It is said frequently and often nowadays that the future economy will be 'hydrogen-driven'. Most of what is written on the subject shows signs of being untouched by the human mind. For one thing, hydrogen is an energy-carrier, not an energy-source. You have to *manufacture* hydrogen, and it is an energy-intensive process, requiring huge amounts of electricity. Where will the electricity come from? One answer is natural gas, which in itself is hardly a real answer if you're talking about moving beyond fossil fuels that pour greenhouse gas into the air. And where will the natural gas come from? According to some petrogeologists, there is no shortage of natural gas, particularly in the USA. Eminent member of the American Association of Petroleum Geologists, "Skip" Hobbs recently assured the US Senate that the US has plenty of natural gas (his testimony is in the Crashlist message archive). But the reality is that existing gas reserves are depleting at an alarming, and unexpected rate; meanwhile the US Department of Energy assumes that a supply of 35 quads of natural gas p.a. will be found to meet expected demand by the year 2020; that is almost double existing US natural gas consumption. Most analysts think the target is unreachable. In short, natural gas will be (a) scarce and (b) much more expensive than it is today. Natural gas supplies 20 per cent of world energy (25% in the US). But to replace petroleum as the prime transportation fuel will mean finding *double* that amount: in the US it would mean finding perhaps 70 quads a year, and even Skip Hobbs isn't suggesting that is feasible. But if all the yhpe and public optimism about fuel-cells is on track, that is exactly what WOULD have to be found. So someone is lying somewhere. Maybe the hydrogen can be found using *alternatives* to produce the necessary electricity? The alternatives comprise: nuclear, photovoltaics, wind and biomass. Together these alternatives today provide less than 5% of total US energy. Can they be ramped up? If alternatives CAN fill the gap left by declining oil, then both capitalism and the biosphere might be saved. In this scenario, hydrogen-driven fuel cells will be the motive-power source of the future; you'll even plug them into your home and power domestic electricity with them, so goes the hype which is repeated even by responsible and well respected people, for example people like legendary James Hansen, the Nasa scientist who practically invented the term 'global warming'. His most recent paper, "Global warming in the twenty-first century: An alternative scenario" (James Hansen, Makiko Sato, Reto Ruedy, Andrew Lacis, and Valdar Oinas) (available from www.pnas.org for $5 or for free by writing offlist to me). This paper, published in August 2000, is already notorious because in it Hansen seems to backtrack on earlier global-warming doom-mongering. He is optimistic about reducing atmospheric CO2, mostly because of a new-found enthusiasm for technology. Hansen now beliecves that fuel cells and similar innovations will save the day: "Investments in technology to improve energy efficiency and develop nonfossil energy sources are also needed to slow the growth of CO2 emissions and expand future policy options," Hansen writes. Hansen is employed by NASA, which practically invented the things, but it is clear that when it comes to fuel-cells he doesn't know what he is talking about, and his new-found techno-optimism is misplaced: natural-gas (or methanol) powered fuel-cells cannot replace gasoline engines, and unluss there is some other way out, the 'hydrogen economy' is likely to be still-born, even assuming fuel-cells can *ever* be manufactured cheaply and in volume, which remains unproven. Enthusiasm for alternatives, borne largely of desperation, is widespread these days. Even James Lovelock, father of the Gaia theory, believes that nuclear power is a possible, and necessary, alternative to fossil fuel, to judge from recent remarks of his (archived in the Crashlist). To replace the world's existing petroleum-based transportation fleets with hydrogen-powered systems (assuming this was technically or financially possible) will require the construction of around 25,000 new nuclear reactors. Oil demand today is about 75 million barrels per day, a power equivalent of 5 trillion watts. Supposing the nuclear plants were 40 percent efficient in transferring nuclear energy to gaseous hydrogen, that requires 12.5 terawatts of electrciity-genertaing capacity. But hydrogen must be condensed somehow, and this raises the input power by, in the representative case of cooling hydrogen until it liquefies at ambient pressure, a factor close enough to 2. This entails an extra global capacity of 25 terawatts, ie about 25k conventional pressurised water reactors of 1 Gw output. Unfortunately, there is already a world shortage of exploitable uranium. Absent viable fusion technologies, such a massive increase in nuclear power generation is not feasible in resource terms (let alone safety terms). Whether such a massive construction of new nuclear power stations would be socially acceptable and/or politically feasible is a separate and interesting question. Others argue for photovoltaics. Actually we can take photovoltaics and biomass together, because both entail using available land (and possibly ocean) surface areas to capture solar energy fluxes. So far no technology exists (either by plant-based photosynthesis or silicon-based or other photovoltaic technology) which is capable of capturing enough solar energy to substitute for more than about 10 percent of today's use of fossil fuels. This leaves wind-power and some other mnore exotic methods (subsea turbines, geothermal). In all cases even the massive application of known technologies will provide orders of magnitude less energy than we get today from fossil fuels. In short, there is no way to make the transition to a non-fossil economy without massive social and economic upheaval and dislocation, even in the *best* case. Mark _______________________________________________ Crashlist resources: http://website.lineone.net/~resource_base To change your options or unsubscribe go to: http://lists.wwpublish.com/mailman/listinfo/crashlist
