August 17, 2009

Solar Power in the Sunshine State (Part II)

By James Stevenson, Extension Specalist, Pinellas County Extension

Photo-voltaic Electricity Generation

In Solar Power in the Sunshine State (Part I), we explored the benefits of including solar power in your overall energy-efficiency package. We then looked closely at the various water-heating systems that can save you approximately 20% of your monthly power bill.

This time we will cover making electricity from sunlight and some of the many ways switching to solar can make you money.

Converting sunlight is to electricity is a fascinating and only slightly complex process.

Light from the sun is referred to as solar electromagnetic radiation. This radiation is made up of little bundles of energy called photons which can behave like waves (think: microwaves and radio waves) as well as behaving like an object with physical properties. The wave-like radiation is broken down into five categories based on the wavelengths; these include familiar UV radiation as well as visible light.

When the photons behave like objects they can produce electricity. When these “solar fastballs” strike certain atoms, they can knock them with such force as to disrupt the electrons associated with those atoms. This disruption causes a release of energy and makes the electrons “excited”. When these “excited” electrons move in a particular direction this is referred to as “current.” Sound familiar?

The current produced is Direct Current (DC), which needs to be converted to Alternating Current (AC) for practical use. In order to do this you need a photovoltaic (PV) device. PV converters have very few parts: a surface covered with a material made up of “excitable” electrons, a simple magnet to move those electrons in one direction, a converter that will change DC power to AC, and the most important part: the Sun.

Currently the most popular material used to provide electrons for knocking about is silicon. Now, silicon is a pretty abundant material, it is what sand is made of. But getting PURE silicon is a tricky and expensive procedure. This makes PV systems costly. Other concerns with silicon are the production process and environmental impacts. However compared to the environmental, social, and geo-political impacts of our dependence on oil as our primary energy source, and solar comes up looking pretty good! In addition, materials other than silicone are being researched, with some success.

Some think that the heat of the sun is somehow a factor in producing PV electricity. Interestingly, the system works a bit less efficiently in extremely high temperatures. Therefore, even though the desert southwest of the US may receive more hours of daylight than Florida, the heat there makes PV systems much more inefficient, therefore making Florida nearly perfect for efficient solar energy production.

There are incentives for including solar energy, both thermal and photo-voltaic into your energy system. Any solar energy system, including the more affordable water-heating systems, is not subject to sales tax. In addition, you can claim 30% of the total cost of the project (including installation) as an income tax write-off as long as the system is operational by December 31st 2010. There is currently a measure before the Florida lawmakers that would prevent the addition of solar technology from adding to a home’s value and driving up the taxable value of that home.

If you are interested in learning more about Solar Power in the Sunshine State, please join us on Saturday, August 22nd here at Pinellas County Extension for a solar energy workshop. Experts from Progress Energy and the Solar Source Institute will be giving lectures and answering questions from 9:30 – 12:00. In addition several local vendors of solar products and services will be displaying their good in a mini-trade show, all right in our main auditorium.

This class is $15 and registration is required by Thursday, August 20. We can not accept walk-ins on the day as space is limited. To register, visit and select the “Online Class Registration” button. Then look for the Sustainable Living tab. We hope to see you there!

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