As we search for ways to become a more green society, the first thing that often comes to mind is solar energy. Harnessing the sun’s power to provide energy seems fairly innocuous to the environment, right? That is not always true. Actually, large amounts of fossil fuels are used in the manufacture of some of the panels, and the disposal of the waste metals not used present their own set of problems. Mercury and chromium are two of the most toxic.

What options do we have? Are there differences within the panels and the way they are manufactured and utilized? There are two types of solar panels, one being solar thermal and the other, photovoltaic. Photovoltaic or PV panels convert sunlight to electricity which can be used to supplement or replace the electricity supplied by the grid.

Solar thermal uses flat collector plates to harness the sun’s energy to heat water. Although their appearance and even installation are similar to the PV panel, solar thermal collectors do not convert sunlight to electricity, but transfer the energy directly to the water. Solar thermal systems replace the electricity or natural gas that would otherwise be required to heat your water.

Many solar developers who had been permitted for solar thermal are now considering, or have already made the decision to move to photovoltaic technology due to the sharp reduction in the cost of PV panels. In addition to reducing developer’s costs this move would also reduce some of the impact that solar thermal presents, such as the cooling ponds for discharged water that attract birds and other animals which often die due to the high salinity of those waters.

There are several environmental wins that are made when switching from solar thermal to PV. Beginning with the reduced use of water, which is obviously used in the both the steam and the cooling cycles. Most plants designed for solar thermal technology use air-cooled condensers (essentially large air conditioners) which have a huge “parasitic load,” adding up to additional electricity needed for that cooling.

With PV technology fewer acres of land are used for roughly the same amount of net generation, or the same amount of land putting more electricity onto the grid, depending upon how one looks at it.

As you can see, when it comes to becoming environmentally savvy, there is a lot more to consider than whether or not your panels will do the job or if they will be eligible for a tax credit. Do your homework and make the decision that is right for you and the environment.