HYDROGEN: THE FUEL THAT DRILL BITS CANNOT REACH

摘要

As realization grows of the damaging cumulative effects of CO_2 on our biosphere, the prospect of substituting hydrogen for oil-based fuels attracts growing attention. Japan provides a leading example of remedial action with the expectation of five million fuel-cell-powered vehicles in operation by 2020. But where will the fuel for these and the rest of a "Hydrogen Age" come from? The hydrogen market used to be straightforward: small-scale or high-purity markets were supplied relatively expensively by electrolysis; the other 95% was supplied much more cheaply by reforming hydrocarbons - mostly using steam-methane reforming (SMR) and low-cost natural gas. The recent rise in the price of hydrocarbons - natural gas as well as oil - plus the need to sequester CO_2 has disrupted this scenario. It seems likely that this is a permanent shift driven by growing demand for limited low-cost sources of fluid hydrocarbons. So the traditional SMR route to hydrogen will be in competition with reforming of heavier hydrocarbons (particularly coal and residual oils) as well as with electrolysis based on electricity produced from low-CO_2-emitting sources. By 2025, new high-temperature thermochemical or thermoelectrolytic sources based on high-temperature nuclear reactors could be in contention. This paper assesses the economics of all these potential sources of hydrogen and their price sensitivities. It also considers their environmental footprints. Is hydrogen from "clean coal" or other lower value hydrocarbons cost-effective if it is also CO_2-free? Is intermittent low-temperature electrolysis based on nuclear- and wind-produced electricity (NuWind) the best way or does the hydrogen future belong to thermochemistry or thermoelectrolytic sources? How can one produce hydrogen to upgrade Canada's vast oilsands resources without the detraction of a large CO_2 processing penalty? Fortunately for our planet, switching to hydrogen is no more than a technical challenge with a range of possible solutions but we need to make that point clearly to the political decision-takers and be able to provide assurance that the preferred solution will not be a source of new problems.