Setting Sun Energy

Monday 18th November 2013

“Have you got a south facing roof, sir?” - That is the question often asked when the telesales person tries to get you to book an appointment with the solar panel salesman, if you are in the northern hemisphere at least. This is accepted wisdom, believed to maximise the amount of sunlight absorbed by the photovoltaic cells.

But it may not be true according to a study of panels on homes in Austin, Texas. The Pecan Street Research Institute found that homeowners who aimed their panels toward the west, instead of the south, generated 2% more electricity throughout the day.

More importantly, those west-facing panels reduced household electricity usage during the times when electricity is most expensive—and power grids are most likely to become overloaded—by 65%, while south-facing panels only reduced usage during those times by 54%. In Texas, as in most places, those “peak times” are from 3pm to 7pm, and correspond with the heat of the day.

Quantifying the way that favoring late-day sunlight helps homeowners save money and utilities flatten out demand could lead to a simple but effective hack for the world’s solar installers: Simply re-orienting solar panels could shorten the amount of time it takes for a return on investment.

So the next time you get that call - say you would rather have the panels fitted on the west facing roof - I am sure you will get an interesting response.

Picture reproduced under CCL.

Categories: General, Renewable, Reviews, Technology

Monday 18th November 2013

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