This is a good one:
A Critical Analysis of Hydrogen & Fuel Cell Cars
By By Alexander E. Farrell & David W. Keith
Sep 9, 2003, 15:34
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From Magazine Hydrogen Cars Business. All rights reserved.
Support for hydrogen cars has reached new heights, especially for fuel-cell vehicles that use hydrogen directly. In the recent article in Science (vol 301, pp. 315-6. July 18, 2003 ) we take a long-term strategic view of energy policy and argue against the adoption of hydrogen cars for several decades. Readers are recommend to the article for a longer discussion with references.
Although obviously technically feasible, both hydrogen vehicles and the necessary refuelling infrastructure would be very expensive. Although hydrogen production is simple, as a low heating-value, low boiling-point gas it is inherently expensive to transport, store, and distribute, all strong disadvantages for a transportation fuel. Technological breakthroughs in hydrogen storage and/or energy conversion will be needed to allow hydrogen cars to matching gasoline-fuelled, internal combustion engine-driven cars in terms of cost, size, range, and fuelling convenience.
Most importantly, hydrogen cars would be more expensive than alternatives currently available to achieve the three goals that drive interest in hydrogen cars: controlling air pollution, reducing dependence on fossil fuels or imported oil, and managing climate change.
Near-term strategies to address the serious challenges posed by air pollution, climate change, and petroleum dependence should focus on emissions from electricity generation and freight transport, on strategic petroleum reserves, on energy efficiency (especially in vehicles) and on research into a wide array of possible future transportation fuels, including hydrogen as well as bio-fuels and electricity and others we may not have though of yet.
Hydrogen cars could essentially eliminate vehicle-related air pollution emissions, but the cost of reducing NO2 emissions (for example) with hydrogen will be on the order of $1 million per tonne NO2. In contrast, programs like tougher emission standards, enhanced inspection and maintenance, and scrappage programs (voluntary programs offering bounties for old vehicles) can achieve the same for less than $10,000. Similar comparisons can be made for other pollutants and for controlling emissions from other sources, such as electricity generation.
Hydrogen cars could essentially eliminate CO2 emissions from cars, but only if the hydrogen was carbon-neutral. Almost none of the hydrogen produced today is carbon-neutral and hydrogen produced by small, distributed natural gas reformers would not be.
The cost of carbon-neutral hydrogen turns on the viability of CO2 capture and storage (CCS). If CCS is found to be socially acceptable, the cost of mitigating CO2 may be as high as $1000 per tonne carbon by using hydrogen cars while only $75-$150/tC by capturing the CO2 from electric power plants. If CCS prove unacceptable, it’s not clear that the situation would be any better for hydrogen cars since converting renewably generated electricity to vehicle fuel instead of using it to replace fossil-generated electricity places substantial extra costs and inefficiencies between energy source and end use.
For several decades, the most cost-effective method to reduce CO2 emissions from cars will be to increase fuel efficiency, especially in the United States . There are many potential improvements to light duty vehicles that would pay for themselves in lifetime fuel savings, possibly more than 50%. Importantly, many of the technologies that hydrogen cars will need, such as electric drive, are included in these enhanced efficiency vehicles.
Hydrogen cars would also reduce the amount of petroleum used consumed and imported by many countries. As above, improved vehicle efficiency would be the most cost-effective way to lower petroleum imports and consumption. Petroleum substitutes that can be stored, transported, and distributed easily (e.g. synfuel production with CCS, biomass-derived fuels) can be introduced less expensively than could hydrogen, and if current refuelling infrastructure and vehicles can be adapted to these substitutes, faster as well..
Eventually, global CO2 emissions and petroleum consumption must decline by an order of magnitude or more, so major changes will eventually be required in automotive technologies. But even if it some day does become desirable to introduce hydrogen as a transportation fuel, a wiser strategy would focus on heavy freight transportation modes such as ships, trains, and large trucks. Hydrogen would be both easier to implement (much smaller distribution infrastructure and less of a premium on onboard space) and provide ancillary benefits (higher emissions).
The real question is whether or not we must decide today that hydrogen cars are the best long-run solution and then act on that decision, or if it is best to see hydrogen vehicles as one of several long-run options that deserve research funding, but not public support for their widespread use.
If, we accept that there is considerable uncertainty about the optimum long-run solution, then early commitment to hydrogen fuel is unwise because it risks technological lock-in. Such a commitment would also cost a great deal of money in the hopes of achieving those technological breakthroughs, although just how much is never made clear by those who advocate it.
The appeal of hydrogen arises, in part, because it is a pristine high-technology solution that promises to resolve multiple problems simultaneously by making a clean break from the present, while avoiding long-standing controversies over issues like drilling for oil in Alaska and fuel economy standards. It is an attractive vision that demands serious investigation, but it’s not a sure thing.
Research must not stand in the way of action. We believe that effective public policies to deal with air pollution, climate change and petroleum consumption are needed today, and we work to discover and promote such policies. But hydrogen cars don’t fit the bill. And transportation R&D should be broadly based, and should focus on basic enabling technologies rather than on a rush to deploy hydrogen cars. |
