Hydropower is one of the oldest methods of producing energy. Long before steam power was used for energy production people were using paddle wheels in rivers and streams to turn motors. In 1950 hydropower accounted for 30% of energy production. However since then there has been a drastic decline in hydropower and it currently only represents 7.3% of energy production in the United States. However the focus on renewable sources of energy has resulted in hydropower energy production being forecast to increase by 3.1% per year for the next 25 years. Not only is hydropower a completely renewable source it also has incredibly high efficiency. It averages around 90% efficiency. To put this into perspective solar panels generally produce electricity at an efficiency rate between 11 and 15%.
When I think of hydropower the first thing that comes to mind are large hydroelectric dams. The problem with these dams is that they require blocking a river to store up potential energy. This stored energy can then be turned into kinetic energy as the water travels through turbines to produce energy. One of the main concerns of hydroelectric dams is the impact they can have on the environment up and downstream. These dams often cause reservoirs to build up flooding a large area and destroying natural habitats upstream. Hydroelectric dams also have consequences downstream that are often overlooked for example restricting the flow of a river can reduce the oxygen concentration of the water which makes it harder for some species of fish to survive.
Despite these drawbacks of hydroelectric dams there is definitely an argument for them being a part of the future of energy production due to their efficiency.
There is another form of hydropower that addresses some of the issues that hydroelectric dams have. Under water tidal turbines run on a similar principle to hydroelectric dams, however the big difference between the two is they don’t rely on restricting the flow of water to generate electricity instead they run of the natural tides of water on the sea bed.
Just like hydroelectric dams, tidal turbines are also a highly efficient and consistent sources of energy because not being dependent on the weather they remain constant and can be scheduled. Although tides can be predicted unlike dams they cannot be controlled to provide a round the clock source of energy. As a result, tidal power plants require an effective energy storage solution to provide round the clock power which can significantly increase the start up cost.
Underwater turbine installed off the shore of Scotland
In a recent report Scotland has committed to generating 100% from renewable sources and to decarbonise its energy production by 2030. Scotland is perfectly suited to tidal turbines due to their fast flowing seas. In May 2020 they installed their first turbine off the island of Eday. This test was a success and has led to the approval of many more turbines to be installed off the shore of Scotland and are set to play a huge role in achieving their goal of 100% renewable energy by 2030.
https://www.eia.gov/tools/faqs/faq.php?id=427&t=3
https://www.usbr.gov/power/edu/pamphlet.pdf