Hydrogen Won't be our Energy
Published on Sunday, June 19, 2005 by the Daily Camera (Boulder,
Hydrogen Won't be our Energy Savior
It takes more energy to produce than it yields
by Frank Kreith and Ron West
Hydrogen is widely viewed by environmentalists, as well as by many
large corporations, as a panacea to air pollution, global warming and
shrinking petroleum supplies. This view has been endorsed by President
Bush who, in his 2003 State of the Union Address stated, "The
first car driven by a child born today could be powered by hydrogen
and pollution free."
Hydrogen-powered cars and trucks that use fuel cells to drive electric
motors instead of internal-combustion engines could potentially
eliminate tail-pipe pollution and dependence on foreign oil. But
hydrogen is not an energy source. It is only an energy carrier that
must be produced from a primary energy source, such as natural gas,
coal, nuclear fuel, wind or solar radiation.
There are two main methods for making hydrogen. The dominant
commercial method uses natural gas and steam to produce ultimately
hydrogen and carbon dioxide. In this process, called steam reforming,
less than 80 percent of the input energy is left in the hydrogen; then
another 15 percent or more is lost converting the hydrogen to liquid
or compressed gas. Thus, at most only two-thirds of the original
energy ends up as useful hydrogen. Moreover, natural gas is an
expensive non-renewable fossil fuel that is in short supply.
Furthermore, natural gas has many other important uses, such as
heating our homes and serving as a feedstock for many chemicals.
The other main way of making hydrogen is by electrolysis. This process
is straightforward, but costs three times as much as steam reforming
to make the same amount of hydrogen. It uses an electrolyzer, in which
a current is passed through water, to split the water into hydrogen
An electrolyzer is essentially a fuel cell operating in reverse. But
the electricity must first be produced from a primary energy source.
At the very best, only half as much electricity can be obtained from
the hydrogen as is consumed to make it. If electricity from the grid
were used to produce the hydrogen, over 50 percent of the electric
energy would come from coal-fired power plants, which are the most
polluting source. If hydrogen produced by electrolysis were used as
fuel, the president's statement should be amended from a
"pollution-free car" to a "pollute elsewhere
Environmentalists recommend using solar energy or wind to generate
electricity for a "renewable hydrogen economy." We have been
staunch supporters of renewable energy for half a century and recently
some renewable options have achieved economic competitiveness in
favorable locations. But the renewable hydrogen path to electricity
would more than double the cost of electricity, and probably would set
back deployment of renewable electric power for decades. Wind, solar
and biomass should be used for heat and power generation, not for
The nuclear industry argues that reactors are the preferred option to
make hydrogen for fuel cells, because they do not generate greenhouse
gases. If the public is willing to accept the risks associated with
transport and storage of nuclear waste, nuclear power is an available
option. But, using nuclear-generated electricity to make hydrogen,
from which to make electricity, is a waste of energy and money.
Petroleum engineers predict that worldwide petroleum production will
peak in 10 to 30 years. Once production begins to decrease, it will be
necessary to supplement oil with some other fuel or to reduce
consumption by conservation measures, such as increased mileage of the
vehicle fleet and using mass transport. Both of these changes will
take time, and we must begin to plan now.
Fortunately, there are several technologies to reduce petroleum
consumption. The most obvious is to increase the mileage of the auto
and pickup fleet. This can be achieved by building smaller cars and
hybrid vehicles, such as the Toyota Prius and Ford Escape. Hybrids use
a small gasoline or diesel engine that always runs at maximum
efficiency and charges on-board batteries when it produces excess
power; when needed, the hybrid draws energy from the batteries to run
an electric-drive motor.
Battery technology has improved enormously in the past decade, and
state-of-the-art batteries in hybrids increase mileage. But even
greater reductions in fuel consumption and pollution can be achieved
with "plug-in," electric-gasoline or diesel hybrids, by
charging their batteries overnight when excess electrical capacity is
available. Demonstration-model plug-in hybrids are on the road and
need no new technology for their large-scale deployment. It has been
estimated that plug-in hybrids could approach and perhaps even exceed
100 miles per gallon of fuel used. It is also possible to replace
petroleum-based fuels with liquid fuels made from coal or biomass,
further reducing our dependence on imported petroleum.
There are no huge technical obstacles to making hydrogen and using it
as a fuel. But a hydrogen economy would be more expensive and use more
primary energy than other options. Moreover, it would require many
hundreds of billions of dollars to build a storage and transport
infrastructure. We should not accept President Bush's statement that
hydrogen will replace oil without examining other options that are
more economical and for which the technology and infrastructure
Frank Kreith and Ron West are retired engineering professors
from the University of Colorado, Boulder, and both live in Boulder.
Kreith also served as Branch Chief at the Solar Energy Research
Institute for 10 years.