Making electricity from solar power is only one kind of solar energy, but it’s the one that draws the most interest in Ontario.
Traditional solar panels are made of double sheets of silicon crystals. When light strikes the silicon, it knocks electrons loose from the top sheet, which has a negative charge, creating an electrical current toward the bottom sheet, which has a positive charge.
The current is carried to a device called an inverter. The inverter is needed because the original flow is direct current, and it must be converted to alternating current, which is used by the electricity grid.
Newer technology has developed solar panels that can be rolled up, then unrolled and nailed to a roof. At MIT, scientists have developed solar cells that can be printed on paper.
Industrial scale solar panels have tracking devices that turn the panels so they’re directly aligned to the sun as it crosses the sky. Housetop panels need to be aligned as close to due south as possible for peak efficiency.
The economics of solar panels is in flux, as the Ontario government is reviewing the price paid for renewables, and the cost of solar panels continues to decline.
One installer says a year ago it cost $70,000 to install a 10 kilowatt rooftop solar array, which produces annual revenue of $9,000. Now it costs $50,000.
Chris Stern of Pure Energies says an industry rule of thumb is that it costs $6 a watt to install a solar array, a small housetop panel; a set-up of five kilowatts would cost $30,000 and generate $3,800 of annual revenue at current prices. His company will sell and install solar arrays, or pay the homeowner a fee for the right to mount panels on the roof and collect the revenue.
Industrial scale solar facilities benefit from some economies of scale, slightly lowering the cost per kilowatt. But real estate and other costs can vary widely from one location to another. Ontario’s domestic content requirements for solar installations can also push up costs.
Sun Edison has just begun construction on a 10-megawatt solar farm near Ingleside with 42,000 panels covering 90 acres under Ontario’s feed-in tariff program.
It’s expected to generate 300 million kilowatt hours over the next 20 years, or an average of 15 million kilowatt hours a year. At the FIT rate of 44.3 cents a kilowatt hour, it will produce revenue of about $6.6 million a year.
That’s more than $73,000 of revenue per acre. An acre of corn, by contrast, produces revenue of about $860.