Tidal energy has been deemed by many as a reliable source of renewable energy. The main advantage of harnessing renewable power with tidal energy is the predictability of ocean tides, as opposed to the varying conditions that affect the capacity of wind and solar power. Some of the common infrastructure used with tidal energy includes tidal turbines and tidal barrages. Tidal turbines are very similar to wind turbines, but the blades are usually much smaller. For the most part, the use of tidal turbines follows the same engineering concepts of wind turbines: renewable forces spin the turbine, the turbine is connected to a generator which produces electric current and voltage, a transformer steps up the voltage to prevent line losses, and finally the power is transmitted to an electric grid, as shown in the figure below. Tidal barrages tend to be more complex than tidal turbines, and they also cause more damage to the environment. The concept behind barrages is to use a dam-like structure to capture water during high tide and then release the water through generator turbines that produce electricity. There is a ton of potential for future use of renewable tidal energy, but certain characteristics of this technology, such as high capital costs, environmental damage, and the fact that tides only flow for ten hours a day, tend to limit the number of large scale commercial projects .
However, The Crown Estate, one of the United Kingdom’s property portfolios, recently awarded its first commercial tidal energy lease . The Crown Estate gained the power to lease offshore renewable energy development sites through the passing of the UK’s Energy Act of 2004 . The lease includes projects that are proposing to supply 1.2 GW of energy capacity located throughout ten different sites off the coast of Scotland. One report quoted the UK’s Energy Minister, Lord Hunt, saying these new tidal projects could reduce 70 million tons of greenhouse gas emissions by 2050 .
This energy project isn’t the UK’s first go around with commercial-scaled wave and tidal energy. SeaGen, a 1.2 MW tidal energy converter which began operation off the coast of Northern Ireland in July 2008, has delivered over 800 MWh of power into the UK’s electric grid . For the most part, the emergence of these tidal energy projects are directly related to the UK’s long-term energy goals addressed in both the Climate Change Act of 2008 and the UK Energy Act of 2008. These energy goals consist of creating competitive energy markets in the UK, maintaining affordable and reliable energy to heat homes, and reducing carbon emissions by 80% of 1990 levels by year 2050 .
The use of renewable energy technology, such as tidal energy, seems to be an obvious way for the UK to reach their energy goals, especially in their attempt to decarbonize their electric generation. Hopefully, we’ll begin seeing large-scale tidal energy projects off the coast of the US in the future because some reports state that Washington, Alaska, and Maine have the potential to compete with the energy production of the UK’s coastline.