Energy is a weak point in our economy. Fossil fuels are cheap (honest!) and convenient, but can cause unacceptable pollution. Some are running out frighteningly fast and may be better for other uses than being burned. However, oil in particular offers unique qualities not easily replaced. It has a remarkably high energy density–one litre of gasoline contains as much energy as about 250 kg of lead-acid batteries. This makes it a portable energy source without equal. Our current technology has no alternatives on the horizon. Once oil runs out (the peak of production is expected around 2020), our societies are in for a dramatic change.
However, a large portion of industry does not run on oil, but on electricity. Much of this is generated from burning fossil fuels, such as natural gas and coal. What are the alternatives for generating electricity? There is much talk of the “hydrogen economy”, but over 90% of the world’s hydrogen comes from fossil fuel. There are really very few primary sources of energy.
Moving water has been used for centuries, previously in waterwheels, and now in huge turbines. However, dams can only be put in certain locations where the geography is acceptable, so available locations for further development are becoming scarce. The last and largest major hydroelectric project is the Three Gorges in China. This project has been controversial because of the displacement of people, destruction of environment and habitat, loss of cultural sites and damage to the river up- and downstream, as well as to coastal areas. This was justified on the basis that it would supply up to 10% of China’s energy needs, but with the growth of China’s demand over the period of construction, it is expected that it will supply barely 3% of the country’s needs at most. There are few new major hydroelectric projects planned, and they will not meet the world’s expanding needs.
Coal has been a traditional source for many centuries, whether for heat alone or to drive trains and steam turbines. There are new technologies to produce power much more cleanly from coal, as well as technologies available to convert coal to gaseous or liquid forms. These forms can be used as substitutes for natural gas or petroleum products. China is at the forefront in instituting these technologies.
Wind power has been touted as an environmentally friendly, renewable energy source. However, wind power installations can only be constructed in locations where wind direction and speed are relatively constant–after all, you cannot dam air. Wind turbines are not without environmental impact, as they can affect weather, wind patterns and soil drying. It seems unlikely that wind power will supply a significant portion of our increasing demand.
Nuclear fission has been in use for several decades. These power plants use the heat generated by the nuclear fission reaction; electric power is generated in turbines powered by steam generated from this heat. Some countries are abandoning it (e.g., Sweden), while others are embracing it (Finland). There are over 400 nuclear power plants in 31 countries, generating about 17% of the world’s electricity. Although it has often been seen as a dangerous power source, in reality it is the cleanest, least environmentally damaging and most efficient source of power currently (forgive the pun) available. It is safer than the next safest form of power generation by an order of magnitude.
Nuclear fusion is the source of the energy that powers the stars. However, it has been 20 years away from commercialization for almost 50 years now. The equipment required to produce fusion is massive, expensive and, as yet, energy negative–it uses more energy than it produces. As with nuclear fission plants, fusion plants would use steam turbines to generate electricity. Much more development is needed to bring the first nuclear fusion plant into production.
There are other primary energy sources–solar, geothermal, oceanic thermal–all suffering from various problems. New demands for electric power will likely have to be met with more nuclear power plants and clean-burning coal, as the only viable sources. However, even with nuclear and coal, once the oil runs out, we will have a difficult time replacing it.
Freelance writer Dan Davies can be reached at [email protected]