi cation Fund Act (Chapter 13:20) of 2002. The Electricity Act created the Zimbabwe Energy Regulatory Authority and provided the legal framework for the unbundling of the state-owned utility, ZESA.
Energy Policies in Zimbabwe Policy support and strategic planning for multiple renewable energy sources. The objectives of the Energy Policy are: • to ensure accelerated economic development. National Energy Policy (2012) • to facilitate rural development. • to promote small-medium scale enterprises. • to ensure environmentally friendly energy development. • to ensure effi cient utilization of energy resources. The act is to regulate the procurement, production, Energy Regulatory Act (2011) transportation, transmission, distribution, importation and exportation of energy derived from any energy source. Zimbabwe Energy Regulatory Authority (ZERA) is mandated and empowered to enforce the act. It issues and withdraws licenses from all players in the Electricity, Petroleum and Renewable Energy Sectors. This provided for the establishment of the Zimbabwe Electricity Regulatory Commission (ZERC). It is responsible for licensing operators in the electricity sector, setting of electricity tariff as National Electricity Act (2002) well as general regulation of the electricity sector to allow for fair competition in the electricity industry. It was established in January 2012. The Act allowed for the establishment of the Rural Electrifi cation Fund Board responsible for all rural electrifi cation projects countrywide. The act allows for the expansion of the Rural Electrifi cation Act (2002) national electricity grid to rural government institutions, business centres and chief’s homesteads on 100% subsidy and 60% subsidy on other connections. It also provides for decentralised electrifi cation using renewable energy.
Clean Energy for School Environment Clubs 6 The Ministry of Energy and Power Development has an overall responsibility for energy issues in Zimbabwe, including promotion of new and renewable sources of energy. The Ministry supervises and oversees the performance of the energy parastatals, ZESA Holdings and the National Oil Company of Zimbabwe (NOCZIM). The Rural Electrifi cation Fund Act (13:20) created a Rural Electrifi cation Agency (REA) that has the mandate for the total electrifi cation of all rural areas, funded by electrifi cation levies and government stipends. The main functions of the agency are the planning of projects, the raising and accounting of rural electrifi cation funds and the monitoring of project implementation. 2.5 Electricity Market Zimbabwe Electricity Supply Authority Holdings (ZESA) controls the electricity market in the country. Through its subsidiaries Zimbabwe Power Company (ZPC) and the Zimbabwe Electricity Transmission and Distribution Company (ZETDC) generates, imports and distributes all electrical energy in the country. National Oil Company of Zimbabwe (NOCZIM), is the state-owned oil company responsible for procurement, storage and bulk distribution of petroleum products to oil marketing companies in the country. 2.6 Key Problems of the Energy Sector • Although national electricity access stands at 40%, access to electricity in rural areas (19%) is much lower than that in urban areas (80%) due to the prohibitive costs of extending national electricity grids. • Capacity is a major concern in Zimbabwe. No new developments have occurred in the country’s generation sector since the commissioning of the Hwange Coal Plant in 1988. Thus, only about 60% of the country’s installed capacity is available. • Furthermore, all coal-fi red stations in Zimbabwe are in need of major upgrades as currently they have frequent production stops or are not producing at all. This has resulted in frequent and long lasting blackouts in the country. • Imports of energy from neighboring countries are not enough to solve the under capacity problem. As a result, power outages continue to affect the economic performance of industries and service delivery although small-scale power generators are used all over the country to ease this situation. Chronic power outages are a common feature in Zimbabwe, negatively impacting on business and household needs. The current power supply in the country is inadequate, leading to load shedding in all sectors. This means that there is need for developing the local power industry, creating partnerships and building local capacities as key to resolving the problem. Such can be achieved if we increase the amount of energy we consume from renewable energy sources such as solar and biogas. The potential of renewable sources of energy such as solar energy have not been fully realized in Zimbabwe. Improved use of renewable sources of energy and the local manufacturing of energy technologies by the private sector in Zimbabwe has the potential to create many green jobs and reduce poverty. The energy crisis is an investment opportunity. Opportunities for investment in the sector include the existence of abundant energy resources such as biomass, coal and solar. In Zimbabwe biomass accounts for 61% of energy use in the country, a situation that leads to environmental degradation as families encroach on forests in search of fi rewood. With the rural electrifi cation rate estimated at 13% and only 5.8% of the rural population having access to modern fuels for cooking and heating, compared to 78.8% in urban households, access to modern energy for thermal applications (cooking and heating) will remain a critical development challenge, experts say. Biogas is an option for bringing energy to rural areas.
7 Clean Energy for School Environment Clubs Figure 5: Transportation of petroleum from Mozambique to a motorist in Zimbabwe
Image by: Munyaradzi Tsodzo / 2016
The above diagram demonstrates one of the challenges the country is facing in importing fuel into the country. Petroleum products (petrol; diesel; illuminating paraffi n and Jet A1 used by airplanes) are transported from petroleum refi neries to the Beira Mozambique port by sea. Once the products are in Beira storage tanks they are then pumped into the pipeline to Feruka Depot in Mutare, Zimbabwe and then to Msasa Depot in Harare, Zimbabwe. From Msasa Depot petroleum products are then distributed by road to service stations. Petroleum products may also be imported into the country by rail and road transport. Challenges: • The fuel transporting system may result in spillages along the way thereby polluting the environment. • The distances travelled are long and so have economic costs for the country which needs lots of foreign currency. • Long distances may also mean unavailability of fuel when and where there are logistical challenges like break down of vehicles. We have seen how expensive it is for our country to transport fuel and to import electricity. Therefore we need to use energy wisely.
Clean Energy for School Environment Clubs 168 3 ENERGY CONSERVATION
3.1 Energy saving tips Ever since the Hydroelectricity Power plant was installed at Kariba Power Station in the late 1950s, there has been an increase in the number of people and gadgets that use electricity in the homes for TV sets, radios, refrigerators, stoves, cookers, water heaters, cell phones etc. It therefore means that the demand for electricity use in the home has gone up while there has not been a matching increase in the electricity generation plants. There is therefore a need to save the available energy in order to reduce electricity unnecessary consumption on some of the appliances. For example, old and ineffi cient appliances need to be replaced because they consume more power unnecessarily. It is important for electricity consumers to understand the need for its effi cient use and save as much as they can. Positive behavior change is critical for all. 3.1.1 Electricity saving in cooking The stove is one of the largest consumers of electricity in the home. Changing cooking practices as suggested below can save both money and electricity. • Match pots and pans with stove plates to ensure maximum heat transfer from the plate. • Switch off stove plates 5 minutes before you fi nish cooking. The stove plate retains enough heat to fully cook the food. • Use tight-fi tting covers on pots and pans to shorten cooking time. • Stove switches must always be in good working order. • Use cooking utensils with fl at bottoms to increase surface area of heat transfer thus reducing cooking time.
• Keep oven doors closed until food is cooked. More electricity is used on maintaining heat lost due to frequent opening of oven doors. • Do not use the stove to warm up the house.
• There is also a need to change from the ordinary stoves to the energy effi cient induction stoves.
9 Clean Energy for School Environment Clubs 3.1.2 Electricity saving on water heating The geyser consumes about 40% of electricity in the home. Money and electricity can be saved by; • Using solar geysers or solar water heaters if you cannot do without warm or hot water. • Taking short showers instead of baths, shower uses less hot water from the geyser. • Installing a geyser timer switch to switch on the geyser an hour or two before water is needed and switch it off immediately after use. 3.1.3 Electricity saving on lighting Electricity can be saved on lighting by doing the following:- • Switching off all lights in unoccupied rooms. • Using natural light where possible. • Installing time switches on security lights. • Replacing all incandescent bulbs with compact fl uorescent lamps (CFLs) commonly called energy savers or replace with light-emitting diode (LEDs).
3.2 Safety in the home To ensure safety in the home take heed of the following tips: • Do not overload power outlets or sockets. Always protect your electrical gadgets with suitable surge protectors. • Do not open or attempt to repair electrical gadgets if you are not trained to do so. • Do not by-pass energy meters or circuit breakers as it is illegal and dangerous. • When electricity goes off, switch off all switches and pull out plugs until power is restored. Leave one light on to show when electricity is restored.
Figure 6: Energy saving bulbs
Source: nobacks.com
Clean Energy for School Environment Clubs 1810 CLIMATE CHANGE RESPONSE: THE NEED TO COPE, ADAPT 4 AND MITIGATE
There is need to understand the facts behind climate 4.1 Climate change change. Weather is the state of the atmosphere at a specifi c place and time considering aspects of wind, temperature and rainfall. For example when we say, “This evening it is raining here in Harare”, the statement is describing the weather. A study of these weather conditions over 25 to 30 years is known as climate. Our climate system is very complicated although it is important to clearly understand it. The rainfall, temperature and humidity patterns bring about seasons and it is these climatic patterns that have changed and thus constitute climate change. Climate change is the long term shift from the normal climatic conditions e.g. wind, rainfall quantity and humidity measured over a long period of time about 30 to 35 years which is attributed to human activity or natural variability that alter the atmospheric composition for example an increase in the amount of atmospheric green house gases like carbon dioxide leading to global warming. This will further lead to reduced water quantity, reduced agricultural production, the spread of more vector borne diseases and reduction of biodiversity. Therefore there is a need to cope with, adapt to and mitigate these climatic changes to avert disaster. tivity Ac In the diagram below can you identify the causes of climate change? Explain how each of these contributes to climate change.
Figure 7: Causes of climate change
Image by: Munyaradzi Tsodzo / 2016 4.2 Global Warming tivity Global Warming refers to the overall increase in Ac average surface temperatures of the planet, based on Can you explain the difference average temperature over the entire surface of the Earth. between the following terms? This will cause the circulation of the atmosphere to change, 1. Greenhouse gases / greenhouse effect. resulting in some areas warming more and others less. 2. Climate change / Ozone layer depletion. Zimbabwe is experiencing more hot and fewer cool days 3. Global warming / desertifi cation. than before. The country’s mean annual temperature 4. Make a model that explains number 2 changed by about 0.4 degrees celsius from 1980 to 2000. above .
11 Clean Energy for School Environment Clubs These cycles of change have been happening in the past, sometimes fast, sometimes slowly but what is now worrying us is the increased frequency of droughts, fl oods and heat waves which are a result of the changes in climate hence we need to act now. The Ozone layer, Ozone Depletion and Global warming The atmosphere is covered by a thick jelly like layer of oxygen 3 atoms. Ozone is responsible for absorbing short waves from the sun (Ultra violet rays, infra red rays and gamma rays) all of which have negative effects on the life on earth. These rays are trapped and refl ected back into space, thus preventing them from getting to the ground surface. This layer, which acts in the same manner as an agricultural green house which retains heat, allows heat from the sun (called short wave radiation) to pass through but does not allow heat generated on the Earth (called long wave radiation) to pass through into space. So heat produced by the earth is circulated in lower layers of the atmosphere. Hence for this action to take place, the ozone has a blanketing effect of retaining the trapped heat which results in an increase in global temperatures also known as global warming. Greenhouse gases like Chlorofl uorocarbons (CFCs), Hydro Fluorocarbons (HFCs), Methane, Nitrous Oxide and Carbon Dioxide are chemically active. Most of these gases are anthropogenic gases which are generated from refrigerators, perfumes, dry cleaners, burning of fossils in industries and fuel in vehicles. Anthropogenic gases contain Carbon, Nitrogen, Sulphur, Chlorine, Fluorine and Hydrogen which are very reactive so these react with the Oxygen atoms in the ozone creating compounds thus weakening the chemical structure of ozone atoms. The jelly like layer is eaten away and weakened by creating a hole through which the earth receives direct sun rays including the Ultra Violet, gamma and infra red rays and this is ozone depletion.
Figure 8: Greenhouse gas emission contributions by different countries Emissions (All greenhouse gases, all sources and sinks) 14000 China 12000 US 10000 EU 8000 India 6000
mio ton CO2-eq. Russian Federation 4000 Japan 2000
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 Source: historical emissions data: inventories data to the UNFCCC (http://unfccc.int/national reports/) emissions with Land Use, Land-Use Change and Forestry; for China and India data from EDGAR, all GHG emissions, all sources and sinks, excl. forest and pit fi res 4.3 Greenhouse gases and greenhouse effect The atmosphere contains greenhouse gases which trap heat from the sun and release it later. This has the effect of warming the atmosphere. Such gases like water vapour (H2O), Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Hydro fl uorocarbons (HFCs), Per fl uorocarbons (PFCs) and Sulphur hexafl uoride (SF6) are known as greenhouse gases because of their properties of trapping heat from the sun.
The natural system that regulates or distributes temperatures among the earth’s land and sea surfaces is known as the greenhouse effect. The concentration of such gases can have a blanketing effect on heat when the radiation from the sun to earth is blocked from re-entering into space. As a result more heat is in the lower levels of the atmosphere when it is supposed to be released back into space.
Clean Energy for School Environment Clubs 12 Figure 9: The Greenhouse Effect
Image by: Munyaradzi Tsodzo / 2016 4.4 The Ozone Layer Depletion The Ozone layer in the earth’s stratosphere at an altitude of about 10 km (6.2 miles) containing a high concentration of ozone (a colorless unstable toxic gas with a pungent odour and powerful oxidizing properties, formed from oxygen (O3) by electrical discharges or ultraviolet light), which absorbs most of the ultraviolet radiation reaching the earth from the sun. This gas is reactive. This layer is shielding the lower levels of the earth from receiving dangerous rays from the sun. It can react with gases like carbon monoxide (CO) and be eaten away thus creating a hole through which ultra violet rays from the sun can reach the ground surface.
Image by: Munyaradzi Tsodzo / 2016
13 Clean Energy for School Environment Clubs Figure 11: Ozone Depletion
3. Chlorine reacts with Ozone 03 and destroys Ozone.
2. Sun breaks CFCs up, 4. More reactions releasing Chlorine. cause more depletion.
1. CFCs released into the environment by industries, Key rises up to stratosphere. Oxygen atom
Carbon atom
Fluorine atom Adapted from eschooltoday.com
Ozone layer depletion, is simply the wearing out (reduction) of the amount of ozone in the stratosphere. Unlike pollution, which has many types and causes, Ozone depletion has been pinned down to one major human activity. Industries that manufacture things like insulating foams, solvents, soaps, cooling things like Air Conditioners, Refrigerators and ‘Take-Away’ containers use something called chlorofl uorocarbons (CFCs). These substances are heavier than air, but over time, (2-5years) they are carried high into the stratosphere by wind action. Depletion begins when CFC’s get into the stratosphere. Ultra violet radiation from the sun breaks up these CFCs. The breaking up action releases Chlorine atoms. Chlorine atoms react with Ozone, starting a chemical cycle that destroys the good ozone in that area. One chlorine atom can break apart more than 100,000 ozone molecules. 4.5 Impacts of climate change If the climate continues to change there is likelihood of: • increased temperatures leading to global warming. • increase in incidences of natural hazards leading to natural disasters e.g. typhoons cyclones, famines and heat waves. • loss and extinction of animal and plant species which fail to adapt to shortages in food, water and harsh living conditions. • changing precipitation that alters hydrological systems, affecting quantity and quality of water resources. • many terrestrial, freshwater, marine species shifting their geographic ranges, seasonal activities, migration patterns, abundances and species interactions in response to climate change. Climate change impacts are felt equally by the rural and urban areas. Rural children will spend more time at water queues, looking for fi rewood and some may fail to go to school as they help source food. There is therefore a need to start action now. Taking action includes for example: • Adapting to the change. • Coping with the change. • Mitigating the impacts of the change for example through enhancing carbon sinks e.g. by planting of trees and reducing emissions. Climate change, is Zimbabwe affected? There is evidence as can be seen in the following diagram that the climate in Zimbabwe has changed between 1962 and 2004.
Clean Energy for School Environment Clubs 14 Figure 12: Evidence of climate change in Zimbabwe
Zimbabwe Annual Mean Maximum Temperature oC (1962 t0 2004)
28.5
28
27.5
27
26.5
26
25.5
25
24.5
24 1962 1963 1964 1965 1966 1967 1968 1989 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Source: Ministry of Energy and Power Development 4.5.1 Children’s fi ndings on climate change UNICEF supported a research in 2014 and a survey among children came up with results which showed that children are aware that the following will happen to them and their communities as a result of climate change.
• Food scarcity • Poverty • Educational problems • Health related problems • Pollution • Water scarcity • Economic problems • Family problems They also acknowledge that the wetlands are drying and the water table levels are going down. They do realize the cause as the fact that there is cultivation in wetlands and industrialization which affect the underground water levels.
vity Acti The above are impacts of climate change. Can you describe how each impact will affect our country and children?
4.6 Adaptation and Mitigation Climate change is real, we need to adapt, cope and or mitigate. Adaptation involves the process of adjusting our systems in response to the actual or expected stimuli and effects which may moderate or harm. The strategies we take help us to cope with the impacts. We need to act now because there is no alternative Earth. Mitigation is an intervention meant to reduce emissions to enhance carbon sinks e.g. by planting trees. The use of energy effi cient gadgets and renewable energy sources act as mitigation strategies.
15 Clean Energy for School Environment Clubs 5 RENEWABLE CLEAN ENERGY
5.1 Why must we go for clean energy? • The climate is changing and has changed before, therefore we need to adapt, cope and mitigate. Organisms which fail to adapt to change die and become extinct. Climate change impacts are being felt in the energy sector particularly by women, children and sometimes by men who need energy for heating and lighting purposes. A good example is the fact that there is reduced and non-consistent rainfall. The rains may come late. There may be sudden fl oods then there is drought for most of the year period. This means that there is less water in rivers for hydroelectricity generation, the trees take longer to grow and animals have less food. • The manner in which we are harvesting trees for wood energy is unsustainable and it will cause desertifi cation in no time. • Continued generation of electricity leads to burning of fossil fuels. • Thermal electricity generation leads to global warming. • Increased droughts cause water scarcity. • Sustainable energy can avoid and reduce air emissions as well as water consumption, waste, noise and adverse land-use impacts. • Renewable energy will never run out. • Renewable sources of energy reduce the rapid depletion of fossil fuel reserves. • There is a reduction in over-dependence on fossil fuels which impact negatively on the environment.
vity Acti Look at the following pictures: a) Can you describe what is happening in each of the following pictures? b) Is it good or bad for the environment? Why? c) Explain why we need to shift from wood energy to different forms of renewable energy.
Clean Energy for School Environment Clubs 16 Figure 13: Unsustainable wood fuel gathering methods
Source: Blessing Jonga the Biogas Technology Expert at CEP Workshops / 2015
5.2 Energy for all: Options and sources of renewable and clean energy Energy access is a key element to improving people’s lives, especially in more remote rural communities where the electricity grid does not reach everyone, and basic needs are met with diffi culty as a result. In these locations there are a number of small-scale renewable energy technologies that can be used. These technologies include micro-hydro, solar energy, wind as well as more effi cient biomass technologies such as biogas and stoves that make use of crop waste and biofuels. We call these clean energy sources. 5.2.1 Solar Energy The average solar installation in Zimbabwe is 5.7 kWh/m2/day. There is an enormous potential for use ofsolar photovoltaic (PV) and solar water heaters and these have not yet been exploited. Technically, solar photovoltaic PV has a potential of 300 mW. At present only 1% of the technical potential for solar water heaters has been exploited. Solar power is mostly installed in rural areas of Zimbabwe at service centers such as schools, clinics, police stations and hospitals.
17 Clean Energy for School Environment Clubs Figure 14: Solar energy in the home
Computer 80W Inverter 150 Watt
Main AC Output
Solar Panel - 55 Watt 12 Bulb
12 Volt Computer Controller
Battery - 120Ah 12 Volt 12 Volt
- Negative+ Positive
Adapted from Ministry of Energy and Power Development
Figure 15: Solar panel Figure 16: Solar cooker
Source: Ministry of Energy and Power Development Solar energy application can be divided into two major categories namely solar thermal for heating and solar Photo Voltai (PV) for electricity. Solar energy includes trapping heat rays or sunlight from the sun and using it for heating, cooking and lighting or as electricity in the home. It relies on the principles of radiation, refl ection and conduction. For example, we can boil water in a black container in the sun. The concept of the greenhouse effect where, as heat passes through glass, some of it will escape back into space while some is retained can be seen in the use of solar food driers. But how can we trap heat for other uses? Solar energy is used in the solar food driers and solar refl ection in solar cookers.
Clean Energy for School Environment Clubs 18 Though the use of solar energy has many benefi ts, it also has its limitations for example: • a parabolic solar cooker cannot operate indoors as it is only usable outside. • a parabolic solar cooker cannot be used when it is cloudy or raining. • the parabolic solar cooker needs constant refocusing following the sun’s position. • in rare cases it can affect children’s eyes if they look directly into it. • in rare situations poor focusing can lead to starting of fi res by refraction and refl ection.
Using Solar Power in the home Zimbabwe has one of the best solar potential in the world, with an average radiation of 3 000 hours of sunshine per year. This resource is currently underutilized. There is great potential for energy saving through the installation of solar water heaters in homes and institutions. Solar can be used to heat water (Solar Thermal Application) for industrial, commercial, institutional and domestic use to replace electrical heaters or geysers, which is known to be an ineffi cient energy conversion process.
Figure 17: Solar water pumping Solar Water Pumping System
Tank SPV Module
Solar Pump
Figure 18: Solar water heating Thermosyphon Flow
Storage tank Hot water to house Hot water from collector tank
Tank Cold water inlet
Collector
Collector Source: Blessing Jonga, the Biogas Technology Expert at CEP Workshops / 2015
19 Clean Energy for School Environment Clubs What is a solar water heater? A solar water heater is a system comprising of mainly a collector and a storage tank. The solar collector is the main part of the solar water heating system that absorbs radiant energy into heat that can be used to heat water, space heating and preheating water for industrial processes. Solar water heating can be useful for domestic use, in hospitality industries, schools, hospitals and in any industry which uses hot water. In the tank (left side insert of Figure 18) dense cold water is at the bottom of the tank and in the collector also known as solar array. The water is heated and becomes less dense. It is syphoned into the tank at the top. Circulation of cold and hot water is by convection currents. Benefi ts of solar water heating (Solar Thermal System) Solar water heaters reduce energy consumption in households or institutions by 40%, thereby reducing electricity bills as well. The technology is environmentally friendly. It is important to note that a 150 litre solar water heater will replace 4.5kWh of electricity per day. The Ministry of Energy and Power Development is promoting the use of solar water heaters in the domestic, commercial and industrial sectors. To this end, two pilot solar water heating systems have been installed and commissioned at Harare Institute of Technology and United Bulawayo Hospitals. The pilot project was funded by the Republic of South Korea.
Parabolic mirror The concept is based on refraction and refl ection of solar Rack energy rays
Adapted from www.energy-knowledge.net
The solar water pumping (Photo Voltaic Products - PVP) system The solar water pumping system consists of three main components: • Solar panel or solar array: The solar panel converts light energy into electrical energy. Either a single panel or an array of solar panels can be used depending on the amount of power required. Most panels used are rated between 80W and 350W. Power produced by the panel is used to power a submersible pump. • Submersible water pump: The pump converts power from the panels into mechanical force which pumps water from water bodies such as rivers, dams and boreholes. The pump is submerged into the water reservoir from which the water is being pumped. • Storage tank: Water pumped is stored in a tank for use at night or when its cloudy. The tank must be installed on top of the roof of a house or on a raised platform so that it can gravitate to consumption points. There may be a need for an inverter to store array batteries in the case of a submersible pump AC whereas the DC pump has no need for an inverter.
Clean Energy for School Environment Clubs 20 Uses of solar water pumping systems The solar water pumping systems are used for: • pumping water for domestic and community use. • pumping water for irrigation; due to the high cost of installing a water pumping system it is recommended that the system must be used to irrigate high value crops. • pumping water for livestock and game; especially in drier areas. Benefi ts of using the solar PVP systems The benefi ts of using the solar PVP system are that: • they use free fuel from the sun. • they are easy to maintain. • the maintenance costs are low. • they can be installed in remote areas, in place of diesel engines. • they are environmentally friendly (no pollution). • where they are used in closed systems such as sealed wells and boreholes they ensure community health and safety by reducing exposure to water borne diseases. Using the abundance of sunshine, the solar pump draws water from a 100 metre deep well, providing families with the water that they desperately need and rendering cases of water-related diseases a thing of the past.
Figure 20: Using solar energy to pump water
Water Water storage points Stock PV array watering
Power conditioning
Water level Solar (photovoltaic) water pumping Pump Tank Solar Array
Motor
Adapted from Practical Action.org
Controller
Solar Pump
21 Clean Energy for School Environment Clubs • A protected hole is drilled 100m down into the earth to reach a water source. A solar panel made of photovoltaic modules powers an electric motor which in turn powers an underground water pump. This pump can draw up to 30,000 litres of clean, fresh water every single day. • All of this fresh water is stored in a water tank. The tank is then connected to water pumps and taps around the village by a system of pipes. • Local villagers are then able to access fresh, clean water without having to travel long distances. • Families now have that most basic need of being able to drink clean water. They can enjoy a life free from the constant fear of water-borne diseases. Also, because they no longer have to spend hours searching for water, children have the time to go to school and women can grow vegetables and other crops to sell at the local market. Figure 21: Fetching water for domestic use
Finding water for domestic use by families in some rural areas means walking up to 10 kilometres in the searing heat to dried-up river beds, running the risk of attack by wildlife on the way. Here women are forced to then dig ‘scoop holes’ with their bare hands, uncovering small amounts of dirty, contaminated water that they have no choice but to drink. The solar-powered water pumps mean rural communities can have access to clean, safe water everyday and they know they can drink in safety. This can be a sustainable solution to the endless problems caused by drought.
Source: Practical Action/energy access4all Figure 22: Solar lighting
Source: Econet Zimbabwe Solar powered household lighting can replace other light sources like candles or kerosere lamps. Solar lamps use renewable energy. How it works Solar-powered lighting consists of a solar panel or photovoltaic cell that collects the sun’s energy during the day and stores it in a rechargeable gel cell battery. The intelligent controller senses when there is no longer any energy from the sun and automatically turns the LED light on using a portion of the stored energy in the rechargeable battery.
Clean Energy for School Environment Clubs 22 5.2.2 Wind Energy The average wind speed in Zimbabwe is estimated to be 3.5 m/s. In the areas of Bulawayo in Matabeleland region and the Eastern Highlands in Manicaland region, there is potential for power generation from wind turbines as these regions have wind speeds ranging from 4 to 6 m/s. 5.2.3 Geothermal Energy Geothermal energy is the heat from the earth. It is clean and sustainable. Geothermal resources consist of thermal energy from the earth’s interior stored in both rock and trapped steam or liquid water. In 1985 the geothermal potential was acknowledged as being 50 mW. Currently not much else is known about the potential of geothermal. Due to Zimbabwe’s proximity to the Rift Valley region, it is reasonable to assume that geothermal power generation can be applied. 5.2.4 Micro-hydropower (Using water power to generate energy) Micro-hydropower is the small-scale harnessing of energy from falling water, such as steep mountain rivers. Using this renewable, indigenous, non-polluting resource, micro-hydro plants can generate power for homes, hospitals, schools and workshops. The micro-hydro station converts the energy of fl owing water into electricity thereby providing disadvantaged communities in rural areas with an affordable, easy to maintain and long-term solution to their energy needs.
Fig 23: Generating electricity from a Mini-hydro Fig 24: Inside a hydropower plant (Micro-hydropower) plant
Powerhouse Reserviour Dam Intake (Forebay tank) Power lines Canal Transformer Generator Forebay
Penstock
Powerhouse Intake Control Penstock Turbine Outfl ow gate Adapted from Practical Action/energyaccess4all Micro-hydro: the basics There is no need for a dam or storage facility to be constructed. In a run of the river or stream through a settling basin, which helps to remove sediment that could harm the turbine water is diverted into a valley. The water then fl ows into the Forebay Tank where it is directed downhill through a pipe called a penstock. When the water reaches the bottom, it drives a specially designed turbine to produce electricity. The turbine drives a generator that provides the electricity to the local community. By not requiring an expensive dam for water storage, run of the river systems are a low-cost way of producing power. They also avoid the damaging environmental and social effects that larger hydroelectric schemes cause, including a risk of fl ooding. Micro-hydro: the environmental impacts Unlike traditional power stations that use fossil fuels, micro-hydro generators have minimal impact on the environment. Since they don’t depend on dams to store and direct water, they are also better for the environment than large-scale hydroelectric stations.
23 Clean Energy for School Environment Clubs • They reduce the need to cut down trees for fi rewood and therefore have a positive effect on the local environment. • The source of power can be used to recharge communities or villages via portable rechargeable batteries. • These convenient sources of electricity can be used to power anything from workshop machines to domestic lighting. • There are no expensive connection costs. The batteries are charged at a station in the village, thus providing the local community with a clean, renewable source of power. • For industrial use, the output from the turbine shaft can be used directly as mechanical power, as opposed to converting it into electricity via a generator or batteries. This is suitable for agro-processing activities such as milling, oil extraction and carpentry. • Micro-hydro schemes are owned and operated by the communities they serve, with maintenance carried out by skilled members of that community. So they provide employment in themselves, as well as providing the power to re-energise entire communities. 5.2.5 Biogas Poo power: organic waste can be used as fuel! With wood fuel becoming increasingly expensive and also scarce in some areas, there is a need to look for alternative cooking fuel. Biogas technology provides a free, sustainable source of power all year round and a useful fertilizer which helps to provide a better yield for better income for farmers. What is biogas? It is a gas produced from the anaerobic breakdown, fermentation or decomposition of any organic materials by methane producing bacteria. Biogas is a combustible gas produced from the decomposition of any organic material such as cow dung, pig waste, kitchen or agricultural waste by bacteria in the absence of air (anaerobic conditions). Biogas comprises mainly of methane (60%) and carbon dioxide (40%) and burns with a blue fl ame. Cow dung is mixed with water and placed into a fermentation tank where it is broken down by natural bacteria, that produce methane. The gas is collected and stored in a storage tank and then piped to point of gas use e.g. kitchen for cooking, heating, refrigeration and lighting. The biogas plants also produce a rich organic fertilizer which can be used as liquid fertilizer. Both fertilizer and wood fuel are increasingly expensive in the country and biogas has a potentially important future. A biogas digester may also be used to manage organic waste in urban settings. The properties of biogas • Biogas constitutes mainly of methane and carbon dioxide and burns with a blue fl ame which does not produce soot and smoke (small percentage of hydrogen sulphur and water vapour). • The methane should be more than 50% for the gas to burn. A biogas digester is a special designed plant in which biogas production takes place in airtight conditions. A typical biogas digester is usually constructed using bricks and cement depending on the technology type. The digester is fed at least daily with the required quantity of organic material. Benefi ts of biogas technology One cubic meter of biogas can: • Cook 3 meals for 4 people • Provide 7 hours of lighting • Run a 300 litre refrigerator for 3 hours • Run a 2 horse power engine for 1 hour • Generate 1.25kWh of electricity
Clean Energy for School Environment Clubs 24 Benefi ts of using biogas to families • Time usually used for fi rewood collection and cleaning pots is saved. Families will have time for other household chores and socializing. • Children will have time to read and the light from biogas will help them even read at night. • Farm crops are signifi cantly increased from using organic fertilizer which will in turn provide food to the family and money from selling some produce. • Families can make money from selling organic fertilizer from the digester. • It is usually said a healthy family is a happy family and this can be made possible by use of biogas. • A family with a minimum herd of six cattle can start the project. Energy benefi ts Biogas is a clean source of energy used for: • cooking and heating using stoves and burners. • lighting using biogas lamps with mantles. • refrigeration of gas refrigerators. Environmental and social benefi ts • Reduces deforestation. • Burns without smoke, soot and odour. • Signifi cantly reduces carbon dioxide emission. • Produces nutrient rich fertilizer. • Is also used for sewerage disposal producing a pathogen-free waste. • The digested slurry is used as fertiliser . Economic benefi ts • Cheaper source of cooking energy as compared to paraffi n and Liquifi ed Petroleum Gas (LPG). • Jobs are created (building and maintenance). Requirements for building and operating a biogas digester • Abundant organic material e.g. cow dung and some water (although there are now some waterless digesters). • Labour force to feed digester. • Construction materials that include cement, bricks, river sand, concrete stones, lime or impermo, brick force, gas pipes and piping connections.
Bill of quantities – what is needed to produce energy from biogas for a family of six
7 cows in paddock or Energy to prepare three 21 free grazing cows on meals and operate 2 – 3 average +/- 70 kgs of Pour into a 9 cubic lights. 3 meals for 12 people cow dung + 70 litres of metre digester. or if there are fewer people water mix at (1:1) ratio and operating 2 -3 lights + refrigeration
General materials needed: • Pit sand, river sand, gravel and stones. • Cement, lime, cement waterproofi ng, chicken wire and bricks. • Round bar, 110 mm polyvinyl chloride (PVC) pipes, GS pipes ½’ and GS pipe ¾’. • The dome pipe, single or double gas stove, biogas lamp and a pressure meter. The quantities of materials required depend on the size of digester being constructed and the sizes range from 4 - 30 cubic meters (m3) for rural households and from 30 - 200 (m3) for institutional digesters.
25 Clean Energy for School Environment Clubs Figure 25: Biogas energy for the home
Image by: Munyaradzi Tsodzo / 2016 Above is a cross-section of a fi xed dome digester • The produced gas can then be used to provide energy for cooking, lighting and refrigeration. • People are freed from the daily drudgery of fi rewood collection, as they now have more time to spend on activities that generate income for the family. • The organic fertilizer from the plant improves the productivity of vegetable gardens. Community members who will have undergone training become skilled at installing and maintaining the biogas plant, which shall develop capacity for development of additional biogas plants in the area as well as neighbouring or surrounding communities. Biogas energy has the potential to replace dirty and bulky traditional biomass energy sources. The biomass most commonly utilised is wood, used mainly by poorer, rural inhabitants for household cooking. These biogas units are simple and can be installed on farms to utilise the waste from cows and obtain a free power supply. This produces enough power to cook, iron and provide heat and light to a home without using a single piece of wood. For the raw materials or inputs manure can be collected from cows in a specially adapted cattle shed where they feed. It is then mixed with water and left to ferment in a large concrete tank or pit. Gas is produced as a by-product of this fermentation process and it is collected in a simple storage tank (manometer) from where it can then be piped into the house when it is needed. One added bonus of using a biogas unit is that women and children are freed from fi rewood collection, the cleaning of smoke-blackened utensils and the disposal of animal waste. They will have gained around two hours a day which they can now employ elsewhere. Around 80% now use this time for various income generating activities, which currently accounts for approximately 24% of their monthly income. There is very little waste from the process and it is environmentally friendly. The liquid or dried manure from the fermentation process is a rich organic fertilizer which can be used to produce organic crops which tend to fetch a higher price on the market.
Clean Energy for School Environment Clubs 26 vity Acti Study the following pictures and make a model of a biogas digester. Demonstrate how it works.
Figure 27: Biogas digester under construction
Image by: Munyaradzi Tsodzo / 2016
27 Clean Energy for School Environment Clubs 5.2.6 Fireless cooker The practical fi reless cooker is helping families to escape the vicious cycle of poverty that is perpetuated by the sheer struggle to survive. Though not a clean energy form, it helps reduce on energy demands indirectly as it conserves energy. It can be used for cooking and cooling. By making families less dependent on wood fuel, they no longer have to make the heartbreaking choice between sending their children to school and short-term survival, or going to work and collecting wood.
Figure 28: A fi reless cooker
Cushion Lid Double layer lining of tough cloth and polythene
Basket
Insulation
Cooking pot with lid
Tray of ash and sand
Source: Practical Action / energy access4all
The “fi reless cooker” uses stored heat to cook food over a long period of time. The food is cooked on a traditional stove, before it’s transferred to the fi reless cooker. The cooker is well insulated, keeping the heat in the food and allowing it to continue cooking inside. A simple basket, insulated with local resources such as banana leaves or old clothes, can reduce fuel use by 40%, preserving scarce wood fuel and saving people hours of precious time.
Clean Energy for School Environment Clubs 28 How to make a fi reless cooker The bags are a simple insulating covering that allow pots to continue to cook food even when they are taken off a source of heat. They maintain the temperature inside as they are a poor conductor of heat. This is just a simple bag that cooks food without fuel. It is made from clean clothing material, banana straws and kaylite which are the insulating materials. The kaylite would otherwise take some 500 years to decay hence this is an environmental way of removing it from the street and making good use of it. The bags are thus a good way of recycling waste. The local Zimbabwean made bag is called the Temp bag. This now has varied uses such as the cooler bag, waste collection bag in a vehicle and cooker.
Figure 29: A Temp bag
Source: Tinashe Manyonga
29 Clean Energy for School Environment Clubs Advantages of a fi reless cooker • Women can cook nutritious foods that previously would have required lots of fuel for simmering such as beans, rice and whole maize. • Improves children’s health. The cooker bag produces no smoke, so there is less risk of children developing respiratory diseases. • Creates opportunities for income generation. Women no longer have to spend hours cooking, freeing up time to earn money at the market or in the fi elds. • Reduces fuel consumption by an average of 40%. Women and children can spend less time foraging for fi rewood and also reduces the need to resort to potentially toxic fuels. • Reduces water usage by 25%. Water is retained in the food, rather than evaporating thereby preserving nutrients, fl avours and precious drinking water. • Helps to preserve local forests and the environment. This ‘green technology’ helps in reducing the demand for scarce natural resources.
Figure 30: How to make the Temp bag (Fireless cooker)
Step 1: Step 2: Locally available The insulating material is materials such as recycled sewn into a strong basket or clothing is collected for box. insulation.
Step 3: Step 4: Dry heat resistant Two cloth cushions are polythene covers the packed around the top and cloth in the inside to bottom of the pot. protect the stuffi ng.
Step 5: Step 6: A lining of tough cloth is A fi reless cooker, ready to glued or nailed to hold use. the insulation in position.
Source: Practical Action / Energy access4all
Some facts: In communities where people lack any access to grid electricity, wood and dung (biomass) are the main sources of energy. ‘Clean’ fuel for cooking, lighting and power to run tools for earning a living is almost non-existent and burning wood creates toxic smoke, which kills. More than 3 million people worldwide depend on fuel such as wood and coal for cooking and heating. Burning these fuels creates a dangerous cocktail of pollutants. It is the poor who rely on the lowest grades of fuel, and each year nearly 2 million people die from inhaling lethal smoke from kitchen stoves and fi res.
Clean Energy for School Environment Clubs 30 5.3 Cookstoves The traditional open fi re cookstoves A traditional open fi re cookstove is heated by burning wood, charcoal, animal dung or crop residue. Cooking over an open fi re can cause increased health problems brought on from the smoke, particularly lung, eye ailments and birth defects. Deforestation and erosion often result from over harvesting of wood for cooking fuel. The traditional method of cooking on a three stone cooking fi re is the cheapest stove to produce, requiring only three suitable stones of the same height on which a cooking pot can be balanced over a fi re. However, this cooking method also has smoke, deforestation, burns and scalds problems. Practical Action, an international NGO working in Zimbabwe realized that many people in the developing world are faced with the problem of shortage of wood fuel. Women who do the gathering of fi rewood face many dangers as they can be raped or can be attacked by wild animals. In certain areas, local sources of fi rewood are completely depleted, leading women to travel long distances or to dig up tree roots, eliminating any chance of the trees growing again. One way of tackling this issue is through the use of more fuel effi cient cookstoves, which are both affordable and easy to use thereby cutting the amount of risky trips for fi rewood collection and allowing more trees the opportunity to grow. Subsequently, burning smaller amounts of wood fuel means that less smoke will engulf their homes and their lungs.
Advantages of improved cookstoves Improved cookstoves are used for cooking and heating food, mostly in developing countries. The cookstoves save wood fuel as compared to an open fi re. Examples include the Eco stove, Mbaula, Tsotso stove and the Chingwa stove. They are used for cooking, heating water and space heating. The major objective of cookstove technology is to introduce fi rewood conservation measures so as to alleviate fi rewood shortages and contribute towards reduction of deforestation. Conservation of wood fuel also gives existing forests a chance to regenerate. Cookstoves have the following benefi ts: • They can be used with different types of pots; metal, clay and even three legged pots. • They ensure a smoke free kitchen thereby reducing eye and respiratory ailments. • They save fi re wood as compared to an open fi re (more than 50% saving). • They save labour and time on fi rewood collection. • They ensure safety against burns and scalds. • They are more effi cient in cooking with some attaining complete combustion thus achieving cleaner burning, less smoke and more useful thermal energy. • There is fl exible use of a multitude of small-size renewable residues (e.g. rice husks, nutshells and saw-dust etc). • They cook fast. • They are safe and hygienic as there is less smoke produced. • Cleaner kitchens due to less smoke. Figure 31: An example of a cookstove • Less heat exposure thus they are safer. • Convenient in keeping fi re going.
Image by: Amy Wickham
31 Clean Energy for School Environment Clubs 5.3.1 Open fi re cooking. It refers to cooking over an open fi re. Cooking over an open fi re is the oldest and most primitive method of cooking known, with glowing red fl ames and smoky ambers mostly lending themselves to frying, grilling and boiling.
vity Acti Analyse the following methods of cooking which are very common in our rural areas: • What are the disadvantages of using such methods? • Can you describe how and why the open fi re cooking method is said to be dangerous and wasteful?
Figure 32: Collage of open fi re cooking
Common scenarios • wasteful • dangerous • smokey
Image by: Roth, Andreatta & Still / 2013
Figure 33: Semi improved and open fi re cooking in Rwanda
Image by: Amy Wickham / 2014 Clean Energy for School Environment Clubs 32 Figure 34: Girl Making an open fi re
Image by: Giacomo Pirozzi, UNICEF / 2011
Figure 35: Comparison of wood savings between open fi re and rocket stove
170kg with open fi re 14 kg with rocket stove Image by: Roth, Andreatta & Still / 2013
33 Clean Energy for School Environment Clubs Figure 36: Improved cookstove in Kenya Figure 37: Marys meals in Malawi
Image by: Amy Wickham / 2014 Image by: Christa Roth / 2007 5.3.2 A Rocket Stove It is an effi cient cooking stove that uses small diameter wood fuel which is burned in a simple combustion chamber containing a vertical chimney, which ensures almost complete combustion prior to the fl ames reaching the cooking surface. Figure 38: Rocket stove principle
Improved combustion: burn the smoke and get Rocket chimney Continuous feed, increases draft. more heat from the fuel Smoke is through fuel controlled Sticks of wood from a fl ame and combusts grate which improves the air to fuel ratio. Only the tips of the sticks are combusted Improved heat-transfer: more cooking from heat Small fuel magazine encourages the user to meter the fuel ratio. Smaller sticks burn more effi ciently
Fuel magazine helps to limit the infl ow of cool air. Cool air reduces the temperature in the combustion chamber and decreases effi ciency Adapted from Roth, Andreatta & Still / 2013
vity Acti Solutions are available! There is need to solve the problem of indoor air pollution in homes and reduce indoor smoke levels by up to 80%. As a club, make a simple design of a cookstove that will help rural mothers in your community? Remember, a simple technology makes a difference!
Clean Energy for School Environment Clubs 34 A range of cookstoves to suit different needs and means Figure 39: A stove to suit every pocket
Source: Roth, Andreatta & Still / 2013
35 Clean Energy for School Environment Clubs Figure 40: An example of a model eco-home
Image by: Munyaradzi Tsodzo / 2016 5.4 What can we do as an Eco Schools environment club? • Form an environmental club if there is none or join an environmental club if there is one at your school. • Develop a school environmental policy (mission statement for the club) one that will guide you to take more action. • Have a green school policy. Plant trees, lawn, herbs and vegetables. • Have your school register for a clean energy project. There are programmes for institutions and communities. For example the biogas project is good for boarding schools in as much as there is a similar project for chief’s homesteads and clinics. • Make models and designs for Science Exhibitions that include clean energy technologies. This is a way to develop skills which can be improved on for the benefi t of all. • Make and use solar cookers. • Make and use eco stoves, jengeta huni, imbawula or mbaura and tsotso stoves whichever is suitable for your area. • Be energy effi cient at home and school, for example switch off lights when they are not in use. • Turn off the taps and fi x broken leaking pipes. • Clean with non toxic chemicals and avoid using poisonous chemicals. • Cycle or walk to keep fi t or use public transport. • Encourage action taking at school or in your communities. • Read and learn about the environment. • Appreciate nature and what the environment does for you. • Sort waste at source to promote sustainable waste management (reduce, reuse and recycle refuse; reject and rethink waste). • Buy local products and compost left over foods. • Participate. Unless someone like you cares a lot, nothing is going to get better. • Make your school sustainable and climate smart. • Maintain clean school grounds.
Clean Energy for School Environment Clubs 36 37 Clean Energy for School Environment Clubs 6.1 Becoming an Eco School Step 1. Form a Club. This can start with a few students who have an interest in tackling environmental issues. The club will need a teacher to mentor and guide it, but positions such as Chairperson will come from the students. Step 2. Conduct an Environmental Audit or review. The club will identify issues or problems affecting the school’s environment. Are water shortages a problem? Is lack of power a problem? Choose to tackle one problem at a time. Step 3. Develop an action plan with realistic goals and select methods to monitor improvements. At the beginning choose only one hands-on project so that it will be easier to make it successful. Allocate positions and tasks to members. Some good examples for a project are: • Plant indigenous and exotic fruit trees around the school. They will provide fruit for sale whilst giving shade, preventing soil erosion and mitigating the effects of climate change. • Devise activities to celebrate all global environment related days such as World Water Day, World Wetland Day and World Animal Day. • Introduce a waste management project to “Reduce, Reuse and Recycle” products that either litter the environment or unnecessarily end up on the municipal landfi ll dump, such as paper, cans, food left- overs, styrofoam and bottles. • Adopt a nearby wetland; monitor the seasonal volumes and quality of water. Take actions to preserve it and monitor the effects on the bird and wild life. • Catch rainwater from the roofs of school buildings and store it for use in the school gardens and orchards. Step 4. Register with Mukuvisi Woodlands Eco School programme to gain assistance, share your experiences and encourage others, and compete in the annual Mukuvisi Woodlands Enviro Challenge Step 5. Monitor and evaluate the projects. Measure the milestones towards you set goals e.g. measure the garbage being collected before and after your project and to see that within 12 months only 20% is being sent to the dump whilst 80% of it is being reused or recycled at school by way of composting and so on. Step 6. Develop, discuss, review and then publicise your school’s Environment Policy. This will list your policies and the actions you promote and should be placed where everyone in the school can see it. Step 7. Inform and involve members of the community outside the club. It is important to get the environmental messages to parents, shopkeepers, local councilors, police and other leaders. Invite them to visit your project and be involved in your activities.
6.2 Membership Eco Schools is open to all educational institutions in Zimbabwe, including primary and secondary schools, universities and colleges. There is an annual registration fee which demonstrates your school’s commitment to the programme, gives your school entrance to Eco School’s events and contributes to the cost of materials and administration. 6.3 Information and Registration. For further information on how to participate you may visit the Mukuvisi Woodlands Environment Education Centre at the corner of Glenara Ave and Hillside Rd, Harare or contact:
The Environment Education Coordinator Mukuvisi Woodlands Nature Reserve and Environment Education Centre P. O. Box GD 851, Greendale, Harare Landlines: +263 4 747111/123/083 or Cell phone: 0774 198 009 Email address:[email protected]
Clean Energy for School Environment Clubs 38 GLOSSARY
Anthropogenic: An effect caused or resulting from human activity.
Atmosphere: It is a layer of gases surrounding the earth and it is retained by gravity. The main gases in the atmosphere are nitrogen and oxygen and this is where life exists.
Biomass: Fuels that are derived from natural material things that once lived, for example wood, dried vegetables and crop residues.
Biogas: A combustible gas produced from the anaerobic breakdown (without the presence of oxygen, fermentation and decomposition of any organic materials by bacteria such materials as cow dung, kitchen or agricultural waste) whose composition is mainly methane (60%) and carbon dioxide (40%).
Chemical Energy: Chemical Energy is energy stored in the bonds of chemical compounds (atoms and molecules). It is released in a chemical reaction, often producing heat as a by- product (exothermic reaction). Batteries, biomass, petroleum, natural gas, and coal are examples of stored chemical energy.
Climate Change: A change in the known average climate conditions which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere which is in addition to the natural variability observed over comparable time periods.
Climate change mitigation: An anthropogenic intervention to reduce the source or enhance the sinks of carbon dioxide.
Climate change adaptation: An adjustment in natural or human system in response to climate change which moderates harm or exploits opportunities. There are several ways which include prevention, tolerance, sharing losses, change in activity and restoration.
Coping strategy: Generally short term actions to ward off immediate risk, rather than adjusting to continuous or permanent threats or change. Coping can undermine the possibility of long term sustainable adaptation.
Fossil Fuels: Fuel (such as coal, oil, or natural gas) that is formed in the earth from dead plants or animals.
Global Cooling: Global cooling was a conjecture during the 1970s of imminent cooling of the Earth’s surface and atmosphere culminating in a period of extensive glaciation.
Geothermal Energy: Geothermal energy is energy derived from the heat of the earth. The earth’s centre is a distance of approximately 4000 miles and is so hot that it is molten. Temperatures are understood to be at least 5000 degrees centigrade.
Global Warming: The gradual rise in the earth’s average atmospheric temperature generally attributed to the effect of greenhouse gases such as carbon dioxide.
39 Clean Energy for School Environment Clubs Greenhouse effect: The presence of greenhouse gases in the atmosphere allow incoming sun rays to pass through to the earth’s surface but trap and absorb heat radiated by the earth surface resulting in elevation of the average surface temperatures. The effect makes the earth surface warmer in the same manner as a greenhouse keeps its inside temperature warmer.
Greenhouse Gases: Gases from the atmosphere that absorb and remit infrared radiation. These can be natural or anthropogenic (carbon dioxide, methane, nitrous oxide, sulphur hexafl uoride, hydro fl uorocarbons and nitrogen oxide.)
Hydro Energy: Hydro energy is a renewable source of energy which uses the force or energy of moving water to generate power. This power or ‘hydroelectricity’ is generated when falling water is channelled through water turbines.
Kinetic Energy: Kinetic energy is the energy of motion.
Non-renewable Energy: Energy that is not self-replacing and comes from fossil fuels.
Nuclear Energy: Nuclear energy is the energy released during nuclear fi ssion or fusion, especially when used to generate electricity.
Photovoltaic: Relating to the production of electric current at the junction of two substances exposed to light.
Potential Energy: Potential Energy is the energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge and other factors.
Renewable Energy: Energy obtained from sources that are essentially inexhaustible (unlike, for example fossil fuels of which there is a fi nite supply). Renewable sources of energy include conventional hydroelectric power, wood, waste, geothermal, wind, photo-voltaics and solar thermal energy.
Sink: Where energy goes to. If heat energy, the sink is always the coldest location. Energy always fl ows from a source to a sink.
Solar Energy: Solar Energy is the radiant energy emitted by the sun.
Sustainable Energy: Produced in ways that support present needs without affecting the ability of future generations to fulfi ll their own needs.
Traditional Energy: Primary energy transformed by the end user to meet basic survival needs.
Clean Energy for School Environment Clubs 40 REFERENCES
Ministry of Energy and Power Development (www.energy.co.zw)
National Education for Sustainable Development Strategy and Action Plan for 2014 and Beyond, Harare 2013
National Energy Policy, Ministry of Energy and Power development
Practical Action, Energy Acess4ALL. www.practicalaction.org
Roth, C., Andreatta, D., & Still, D. (2013). Stoves 101. Retrieved from http://ethoscon.com/pdf/ETHOS/ ETHOS2013/BaymontInn/Stoves%20101.pdf
Rural Electrifi cation Agency www.rea.co.zw
Tafi reyi, C. (2014). GOAL Zimbabwe
Tbilisi Declaration 1977
Wickham, A. (2014). Zimbabwe: UNICEF
World Commission on Environment and Development: Our Common Future (The Brundtland Commission 1987)
Zimbabwe Agenda for Sustainable Socio-Economic Transformation (Zim Asset) “Towards an Empowered Society and a Growing Economy”, October 2013- December 2018
Zimbabwe Energy Regulatory Authority (www.zera.co.zw)
Zimbabwe National Constitution 2013 Zimbabwe’s National Climate Change Policy Strategy, Ministry of Environment, Water and Climate 2014
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