Study: Renewable energies' potential untapped

If you think the lack of technology is the reason we don't have more wind and solar power, think again.

The National Research Council on Monday published a report that finds that renewable energy sources--wind, solar, geothermal, wave, tidal, and biomass--could supply 10 percent of U.S. electricity supply in 2020 with existing technology. Today, renewable energies excluding hydro power are about 2.5 percent of the U.S. electricity mix.

Getting to 20 percent of U.S. electricity by 2035 is possible with sustained policies and investment, it said. To achieve more than 50 percent of electricity generation from renewable sources, excluding hydro power, beyond 2035 would require new scientific advances and dramatic changes in the power-generating industry, the report concludes.

The primary barriers to deeper penetration in the near and medium term are cost, policy, and insufficient transmission lines, the report finds.

More solar power in the cards?

(Credit: Martin LaMonica/CNET)

The study, called "Electricity from Renewable Resources, Status, Prospects, and Impediments," was done to inform politicians on energy policy, which is in a crucial period. The House and Senate are considering bills to mandate more renewable energy and efficiency. The House bill includes regulations to cap greenhouse gas emissions. The National Research Council is the main operating agency of the National Academy of Sciences and the National Academy of Engineering.

Of the technologies available, wind and solar offer the most potential in the U.S., which has good resources for both in different regions. Conventional geothermal and biomass resources are also ready for deployment. Enhanced geothermal--which involves fracturing rock underground and injecting water to heat it--and wave and tidal power are still not commercially available.

On-land wind farms could provide 10 percent to 20 percent of current electricity demand. The only technological improvements in the short term revolve around optimizing performance of components and better integrating wind into the grid.

Solar energy--both photovoltaic panels and concentrating solar power systems--"is capable, in principle, of providing enormous amounts of electricity without stress to the resource base."

To increase the penetration of renewable energy beyond 20 percent, the report says that energy storage technologies are required. Smart-grid technology to better manage the flow of energy from variable resources like the sun and wind is also necessary.

Technology, policy, capital
Costs for solar, wind, and other renewable energy sources are going down but are still more expensive than fossil fuel-derived electricity.

The report says that consistent policies, such as renewable portfolio standards, are required to attract investment in renewable energy, which should improve the technology and bring down costs. Attaching a price for releasing large amounts of greenhouse gases into the atmosphere through carbon regulations will make cleaner forms of energy generation than fossil fuels more cost-competitive, it said.

"Currently, use of renewable resources for electricity generation generally incurs higher direct costs than those currently seen for fossil-based electricity generation, whose price does not now include the costs associated with carbon emissions and other unpriced externalities. Some form of market intervention or combination of incentives is thus required to enable renewable resources to contribute substantially to the national electrical energy generation mix," according to the report.

Another key challenge related to cost is industrial scale. Without an increase in manufacturing capacity for energy products, it will be difficult for renewable energy to move beyond single-digit contributions, the study said.

For example, a Department of Energy report calculated that to increase wind power to 20 percent of U.S. electricity would require construction of 100,000 wind turbines, an additional $100 billion of capital, and 140,000 workers in manufacturing and transmission upgrades.

On an environmental level, a significant barrier to wind and solar is conflict over how land is used for power plants and new transmissions lines.

The report says that investments in research and development are needed now to improve costs and for enabling technologies, such as storage and grid management. "Overall, technological developments and consistent policy will need to be coordinated with manufacturing capacity and access to capital in order to accelerate deployment of renewable electricity."