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Hydrogen as an energy source |
Hydrogen as an energy source
Hydrogen is considered to be an ideal energy carrier in the foreseeable future.
It can be produced from water by using a variety of energy sources, such as
solar, nuclear and fossils, and it can be converted into useful energy forms
efficiently and without detrimental environmental effects. The only by-product
is water or water vapour.
To better understand hydrogen’s benefits as an energy source, let us first
review some of the present concerns with the structure of the existing energy
economy.
Realities that suggest our current energy economy is not sustainable:
- The demand for energy is growing and the raw materials for the fossil fuel
economy are diminishing. Oil, coal, and natural gas supplies are not replenished
as it is consumed, so an alternative must be found.
- Most of the people who consume fossil fuels don't live where fuels are
extracted. This situation creates enormous economic motivation for the consuming
nations to try to exert control over the regions that supply the fuels.
- Emissions from fossil fuel usage significantly degrade air quality all over
the world, especially in the North-eastern United States. The resulting carbon
by-products are substantially changing the world's climate. For many people and
governments in the world the resulting health and climate impacts are
unacceptable.
- Third world economies are especially susceptible when developing energy
systems needed to improve their economies. The fossil fuel economy puts people
and nations under the undue influence of energy suppliers. This lack of economic
independence is unacceptable to many businesses and governments.
Hydrogen has three basic benefits that address these concerns:
- The use of hydrogen greatly reduces pollution. When hydrogen is combined with
oxygen in a fuel cell, energy in the form of electricity is produced. This
electricity can be used to power vehicles, as a heat source and for many other
uses. The advantage of using hydrogen as an energy carrier is that when it
combines with oxygen the only by-products are water and heat. No greenhouse
gasses or other particulates are produced by the use of hydrogen fuel cells.
- Hydrogen can be produced locally from numerous sources. Hydrogen can be
produced either centrally, and then distributed, or onsite where it will be
used. Hydrogen gas can be produced from methane, gasoline, biomass, coal or
water. Each of these sources brings with it different amounts of pollution,
technical challenges, and energy requirements.
- If hydrogen is produced from water we have a sustainable production system.
Electrolysis is the method of separating water into hydrogen and oxygen.
Renewable energy can be used to power electrolyzers to produce the hydrogen from
water. Using renewable energy provides a sustainable system that is independent
of petroleum products and is non-polluting. Some of the renewable sources used
to power electrolyzers are wind, hydro, solar and tidal energy. After the
hydrogen is produced in an electrolyzer it can be used in a fuel cell to produce
electricity. The by products of the fuel cell process are water and heat. If
fuel cells operate at high temperatures the system can be set up as a
co-generator, with the waste energy used for heating.
When considering the production process, the cost of electricity required for
the electrolysis process is one of the barriers to sustainable energy. Presently
Hydrogen Energy Center is researching wind, solar, tidal and hydro as renewable
energy sources. Wind generators have been significantly improved in recent years
and can produce electricity for $.04 per kWh which is competitive with
conventional means of generating electricity. If the site has adequate wind then
there is substantial potential for a hydrogen production facility. Small scale
hydro holds promise for sites where local production and use are determining
factors. Tidal power is gathering momentum and demonstration projects have been
successful. Improvements with solar arrays of photovoltaic cells continue to
lower the cost of producing electricity. Given the right climate and set of
circumstances solar is a viable solution.
Besides electrolysis the production of hydrogen has been accomplished by a
catalytic reaction of waste aluminium. The end products are hydrogen, and alumina
which can be reused to make aluminium.
Aside from the production of hydrogen, the everyday use and acceptance of
hydrogen must be carefully introduced. Hydrogen today is being used to power
commercial buses both by internal combustion engines burning a combination of
hydrogen and other fuels and solely by hydrogen used in fuel cells. Hydrogen is
used in many commercial applications from welding metal to dying fabrics to
making electronics, plastics and fertilizers. When a renewable economically
viable production process of hydrogen can be achieved the advantages will be
spread out to many industries. Some of the proving grounds for various
production methods can be locally developed to provide hydrogen for these
industries.
Renewable energy sources are often limited for commercial use due to their
intermittent availability. Sometimes the wind doesn’t blow or the sun doesn’t
shine, so hydrogen can be the critical link used as a storage medium to supply
power during these periods. Hydrogen can be used as a mobile source of power for
transportation by being compressed and stored in small tanks for applications
similar to gasoline or propane.
With increasing use of hydrogen and technical advances, the costs of production,
distribution and product manufacturing will become increasingly affordable. By
continuing to build partnerships between business, government, universities and
non-profit organizations hydrogen could be the foundation of a sustainable energy
economy.
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