Monday, August 6, 2012

Ancient Village Endures 5,000 Years in Scotland

Skara Brae on Solaripedia
Skara Brae was inhabited before the Egyptian pyramids were built, and flourished for centuries before construction began at Stonehenge. After 5,000 years, the houses at Skara Brae still tell a story of the inhabitants' 600 years of culture and history through intact ruins on the west coast of Mainland, Orkney, Scotland. The secret of their endurance lies partly in their semi-subterranean stone construction, as well as being covered by sand for eons. The ten homes were buried in ancient middens - which would have provided effective insulative value - and the buildings are connected to each other via mostly underground passageways, forming a tight-knit little village. In 3,000 BCE, the community would have been farther inland, before the sea eroded the shore to where it is today. There may be a lesson in such stone construction; even Thomas Jefferson counseled against structures made of wood, which he believed could never improve a country to any considerable degree. Wood, he wrote, whose duration is estimated at 50 years, becomes a tabula rasa every half century. "Whereas when buildings are of durable materials, every new edifice is an actual and permanent acquisition to the state, adding to its value as well as to its ornament.”

Saturday, August 4, 2012

Alcatraz Island Completes Photovoltaic System

Two years ago, in June 2010, we reported that Alcatraz Island was planning to go solar.We're happy to report now that the former prison is host to 1,300 solar panels, powering lights and appliances that for 75 years were powered by diesel fuel ferried across San Francisco Bay. Hurray for the National Park Service (NPS) and the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to bring clean energy to national parks and landmarks! The 307-kilowatt photovoltaic (PV) array sits on the roof of the main Cellhouse building (shown in the photo), attached to two 2,000-amp-hour battery strings and an inverter plant. The new 1,300-panel system produces close to 400,000 kilowatt-hours of electricity a year, reducing carbon dioxide (CO2) emissions by about 337,000 kilograms a year and reducing the time the diesel generator runs from 100% to 40%. The NPS also made energy efficiency changes, such as better light bulbs and changes in operation to reduce energy consumption. A massive solar battery system helps power the island when the sun doesn't shine — and it, too, is hidden from the view of the 1.4 million visitors the island and prison get each year.,360_panels.html