Centralised Mt Wilson/Mt Irvine Power Options

Task: The purpose of this short paper is to examine the options for replacing the current Integral power lines with a sustainable power source(s) which will be a central generator which will be dispersed to all the houses in Mt Wilson and Mt Irvine. It is task of others to examine the generation of power on a local (house by house) mode.

There appears to only be two general options for generating sufficient power for the community (both Mt Wilson and Mt Irvine), without relying on fossil fuel as currently – wind and solar.

Background: The two villages consume about 500KW in average time and have a peak demand of 1MW . Any power solution must be able to provide 1MW continuously.

Wind: Integral has installed two wind generators at Hartley. The facts concerning the Hartley are below: Name: Owner: Hampton Company – (Hugh Litchfield) / Wind Corporation Australia (CVC-REEF) / SEDA Installed: 2001 Details: 2 x 660 kW V–47 turbines Power Output: 1.32 MW, enough energy for approx. 470 homes Dimensions: 74 metres in total height, and with rotors of 47 metres in diameter. Each rotor consists of three blades and rotates at 28.4 revolutions per minute. The rotors do not turn in very low winds. They start turning when the wind sustains 4 metres per second (14 km/h) and reach nominal generation at 13-16 m/s (46-58 km/h). They stop turning at over 25 m/s (90 km/h) to avoid damage. Cost: $2.4m Project Manager and Engineer: Sinclair Knight Merz (SKM) Commercial and financial management services and provision of funds: CVC REEF Power purchaser: EPC Contractor: Vestas Financing and commercial details : Wind Corporation Australia, the NSW Sustainable Energy Development Authority, Integral Energy and Hickory Hill Wind Energy, the landowner's company, are partners in the project. Wind Corporation Australia provided technical and commercial expertise as well as capital. SEDA provided initial financial assistance. Wind Corporation Australia received funding from the CVC Equity Fund (REEF), a $26.5 million venture capital fund established by the Federal Government to increase investment in renewable energy technologies.

Specific tasks undertaken by SKM included: • preliminary electrical design for the installation and preparation of specification and tender documentation for the electrical equipment and installation works • tender review and negotiations for the electrical equipment supply, electrical installation works, civil/structural and cranage contracts • investigation of future study options, and preparation of application for Australian Greenhouse Office (AGO) Renewable Energy Industry Development funding • Grid Connection Agreement negotiations and technical review • coordination, planning and management of the site construction works, contract administration, review of commissioning and QA documents, resolution of construction issues and liaison with the network provider for the physical grid connection

• liaison with local government, the project stakeholders and the local community.

Name: Output: 10MW Details: 15 wind turbines, each with an electricity capacity of 660 kW. The height of the tower is approximately 43 metres above the ground and its approximate diameter is 3 metres at the base and 2 metres at the top. The tower is located on a reinforced concrete foundation with dimensions of about 10 metres x 10 metres. The foundation is located below ground level and after construction is backfilled with soil and then grassed. Each turbine is 3-bladed, about 47 metres in diameter and rotates at approximately 28 revolutions per minute when operating. The blades are constructed of a fibreglass material and are attached to a steel hub and drive. The turbine hub height is 45 metres above the ground. The nacelle is the housing, constructed of steel and fibreglass, that is mounted on top of the tower. The nacelle encloses the rotor bearing, gearbox, generator and controls. Weather monitoring equipment located on top of the nacelle provides data for the automatic operation of the . The wind turbines have a control system that faces them into the wind so that the turbine is upwind of the supporting tower. The controls start the turbines at a wind speed of about 4 metres/second (15 kmh). The turbines reach full output at 16 metres/second (55 kmh) and the controls shut the turbines down for safety purposes when the wind speed reaches 25 metres per second (90 kmh). . Name: Operation since: July 1998 Details: There are eight turbines, each 45m high, with rotors over 44m in diameter. Each turbine has a 600kW capacity with a total generation of 4.8MW. Auto start-up will occur when wind speed exceeds 15 km/hour. 54 km/hour wind speed for maximum power, Auto cut-out mechanisms shut down the turbine in very high winds greater than 72 km/hour. 45 metre hub height from ground, 44 metre blade diameter, 28 rpm rotational speed, 360º directional movement of nacelle, 105m³ of reinforced concrete foundation, 36 tonne steel tower, 27.5 tonne nacelle, hub and blades (total)

Conclusions Regarding Wind: The villages would only need a project the size of the Hampton Wind Farm – two turbines – one in Mt Wilson and one in Mt Irvine would work. I am concerned about the wind spends needed for operation. Wind amps are available (for a price) and the history of the Hampton project itself would be a good guide. However Integral are not currently measuring the output of Hampton so information is available from this source.

Solar: Fundamentals: 1. Normal Solar Arrays: During a typical sunny day, an array of solar cells one metre square exposed to the sun at noon will receive approximately 1 kilowatt (kW) of power. BP Solar’s multicrystalline cells convert roughly 15% of this into electricity, hence 1m² of cells generates 150 electric Watts in full sunshine. Thus in order to generate 1MW of power using an array of solar cells 1000/0.15 = 6,666 sqm of solar cells would be needed. This is 0.67 of a hectare or a little over 1.5 acres.

For example, SunPower Corporation's subsidiary, PowerLight Corp., has completed construction of Mungyeong SP Solar Mountain, a 2.2-megawatt (MW) solar electric power plant in Mungyeong, Korea. The plant is comprised of 10,500 panels and covers an area of approximately 43,000 square meters (4.3 hectares).

Contrary to most people's intuition, solar electric panels actually generate more power at lower temperatures with other factors being equal. This is because solar cells are electronic devices and generate electricity from light, not heat. Like most electronic devices, solar cells operate more efficiently at cooler temperatures. In temperate climates, solar panels will generate less energy in the winter than in the summer but this is due to the shorter days, lower sun angles and greater cloud cover, not the cooler temperatures.

2. Solar Trough System

Trough systems predominate among today’s commercial solar power plants. Because of their parabolic shape, troughs can focus the sun at 30 to 60 times its normal intensity on a receiver pipe located along the focal line of the trough. Synthetic oil captures this heat as the oil circulates through the pipe, reaching temperatures as high as 390°C. The hot oil is pumped to a generating station and routed through a heat exchanger to produce steam. Finally, electricity is produced in a conventional steam turbine.

In the US, a 1 MW plant is being built by Arizona Public Service's at its Saguaro Power Plant and a 64 MW plant is being built in Eldorado Valley near Boulder City, NV. Solargenix is the prime contractor on both projects in conjunction with EERE/NREL. SHOTT North America is supplying the receivers.

3. Solar Dish/Engine Systems

These systems, with net solar-to-electric conversion efficiencies reaching 30%, can operate as stand- alone units in remote locations or can be linked together in groups to provide utility-scale power

Solar dish/engine systems convert the energy from the sun into electricity at a very high efficiency. Using a mirror array formed into the shape of a dish, the solar dish focuses the sun’s rays onto a receiver. The receiver transmits the energy to an engine, typically a kinematic Stirling engine (although Brayton-cycle engines are also being considered), that generates electric power.

Because of the high concentration ratios achievable with parabolic dishes and the small size of the receiver, solar dishes are efficient at collecting solar energy at very high temperatures. Tests of prototype systems and components at locations throughout the United States have demonstrated net solar-to-electric conversion efficiencies as high as 30%. This is significantly higher than any other

Example: Cloncurry Solar

Cost: A$7 million Details: 10-megawatt power station would be able to generate electricity on rare cloudy days and at night from the station, which runs off heat stored in graphite blocks. 8,000 mirrors will reflect sunlight onto graphite blocks Water will be pumped through the blocks to generate steam which generates electricity via turbines. Heat stored in the graphite produces steam well after the sun goes down, allowing electricity generators to keep running at night

Example: Keahole Solar Trough Project

Sopogy is finally moving forward with the construction of its one-megawatt solar farm at the Natural Energy Laboratory of Hawaii after a year of working through state and county permitting processes.

The Keahole Solar Power concentrated solar farm is situated in Kailua-Kona on the Big Island. The project is using $10 million in state-backed special-purpose revenue bonds, approved during the 2007 legislative session.

Once the first phase of the project is completed, Keahole Solar Power will produce electricity for over 100 homes. The one-megawatt solar farm will be capable of powering 500 homes and offsetting over 2 million metric tons of carbon dioxide emissions, the company said.

Unlike photovoltaic cells that convert light to electricity, Sopogy's proprietary solar technology uses curved mirrors to intensify and focus the sun's energy to heat mineral oil, which is then used to drive turbines and generate electricity

The aluminum trough-shaped solar collectors developed in the warehouse of Honolulu-based Sopogy Inc. do not represent the next revolution in solar energy generation.

Next-generation technology Sopogy builds next-generation parabolic reflectors that concentrate solar power, maximizing energy output from a low-cost, durable system that can be set up on or off the power grid.

The strategy has earned Sopogy the attention of two local venture capital groups, as well as the state, which this year made available up to $10 million in special-purpose revenue bonds to finance a one-megawatt power plant to be connected to the Big Island grid.

"Darren's company is taking technology that has been proven to work in other areas, but has not been fine-tuned in Hawaii," said state Sen. Carol Fukunaga, D-Makiki-Tantalus-Punchbowl, who proposed the legislation to provide the revenue bonds. "He has been very innovative in his approach."

The 3,000-reflector plant will be built on six acres of lava rock at the Big Island's Natural Energy Laboratory of Hawaii Authority for an estimated $8 million and run by a newly formed Kimura company, Keahole Solar Power.

"Our goal is to use this as a showcase," Kimura said. "We're a Hawaii-based company, but our market is the world."

Kimura isn't ready to put a price tag on his units yet, but said Sopogy's focus has been to build a system that costs about half as much as a comparable photovoltaic system, with a return on investment in three to five years.

Sopogy's solar units differ from the more widespread, flat-paneled photovoltaic systems seen on residential and commercial rooftops. The company's researchers focus on concentrated solar power designs, models with oil- or water-filled pipe that runs through parabolic reflectors, capturing heat used to generate steam.

That concept isn't new.

The innovation comes in the form of nanocoating that insulates the reflectors from salt damage, of axes that allow the reflectors not only to track the sun in quarter-degree increments, but also to be flipped over and protected with additional casing in a hurricane.

A California company manufactures the units from glass, aluminum and concrete -- an attractive element of the project for investors.

"They figured out how to use a low-cost manufacturing process," said Joelle Simonpietri, a partner at Kolohala Ventures, which invested in Sopogy last year.

Sopogy is working with two different commercial models -- the 2.5-foot-wide SopoFlare and the 5- foot-wide SopoNova.

"We're the only company out there that is trying to shrink these systems," Kimura said.

Conclusions Concerning Solar

Any solar technology uses a huge area for generation, which is a negative. In addition any other technology, other than normal solar arrays are prohibitively expensive. We should do more research on the Cloncurry project – whose capital cost is low. Operating costs for passive solar are presumably very low, but the trough technology has a generator attached and so is assumed to be higher.

Comparative Costs:

A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3.2 pence per kilowatt hour (2005). Cost per unit of energy produced was estimated in 2006 to be comparable to the cost of new generating capacity in the United States for coal and natural gas: wind cost was estimated at $55.80 per MWh, coal at $53.10/MWh and natural gas at $52.50. Other sources in various studies have estimated wind to be more expensive than other sources

Technology Area Capital Cost ($/MW) Operating Cost Wind Small $2.4m small Solar Arrays 1. 5 acres $0.7m smallest Solar Trough 6 acres US$10m moderate