Solar energy has had its ups and downs over the past few years. Years ago, solar energy was hyped as being the next best thing for the world. It spearheaded the green revolution. Yet it’s struggled at getting mass adopted because the economics never made sense. PV (photovoltaics) cells were extremely expensive therefore installing them for the masses was not viable. However, the price per watt is freefalling and the efficiency of solar cells is growing exponentially. Tack on the federal and state tax incentives as well as homeowners desire to lower their bills and we have potential for a huge growth in solar energy.
Up until the last decade, if you were to install solar panels on your roof, it would look something like this:
These panels were not aesthetic. You did not want to be that one house on the street with massive obstructive panels on its roof. However in the past five years, solar cells have been integrated within shingles in order to create an aesthetically pleasing and efficient shingle design.
These new shingle materials are called “building-integrated photovoltaics” (BIPVs). They combine solar cells with a variety of traditional roofing materials such as slate, metal or even the most popular asphalt roofing.
Just one shingle contains anywhere from 50 to 200 watts of power, which is enough to power a window fan. Now this is not a lot of power itself. Nevertheless the efficiency is set to increase as engineers keep on developing and improving the technology. If you add the hundreds of square feet of shingles on a rooftop, you have a meaningful amount of watts which can generate quite a bit of electricity.
Currently in 2013, solar shingles will not allow you to cut off your entire electricity supply. You will still need to rely on the local supply grid but to a much lesser extent. When the shingles don’t produce energy, such as at night and on rainy days, you will still have access to electricity through the local supply grid. Nevertheless, if your shingles create more energy than your home requires (which is the case in some sunny states such as California and Arizona), there are 39 states which allow you to sell back your unused electricity back to the grid.
Check out the following example from a family in California. They installed a 2-kilowatt BIPV system on their roof. The general rule of thumb is 1-kilowatt (1,000 watts) per 1,000 square feet of roof space. This system had a total cost of $15,000 and it was installed on the existing cement-tile roof already installed on their home. They were able to add the cost to their mortgage which added only $100 to their monthly mortgage bill. Given the Energy Policy Act of 2005, the family also get a tax credit of 30% or up to $2,000 which can be used towards the cost of the system. Guess how much their new electricity bill is? Less than $4 a month! The system will pay for itself over the next few years and then provide a positive return on the investment.
The economics work for the family in the example because they live in California. A system in the Southern States can produce 25% more energy than those in Northern States. Therefore if you are interested in solar shingles, you must determine if it is cost-effective based on your location.