The Hydrogen Economy

 The term hydrogen economy has been coined to describe a system in which hydrogen is produced from renewable energy and used in place of hydrocarbon fuels.

The two most promising carbon-free and renewable energy resources are solar and wind energy, but these forms of energy are intermittent and therefore can meet only a portion of primary energy demand. Furthermore, wind and solar energy often do not coincide with the locations of large energy demand.

Hydrogen Economy as Energy Currency

One way to resolve the space–time mismatch between the supply of solar and wind renewable energy on the one hand, and energy demand on the other, would be to use hydrogen (H2) as an energy currency that would complement electricity. Electricity is an energy currency, but it cannot be stored on a large scale and cannot be used in all end-use applications.

Hydrogen can be produced from electricity (by electrolysis), transmitted long distances and stored, and either converted back to electricity (using fuel cells) when and where needed, or used in place of fossil fuels in all other end-use applications where fossil fuels are currently used. Electricity and hydrogen would be the two interchangeable energy currencies in an energy system based entirely on renewable energy.

Hydrogen Economy Challenges

Hydrogen isn't an energy source – it's an energy carrier, like a battery. You have to make it and put energy into it, both of which take energy. Ninety-six percent is made from fossil fuels, mainly for oil refining and partially hydrogenated oil. In the United States, ninety percent is made from natural gas, with an efficiency of %, which means you've just lost 28% of the energy contained in the natural gas to make it (and that doesn't count the energy it took to extract and deliver the natural gas to the hydrogen plant).

The hydrogen economy has enormous technical and societal appeal as a potential solution to the fundamental energy concerns of plentiful supply and minimal environmental impact. The success of the hydrogen economy comes down to how the market reacts: does hydrogen technology provide more value than today's fossil fuels? Although the market will ultimately drive the hydrogen economy government investments in R&D are critical in establishing goals, providing research support, sharing risk and establishing incentives in order to prime the emergence of a vibrant, market-driven hydrogen economy.

Technological Milestones Needed for Hydrogen Economy Success

Incremental advances of present technology provide low-risk commercial entry into the hydrogen economy. Those advances include improving the yield of production for lower cost and efficiency; improving the strength of container materials for high-pressure storage of hydrogen gas; and adapting internal combustion engines to burn hydrogen. To increase the the energy supply and decrease carbon emission and air pollution, however, the hydrogen economy needs to go beyond incremental advances. Hydrogen must replace fossil fuels through efficient production using solar radiation, thermochemical cycles to split water. Hydrogen must be stored and released in portable solid-state media and fuel cells that convert hydrogen to electrical power and heat must be put into widespread use.

Achieving these technological milestones while satisfying the market discipline of competitive cost, performance and reliability requires technical breakthroughs that only come from intensive research. Without these advancements the hydrogen economy is simply a pipe dream.

 The Hydrogen Economy copyright 2011