Renewable Energy Needs Support to Grow

The Sun, the wind, and other renewable sources could provide nearly 80% of global energy needs by 2050, according to a new report from the United Nations' Intergovernmental Panel on Climate Change (IPCC). But researchers caution that renewable energy growth depends on "the right public policies," which "recognize and reflect the wider economic, social, and environmental benefits of renewable energies, including their potential to cut air pollution and improve public health."

The findings are summarized in the "Special Report on Renewable Energy Sources and Climate Change Mitigation," a short version of a 1,000-page report on energy alternatives prepared by IPCC's Working Group III (WGIII). The panel, which includes more than 120 industry experts worldwide, said renewable energy growth also hinges on successfully integrating alternative sources with power grids and using new technologies to optimize infrastructure capacity.

At a press conference in Abu Dhabi to release the summary report last week, Ottmar Edenhofer, professor of the Economics of Climate Change at the Technical University Berlin in Germany and co-chair of WGIII, said renewable sources can "contribute substantially to human well-being by sustainably supplying energy and stabilizing the climate." But he concedes transforming a theoretical possibility to reality is "technically and politically very challenging."

WGIII co-chair Youba Sokona, an engineering professor and head of the Sahara and Sahel Observatory, an intergovernmental African organization for sustainable development, characterized renewable energy as "polarizing."

The panel will release the full report May 31. In its summary, it identifies the most promising renewable energy technologies as:

• Bioenergy, including energy crops; forest, agricultural, and livestock residues; and second-generation biofuels (See Whiskey & Vodka Could Drive Your Car.)
• Direct solar energy, including photovoltaics and concentrating solar power (See Analysts Take GT Solar’s $84.3M in Sales in Stride.)
• Geothermal energy, based on heat extraction from the Earth's interior
• Hydropower, including run-of-river, in-stream, or dam projects with reservoirs
• Ocean energy, ranging from barrages to ocean currents and those that harness temperature differences in the marine realm
• Wind energy, including on- and off-shore systems (See Wind Energy Industry Blows Hot & Cold.)

Though it can still cost more to produce renewable energy in some cases, the report notes that costs have declined during the past decade and should continue to fall as technology advances. In addition, if environmental impacts such as emissions of pollutants and greenhouse gases are factored in, "more renewable energy technologies may become economically attractive."

The fastest-growing technology is grid-connected solar electric power, which saw a 53% increase in installed capacity during 2009. However, the report suggests that solar photovoltaics will continue to be among the more expensive options, at least in the short term. Under the most optimistic scenario, the group suggests, solar will grow to provide about a third of all global energy by mid-century. However, it will more likely grow less aggressively and is unlikely to represent more than 10% of electricity generation.

Wind power is expanding in Europe, North America, and, more recently, in China and India. By 2050, it could supply more than a fifth of the world's energy.

Geothermal and ocean energy will likely represent a relatively small amount of total energy production, and the importance of bioenergy and hydropower are likely to decline, the report notes.