Solar PV Energy Payback
Posted by Max Dunn Thu, 10 Sep 2009 21:25:00 GMT
Some people claim that more energy goes into making a solar photovoltaic (PV) panel than it will ever produce. While years ago that may have been the case, it certainly isn’t true any longer.
The US Department of Energy looked at several studies and concluded that multi-crystalline PV has an energy payback of less than 4 years and this will likely go down to below 2 years soon. Thin-film technologies have an even shorter payback period. With an estimated 30-year life, solar PV is actually a very good energy investment!
According to the handy chart, a current-technology polycrystalline module with the standard aluminum frame has a net energy ratio of about 8 to 1. Not spectacular, but not quite as bleak as the 1 to 1 (why bother) claims of the post-carbon survivalist types. A thin-film module with “anticipated” efficiency and no frame is projected to be closer to 30 to 1, and an anticipated unframed polycrystalline is roughly 13 to 1. Not the glory days of 100 to 1 oil gushing out the ground all by itself, but not wildly mismatched from today’s costly fossil fuel, right?
Also very worthy of note: the racking systems, especially ground-mount installations (probably because of concrete foundations), can cut these net energy ratios by a third to a half in the more optimistic anticipated PV technology cases.