Following are findings by the United Nations' Intergovernmental Panel on Climate Change (IPCC) in a draft report about renewable energy (RE).
TOTALS - RE accounted for 12.9 percent of global primary energy supply in 2008. The top contributor was biomass (10.2 percent) -- mainly firewood used in developing nations -- ahead of hydropower (2.3), wind (0.2), direct solar energy and geothermal (0.1 each) and ocean (0.002 percent).
RECENT EXPANSION - Of about 300 gigawatts of new electricity generating capacity added globally in 2008 and 2009, 140 GW came from RE. Developing countries host more than 50 percent of global RE power generation capacity, with China adding more capacity than any other country in 2009.
OUTLOOK - "Studies have consistently found that the total global technical potential for RE is substantially higher than both current and projected future global energy demand." Solar power has the highest technical potential.
CLIMATE CHANGE - Climate change could affect RE availability -- trees might grow in different regions, cloud formation could affect solar power and rainfall shifts can affect hydropower. "Research into these possible effects is nascent," it said.
COSTS/TECHNOLOGY - "The levelized cost of energy for many RE technologies is currently higher than market energy prices, though in other cases RE is already economically competitive."
More RE technologies would be economically attractive if impacts such as greenhouse gases emissions were included.
"The cost of most RE technologies has declined and significant additional technical advancements are expected...further cost reductions are expected."
Areas of potential improvement range from next-generation biofuels to turbine designs for offshore wind energy. Further cost reductions for hydropower are "likely to be less significant" than some other RE technologies.
DEVELOPMENT - RE can help development goals in poor nations. In poor rural areas lacking grid access, RE can lead to substantial cost savings already.
REVIEW OF 164 EXPERT SCENARIOS - Shows RE could give carbon dioxide savings of between 220 billion and 560 billion tonnes from 2010 to 2050 compared to 1,530 billion tonnes of cumulative fossil and industrial CO2 emissions in a reference scenario.
In most scenarios reviewed, RE makes a higher contribution to low-carbon energy supply by 2050 than the options of nuclear power and fossil carbon capture and storage.
In 2008, total RE production stood at roughly 64 exajoules (EJ). In contrast, projected levels of RE deployment in 2050 are greater than 100 EJ/yr in most scenarios and reach 200 EJ/yr to 400 EJ/yr in many scenarios.
"An increase of production level of RE (excluding traditional bioenergy) anywhere from roughly three-fold to twenty-fold is necessary," it said.
"The scenarios indicate that even without efforts to address climate change RE can be expected to expand."
"Scenarios do not indicate an obvious single dominant RE technology at a global level."
POLICIES - "A shift to a low-carbon economy based largely on RE will require additional policies to attract significant increases in investment in technologies and infrastructure."
Four illustrative scenarios estimate global investments ranging from $1.36 to $5.10 billion for 2011-20, and from $1.49 to $7.18 billion for the decade 2021-30. Real costs will be lower, partly because of savings in other energy investments.
"Policy mechanisms enacted specifically to promote RE are varied and can apply to all energy sectors. They include fiscal incentives such as grants and tax credits; public finance policies such as low-interest loans; and regulations such as quantity-driven policies like quotas and price-driven policies including feed-in tariffs for electricity; mandates for RE heating installations, and biofuels blending requirements."
"Some policy elements have been shown to be more effective and efficient in rapidly increasing RE deployment, but there is no one-size-fits-all policy," it said.
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