Of course there's a maximum number of watts per sq metre of panel available from the sun, so that's an important factor to consider when justifying any investment.
On the other hand, by covering a roof (and perhaps a south-facing wall) with solar panels, the panels intercept the incoming solar radiation and substantially lessen the air conditioning load in the building. That itself can result in substantial electrical/$ savings. P. ----- Original Message ---- From: Michel Jullian <[EMAIL PROTECTED]> To: vortex-l@eskimo.com Sent: Wednesday, May 14, 2008 9:09:11 AM Subject: [Vo]:Southern California Edison now installing 250 MW of rooftop PV @ 1MW/week Wow! If urban photovoltaic already makes economical sense, even with already commercially available panels, even on rooftops, even at Californian installation manpower costs, nothing will stop its development now! Let's try and guess what kind of PV technology they are using: 65 million ft^2 is ~6 million m^2, i.e. 6E6 peak incident kW, i.e. 6000 peak incident MW 250MW/6000MW =~ 4%, it must be some kind of thin film, mustn't it? Michel http://www.edison.com/pressroom/pr.asp?bu=&year=0&id=7002 << ROSEMEAD, Calif., March 27, 2008 – Southern California Edison (SCE) today launched the nation’s largest solar cell installation, a project that will place 250 megawatts of advanced photovoltaic generating technology on 65 million square feet of roofs of Southern California commercial buildings – enough power to serve approximately 162,000 homes. “These are the kinds of big ideas we need to meet California’s long-term energy and climate change goals,” said Governor Schwarzenegger. “I urge others to follow in their footsteps. If commercial buildings statewide partnered with utilities to put this solar technology on their rooftops, it would set off a huge wave of renewable energy growth.” “This project will turn two square miles of unused commercial rooftops into advanced solar generating stations,” said John E. Bryson, Edison International chairman and CEO. “We hope to have the first solar rooftops in service by August. The sunlight power will be available to meet our largest challenge – peak load demands on the hottest days.” SCE’s renewable energy project was prompted by recent advances in solar technology that reduce the cost of installed photovoltaic generation. When combined with the size of SCE’s investment, the resulting costs per unit are projected to be half that of common photovoltaic installations in California. “The scale of this project is unprecedented,” said Mike Peevey, California Public Utilities Commission (CPUC) president. “It clearly illustrates once again Edison’s leadership position in the development of new renewable technology.” SCE today asked the CPUC for approval to install the solar cell technology during the next five years. The request estimates the total project cost will be $875 million (in today’s dollars). The utility plans to begin installation work immediately on commercial roofs in Southern California’s Inland Empire, San Bernardino and Riverside counties, the nation’s fastest growing urban region. “These new solar stations, which we will be installing at a rate of one megawatt a week, will provide a new source of clean energy, directly in the fast-growing regions where we need it most,” said Bryson. SCE sees numerous customer benefits from its new solar program, among them locating the new generation in areas of growing customer demand. And the clusters of solar modules SCE plans to install will be connected directly to the nearest neighborhood circuit, eliminating the need to build new transmission lines to bring the power to customers. Additionally, solar units produce the most power when customer usage is at its highest. SCE believes its commercial solar roofs program will boost several California environmental initiatives, especially the Million Solar Roofs program that provides incentives to encourage Californians to install solar projects by 2017. SCE’s solar program supports the state’s Global Warming Solutions Act requiring the reduction of greenhouse gas emissions to 1990 levels by 2020, as well as California’s renewable portfolio standard requiring that 20 percent of the state’s electricity be generated with renewable energy by 2010. >>
