Can We Awaken the Sleeping Giant?

Date: 
Friday, December 1, 2006

A Renewable Future for US is Achievable

by Daniel Kammen

The sorry statistics are by now well-known: the United States has just 5% of the world's population, but produces 25% of its greenhouse gas emissions. Efforts to reverse this trend have lagged significantly, and the US continues to block efforts toward international progress. Here, Dan Kammen – one of the nation's top energy experts – lays out a plan to de-carbonize the US economy.Renewable energy science and technology has undergone dramatic advances over the past several decades. Renewable energy and energy efficiency have now come of age to the point where cities, states, and nations plan and implement low – and even near zero – carbon energy systems.

At present the US economy is decarbonizing at just over 1% per year, largely due to advances in energy efficiency. Despite a history of successes in energy efficiency – efficient lighting, refrigeration, heating and cooling, and appliance standards – increased demands for electricity as well as energy for transportation continue to drive energy needs markedly upward. In this context, low- and no-carbon sources of energy are critically needed along with carbon sequestration and long-term dedication to continual advances in energy efficiency. Only with a major commitment to low carbon supply-side technologies can we realistically achieve the needed decarbonization of the global economy, an 80-100% reduction in carbon emissions by mid-century. This is now achievable, but will require scientific, technical, political, and economic commitment. We are now in an era where the economics and political opportunities for renewable energy sources are unprecedented, making this a moment of opportunity to dramatically advance clean power for decades to come.

Significant differences exist at the state and federal levels in the US in terms of what goals are realistic and achievable. The federal government plan for an 18% decarbonization by 2012 from 2002 level in tons of carbon per unit of GDP would actually allow emissions to grow by 12-16%. This target would thus represent a larger increase than the 10% increase that occurred in the previous decade. By contrast, California plans to reduce greenhouse gas emissions to 2000 levels by 2010, and by 80% by 2050. The focus of this article is on the technologies and policies available to meet targets more akin to California's plan, as well as those under discussion in the US northeast and Europe.

Renewable Energy Technologies

The global solar cell (PV) industry has grown by over 20% per year for the past decade, and on a percentage basis is the world’s fastest growing supply-side sources of energy. In 2005 the global PV market grew by a remarkable 50%, reaching a total production volume of over 1,100 MW.

Solar PV represents a particularly easy to use form of renewable energy. The state of California has joined Japan and Germany in leading a global push for solar installations, with a new "Million Solar Roof" commitment that will bring 3,000-10,000 MW of new solar PV. The potential for this technology is virtually unlimited. Work in my research group, the Renewable and Appropriate Energy Laboratory, reveals that the current 0.5 GW of solar PV installed in the US could grow to over 700 GW in only 20 years.

Currently, PV is relatively expensive, with costs of 20-25¢/kWh for crystalline cells. For comparison, coal-fired electricity is 4 -6¢/kWh, natural gas is 5-7¢/kWh, biomass-fired power costs 6-9¢/kWh, and nuclear, where the most disagreement over costs exists, is between 3-12¢/kWh, depending on what is included in the analysis.

Large PV installations have installed costs as low as $5/watt. Costs have not only been falling consistently over the past decade, and aggressive programs in Japan (where 290 MW of solar was installed last year) and in California (where 50 MW was installed) have each observed significant year to year cost reductions, of over 8%/year in Japan and 5%/year in California.

Thin film and amorphous silicon solar cells are also in commercial use today, with Kenya, surprisingly, the global leader in solar systems (not watts) installed per year. Over 30,000 very small (12-30 Watt solar panels) systems are sold in Kenya each year, at costs as little as $100/system. More Kenyans make new electricity connections through solar each year than through new connections to the grid. The efficiency of amorphous solar cells are lower than crystalline by a factor of two or more, but the costs are less by a factor of at least four, making these more affordable and useful for the two billion people on earth without current access to electricity.

Photovoltaics may be the most prominent form of solar power, but solar thermal systems are also undergoing a resurgence. Solar thermal systems, combining focusing mirrors on a working fluid such as oil, high-efficiency, and very low-cost central-station power plants. In the fall of 2005, Stirling Energy Systems (SES) signed two long-term electricity contracts with California utilities that will enable it to build two large solar-dish power plants in southern California.

As part of its fulfillment of the state of California’s Renewable Portfolio Standard (RPS), Southern California Edison signed a 20-year power purchase agreement with Stirling Energy Systems for a 500 MW solar plant to be built in the Mojave Desert. The plant will consist of 20,000 dish concentrators arrayed over 4,500 acres, producing approximately 1,000 GWh of electricity annually. The plant could be expanded to 850 MW. The utility signed a second contract with San Diego Gas and Electric to build a 300 MW plant in the Imperial Valley (with possible expansion to 600 MW).

Costs for the California Stirling plants have not been made public, but estimated levelized electricity costs for current concentrating solar power technologies are: 5-9¢/kWh for towers, 7-11¢/kWh for focusing troughs, and 9-13¢/kWh for dishes (the California Stirling projects). Projected costs, assuming reasonably attainable cost reductions in the next 10 years are: 3.5-5¢/kWh for towers, 6-9¢/kWh for troughs, and 4-6 ¢/kWh for dishes. With their very large scale and long-term contracts, the two projects are likely to have costs closer to the 4-6¢ projected estimates.

The Wind Revolution

Growth in the wind industry has been nothing short of explosive. In 1994 there was a mere 1.600 MW of wind installed in Europe, but now reaching 40,000 MW in 2005. An aggressive construction and installation program in Germany has resulted in over 18,000 MW installed. The north German state of Schleswig-Holstein currently meets 25% of annual electricity demand with over 2,400 wind turbines. In addition to Germany’s progress, there is 10,000 MW in Spain, 3,000 MW in Denmark, and over 1,000 MW in Great Britain, the Netherlands, and Portugal.

The US has also seen a dramatic increase in installed wind power, with a 43% growth in 2005, and total capacity at 9,100 MW. The US however has a tremendous land-based wind resource with about 11 trillion kWh of achievable production – more than three times the total of all electricity produced in the US last year. The global wind industry has also been producing increasingly large and efficient turbines, with 4, 5, and 6 MW turbines now in production for land and ocean-based applications. North Dakota, for example, has a larger wind resource than Germany, yet only 98 MW is installed. Wind is also, in many locations, the cheapest form of new power, with costs generally in $0.04-$0.07/kWh range.

Excitement also exists around tidal power, the ability to utilize the emerging field of synthetic biology to cleanly and cheaply create biofuels, hydrogen for use in fuel cells, and novel means of power storage.

Each of these technologies are now at or near what is often called tipping points; technological and economic stages in their evolution where investment and innovation, as well as market access could move these attractive but generally marginal contributors to playing major roles in the regional and global energy supply.

At the same time aggressive policies to open markets for renewables – solar, wind, biomass sources and programs that reward energy efficiency – are taking hold at city, state, and federal levels around the world. These policies have been adopted for a wide variety of reasons: promoting market diversity or energy security, investment in local industries and job creation, and the protection of the environment. More than 20 US states have adopted significant standards for the fraction of electricity that must be supplied with renewables, while Germany and Sweden are committed to plans to reduce the use of fuels by 80% and 100%, respectively, in two decades. The world of renewable energy is changing.

Financing in Retreat

The US federal government and private industry are both reducing their investments in energy R&D at a time when geopolitics, environmental concerns, and economic competitiveness are all increasing the need for a major expansion in our capacity to innovate in this sector. Our ability to respond to the challenges of climate change, or to the economic vulnerability of the nation to disruptions in our energy supply have both been significantly weakened by the lack of attention to long-term energy planning.

Calls for major new commitments to energy R&D are now common, and calls for energy "Manhattan Projects" have become frequent. Strong correlations exist between public and private sector R&D, and innovation as represented by patenting activity. The scale of the energy economy, and the diversity of potentially critical low-carbon technologies to address climate change, all argue for a set of policies to energize both the public and private sectors.

My lab reviewed spending patterns of the six previous major federal R&D initiatives since 1940 and compared them to scenarios of increasing energy R&D by factors of five and ten. Based on IPCC assessments of the cost to stabilize atmospheric CO2 at 550 ppmv, and other studies that estimate the probable success of energy R&D programs and the resulting savings from the technologies that would emerge, $15-30 billion/year in the US would be sufficient. We found that the fiscal magnitude of a large energy research program – dramatically increasing our meager $3 billion annual national investment in energy research -- is well within the range of programs in other sectors, each of which have produced demonstrable economic benefits. US energy companies could also increase their R&D spending by a factor of 10 and still be below average relative to the R&D intensity of US industry overall.

Where Do We Go From Here?

The challenge we face is larger than simply increasing energy budgets, public or private sector. First and foremost, the country needs an energy plan and a goal. The US addiction to imported fossil fuels comes not only at an environmental price, but geopolitical and economic ones as well. Climate change, which promises to be a disaster if we continue our present path, can also be the rallying point for an economic clean-tech revolution.

We can and should make energy a national priority, and to do that we must:

  • Make energy and the environment a core area of education in the US. We must develop in both K-12 and college education a core of instruction in the linkages between energy and both our social and natural environment.
  • Establish a set of energy challenges worthy of federal action. Establish what could be called Sustainable Energy USA awards that inspire and mobilize academia, industry, civil society, and government. These initiatives would support and encourage groups to take action on pressing challenges. An initial set of challenges include campaigns to design and deploy:
  • Buildings that cleanly generate significant portions of their own energy needs ("zero energy buildings");
  • Commercial production of 200-mile-per-gallon vehicles, as can be achieved today with prototype plug-in hybrids using a low-carbon generation technologies accessed over the power grid, or direct charging by renewably generated electricity, and efficient biofuel vehicles operating on ethanol derived from cellulosic feedstocks.
  • Zero Energy Appliances (Appliances that generate their own power)
  • ‘Distributed Utilities’; challenges and milestones for utilities to act as markets for clean power generated at residences, businesses, and industries.
  • Invest in clean energy commensurate with its importance. Public sector spending alone will not solve our crisis of underinvestment, but a healthy private sector requires us to "prime the pump."
  • Expand international collaborations that benefit developing nations. Greenhouse gases emitted anywhere impact us all, not only today but for decades to come. In many cases, tremendous opportunities exist to offset future greenhouse gas emissions and to protect local ecosystems both at very low cost, but also to directly address critical development needs such as sustainable fuel sources, the provision of affordable electricity, and clean water.My laboratory has recently detailed the local development, health, and global carbon benefits of research programs and partnerships on improved stoves and forestry practices across Africa. We find that dramatic decreases in respiratory illness, and much more sustainable forest management is possible across much of Africa through program and policies that emphasize best practices in legal, managed, charcoal production as well as programs to disseminate improved stoves. Far from an isolated example, such opportunities exist everywhere.
  • Recognize and reflect economically the value of energy investment to the economy. Clean energy production – through investments in energy efficiency and renewable energy generation – has been shown to be a winner in terms of spurring innovation and job creation. This should be reflected in federal economic assessments of energy and infrastructure investment. Grants to states, particularly those taking the lead on clean energy systems, should be at the heart of the federal role in fostering a new wave of clean-tech innovation in the energy sector.
  • And finally, we must put economics to work and begin a serious federal discussion of market-based schemes to make the price of carbon emissions reflect their social cost. A carbon tax and a tradable permit program both provide simple, logical, and transparent methods to permit industries and households to reward clean energy systems and tax that which harms our economy and the environment. Cap-and-trade schemes have been used with great success in the US to reduce other pollutants, and several northeastern states are experimenting with greenhouse gas emissions trading. Taxing carbon emissions to compensate for negative social and environmental impacts would offer the opportunity to simplify the national tax code while remaining, if so desired, essentially revenue-neutral. A portion of the revenues from a carbon tax could also be used to offset any regressive aspects of the tax, for example by helping to compensate low-income individuals and communities reliant on jobs in fossil-fuel extraction and production.


In summary, R&D is an essential component of a broad innovation-based energy strategy that includes transforming markets and reducing barriers to the commercialization and diffusion of nascent technologies. The evidence we see from past programs indicates that we can effectively scale up our energy R&D effort substantially. We recommend a sustained increase in funding by at least a factor of five to meet the energy challenges of the 21st century. The economic benefits of such a bold but long overdue move would help transform our economy into what at one time seemed impossible: a vibrant, environmentally sustainable engine of growth.



Daniel Kammen is the "Class of 1935 Distinguished Professor of Energy" at the University of California, Berkeley, and founding director of the Renewable and Appropriate Energy Laboratory. A longer version of this article appeared in
Scientific American.