Thursday, December 6, 2012
It takes energy and raw materials to build solar panels, but over their lifetimes, they more than make it back.
“It is sometimes said that photovoltaic (PV) solar electric panels require more energy for their production than they every produce during their lifetime. This seems to be the kind of ‘urban myth’ that is hard to eradicate,” says the Welsh Centre for Alternative Technology.
Solar power has burgeoned in the Islands and some have expressed concern over the life cycle cost—since it takes a lot of energy to manufacture them. Multiple studies put those concerns to rest.
The Welsh site suggests an energy payback time of 2.5 to 7 years, depending on assumptions about the panels and the amount of sunlight in the place the panels are used. It cites this British report in saying that the carbon footprint of solar panels is one-tenth that of plants burning fossil fuels.
A study posted on the state of Oregon’s website, performed by Good Company, notes that while solar panels consume energy while being built, they displace fossil fuel energy when used.
“The positive impacts of that displacement far outweigh the negative impacts of the production phase of the life cycle of silicon solar panels,” says the report, on the website of Oregon’s Office of Innovative Partnerships and Alternative Funding.
This study suggests that it can take one to four years to pay back the energy cost of manufacture, and since solar panels have an assumed 30-year life, the overall payback is 9 to 17 times the energy cost.
The study also argues that recycling of old solar panels is needed, and that it will allow the production of new panels at one-third the energy cost of building ones from raw materials.
The U.S. National Renewable Energy Lab, in this study on thepayback times for photovoltaics, says a lot of the calculation has to do with the type of photovoltaic panel you use
“Energy payback estimates for rooftop PV systems are 4, 3, 2, and 1 years: 4 years for systems using current multicrystalline-silicon PV modules, 3 years for current thin-film modules, 2 years for anticipated multicrystalline modules, and 1 year for anticipated thin-film modules,” the NREL study says.
It goes on:
“With energy paybacks of 1 to 4 years and assumed life expectancies of 30 years, 87% to 97% of the energy that PV systems generate won’t be plagued by pollution, greenhouse gases, and depletion of resources. Based on models and real data, the idea that PV cannot pay back its energy investment is simply a myth.”
There are plenty of other studies on the issue. See the citations at the bottom of the NREL study for several of them.
© Jan TenBruggencate 2012