<!--intro-->London's fabulously successful Tate Modern art gallery has wowed the public. Now it seems that the gallery, housed in the disused Bankside power station, has captured the industrial zeitgeist, too. Power stations, the behemoths of the industrial age, could be on the way out.<!--/intro--> As politicians in the Hague this week thrash out ways of limiting the amount of greenhouse gases in the atmosphere, industry strategists are forecasting the demise of giant, centralised generating stations. The environmental benefits could be immense. <center ><a target="_new" HREF='http://www.exosci.com/portal.php?url=http%3A%2F%2Fwww.newscientist.com%2F&what=link&item=20001115202740695'><img SRC='http://www.newscientist.com/ads/people_why.gif' BORDER=0></a></center> The people that spread thousand-megawatt power plants across the planet now see the future in small generators, each little more than a millionth as powerful, in basements and backyards round the world. One of the biggest enthusiasts is Karl Yeager, who heads the US industry-funded Electric Power Research Institute in Palo Alto, California. By 2050 he thinks that most of our electricity will come from millions of microturbines, solar panels and, most importantly, hydrogen-powered fuel cells. <img hspace = 7 SRC="http://www.newscientist.com/ns_images/2265/226520F1.JPG" align=right>"Within five years I'll be able to go down to Wal-Mart and pick a microgenerator off the shelf to power my house," says Yeager. "I will take it home and connect it to the gas pipe. It will generate power as well as heating my house and producing hot water. And it will be much cheaper than using the power grid." Existing national power grids won't disappear. But Yeager believes they will operate more like the Internet, as part of a complex web through which people will supply electricity as well as downloading it. And countries that don't have large-scale power networks will cease to need them. The result will be greater efficiency, less pollution and an end to power cuts. Dan Rastler, a researcher at the EPRI, thinks his boss is being conservative. He notes that natural-gas fuelled microgenerators for the home are being tested this year. "I anticipate some market penetration as early as 2002," he says. The cost of a 5-kilowatt kit--which would provide more than enough power for most houses--will be about $2500. Some will buy bigger and sell to the grid; others will buy smaller and top up from the grid when they need to. Seth Dunn of the Washington environmental think tank the Worldwatch Institute shares Yeager's vision. In a new pamphlet, Micropower: The next electrical era, he writes: "An electricity grid with many small generators is inherently more stable than a grid serviced by only a few large plants." And it will be the perfect way to introduce renewable energy. It will also, as it happens, be much like the world Thomas Edison envisaged when he opened his first power plant in downtown New York in the 1880s and forecast that soon every community would have one. Two technological developments are driving the revolution. First, the new generation of clean and cheap electricity generators small enough for domestic use. Second, the emergence in recent years of "intelligent" grids able to collect as well as distribute electricity at every node. These will allow people to sell their surplus electricity or even trade regularly in electricity. Besides natural gas-powered electricity, the world is on the verge of adopting cheap fuel cells, electrochemical devices that combine hydrogen and oxygen to produce electricity and water. A big thrust for this research comes from car manufacturers looking for a more efficient, less polluting alternative to the internal combustion engine. Yeager sees the involvement of the car industry as a big plus. Its manufacturing capacity dwarfs that of the electricity generators. Every two years it makes internal combustion engines with a combined power capacity equal to all the world's electricity generating stations. Replace those car engines with fuel cells and it takes no great leap of the imagination to envisage millions of similar cells being manufactured to power homes. The fuel cells will run on hydrogen, and Rastler says he sees homes receiving piped supplies. It is even possible that cars and homes might share the same power source. "When you get home at night you will be able to drive into the garage and plug the fuel cell into the home circuit to power the microwave and the TV," forecasts Yeager. "There is no reason why the auto shouldn't be a power source for your home when you are not driving it. In fact, vehicles could provide an extensive power generation and storage network." A million fuel-cell vehicles plugged into the grid could generate up to a tenth of US electricity needs. Hydrogen will have to be manufactured, of course, and for this there are two routes. One involves splitting water molecules using electricity. It requires much more electricity than you'll get back from the fuel cells, so the gain only arises if that electricity is made using non-polluting sources, such as solar, wind or hydroelectric power. The alternative is extracting hydrogen from a hydrocarbon such as oil, methanol or natural gas. Either way there can be real environmental gains in terms of carbon emissions into the atmosphere. On top of that, a big spur is the growing problem of power cuts. The ageing and underfunded grid system in the US is creaking. Dunn estimates that power cuts cost the country as much as $80 billion a year. Losses of power lasting as little as a few hundredths of a second can cause mayhem, says Yeager, "crashing servers, computers, life-support machines and automated equipment". "In the digital economy you need ultra-reliable power," says Dunn. "It's got to be better than 99.9999 per cent. Conventional utilities just cannot do that." That's why, says Yeager, California's computer companies are all developing their own power systems. No wonder share prices for the pioneers of micropower and fuel cells surged earlier this year in the US. Countries with national power grids will continue to find them useful as devolved power networks. But places that don't have extensive grids--like much of the developing world--shouldn't bother building them. Currently, 1.8 billion people, almost a third of humanity, don't have access to any more electricity than they can get from a car battery. Rather than copying 20th- century technology--as many countries are often expensively and inefficiently attempting to do--their governments should "leapfrog to the higher efficiencies of the digital age", says Yeager. Local networks running on solar cells will provide all the electricity that most consumers need, says Dunn. But the biggest gain for the world could be in curtailing global warming. EPRI researcher Steve Gehl anticipates that by 2050 disconnected communities will gain access to basic electric power of the kind available to Americans in the 1920s. Taken together with trends in the rich countries, that would require a global generating capacity totalling three times today's. Doing the job the 20th-century way would mean building a new 1000-megawatt power plant somewhere in the world every two days for the next 50 years. And that would send carbon dioxide emissions soaring way out of control. The world's governments know that they need to do vastly better than the Kyoto agreement if they are to prevent CO2 concentrations in the atmosphere exceeding the safety ceiling of 550 parts per million being suggested by the world's scientists. That's twice pre-industrial levels and 50 per cent above today's. It is not consistent with a business-as-usual electricity industry. Yeager says it is possible to electrify the poor world while staying below the 550 ppm ceiling. But it will require drastically cutting the volume of CO2 emissions for every unit of electricity generated. He says that by 2050 we must cut average emissions to a fifth of those from a modern, efficient coal-burning power station and to less than half those from natural-gas plants. And to remain below the ceiling till the end of the century will require moving to an essentially carbon-free energy economy. Some people don't believe the job can be done without massive disruption to the world economy. Yeager and Dunn both say it can be--and the first step is to overthrow the tyranny of the multi-megawatt power station. Fred Pearce From New Scientist magazine, 18 November 2000.