Michael Webber, the Associate Director Centre for International Energy and Environmental Policy, has completed an analysis of the water requirements for a burgeoning hydrogen economy slated to arrive near 2040. Around this time, it is predicted that the annual production of hydrogen would top 60 billion kg. The hydrogen, of course, will be coming from water, and he estimates that 19-69 trillion gallons of water will be needed for electrolysis and for coolant of power plants. Considering that means somewhere between 50-200 billion gallons of water per day, water is looking more and more not to be the inexhaustable resource as it was once touted, not to mention that this needs to be fresh, distilled water... so much for the oceans without energy-intense desalination plants.
To add fuel to the fire, electrolysis is only currently at about 60-70% efficiency. At 100% efficiency, a rate we will never achieve, it takes 40kWh to produce a kilogram of hydrogen. This means between 1134-2754 billion kWh at an efficiency of 75% will be needed to produce the amounts they are predicting.
With local water resources being depleted, water prices skyrocketing and the question of where these billions of kWh will come from, Michael makes a sobering statement in his report:
Each of the energy choices we can make, in terms of fuels and technologies, has its own tradeoffs associated with it. Hydrogen, just like ethanol, wind, solar, or other alternative choices, has many merits, but also has some important impacts to keep in mind, as this paper tries to suggest. I would encourage the continuation of research into hydrogen production as part of a comprehensive basket of approaches that are considered for managing the transition into the green energy era. But, because of some of the unexpected impacts—for example on water resources—it seems premature to determine that hydrogen is the answer we should pursue at the exclusion of other options.
All the more reason to avoid thermoelect
written by Tom Konrad, October 22, 2007
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