Solar cell efficiencies are improving, and a number of solar-powered projects are popping up around the world. Here are a few highlights, including single buildings and large solar plants. Hopefully, their successors will be even bigger and better...
1. Dunster Castle, Somerset, UK
Image credit: Mike Crowe
About 15-20% of the energy used by Dunster Castle is generated by solar cells on its roof. Although the 55,000-pound investment completed just weeks ago won't pay off financially, the castle's electric bills will be about 550 pounds cheaper per year. Owned by the Luttrell family for more than 600 years, the 1,000-year-old Dunster Castle was given to the National Trust in 1976, which uses renewable energy on a number of its other buildings, but the castle is the only "Grade 1" building to use the technology.
2. Strizki House, New Jersey, US
Lots of houses have solar cells on their roofs. What's different about civil engineer Mike Strizki's house in East Amwell, New Jersey, is that it's a hybrid solar-hydrogen house -- the first of its kind in the US. The combined use of solar panels and a hydrogen fuel cell with storage tanks provides 100% of the house's electricity year-round. That's no small feat, considering the house is 3,500 square feet and contains a big screen TV and hot tub. But the system, which cost $500,000 to install, is too expensive to implement on a large scale.
3. Edificio Telefonica, Madrid, Spain
Spanish telecom company Telefonica is getting a new office building that will contain 16,000 solar cells, covering the entire length of the roof. With an estimated power generation of 3 megawatts at peak power, the building is one of Europe's largest solar-powered buildings. The company hopes to knock about 15% off their heating bills, and 34% of their air conditioning bills.
4. Dana Building, Michigan, US
The University of Michigan's Dana Building is covered with solar cells that generate about 30 kilowatt-hours of energy. The project was originally a research effort intended to compare two different types of solar panels. The building also uses passive solar power methods, such as making the building more susceptible to sunlight through many of its windows.
5. Four Times Square, New York, US
Four Times Square in the heart of Manhattan incorporates solar cells into the building itself. The relatively new (completed in 2000) 48-story building has photovoltaic panels integrated into the spandrel on the southern and eastern sides of the building are thin-film photovoltaic panels. The 1.6-million-square-foot skyscraper fits into its different surroundings, with its west and north facades embodying the liveliness of Times Square, and its south and east facades maintaining the elegance of corporate Manhattan.
6. Washington Capitol Building, Washington, D.C., US
In 2005, the Capitol Building in Washington was renovated with 144 solar panels which generate about 20,000 kilowatt-hours of energy per year -- enough to light the capitol dome and lantern every night.
7. Pocking Solar Park, Bavaria, Germany
One of the largest solar cell arrays in the world, Pocking Solar Park produces 10 megawatts of electricity -- enough to deliver power to the houses of 3300 Germans nearby. The site is a former military grounds, where solar panels cover about 10 miles of land, and reduce carbon dioxide emissions by about 10,000 tons per year since its installation in April of 2006.
8. Beneixama Solar Plant, Beneixama, Spain
With 100,000 solar panels covering about 500,000 square meters of land, the Beneixama photovoltaic power plant is another of the world's largest solar parks. The plant, which generates 20 megawatts of power, was just completed in the second half of 2007.
9. Nevada Solar One, Nevada, US
Image credit: Ted Robbins, NPR
Since June of 2007, Nevada Solar One has been producing 64 megawatts of electricity, which powers up to 40,000 homes in the Las Vegas area on hot days at peak times. Instead of solar cells, Nevada Solar One uses a parabolic trough of curved mirrors connected in a gigantic array. In the center of the mirrors, an oil-filled tube is heated by the sun. The oil then flows into a plant where it turns water into steam, which itself turns a turbine to generate electricity.
10. Girassol Solar Plant, Moura, Portugal
Image Credit: www.reuk.com
The Girassol (sunflower) solar power plant will be the second largest solar plant in the world when completed in the near future. With an upgrade in phase two of the project, it will generate 62 megawatts of peak power with nearly 350,000 solar panels, some in fixed positions on land equivalent to 150 football fields, and others which track the sun. Located in one of the sunniest as well as economically depressed regions in Portugal, the plant will provide electricity for more than 20,000 homes.
Plus one extra:
11. Victorian Solar Park, Victoria, Australia
Although it's still in the works, the Victorian Solar Park will generate more than twice the energy as the second largest solar plant, Girassol. Australian company Solar Systems is designing the plant with advanced "heliostat" solar panels, which will provide up to 154 megawatts of power at peak levels. The solar panels, originally developed to power satellites, can concentrate the sun by 500 times, according to Solar Systems. The $420-million project will provide energy for more than 45,000 homes when it is completed in 2013.