When Green Energy is Blue Energy: Power From the Sea
However, some other countries use oil more heavily for electricity than we do. For example, until recently Mexico generated more electricity from oil than from any other fuel. The worldwide savings in oil from green sources of electricity, while small compared to worldwide use of oil for transportation, is larger than it would appear from just the United States’ experience.
Furthermore, according to both peak oil theory and common sense, one day oil will start to run out. When it does, not only will oil prices increase, but it will become more economically attractive to convert other fossil fuels, such as coal, into oil. Anything that reduces fossil fuel use for electricity will extend total fossil fuel, including oil, reserves. That means that if you use fossil fuels for any purpose—and that includes home heat as well as transportation, paving and asphalt, fertilizer, and plastics—you benefit from technologies that replace fossil fuels for electrical generation.
Plus, of course, there are the advantages that accrue from reducing carbon emissions. The less carbon emitted in generating electricity, the more carbon emissions are “preserved” for other uses, such as transportation or heat. If we can reduce the carbon footprint of our electric power, we need to worry less about reducing our footprint in other ways. Therefore, green or blue electrical energy saves carbon emissions for other purposes.
How the Oceans Can Be Used to Generate Electricity
Broadly speaking, there are four main sources of ocean power:
- Currents—tapping the energy in ocean currents, such as the Gulf Stream
- Waves—tapping the energy in waves, especially breaking waves near the shore
- Tides—tapping the power of the tides
- Thermal—tapping the energy available from the temperature difference between warm surface and colder subsea waters
So many companies and universities are developing ocean power that, while we’ll discuss a representative sample of ocean power devices, this is not an exhaustive, up-to-the-moment survey—such a survey would quickly become out of date.
Current Events: Using Ocean Currents
Ocean currents are like rivers without beds or banks—vast flows of water through more-or-less predictable “channels” within the greater ocean. The best known (at least in America) current is the Gulf Stream that flows up the East Coast, bringing warm, tropical water. Since ocean currents resemble both rivers and wind (which are air currents), their power can be tapped in ways similar to more conventional hydroelectric or wind power: simply anchor turbines in the flow. As the water passes the turbines, it spins their blades, generating electricity.