Hydroelectricity seems to be our most effective option in achieving a sustainable energy mix. It makes up the largest share of energy production among renewables, accounting for approximately 16% of global output. Over time, hydroelectricity produces significantly less greenhouse gas emissions than conventional fossil fuels. However, the main means of producing hydroelectricity, through dams, seriously damages the surrounding environment. For these reasons, it is important to consider both the benefits and the tradeoffs of hydroelectricity in the world’s energy mix.
Hydroelectricity, in the long run, is significantly greener than fossil fuels. It has the benefit of being a zero-emission means for energy production and, since only water is being used in the process, it does not create any waste products. The water that is contained can also be used for drinking, sanitation and industrial processes. In the event of a power failure, reservoirs can be used to wind up the turbines and begin providing immediate power. With large scale dams, sections of river bed can be emptied and used for agricultural, residential and industrial purposes. In areas susceptible to flooding, dams can be used to protect those in affected areas by blocking off rivers. Many hydroelectric dams are also required to provide recreational services to the public such as fishing and swimming.
However, hydroelectricity does have some serious shortcomings. For one, building a dam requires the displacement of many communities and the flooding of massive swathes of land, which destroys ecosystems. It is also a risk for riverbank ecosystems as they have been known to cause low dissolved oxygen levels in water, which suffocates marine life. Reliability is another problem in many areas, as electricity cannot be produced in times of drought. Another huge detriment is the cost as many of these projects can cost billions of dollars, which means quite a bit of money is lost if the dam cannot operate for any reason.
Is hydroelectricity the silver bullet for our energy demands? Definitely not. However, it must be part of the future of energy and we must consider it as part of a realistic solution to a very complex problem.