A switch to sustainable renewable technologies would appear to offer a practi- cal means to control power plant emissions of carbon dioxide, but it will not solve all global problems associated with fossil fuel. What about all the other uses, particularly for automotive power? A more radical solution might be to switch from an economy based on fossil fuel to one based on hydrogen.
Fossil fuels, particularly oil and gas, have become a lynch pin of the global economy because they are so versatile. The fuels are easily stored and trans- ported from one location to another. They can be used in many different ways, too: power stations, internal combustion engines, cookers, refrigerators—all these and more can be powered will one of these fuels.
Renewable electricity sources such as hydropower, solar power, wind power, and biomass can replace fossil fuel in power generation but they cannot easily be adapted to meet all the other uses to which fossil fuel is put. The most salient of these is transportation. One solution that is being followed by vehicle manufacturers is to build electric vehicles that have batteries to provide their energy source. These batteries must then be recharged regularly from the grid, perhaps using renewably generated electricity. This is one vision of a fossil fuel–free future.
Hydrogen offers an alternative. Instead of a battery, a vehicle can carry a supply of hydrogen that it can burn in a conventional reciprocating engine to provide power. Alternatively, the hydrogen can be used to provide energy for a fuel cell that will generate electricity from it. This then provides convergence with battery-powered vehicles.
Hydrogen has the immense advantage that it can replace fossil fuels not just in vehicles but in virtually all applications. Not only can it be used to power an internal combustion engine, but it can be burned to provide heating or cooling. Conventional fossil fuel power plants can burn it to generate electricity. More- over, it can be stored and transported with relative ease. And it is clean. When it is burned, the only product of its combustion is water.
Where would the hydrogen for a hydrogen economy be found? The primary source would be water, and the best way of making it would be by use of electrolysis. Renewable energy power plants would generate electricity and the electricity would be used to turn water into hydrogen and oxygen. The hydrogen would be captured and stored for future use.
This may seem like an expensive and inefficient method of generating fuel. It is, although scientists are working hard to improve the efficiency. For a hydro- gen economy to work today electricity from renewable sources needs to become much cheaper—cheaper probably than all but the cheapest electricity today. Even so, it offers a vision for the future in which life continues in much the same way as it does today. That can be seductive.