By John Roach, contributor
Introduction
Four dollars for a gallon of gas? Experts say rising fuel prices reflect a combination of squeezed oil supplies, soaring international demand and market speculation. As a result, alternative forms of energy are getting a serious look – not only to ease the price squeeze, but also to cut greenhouse-gas emissions. Many experts say a switch to a fuel efficient gas/electric hybrid vehicle, such as the Toyota Prius pictured here, is the easiest and most immediate way to stretch your energy dollar and limit your carbon footprint. But hybrids cost more than conventional models, which means the financial payback comes several years down the road. Click the \"Next\" arrow above to learn about nine other alternative-energy technologies.
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Can fuel cells keep traffic moving?
Alternative-energy advocates have long eyed a future in which cars use fuel cell stacks to create electricity by combining hydrogen and air. Water is the only byproduct – there would be no gases or fumes linked with global warming or pollution. But fuel cells remain expensive. Today, hydrogen must be extracted from sources like natural gas, and there are few roadside hydrogen filling stations. Nevertheless, automakers are busy rolling out new models they hope will appeal to the driving public. Pictured here is the Honda FCX Clarity, which can reach a top speed of 99 mph and will lease starting this summer in California for $600 a month.
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ALTenergy_science[i++] = new Array("","Is the answer blowing in the wind?","","http://msnbcmedia.msn.com/j/ap/9a461ce6-79fd-4d51-bcf0-62713b868e25.hmedium.jpg","","", "", "", "", "", "", "Charlie Riedel", "AP", "264", "423", "#000000", "", "", "", "");
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Is the answer blowing in the wind?
A recent U.S. government study found that energy wrung from the wind could supply 20 percent of the nation's electricity by 2030. Wind currently accounts for about 1 percent of the energy mix, though it has been growing at a record-shattering pace. Last year, the nation's wind capacity increased 45 percent with the installation of nearly 3,200 wind turbines, which is enough to power 1.5 million homes for a year. To reach the 20 percent goal will require 75,000 additional new wind turbines and a major expansion of the nation's electricity grid, experts say. The turbines must also overcome concerns that they mar vistas and are deadly to migrating birds. The turbines in this image may be in the flight path of endangered whooping cranes.
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ALTenergy_science[i++] = new Array("","How much power is in the tides? ","","http://msnbcmedia.msn.com/j/ap/21310762-d6a4-46ca-b176-beaffe4d14f3.hmedium.jpg","","", "", "", "", "", "", "", "AP", "273", "364", "#000000", "", "", "", "");
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How much power is in the tides?
In the unending quest for clean, renewable energy, scientists are turning to the predictable ebb and flow of the tides. The turbine in this image is part of a pilot project in New York's East River to harness tidal flows, using the same principle as wind turbines that wring electricity from the breeze. Since water is denser than air, fewer turbines are required to produce the same amount of electricity as wind turbines. And since the contraptions are underwater, they lack the aesthetic issues associated with wind farms. Nevertheless, the infant technology could impact fish, alter tidal flows and have other unforeseen impacts on the environment.
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ALTenergy_science[i++] = new Array("","Is the nuclear option back on the table?","","http://msnbcmedia.msn.com/j/msnbc/Components/Photos/070117/Top5/070117_wattsbar_hmed_2p.hmedium.jpg","","", "", "", "", "", "", "Wade Payne", "AP", "248", "423", "#000000", "", "", "", "");
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Is the nuclear option back on the table?
The nuclear accidents at Pennsylvania's Three Mile Island in 1979 and Russia's Chernobyl in 1986 consigned atom-splitting energy to has-been status. Soaring coasts and mountains of unwanted waste added to the woes. Tennessee's Watts Bar Nuclear Plant, shown in this image, was the last to go online in the U.S. It began operating in 1996 after 23 years of construction delays. Today the nuclear option is back on the table, thanks to improvements in plant design and efficiency as well as the technology's ability to operate without spewing greenhouse gases into the atmosphere. Nuclear waste storage, weapons proliferation and high costs continue to raise concerns.
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ALTenergy_science[i++] = new Array("","How hot is geothermal energy?","","http://msnbcmedia.msn.com/j/msnbc/Components/Photos/061116/061116_geothermal_hlrg_9a.hmedium.jpg","","", "", "", "", "", "", "David Mcnew", "Getty Images file", "184", "423", "#000000", "", "", "", "");
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How hot is geothermal energy?
Earth’s depths really are devilishly hot, which could be a heavenly solution to the world's energy woes. Geothermal power plants such as the one in California pictured here tap hot rocks miles beneath the surface and connect them with water, producing steam that spins electricity-generating turbines. According to a 2006 study conducted by researchers at the Massachusetts Institute of Technology, investments in new geothermal power plants could help the U.S. meet 10 percent of its electricity needs by 2050. Critics say construction costs are high, pose seismic risks and consume too much valuable water.
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ALTenergy_science[i++] = new Array("","Will we be saved by the sun?","","http://msnbcmedia.msn.com/j/msnbc/Components/Photo_StoryLevel/080220/080220-greendispute-12p.hmedium.jpg","","", "", "", "", "", "", "Jeff Chiu", "AP", "271", "423", "#000000", "", "", "", "");
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Will we be saved by the sun?
The amount of energy in sunlight beamed daily on the continental United States far exceeds the nation's needs. To date, however, solar energy accounts for less than 1 percent of the nation's electricity mix. Challenges for the technology include the high cost and low efficiency of the silicon chips that convert sunlight to electricity, storage for the generated juice and the unreliability of clear skies at any one location. Nevertheless, the technology is experiencing an investment boom, and eco-friendly tax incentives in places such as California are encouraging homeowners to install solar cells on their roofs. The gentleman in this image took the bait but is now complaining that his neighbors' trees illegally block his rays.
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ALTenergy_science[i++] = new Array("","Will new dams unleash more cheap power?","","http://msnbcmedia.msn.com/j/msnbc/Components/Photo_StoryLevel/080303/080303-dams-hmed10a.hmedium.jpg","","", "", "", "", "", "", "Nick Geranios", "AP file", "254", "423", "#000000", "", "", "", "");
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Will new dams unleash more cheap power?
Hydroelectric dams are considered an important source of cheap, abundant and carbon-free electricity. The mechanics are straightforward: Trap water behind a wall of concrete and channel it through a turbine to generate electricity. The era of massive dam construction, such as Washington state's Grand Coulee Dam shown in this image, ended in 1966 largely because the projects drowned landscapes, tamed rivers and proved disastrous to fish. But dams also provide irrigation water to farmers, and with forecasts of less reliable stream flows in a warmer world, new river plugs are again on the drawing board.
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ALTenergy_science[i++] = new Array("","Can coal come clean?","","http://msnbcmedia.msn.com/j/msnbc/Components/Photos/060618/060618_futuregen_hmed_2p.hmedium.jpg","","", "", "", "", "", "", "U.s. Department Of Energy / Ap", "", "212", "423", "#000000", "", "", "", "");
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Can coal come clean?
The name \"clean coal\" in and of itself implies that the current source of more than half of the U.S. electricity supply is dirty. But many experts argue that coal is too cheap and abundant not to be part of the future energy mix. It just needs to be \"clean\" in order to limit the contribution to global warming. A U.S. government-sponsored project called FutureGen, which is pictured in this artist's rendering, was supposed to demonstrate a technology to captures and store coal's carbon-dioxide emissions underground. But the prototype project was put in limbo because of cost overruns.
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ALTenergy_science[i++] = new Array("","Can biofuels be truly ‘green’?","","http://msnbcmedia.msn.com/j/msnbc/Components/Photos/060517/060517_Module2_hmed_12p.hmedium.jpg","","", "", "", "", "", "", "", "GreenFuel Technologies", "231", "423", "#000000", "", "", "", "");
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Can biofuels be truly ‘green’?
Ethanol distilled from crops such as corn and soybeans have given biofuels a bad name recently by helping drive up food prices and, according to some studies, doing little if anything to reduce greenhouse-gas emissions. Researchers are scrambling to find more acceptable feedstock, ranging from non-edible wood chips and switchgrass to food waste and rotting jellyfish. Among the more intriguing possibilities is algal fuel. The green slime, pictured here, ingests carbon dioxide in the photosynthesis process. Some species of algae contain as much as 50 percent oil, which can be used to produce biodiesel. The scraps can be transformed into ethanol and animal feed. A major challenge is cost: A gallon of algal fuel today is about $20, which is expensive compared to $4 gasoline.
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// END editorial data