Renewables Can Turn the Tide on Global Warming

The American Solar Energy Association (ASES), with the backing of several U.S. representatives and a senator, released its new nuts and bolts approach to reducing carbon emissions with a combination of renewable energy and energy efficiency technologies.

The report comes at an opportune time: the release of the United Nation's Intergovernmental Panel on Climate Change's (IPCC) latest climate change report is expected to finally clear up any lingering uncertainty about the role fossil fuel burning and other human activities have in changing the Earth's climate. As the deniers and obstructionists lose all credibility, the debate now turns to solutions.

The ASES report, titled "Tackling Climate Change in the US -- Potential Carbon Emissions Reductions From Energy Efficiency and Renewable Energy by 2030," makes this extraordinary claim: "Energy efficiency and renewable energy technologies have the potential to provide most, if not all, of the US carbon emissions reductions that will be needed to help limit the atmospheric concentration of carbon dioxide to 450 to 500 ppm."

The ASES report was presented at a press briefing in the Capitol with the support of Senator Jeff Bingaman, Chair of the Senate Energy and Resources Committee, Representative Henry Waxman, Representative Chris Shays, Sierra Club president Carl Pope, and NASA's chief climate change scientist, Dr. James Hansen.

Hansen's backing is especially important because the report is aimed at meeting a target for emissions reductions that he and other scientists agree is the minimum necessary to preserve a habitable planet. The target is to keep the global average temperature from rising by more than one degree Celsius, and to do that, it will be necessary to limit atmospheric CO2 levels to 450 to 500 ppm. That means reducing U.S. emissions by 60 percent to 80 percent by mid-century.

Over the past several years, as the dimensions of the energy and climate crisis have unfolded, the press, the public and politicians have embraced various "silver bullet" solutions one after another according to the fad of the day: at one moment it's hydrogen, then ethanol, then nuclear power, then wind. Today there is a growing recognition that no single energy technology can replace fossil fuels, but there is still no recipe that tells us how to combine energy technologies into a healthful brew that can save our planet and our civilization.

The ASES report takes a unique approach. Instead of turning to the systems analysts who normally tackle such problems, ASES asked the experts in each technology to estimate how much carbon-emitting energy their technologies could displace. Each technology is conceived of as a "wedge" in a stack of wedges that add up to a replacement for fossil fuels. The report consists of separate papers on each technology, including energy efficiency, concentrating solar power, photovoltaics, windpower, biofuels and geothermal.

Each paper was written by experts in the technology, presumably giving the most realistic possible assessment of the capabilities of the technology. And each technology was evaluated in terms of its current capabilities without relying on any major new technical breakthroughs, although some research and development to increase efficiency and reduce costs was assumed. The papers took economic factors into account and real world constraints like the silicon supply shortage that has hampered photovoltaic productions.

Despite its conservative assumptions, the ASES report concludes that renewables and efficiency alone can meet the goal of a 60 to 80 percent emissions reduction by mid-century while the economy continues to grow. Energy efficiency accounts for 57 percent of the reductions, and the renewable energy technologies provide the other 43 percent.