Monthly Archives: February 2011

Massachusetts town to turn landfill into largest solar array in New England

Canton, Massachusetts officials decide to turn an old, capped town dump into the largest solar array in New England. The dump was capped twenty five years ago and was unused until last year when the town envisioned it as a green energy powerhouse. The array is expected to generate 5.6 megawatts of power as early as 2012 and will generate about $70 million in revenues and energy savings over the next 25 years.

It turns out that landfills that have been covered are prime places to put solar arrays. Capped landfills tend to be raised and free of trees — the roots cause problems for the linings — they are stable enough to be built upon, and don’t have shadows from surrounding buildings or structures. “Once you cap and close them, they have a tendency to look like a mini-pyramid,” said Jeffrey Osuch, the executive secretary of Fairhaven, another town hoping to top its capped landfill with a solar array. “You don’t have any trees or building shadows.”

The solar array will be built by Southern Sky Renewable Energy, who will install 24,000 three-foot by five-foot solar panels. Southern Sky Managing Director Frank McMahon noted that the Canton project will be their first built on a capped landfill. The town of Canton and Southern Sky will be benefitting from Massachusett’s Solar Renewable Energy Certificates program which is helping to ensure that the state will meet its goal of having 250 megawatts of solar power installed by 2017.


Multilayered solar cell boosts efficiency

Solar Junction is a 4-year-old company spun out of Stanford University that designs high-efficiency, multi-junction solar cells for concentrating photovoltaic (CPV) solar collectors. The National Renewable Energy Laboratory recently certified that its solar cells can operate at 40.9% efficiency, a significantly higher efficiency than typical silicon solar cells that convert sunlight to electricity at an efficiency of about 15-20%.

The 4-year-old company said last week it expects to start production of its high-efficiency solar cells by early next year in its home town of San Jose, California. It is also awaiting word in the next few months on an $80 million loan from the Department of Energy, which would give it favorable financing to expand its current demonstration plant to produce 250 megawatts worth of cells per year, said co-founder Craig Stauffer.

Solar Junction cells are designed to be fitted into concentrating photovoltaic (CPV) solar collectors. Originally used in space, CPV systems concentrate the light hundreds of times using mirrors and lenses onto a small but relatively efficiency solar cell. They are typically mounted on racks to follow the sun in desert areas and are used for installations up to 50 megawatts.

These types of cells, called multijunction cells, achieve those higher conversion rates by using different materials than the traditional silicon cell and multiple semiconductors within a single package. During manufacturing, there are multiple layers of material deposited onto a gallium arsenide substrate, with each layer optimized to convert a different portion of the sunlight’s spectrum. “In essence, you have three basic subcell materials that take in some light and pass the rest to the next. They are connected serially inside the device just like battery cells,” Stauffer explained. There could be up to 20 layers of material used on each cell which is usually a square of about five millimeters, or just a fraction of an inch.

The main customers for these multijunction cells are CPV solar makers such as Amonix and Concentrix Solar in Germany. But even though this technology has been around for years, it still hasn’t become as established or widely used for wholesale electricity production as regular flat solar panels. Multijunction cells are more complex and expensive. But Stauffer said that the costs of CPV systems with those cells are getting more attractive due to efficiency gains and higher levels of concentration. CPV solar collectors can now concentrate light 1,000 times, compared to 500 times in the past year or two, he said.

Solar Junction expects to stand out from other multijunction suppliers with better reliability in high temperatures and higher efficiency, which Stauffer projects will go over 50 percent in five years as the company adds more layers to capture different wavelengths of light.

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EADS and Scottish scientists are working on new storage tanks for hydrogen

Glasgow – EADS Innovation Works, the global aerospace and defence company’s corporate research arm, is working with university researchers to find a new solid state storage system for hydrogen. This technology would make it possible to use hydrogen as a clean alternative to traditional hydrocarbon-based fuels in aeroplane and car engines.

Hydrogen is a clean fuel which produces only water on combustion or when combined with oxygen in a fuel cell to produce electrical power. However, it can be expensive and difficult to store safely. In addition, to store hydrogen as a gas demands high volumes, while to store as a liquid increases weight and the energy requirement (to compress it). Storage of hydrogen in a solid is, therefore, very attractive but minimising weight and volume of the store is challenging and the rate of transfer from the tank to a fuel cell or engine is often slow. These barriers are currently holding back the use of hydrogen on an industrial scale in fuel cells to provide power for aeroplanes and road vehicles.

Chemists at the University of Glasgow are working with EADS by using nanotechnology to alter the design and material composition of a storage tank with the aim of making it so efficient that it will be feasible to use solid state hydrogen on an industrial scale for aeroplanes and cars. If the developments to the tank structure are successful, EADS is planning to fly an un-manned hydrogen-powered test plane in 2014 with a longer term view of introducing commercial aeroplanes powered by hydrogen.

“Replacing traditional hydrocarbon-based fuels with pollution-free hydrogen in aeroplane and car engines would deliver huge benefits to the environment because carbon emissions would be dramatically reduced” said Dr.-Ing. Agata Godula-Jopek, Fuel Cells Expert in the EADS Power Generation Team, which is coordinating the programme for the company. Duncan Gregory, Professor of Inorganic Materials at the School of Chemistry at the University of Glasgow, is leading the research. He is using nanotechnology to alter the structure of the Hydrisafe Tank, which is a new design under development by Hydrogen Horizons, a Scottish-registered start-up company. The University and EADS IW have secured funding from the Materials Knowledge Transfer Network – part of the UK Technology Strategy Board – and the Engineering and Physical Sciences Research Council (EPSRC). This will allow a student to carry out a four year PhD project, spending time at the University and the company’s German offices in Ottobrunn.

The research will involve testing the Hydrisafe tank with alternative hydrogen storage materials. The tank currently uses the established and commercially available lanthanum nickel (LaNi5) storage alloy. The research will look into replacing LaNi5 with other hydride materials such as magnesium hydride (MgH2), which has been modified at the nanoscale to allow it to receive and release the hydrogen at an even faster rate.

Modifying the construction of the tank will extend its longevity, making it suitable to have a solid state hydrogen storage system that can feed a fuel cell at the required energy densities required on an aeroplane. Professor Gregory said: “Using new active nanomaterials in combination with novel storage tank design principles presents a hugely exciting opportunity to address the considerable challenges of introducing hydrogen as a fuel for aviation. This collaboration between engineers and chemists and between industry and academia provides the pathway to achieve this”

There is a recognition that while there is a strong potential for the adoption of fuel cells into the portable fuel cells market, key barriers to delivering this are the safe, efficient and cost-effective storage of hydrogen. The research project,if approved, would explore how best to deliver a practical solid state hydrogen solution for portable and micro fuel cell systems.

Source: Press release EADS

400 Solar Power Users Are Paid For Electricity In Tennessee

NASHVILLE, Tenn. — More than 400 property owners who use solar power to generate electricity at their homes or businesses are getting paid for it with the help of the Tennessee Valley Authority and local power distributors. Some residents have large enough arrays of solar electric generation panels that they get rolling credits on their electricity bill or year-end checks. Most are in Tennessee and The Tennessean reports another 200 projects are in the pipeline.
The Generation Partners program allows property owners to feed electricity into the grid and some distributors, like the Nashville Electric Service, pay more than double what the utility charges for power. The program has grown increasingly popular. NES now has 63 customers generating power and 15 others about to begin.

In Ashland City, Carly and Ed Wansing have a $100 credit on their most recent home electricity bill. They installed their panels in 2007 and are leaving the credit to make up for other months when they might use more electricity.”We build up our credit in the spring and the fall and use the credit in the summer and the winter,” said Carly Wansing, an architect with Street Dixon Rick, which also has solar panels. Their 2.16-kilowatt solar panel system cost them $11,500 after incentives and should take 12 more years to pay off. Along with a $2,000 federal tax credit, the Wansings got a $500 sign-up payment from TVA’s Generation Partners program.

Andy Sudbrock got checks from his electric utility in Williamson County last month that totaled $2,010 for electricity generation from panels on the barn at his plant nursery company, Nashville Natives. “That doesn’t factor in all the electricity we didn’t have to pay for, either,” he said. “We had zero electricity bills all year.” He virtually paid for the $60,000 8.28-kilowatt solar power system in the first year, thanks to some incentives.

Via: The Huffington Post