As carbon-based energy supplies are dwindling, other sources of energy are being explored
In general, an alternative energy is a source or method for deriving energy that is not based on traditional carbon fuels such as oil, coal, or wood.
Our society is currently dependent on carbon fuels. However, carbon fuels, in particular oil, are becoming increasingly scarce, and are often cited as aggravating conflicts if produced in a politically unstable country. The combustion of carbon fuels also produces pollution, and are the most likely culprit for global warming. The search is on for viable alternative energies.
Two Problems in One
Energy sources are required for two different situations. In order to solve the energy crisis, both problems must be addressed.
Homes, businesses, and factories, are all stationary and all require electricity. In the industrialized world, buildings are hooked up to an energy grid, and often consumers have no choice about what energy source they are using.
Mobile energy consumption is the other side of the problem. Vehicles on land, sea, and in the air all require an energy source. Here the sources can vary greatly, and consumers have an increasing number of choices. However, fossil fuels still predominate here.
Renewable vs. Non-renewable
There are two types of energy source, renewable sources that are easily replenished, and non-renewable sources that slowly become depleted and cannot be replaced. Technically, fossil fuels are renewable sources, but since they are formed from the compression of decaying biomass over millennia, they are extremely slow to replenish.
Non-renewable Sources
- Petroleum (oil, natural gas)
- Coal
- Uranium (for nuclear reactors)
Non-renewable sources are generally fuels that must be mined from the ground. These fuels produce energy very efficiently and relatively cheaply in comparison to other sources. They also have a tremendous environmental impact. Mining itself is an energy intensive activity and can potentially destroy local ecology is mismanaged. The burning of fuels releases carcinogens, greenhouse gases, and particulate pollutants (dust) that can cause health problems and affect the climate. Non-renewable sources are popular because they are rather easy to obtain and require a low technological investment to exploit.
Renewable Sources
- Solar
- Wind
- Tidal
- Hydroelectricity
- Biomass
- Hydrogen
- Geothermal
Renewable energy is vastly more abundant that non-renewable sources. Unfortunately, on average, these sources are much more difficult to exploit. Hydroelectricity, tidal, and geothermal sources in particular require building expensive facilities to harvest the energy. These facilities, while efficient and clean, may have adverse effects on the surrounding environment, such as disrupting marine ecologies or flooding forest habitat.
Some renewable sources require a large amount of energy to produce. Hydrogen, which is being touted at as replacement fuel for vehicles, requires about 50% more energy to produce than it ultimately gives. If it is produced using other renewable sources it is a good, clean-burning, mobile substitute for fossil fuels in vehicles.
Biomass also requires a large amount of energy to produce, but this is largely solar energy. Burned biomass still produces similar pollutants to fossil fuels, though overall it is carbon-neutral - locking up carbon and releasing it within an extremely short period of time. Widespread use of biomass should not exacerbate global warming, though when plants are grown to produce fuel exclusively, the procedure competes with production of food crops.
The solar energy raining down on the Earth from the Sun in one minute can provide for the energy needs of the entire planet for about a year. We just don't have the technology to tap into that efficiently. Even fossil fuels are essentially solar energy gathered by long dead plants and locked up from the past. Solar energy is the safest, most available energy source. Ideally, it could replace other sources in feeding the global energy grid.
Efficiency
One factor that is often grossly looked over in the debate over energy is energy efficiency. Changing the way we use energy by being more efficient and producing and consuming more efficient energy devices could have the greatest short-term impact on resolving the energy crisis.
