BUSINESS AND THE ENVIRONMENTAL REVOLUTION

Great Posting, I'm wondering how long residential solar panels must be used to offset the energy needed to make them

Due to the growing demand for renewable energy sources, the manufacture of solar cells and photovoltaic arrays has advanced dramatically in recent years. Photovoltaic production has been doubling every 2 years, increasing by an average of 48 percent each year since 2002, making it one of the world’s fastest-growing energy technology. *1

The energy payback time is the time required to produce an amount of energy as great as what was consumed during production. The energy payback time is determined from a life cycle analysis of energy. The energy needed to produce solar panels is paid back in the first few years of use. *2

Another key indicator of environmental performance, tightly related to the energy payback time, is the ratio of electricity generated divided by the energy required to build and maintain the equipment. This ratio is called the energy returned on energy invested (EROEI).

Life-cycle analyses show that the energy intensity of typical solar photovoltaic technologies is rapidly evolving. In 2000 the energy payback time was estimated as 8 to 11 years,*3 but more recent studies suggest that technological progress has reduced this to 1.5 to 3.5 years for crystalline silicon PV systems.*4

Thin film technologies now have energy pay-back times in the range of 1-1.5 years (S.Europe).*4 With lifetimes of such systems of at least 30 years, the EROEI is in the range of 10 to 30. They thus generate enough energy over their lifetimes to reproduce themselves many times (6-31 reproductions, the EROEI is a bit lower) depending on what type of material, balance of system (or BOS), and the geographic location of the system.*5
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*1 Solar Expected to Maintain its Status as the World's Fastest-Growing Energy Technology

*2 "Laser technology for photovoltaics manufacturing. (Germany)." Advanced Manufacturing Technology 30.4 (April 15, 2009): 5(1). Expanded Academic ASAP. Gale. Bentley Upper School Library (BAISL). 6 October 2009.Galegroup.com

*3 Andrew Blakers and Klaus Weber, “The Energy Intensity of Photovoltaic Systems”, Centre for Sustainable Energy Systems, Australian National University, 2000.

*4 Alsema, E.A.; Wild - Scholten, M.J. de; Fthenakis, V.M. Environmental impacts of PV electricity generation - a critical comparison of energy supply options ECN, September 2006; 7p. Presented at the 21st European Photovoltaic Solar Energy Conference and Exhibition, Dresden, Germany, 4–8 September 2006.

*5 Joshua Pearce and Andrew Lau, “Net Energy Analysis For Sustainable Energy Production From Silicon Based Solar Cells”, Proceedings of American Society of Mechanical Engineers Solar 2002: Sunrise on the Reliable Energy Economy, editor R. Campbell-Howe, 2002.

Thanks this was great info