Tidal power is a strong, reliable and predictable source of renewable energy. The idea revolves around placing large underwater turbines in places with high tidal movements. The gravitational interaction between the earth, moon, and the oceans causes tides to cycle back and forth twice each day. Having turbines in the tidal flow allows tidal power stations to basically extract energy from the effects of the moon.
Historically tidal power has been around for hundreds of years. It has been used in both early Europe and the early American settlements to power mills for grinding flower and other grains. Tidal power is not as well known or well utilized as many other alternative energy sources like solar power or wind power. One of the main reasons for this is the initial cost of tidal power. A main disadvantage of utilizing tidal power is the very expensive start up cost. This makes the return on investment long term. Tidal power plants must also consider effects on estuaries, sea life migration, and local ecosystems. French engineers have also predicted that if the use of tidal power on a global scale was brought to high enough levels, the Earth would slow its rotation by 24 hours every 2,000 years.
There are some significant advantages to using the tides for energy production though. The predictability of ocean tides, makes tidal power one of the most reliable sources of alternative energy. When solar power cells don’t see the sun, and when wind power doesn’t have a wind they don’t work. Tidal turbines can always be counted on day or night and regardless of the weather. Additionally, most of our world’s population lives in coastal areas. This means that tidal power will naturally be in close proximity to the electric grid and existing infrastructure. Another advantage is that tidal power technology is situated on the sea floor avoiding the land-use and visual impact considerations associated with many other forms of power generation.
Most believe that in order for tidal power to work successfully it requires a tide difference of at least 5 meters (16ft). Studies show that there are many favorable places for tidal power generation in both the Pacific Northwest and the Atlantic Northeast. Indeed the first commercial tidal power project is launching just off the coast of Eastport, Maine. The TidGen Cobscook Bay project places turbines in 50-100 feet deep water to take advantage of the 100 billion tons of water that flow in and out of Cobscook Bay each day. Initially the turbines will generate enough power to support between 75 and 100 homes. Eventually enough turbines will be installed to generate 3MW of power. This is enough power to support the needs of over 1,000 homes and businesses.
Unfortunately tidal power isn’t a perfect fit for every market. But when you weigh the pros and cons tidal power does have the potential to outperform solar and wind power because it can consistently supply energy at predictable times and levels. The ability to precisely calculate the tidal cycles and therefore energy production is enormously desirable to energy suppliers who have to guarantee to meet electrical demand. Beyond providing clean, local and renewable energy, tidal power development has the potential to reduce a region’s carbon footprint and create thousands of new green jobs.