18-8 Hydrogen

Can Hydrogen Replace Oil? Goodbye Oil, Smog, and CO2 Emissions, Hello Hydrogen

When oil is gone or what is left costs too much to use, how will we fuel vehicles, industry, and buildings? Many scientists and executives of major oil companies and automobile companies say the fuel of the future is hydrogen gas (H2).

Proponents envision using hydrogen in energy-efficient and nonpolluting fuel cells to provide electricity for running buses, cars, houses, and other buildings. Widespread use of hydrogen could provide most of the energy needed to run an economy. Proponents believe that such systems can be available by 2020–30 and then be phased in during this century.

There are three problems in turning the vision of widespread use of hydrogen as a fuel into reality:

  1. First, hydrogen is chemically locked up in water and organic compounds such as methane and gasoline.

  2. Second, it takes energy and money to produce hydrogen from water and organic compounds. In other words, hydrogen is not a source of energy. It is a fuel produced by using energy—lots of it.

  3. Third, fuel cells are the best way to use hydrogen to produce electricity, but current versions are expensive.

Most proponents of hydrogen believe that if we are to get its very low pollution and low CO2 emission benefits, the energy used to produce H2 by decomposing water must come from low-polluting, renewable sources that emit little or no CO2. The most likely sources are electricity generated by wind farms, hydropower, geothermal energy, solar cells (when their prices come down), or biological processes in bacteria and algae.

Once hydrogen is produced we must have a way to store it for use as needed. Here are some of the ways that scientists and engineers are investigating for hydrogen storage:

  • Store it in compressed gas tanks

  • Store it as more dense liquid hydrogen

  • Store it in solid metal hydride compounds

  • Absorb hydrogen gas on activated charcoal or graphite nanofibres

Hydrogen is highly flammable and burns with an invisible flame. But it may be safer than gasoline for two reasons:

  1. When this light gas is released it quickly disperses into the atmosphere instead of posing a fire hazard by puddling on the ground like gasoline.

  2. Metal hydrides, charcoal powders, graphite, nanofibres, and glass microspheres containing hydrogen will not explode or burn if a vehicle’s tank is ruptured in an accident.

Will Widespread Use of Hydrogen Decrease Protective Ozone in the Stratosphere? Probably Not with Careful Use of Hydrogen

In 2003, researchers Tracey Tromp and John Eiler at the California Institute of Technology published a paper that sent shivers down the spines of hydrogen proponents. On the basis of computer models, they projected that if hydrogen eventually replaces all fossil fuels, hydrogen gas leaking from such a global system could rise into the stratosphere, be oxidized to form water vapour, increase depletion of the ozone layer over Antarctica during part of the year, and allow more harmful ultraviolet radiation to reach the Earth’s surface

Most press reports failed to note that the authors and other scientists gave several reasons why this problem may not be as serious as this preliminary study suggest:

  1. The authors’ model is based on still poorly understood atmospheric chemical interactions involved in the hydrogen fuel cycle. This includes the possibility that excess hydrogen in the troposphere would be absorbed by soils or removed by reactions with other chemicals in the atmosphere before most of it can reach the stratosphere.

  2. The assumptions about leakage of hydrogen may be much too high because of improved technology and vigilance to reduce such leaks.

  3. Global efforts are in place to drastically reduce ozone depletion in the stratosphere by 2050, mostly from chlorine and bro- mine compounds we have been putting into the atmosphere.

What Are Some Possible Potholes in the Hydrogen Highway? Getting Diverted

While we are working to develop a renewable-energy hydrogen revolution, energy analysts call for us to focus on two more immediate and important priorities. One is the related challenge of sharply reducing our emissions of carbon dioxide and other greenhouse gases to help slow global warming and climate change. Analysts suggest that we do this by:

  1. Greatly improving fuel-efficiency standards for motor vehicles through a combination of mandatory government standards and much higher taxes on gasoline and diesel fuels, coupled with a corresponding reduction in income and payroll taxes.

  2. Providing large tax breaks for people and businesses using fuel-efficient cars, buildings, heating systems, and household appliances and keeping such breaks in place for at least 25 years.

  3. Investing much more in public transit running on less polluting natural gas as an alternative to the car and using at least half of the money collected by gasoline taxes to promote this change.

  4. Greatly increasing research and development subsidies for development and phasing in of renewable-energy technologies, such as wind power, solar cells, biomass, and geothermal energy, and providing such subsidies for at least 25 years.

  5. Providing very large tax breaks for people and businesses using renewable-energy technologies and keeping such breaks in place for at least 25 years.