The Future of Energy
World reserves of fossil fuels are finite. Looked at chemically, there is only a finite, yet large, amount of oxygen in the atmosphere to even burn fossil fuels. What does this mean for the future of energy use? It’s fairly obvious that if humanity is going to keep using energy at an accelerated rate, new sources for this power must be found.
The prime source of power in the universe is the fusion reaction that occurs in stars. This energy streams down continuously on earth from the sun and costs nothing. Solar energy keeps the earth from being a dark, frozen rock in the depths of space. While this source of energy is not as concentrated as the energy derived by chemically combusting a fuel, it is available everywhere. The only thing we need to do to harvest this energy is to collect it somehow.
Photovoltaic solar cells convert sunlight directly into electricity. They are however, not very efficient. Even the best solar cells only convert 27% of the light that falls on them into electrical power. Still, even though there is loss of energy in this technology, the energy produced is easily stored and used. Solar cells have a distinct drawback. They are very costly to produce, both in terms of money and energy. Still, it would be possible to power the entire earth if enough solar cells were made and distributed. They last for a long time and have no moving parts. The panels would have to be cleaned occasionally, and any defective cells replaced. The only thing keeping people from powering this whole planet on solar electricity is the cost.
Wind and weather are other manifestations of solar energy on the earth. Wind turbines can produce power, when the wind blows, but it takes some machinery to accomplish this. Moving parts wear out. Some days the wind does not blow. Hydroelectric power plants are more reliable. Rainwater stored in reservoirs falls through a turbine and spins a generator. This technology has been used for many years. Even ancient people used water wheels to grind grain. The limits to hydroelectric power are that there are limited places on earth where these dams and power stations can be built. They require rainfall and the control of vast quantities of water. Dams use significant amounts of concrete and steel and take considerable effort to build. Still, once built and properly maintained, there is no reason a hydroelectric station should not last for many years, perhaps even centuries.
Heat from the interior of the earth can be used to produce steam and spin turbines and generators. In volcanically active regions, like Iceland, considerable potential for such geothermal power generation is available. There are a limited number of regions on earth where the interior heat of the earth is close enough to the surface to supply energy for these stations. Still, deep drilling and good design can make this source of energy more widely distributed. Geothermal heat comes from the decay of radioactive elements in the interior of the earth.
Nuclear power is one source of energy that is being used to power society. Nuclear reactors run on the fission of Uranium 235 or Plutonium in carefully-designed and fail-safed power stations. There is a lot of Uranium available for use in reactors. In some reactors, such as the Canadian Candu design, it is not even necessary to enrich the fuel. Of course, like anything else, there are problems with nuclear energy. Reactors, because of the neutron flux from fission, create radioactive waste. This material can be hazardous for thousands of years. Stable underground storage and responsible handling of radioactive waste is one of the necessary factors that must be considered in any plans to derive power from nuclear fission.
Scientists have been working on designing a fusion reactor for over 50 years now. There is much potential for nuclear fusion power, but the task itself is extremely difficult. It takes high temperatures and pressures to produce fusion. In a fusion bomb, these conditions are produced by detonating a fission bomb in the vicinity of fusion fuel. This approach is not useful in a power reactor. Large vacuum chambers with powerful magnets are used to contain the compressed and heated hydrogen isotope plasma in such devices as the Tokamak. Fusion reactors also produce neutrons, so radioactive waste is also a factor in their operation.
There are several other schemes for extracting energy from the environment. Ocean currents, waves, and tides have all been harnessed to provide electrical power. Many crops such as sugar cane, corn, soybeans, and palm oil are grown to produce biofuels. Plants are not as efficient as solar cells at harvesting energy from sunlight, but they have been doing this for billions of years. One of the latest areas of research is into the use of algae as a source for oil for biodiesel. There is still a lot of coal in the ground, and it has been estimated that the world could operate at present energy consumption rates for the next 300 years on just this source of energy.
As long as people live in modern society, they will continue to use energy at ever-increasing rates. Instead of waiting for supplies of fossil fuels to run out, people are actively working on alternative technologies for powering the earth. As fuel prices increase and the cost of fossil fuels goes up, the alternative, renewable sources of power will become more economically feasible. If industry and government do not realize the finite nature of fossil fuel reserves and begin to switch over to sustainable sources of energy, there will be a crisis at some time in the future that will be disastrous for humanity. It is a simple thing to get power from the sun, which drives all life on earth. It is stupid to waste the resources we have now and not work on ways to replace them with technology that will last for all time in the future.
