Comparing the sustainability parameters of renewable, nuclear and fossil fuel electricity generation technologies Annette Evans Graduate School of the Environment, Faculty of Science, Macquarie University, NSW, Australia 2109 [email protected] Assoc. Prof. Vladimir Strezov Graduate School of the Environment, Faculty of Science, Macquarie University, NSW, Australia 2109 [email protected] Dr. Tim Evans Graduate School of the Environment, Faculty of Science, Macquarie University, NSW, Australia 2109 [email protected] Abstract —The sustainability parameters of electricity generation have been evaluated by the application of eight key indicators. Photovoltaics, wind, hydro, geothermal, biomass energy crops, biomass residues, natural gas, coal and nuclear power have been assessed according to their price, greenhouse gas emissions, efficiency, land use, water use, availability, limitations and social impacts on a per kilowatt hour basis. The relevance of this information to the Australian context is discussed. Also included are the results of a survey on Australian opinions regarding electricity generation, which found that Australian prefer solar electricity above any other method and also support wind power, with over 90% support, however coal, biomass and nuclear power have low acceptance rates at 30% or less. Most Australians, greater than 90%, believe that the government is not doing enough to support renewable electricity. Keywords -electricity; sustainability; life cycle I. INTRODUCTION The generation of electricity worldwide is heavily dominated by the use of fossil fuels. The combustion of these fuels releases large amounts of carbon dioxide and pollutants to the atmosphere. Fossil resources are also ultimately limited, with finite amounts in existence. While coal reserves are still abundant, the excessive consumption of coal by the electricity sector is responsible for the greatest share of carbon dioxide emissions globally, as well as emitting large amounts of pollutants, such as NO x, SO 2, CO, particulate matter and air toxics to the environment. World electricity production by fuel is shown in Figure 1 indicating coal and peat fuels contribute to over 40% of the world electricity generation, with fossil fuels in total accounting for over 65% of the electricity generated in 2006. Renewable energy sources are rapidly increasing in usage, however current market shares, excluding hydropower, are so low that it will be some time before a significant percentage of world electricity is produced by non-hydro renewable energy sources [1]. For example, in 2008 solar accounted for only 0.02% of the world’s electricity production [2], despite its 33% market growth between 1997 and 2005 [3]. Similarly, wind power has undergone an annual growth rate of nearly 50% between 1971 and 2004, yet only accounted for nearly 0.5% of the total world electricity production in 2004, with over 82 TWh generated globally [4]. Other, 2.3% Hydro, 16% Coal/Peat, 41% Nuclear, 14.8% Oil, 5.8% Gas, 20.1% Figure 1 World electricity production by fuel 2006 [1] Increased electricity demand strengthens the need for reduced impacts from electricity generation per unit produced. Demand for electricity increased at an average of 1.8% per year between 1990 and 2004 [5]. IEA predictions show that, if the current coal dependence is not reduced, coal fired power stations in developing countries alone will produce more greenhouse gas emissions than the entire OECD power sector in the year 2030 [6]. The impacts of developing nations working to achieve better standards of living, compounded by the number of people in these nations will cause electricity consumption rates to keep increasing. In order to meet increasing energy requirements with minimal environmental impact, changes to the current energy generation practices are essential. Changes need to include increased energy efficiency from fossil fuel combustion technologies through introduction of oxyfiring and IGCC technologies, as well as increasing the share of alternative energy generation technologies, including hydropower, wind energy, geothermal, biomass combustion and gasification, solar and tidal power. Renewable energy sources provide freedom from the price fluctuations, trade and transport issues associated with uranium, gas and coal, and can potentially improve energy security to countries deficient in mineral resources. However, traditional coal and gas based technologies offer high reliability and low prices. Careful evaluation of the sustainability of each technology is needed to direct future investment and policy. This paper presents a sustainability assessment of electricity generation according to the sustainability indicators of price, greenhouse gas emissions, efficiency, land use, water use, availability, limitations and social impacts. Technologies are then compared and implications for electricity generation in Australia are discussed. Following this are the results of a survey of Australian public attitudes towards different methods of electricity generation. A. The Sustainability Indicators To assess the impacts of electricity generation, eight key sustainability indicators were selected that together highlight the financial, environmental, engineering and social sustainability of each technology. The cost is the first consideration in this study. Securing financial benefits is one of the key important figures that allow sustainable development. Efficiency of energy transformation is considered because it has a direct impact on cost and provides an indication of the maturity of the process with greater efficiencies achieved as the process is further developed. Greenhouse gas emissions, including carbon dioxide (CO 2) and methane (CH 4) determine the global warming potential of the technology. Carbon accounting is now becoming the single key emission parameter that determines sustainability. Emissions from criteria pollutants (SO 2, NOx, CO, Pb, PM 10 and O 3) are not considered here because there is a system in place controlling these emissions through policy and environmental compliance, which is already resulting in declining emissions of criteria pollutants, while the greenhouse gas emissions are showing an increasing global trend. Water use, as an indicator of sustainability, is particularly important in arid climates, such as Australia. Availability and limitations account for the ability of each technology to provide baseload electricity. Land use or the footprint is of most importance when technologies compete for space with housing, agriculture or culturally significant sites. Social impacts are the consideration of the direct and indirect affects on human health and quality of life, often not covered adequately or at all in other categories. B. Assessment Methods An extensive literature review was performed to collect the data necessary to perform the sustainability assessment. All assessments are performed over the life cycle of each unit, on a per kilowatt hour basis where applicable. A survey was conducted anonymously online, inviting members of the Australian community to share their opinions on different methods of electricity generation. Participants were asked about their preferred methods of electricity generation, nationally and locally, whether they support the idea of wind farms, solar farms, hydropower, biomass, coal and nuclear power stations and whether they think the government is doing enough to promote renewable technologies. II. SUSTAINABILITY ASSESSMENT A. Price The average electricity price for all technologies is shown in USA dollars per kilowatt hour, averaged over the life cycle of the technology, as shown in Figure 2 [4][6-61]. Biomass dedicated energy crops are represented as Biomass DEC and biomass residues as Biomass RES. 10 1 0.1 Price $/kWh Price 0.01 0.001 l . l c o a C s a ind dr E a o ltai G C vo W Hy o s D ss Res s a Nuclear hot P Geotherm iom Bioma B Figure 2 Prices of electricity generation Nuclear, coal and gas are the cheapest methods of electricity generation costing on average 4.3, 4.8 and 4.8 c/kWh, respectively. Hydro, biomass residues, wind, geothermal and biomass energy crops are slightly more expensive, at 5.1, 5.4, 6.6, 6.8 and 8 c/kWh on average. The average cost of photovoltaics is quite prohibitive under normal circumstances, at 24c/kWh. It is nearly 6 times more expensive than the average nuclear price. There is significant variability within the results, particularly for the renewable energy sources. Hydroelectricity has the largest data range and also the lowest possible cost at only 0.7c/kWh [29] and all renewable energy sources, even photovoltaics have the potential to be cheaper than coal and gas. Electricity produced from hydro, geothermal, biomass residues and wind can also be cheaper than nuclear at their lowest prices, while the lowest costs for photovoltaics and biomass energy crops are slightly higher than for nuclear. This highlights the importance of careful site selection and planning. Electricity produced from coal and gas show more stable price ranges, compared to renewable energy sources. This is primarily due to the maturity of these technologies and the consistency of fuel products across the world. B. Efficiency The efficiency of conversion from the energy in the fuel source into electricity is an important parameter which needs to be considered when assessing electricity production technologies. Efficiencies strongly influence prices as well as sustainability, since the high