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Myth 1- Renewable hydrogen is too costly.
Fact: Renewable energies are becoming less expensive as rapidly as fossil fuels are becoming more expensive. We cannot expect, and do not suggest, replacing all of our fossil fuels with renewable energy by January 1, 2006. We do expect, and do suggest, that we start now. Even a slow transition requires that we pursue our plan with a sense of purpose.
In 1999, hydrogen derived from natural gas cost $.65 per kilogram, gasoline was less than $1.00 per gallon, and electricity from wind power cost $0.10 per kilowatt-hour. In early 2005, hydrogen derived from natural gas costs $1.20 per kilogram, gasoline is hovering at and above $2.00 per gallon, and electricity from wind power is approaching $0.04 per kilowatt-hour before subsidies. Using present-day electrolysis technology, we can manufacture wind-powered hydrogen at prices less than $4.00 per gasoline gallon equivalent (roughly a kilogram). The per-gallon cost of gasoline and the per-kilogram cost of renewable hydrogen are steadily approaching the same figure. |
Myth 2- Making hydrogen is inefficient.
Fact: In competitive electricity markets, it may make good economic sense to use hydrogen as an electricity storage medium. True, the overall round-trip efficiency of using electricity to split water, making hydrogen, storing it, and then converting it back into electricity in a fuel cell is relatively low at about 45% (after 25% electrolyzer losses and 40% fuel-cell losses) plus any byproduct heat recaptured from both units for space-conditioning or water heating. But this can still be worthwhile because it uses power from an efficient baseload plant (perhaps even a combined-cycle plant converting 50-60% of its fuel to electricity) to displace a very inefficient peaking power plant (a simple-cycle gas turbine or engine-generator, often only 15-20% efficient).
This peak-shaving value is reflected in the marketplace. When the cost of peak power for the top 50-150 hours a year is $600-900/MWh, typically 30-40 times the cost of baseload power (~$20/ MWh), the economics of storage become quite interesting. Distributed generation provides not only energy and peak capacity, but also ancillary services and deferral of grid upgrades. Hydrogen storage can also save power-plant fuel by permitting more flexible operation of the utility system with fuller utilization of intermittent sources like wind.
Once all the distributed benefits are accounted for, using hydrogen for peak storage may be worthwhile, particularly in cities with transmission constraints (such as Los Angeles, San Francisco, Chicago, New York City, and Long Island). Such applications may be able to justify capital costs upwards of $4,000/kW. Another attractive use of large-scale hydrogen storage would be in places like New Zealand or Brazil, whose hydroelectric systems have too little storage (12 weeks in NZ) to provide resilience against drought - but whose snowmelt or rainy seasons provide cheap surplus hydropower that could be stored as hydrogen, even in old gas-fields. |
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Myth 3- Hydrogen is just too dangerous.
Fact: The hydrogen industry has an great safety record spanning more than half a century. Any fuel is hazardous and needs it's care, but hydrogen's hazards are different and generally more easily handled than those of hydrocarbon fuels. In the vast majority of cases, leaking hydrogen, if lit, will burn but not explode. And in the rare cases where it might explode, its theoretical explosive power per unit volume of gas is 22 times weaker than that of gasoline vapor. It is not, as has been claimed, "essentially a liquid or gaseous form of dynamite."
Hydrogen is four times more diffusive than natural gas or 12 times more than gasoline fumes, so leaking hydrogen rapidly disperses up and away from its source. If ignited, hydrogen burns rapidly with a non-luminous flame that can't readily scorch you at a distance, emitting only one-tenth the radiant heat of a hydrocarbon fire and burning 7% cooler than gasoline. Although firefighters dislike hydrogen's clear flame because they need a viewing device to see it in daylight, victims generally aren't burned unless they're actually in the flame, nor are they choked by smoke.
One videotaped test of a standard passenger car compared a hydrogen leak with a gasoline leak. In the first test, a hydrogen leak was created, assuming a very unlikely triple failure of redundant protective devices. The leak discharged the entire 1.54-kg hydrogen inventory of the fuel-cell car, but the resulting vertical flame plume raised the car's interior temperature by 1-2C° (0.6-1.1 F°). The passenger compartment was unharmed. In the second part of the test, gasoline leaked from a 1.6-mm (1/16") hole in the fuel line. The resulting explosion gutted the car's interior and would have killed anyone trapped inside. Because the hydrogen-leak test didn't damage the car, the gasoline part of the test was conducted using the same car. Had the gasoline portion of test been done first, a second car would have been required for the hydrogen leak test.
Contrary to a popular misunderstanding, these safety attributes of hydrogen actually helped save 62 lives in the 1937 Hindenburg disaster. An investigation by NASA scientist Dr. Addison Bain found that the disaster would have been essentially unchanged even if the dirigible were lifted not by hydrogen but by nonflammable helium, and that probably nobody aboard was killed by a hydrogen fire. (There was no explosion.) The 35% who died were killed by jumping out, or by the burning diesel oil, canopy, and debris (the cloth canopy was coated with the primary chemical components of rocket fuel which ignited due to discharge of static electricity when the dirigible docked). The other 65% survived, riding the flaming dirigible to earth as the clear hydrogen flames swirled harmlessly above them. |