Greg Bosscawen, manager of renewable energy for Pacific Gas and Electric Co., walks past solar panels at PG&E’s Vaca-Dixon solar energy site near Vacaville, Calif., Tuesday, April 12, 2011. (AP Photo/Rich Pedroncelli)

Interesting new story out from my buddy Mike Casey at The Associated Press:

ABU DHABI, United Arab Emirates (AP) — Renewable sources such as solar and wind could supply up to 80 percent of the world’s energy needs by 2050 and play a significant role in fighting global warming, a top climate panel concluded Monday.

But the U.N. Intergovernmental Panel on Climate Change said that to achieve that level, governments would have to spend significantly more money and introduce policies that integrate renewables into existing power grids and promote their benefits in terms of reducing air pollution and improving public health.

Authors said the report concluded that the use of renewables is on the rise, their prices are declining and that with the right policies, they will be an important tool both in tackling climate change and helping poor countries use the likes of solar or wind to develop their economies in a sustainable fashion.

“The report shows that it is not the availability of the resource but the public policies that will either expand or constrain renewable energy development over the coming decades,” said Ramon Pichs, who co-chaired the group tasked with producing the report. “Developing countries have an important stake in this future — this is where 1.4 billion people without access to electricity live yet also where some of the best conditions exist for renewable energy deployment.”

As explained in the IPCC press release:

The findings, from over 120 researchers working with the Intergovernmental Panel on Climate Change (IPCC), also indicate that the rising penetration of renewable energies could lead to cumulative greenhouse gas savings equivalent to 220 to 560 Gigatonnes of carbon dioxide (GtC02eq) between 2010 and 2050.

The upper end of the scenarios assessed, representing a cut of around a third in greenhouse gas emissions from business-as-usual projections, could assist in keeping concentrations of greenhouse gases at 450 parts per million.

This could contribute towards a goal of holding the increase in global temperature below 2 degrees Celsius – an aim recognized in the United Nations Climate Convention’s Cancun Agreements.

The release continued:

Over 160 existing scientific scenarios on the possible penetration of renewables by 2050, alongside environmental and social implications, have been reviewed with four analyzed in-depth. These four were chosen in order to represent the full range. Scenarios are used to explore possible future worlds, analyzing alternative pathways of socio-economic development and technological change.

The researchers have also studied the challenges linked to how renewable energy can be integrated into existing and future energy systems including electricity grids and likely cost benefits from these developments.

While the scenarios arrive at a range of estimates, the overall conclusions are that renewables will take an increasing slice of the energy market.

The most optimistic of the four, in-depth scenarios projects renewable energy accounting for as much as 77 percent of the world’s energy demand by 2050, amounting to about 314 of 407 Exajoules per year. As a comparison, 314 Exajoules is over three times the annual energy supply in the United States in 2005 which is also a similar level of supply on the Continent of Europe according to various government and independent sources.

77 percent is up from just under 13 percent of the total primary energy supply of around 490 Exajoules in 2008. Each of the scenarios is underpinned by a range of variables such as changes in energy efficiency, population growth and per capita consumption. These lead to varying levels of total primary energy supply in 2050, with the lowest of the four scenarios seeing renewable energy accounting for a share of 15 percent in 2050, based on a total primary energy supply of 749 Exajoules.

While the report concludes that the proportion of renewable energy will likely increase even without enabling policies, past experience has shown that the largest increases come with concerted policy efforts.

Though in some cases renewable energy technologies are already economically competitive, the production costs are currently often higher than market energy prices. However, if environmental impacts such as emissions of pollutants and greenhouse gases were monetized and included in energy prices, more renewable energy technologies may become economically attractive.

For most of them, costs have declined over the last decades and the authors expect significant technical advancements and further cost reductions in the future, resulting in a greater potential for climate change mitigation.

Public policies that recognize and reflect the wider economic, social and environmental benefits of renewable energies, including their potential to cut air pollution and improve public health, will be key for meeting the highest renewables deployment scenarios.

You can read a summary of the study here, and the entire report is due out at the end of the month.