PV Gap

Karen Said:

Which more environmentally friendly: A roof with solar panels or a green roof?

We Answered:

Glad to see that you are actively trying to preserve the environment, Michael.

The answer is that it really depends on how many solar panels you are going to mount on your roof and your heating and cooling needs.

A green roof will reduce your current heating and cooling needs by about 25%. Keep in mind though, that a well insulated attic and reflective metallic roof shingles could have the same effect.

You will also need to calculate how much power your solar panels produce vs the amount saved by the green roof and go with whichever one lowers your power consumption more.

Another thing to take note is that a green roof needs active maintenance, whereas solar panels generally require very little maintenance.

Sorry I couldn't offer a more concrete answer than this, bud.

Billie Said:

How green/eco friendly is the fabrication of Solar Panels?

We Answered:

Solar panels are quite energy intensive to make, since you need very pure silicon. You then have to dope them with other materials (original phosphorous and boron). Some solar panels use cadmium telluride instead of silicon. Cadmium is toxic.

According to Alsema & Wild (2006), the energy payback time of a solar panel is 1.5-3.5 years depending on where it is, how it's made etc.

Solar panels last for 30-50 years, so they produce between 10 and 33 times the energy needed to fabricate them. This proportion is expected to increase due to better technology (like thin film panels).

Calvin Said:

What is the breakeven point when the solar panels become green?

We Answered:

Energy breakeven is about 2 years, according to both industry and DOE studies. Since panel life is in excess of 30 years, a panel produces at least 15x as much energy as required to make it.

Jeff Said:

With everyone thinking green...how green are solar panels?

We Answered:

Most of the early panels were not very green. They were not very efficient and did not have a real long life span. The newer one are getting much better and there are several companies have cropped up that rebuild many different kinds of panels. Some of these newer panels have a life span in excess of 30 years and are much easier to maintain. The biggest problem with solar systems is that they are not kept clean and loose efficiency. If interested in setting up a system for your self, Please be very careful who you have do the work and what system you buy. There are many companies out there that are just trying to make a quick buck at your expense.