Image: Solar panels at Pocono Raceway
Matt Slocum  /  AP
This wide-angle view shows a field of solar panels at Pocono Raceway in Long Pond, Pa. When the raceway flipped the switch on its 25-acre solar farm last month, it turned the NASCAR track into the world's largest solar-powered sports facility.
By Alan Boyle Science editor
updated 8/16/2010 7:19:33 PM ET 2010-08-16T23:19:33

Today there's a whole menu of options for going beyond the petroleum era, from biofuels and next-generation nuclear power to solar-powered syngas production. But which option will be the "magic bullet" for America's next energy era? It turns out that every energy alternative has its pluses and its minuses, just as oil, coal and natural gas do.

The current renewable-energy debate focuses on how to strike the right balance using all those alternatives — and avoid getting burned in the process.

Some of the emerging solutions for the world's energy woes are outlined in a series of reports appearing in the current issue of the journal Science. Usually, Science's articles are available only by purchasing the magazine, or looking it up at the library. But Science's editors at the American Association for the Advancement of Science believe the energy issue rates so highly in the public interest that they're making the reports in their special section freely accessible for the next two weeks. (Free registration is required to access some of the reports.)

Science's editor emeritus, Donald Kennedy, observes in an editorial that future energy solutions won't be as simple as buying a plug-in hybrid electric vehicle, or putting biofuel in your tank, or buying a woodstove. He says the 21st century's fossil-fuel crisis will be nothing like the oil crisis of the 1970s.

"The contemporary challenge is not that there isn't enough oil; there is far too much of it," Kennedy writes. "Oil has produced environmental devastation on Gulf shores, more of the same in Amazonian forests, emissions from transportation systems that endanger public health, and supplies managed by nation-states that threaten global security. The abuses that result from an overdependence on oil amount to a national crisis, and its resolution will depend on cooperative actions taken by government, industry and the public."

Here are some of the intriguing possibilities outlined in the Science special report:

  • Huge solar-power farms are being built to feed gigawatts of electrical power into the global grid — but how do you get the power from sunny climes to places where the sun doesn't shine? As outlined in Daniel Clery's report for Science, one of the world's most ambitious projects in this field is the multibillion-dollar Desertech venture, which aims to build solar farms in Africa and the Middle East, and transmit much of that power to Europe. The project has been compared to the Apollo space program, but it's not without precedent. Concentrated-solar-power (CSP) facilities are also operating in California and Spain. But such facilities have sparked debate over their impact on the environment .

  • German researchers report that electricity isn't necessarily the only payoff from concentrated solar power. CSP systems can also be used to desalinate seawater, or drive chemical reactions that can turn water and carbon dioxide into hydrogen fuel. If the temperatures are high enough, the H2O-CO2 mix can be turned into hydrogen gas and carbon monoxide (which would go through further chemical conversion). Tests of such technologies are being conducted at the Plataforma Solar de Almeria facility in Spain. But much more research and development will be needed before you can put solar synfuel in your tank.

  • Five years ago, cellulosic ethanol - produced from humble grasses and wood waste — looked as if it could be a "simple solution to pain at the pump." But in Science's special report, Robert F. Service says the federal government's plan for ramping up cellulosic-ethanol production is in "deep trouble" because the economics of ethanol don't make as much sense as folks thought they would back then. Technically, it's still tougher than expected to convert cellulosic feedstock into fuel than it is to use American corn or Brazilian sugar cane. The market for ethanol is limited because most automobiles can use only a 10 percent ethanol blend. That situation could change, however, if automakers give an extra push to cars that can take in 85 percent ethanol (known as E85). In other reports, researchers note little attention has been paid to determining which crops make for the best biofuels ... or how America's energy infrastructure will have to change to accommodate those biofuels.

  • Experts say the "most promising" sources for biofuels include some of the world's smallest organisms: microscopic algae. We've talked about algae power previously , but in the journal Science, Dutch researchers provide a progress report on advances in the field. They also say more work will be needed to harness all that (literally) green power — including genetic engineering to maximize the organisms' production of fatty acids, and systems engineering to maximize the extraction of fuel from those super-algae. They say "10 to 15 years is a reasonable projection for the development of a sustainable and economically viable process for the commercial production of biofuels from algal biomass."

  • Wind power is the renewable-energy technology that's closest to prime time as a significant contributor to the electric grid. Right now, about 2 percent of U.S. electricity is generated by wind turbines, but energy planners want that figure to rise to 20 percent in the next 20 years. Science's Eli Kintisch, author of "Hack the Planet," says the biggest obstacle to that is a "not in my backyard" syndrome, fueled by environmental and aesthetic concerns. The siting problem applies to other renewable-energy technologies as well, ranging from solar to geothermal.

  • Some experts see nuclear power as the only realistic near-term alternative to fossil fuels for large-scale energy generation. It's not "renewable power," as that term is usually defined, but British engineers Robin Grimes and William Nuttall foresee a "two-stage nuclear renaissance" that eventually includes safer techniques for reusing spent nuclear fuel. One of the ventures taking this approach is TerraPower, which has generated buy-ins from venture capitalists and buzz from green-power pundits. Will nuclear power eventually be seen as a green-power option?

The bottom line from the Science special report is that the transition to the next energy era will be more complex and take longer than many of the proponents of renewable energy probably think. It will take decades, even if you subscribe to futurist-inventor Ray Kurzweil's view that solar power will bail us out by the 2030s . The long lead time shouldn't be surprising, though. Science's Richard A. Kerr points out that it took more than half a century for humanity to make the transition from wood power to petroleum power.

What are your favorite green-power possibilities? Which options just don't make sense? Check out Science's podcast and PDF graphic on energy tradeoffs — and feel free to weigh in with your comments on Cosmic Log.

© 2013 Reprints

Explainer: Green-energy ideas so crazy they just might work

  • LM Otero  /  AP

    Fields of windmills spinning in the breeze and deserts covered with solar panels are familiar options for renewable energy. But they are far from the only technologies under consideration. Click the "Next" arrow above to check out six other green energy ideas that are so wacky they just might work.

    — John Roach, contributor

  • Artificial leaves and trees?


    Leaves, observers will note, convert sunlight into energy efficiently to stay alive through photosynthesis. Now scientists are racing to create artificial leaves and trees to power our lives as well. A team at Imperial College London is trying to build leaves that mimic photosynthesis to generate clean fuels such as hydrogen and methanol, The Guardian newspaper reports.

    Another company, London-based SolarBotanic, is in the R&D stage of building artificial trees fitted with "nanoleaves" that generate electricity from sunlight and heat. In addition, piezoelectric generators capture energy from the wind, sound and rain. In theory, the trees will blend in with their surroundings, providing an aesthetically appealing source of energy. An illustration of an artificial hornbeam tree is shown here.

  • Snakes in a wave

    Courtesy of Engineering and Physical Sciences Research Council

    "Snakes on a Plane" made a splash at the box office, and now British researchers are hoping snakes in a wave will make a splash in power generation. The concept calls for placing a long, enclosed, water-filled rubber tube just below the sea surface, with one end facing oncoming waves. As rollers hit the tube, they squeeze it and generate a "bulge wave" reminiscent of a meal inside a real snake. The wave pushes the bulge along the tube, causing it to get bigger as it goes along. At the end of the tube, the bulge wave spins a turbine to generate electricity that is shipped to shore via a cable.

    The project, called Anaconda, is under development at the University of Southampton. A full-scale Anaconda, researchers say, would be about 660 feet long, 25 feet in diameter and capable of generating 1 megawatt of electricity — enough to power 2,000 British homes. An artist's concept for the Anaconda is shown here.

  • Space solar power

    Mafic Studios Inc.

    Solar power from outer space may not be such a far-out idea after all. California energy utility Pacific Gas & Electric agreed to purchase 200 megawatts of electricity that Solaren Corp., a startup company, plans to beam down from solar panels in Earth orbit beginning in mid-2016. The companies said the energy should be competitive with other forms of energy production when it comes to performance and price.

    While the specifics of the set up are not yet public, this artist's rendering shows how a space solar power system might work. An advantage over ground-based solar power is the ability of space solar satellites to generate power 24 hours a day — as they are unaffected by cloudy days and Earth's day-night cycle.

  • Islands for energy and water

    Energy Island

    Some scientists and engineers are looking out to sea with fresh eyes, focusing on an old idea for generating electricity from the temperature difference between warm surface waters and cold water at depth. A few pilot projects were attempted in the 1930s and late 1970s, but were abandoned due to high costs and technical limitations. Improved structural engineering and more favorable market conditions are spurring backers of the Energy Island concept shown here to try again with a more integrated approach.

    It goes like this: Warm surface water is evaporated in a vacuum, producing steam to drive a turbine that generates electricity. Cold water pumped up from depth causes the steam to condense as desalinated water. Wind turbines, solar cells and wave energy converters kick in additional juice. A few islands linked together could produce enough energy to power a small city and desalinate a tanker's worth of water a day, the company says.

  • Fishy concept for renewable energy

    Omar Jamil

    There's something fishy about the way the cylindrical rods depicted in this illustration capture energy from slow-moving ocean and river currents, according to University of Michigan engineer Michael Bernitsas. As water flows past the rods, it creates what are called vortex-induced vibrations. The eddies, or swirls, form in an alternating pattern, pushing and pulling an object up or down or side to side to create mechanical energy. Bernitsas and colleagues are developing technology to capture this mechanical energy and convert it to electricity.

    The concept, called Vortex Induced Vibrations for Aquatic Clean Energy, or VIVACE, was inspired by fish. "Fish curve their bodies to glide between the vortices shed by the bodies of the fish in front of them. Their muscle power alone could not propel them through the water at the speed they go, so they ride in each other's wake," Bernitsas explains.

    An array about the size of a running track and about two stories high could generate enough electricity to power about 100,000 homes, according to project researchers.

  • Artificial 'trees' scrub CO2

    Global Research Technologies

    Chances are that CO2-emitting forms of energy generation are not going to completely go away any time soon, and even if they do, the atmosphere would retain their legacy of greenhouse gases. That's where the structure shown in this drawing comes into play. Researchers are hoping it will behave like a tree and scrub carbon dioxide from the atmosphere.

    The so-called artificial tree is one of several ideas under development that use a proprietary absorbent material to trap carbon dioxide from the air. The gas is then stored, and the absorbent material is recycled to capture even more carbon dioxide.

    The design shown here is from Tucson, Ariz.-based Global Research Technologies. The company envisions selling the trapped gas to users such as greenhouses to enhance plant growth and soda makers for carbonation. Oil and natural gas companies could pump the gas underground to force more petroleum to the surface. The main hurdle to the technology is economic feasibility.


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