SHOULD developing a 鈥渉ydrogen economy鈥� be the number one priority for meeting our long-term energy needs while cutting greenhouse emissions? Or should we be investing in more immediate ways to cut emissions, such as burying the carbon dioxide produced by fossil fuels? Energy experts are bitterly divided on the issue.
John Turner of the US Department of Energy鈥檚 National Renewable Energy Laboratory in Golden, Colorado, is a leading advocate of hydrogen. He argues in the journal Science (vol 305, p 972) that using renewable energy to generate hydrogen is the only 鈥済reen鈥� way to produce the energy to run our cars and trucks. Electricity from renewable sources such as wind, wave and solar would be used to split water into hydrogen and oxygen. The hydrogen could then be burnt directly or used to power a fuel cell.
But other experts contacted by 快猫短视频 are highly critical of this approach. They argue that making hydrogen from renewables is far from being economically feasible. Technical problems such as compressing enough hydrogen into a car鈥檚 fuel tank and bringing down the costs of fuel cells will take decades to solve. We need strategies to reduce greenhouse gases right now, they say. If we concentrate only on hydrogen, the problem of CO2 emissions would just get worse.
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The US Department of Energy is backing the second approach. Its budget for 2004 includes $62 million for research into 鈥渟equestering鈥� carbon 鈥� burying CO2 released from burning fossil fuels so that it cannot affect the climate. And in February 2003, President Bush announced a 10-year, billion-dollar research programme to build 鈥渢he world鈥檚 first integrated sequestration and hydrogen production research power plant鈥� using coal as fuel.
Turner is scathing of this stepwise approach. 鈥淓very intermediate step takes money and energy,鈥� he says. These steps will not be used long enough to pay back the investment, he says, and the funds could be better used to work towards the final goal of renewables-generated hydrogen. Some experts are also worried that an accidental release of CO2 from such a store could be catastrophic.
In turn, Turner鈥檚 critics argue that he is being unrealistic about the prospects for a hydrogen economy. Joseph Romm, an official responsible for renewable energy during the Clinton administration, says the focus on hydrogen is damaging our chances of solving the climate problem. He calls it a 鈥渂ait and switch鈥� strategy. 鈥淧eople promise renewable hydrogen, but what you get is dirty hydrogen,鈥� he says. In the short term, hydrogen will come from natural gas 鈥� a process that produces CO2. This is currently the cheapest way to make hydrogen.
Romm predicts that it will be 2035 before hydrogen-powered cars start making an impact on climate change. 鈥淭hirty years is a long time. We can鈥檛 sit on our hands,鈥� he says.
He also insists that hydrogen generation is not the best use of renewable energy. When losses from distributing and storing hydrogen are taken into account, about 50 per cent of the energy used to make it is lost. Romm and Turner agree that the best short-term use of electricity produced from renewables is not to produce hydrogen but to offset coal. Under current plans, coal burning in the US is set to increase by 50 per cent by 2025. 鈥淭he first, second and third things you need to do is to replace coal,鈥� Romm says.
But Turner wants to keep pushing for hydrogen from renewable energy. However, Romm argues that there will have to be basic scientific discoveries of 鈥淣obel quality鈥� before the hydrogen economy becomes reality. 鈥淚t would be a tremendous mistake to bet the farm on hydrogen.鈥�
Ian Fells, head of the New and Renewable Energy Centre in Northumberland, UK, is also sceptical. He favours an expansion in nuclear power to meet rising energy demands without adding to the greenhouse effect. Otherwise, he argues, it will be like 鈥渇ighting a battle with one arm behind your back鈥�.