According to What is Sustainable Development? Goals, Indicators, Values, and Practices written by Kates W. Robert, sustainable development can be looked at as an oxymoron, meaning there are far too many ideas and opinions on the matter to fully reach a consensus on what it truly means. However, to put it into broader terms, we can take example from the Brundtland Commission, who have described sustainable development as: “to meet the needs, now and in the future, for human, economic, and social development within the restraints of the life support systems of the planet” (Robert, 2005).
One aspect of sustainable development is green energy. From wind turbines to LED lightbulbs to solar power, our use of energy is forever changing to becoming more renewable and exceptionally less damaging to our ecosystem. Green energy has been pushed and encouraged more and more as our modern society has developed, and it is safe to say that it is an inevitable solution to global warming and reducing production of greenhouse gasses. To narrow the range of these types of green energy, we will focus on water energy, specifically hydroelectric plants. It has been thought by many that there is not much left to discover or invest in hydroelectricity, being as age-old as it is. However, there are hundreds of opportunities to improve, expand, and adapt hydroelectric plants to make them truly eco-friendly and renewable. Hydropower, simply put, is the generation of power using turbines, whose blades are turned by the currents of falling or flowing bodies of water. Hydropower is considered renewable because of its nearly permanent fuel source: water. This makes Hydropower reportedly a climate-friendly power source and produces virtually no air pollution in the generating process compared to non-sustainable electricity plants such as coal or oil, contributing greatly to the restoration of our atmosphere (Office of Energy Efficiency and Renewable Energy (EERE), 2016). But is this entirely true? In this report, the main effects that hydropower plants have on the economy will be discussed, as well as some potential ways to decrease the risks and damages produced by these plants and increase their eco-friendly possibilities.
Methane Gas: Just How Serious is it?
Although hydropower appears sustainable at first glance, it is not entirely that simple. Roughly 60% of global methane emissions produced each year are due to human activities, and the main source of this production comes from oil and gas industries, agriculture (fermentation, manure management, and rice cultivation), landfills, water treatment, coal mines, and now, hydropower (UNECE, 2016). In a recent study conducted from Washington State University, it was found that methane makes up 80% of emissions from the reservoirs created for hydropower dams. This number is staggering, given that methane is “at least 34 times more potent than carbon dioxide” (Harrison, 2016) and that, according to the National Hydropower Association, hydro plants make up 52% of renewable energy production in the United States (National Hydropower Association, 2017).
(IPCC Fourth Assessment Report: Climate Change 2007)
The production of methane appears to be a major issue in many sustainable energy sources. While it is true that most do not produce carbon, this does not necessarily mean that these sources come without risk. An increase in methane in our atmosphere can potentially mean an increase in temperature, and while it is not as present in our atmosphere as carbon dioxide, its potency poses an enormous risk and factor in global warming (Russel, 2006).
The main factor in methane emissions in hydroelectric plants resides in their reservoirs. This is mainly from the decomposition of water and land vegetation naturally growing or carried by currents at the bottom of the reservoirs, where oxygen is decreased, and bacteria then begins to break the plant life down. As they are broken down, methane is released, part of which becomes carbon dioxide, and the rest is carried and released to the surface in air bubbles. The production of methane gas is not related to the location of these power plants, but rather the amount of organic life that resides at the bottom of them (Deemer, 2016). The algae present at the bottom of these dams may contribute to methane production more than usual as well, as they have the potential to receive more nutrients due to nitrogen and phosphate travelling downstream from watersheds that reside upstream and becoming more present in reservoirs. Rotting vegetation in reservoirs have been found to have emitted over one billion tonnes of greenhouse gasses every year, most of which containing methane gas (Deemer, 2016). This makes up about 1.3% of man-made global emissions produced every year. Methane gas stays in the atmosphere for 10 years, whereas carbon dioxide remains for centuries. However, this does not mean it does not pose a risk, as its potency contributes to global warming nearly three times as much as carbon dioxide does over a 20-year period (84%). (Deemer, 2016)
(Pfister S, 2016)
This figure comes from a report done by engineers at Switzerland’s Institute of Environmental Engineering and shows all hydro plants across the world that produce a minimum of 10 kilograms of Methane to a maximum of 1000 kg of Methane per megawatt hour. These engineers report that the largest producing plants “exceed the median, indicating that the average carbon footprint is driven by a few hydroelectric power plants with very high emissions” (Pfister, 2016). Given that Methane is 34 times as potent as carbon dioxide, this means that for every kg of Methane produced, it is 34 times as damaging as every kg of carbon dioxide released into the atmosphere by non-renewable energy sources. During the study done Washington University Students, over 250 dams were analyzed and found to have emitted more methane than any naturally occurring lakes, wetlands, and even rice cultivation. (Harrison, 2016)
Conclusion: What Can be Done?
Given its potency and it being more present in our atmosphere now than ever before, it can be difficult to foresee a way to harness and control the emissions of methane gas from hydropower plants. However, there are an abundance of possibilities to do just that. In fact, methane within itself can be considered as a source of energy and can be oxidized where it is formed before it is released into the atmosphere, allowing it to be burned and used for electricity, fuel, and heating (Pfister, 2016). The recovery rate of methane gas is about 60% and can be recovered with low budget machinery. Using this method not only means a cleaner atmosphere by using 60% of the methane produced from reservoirs, but it also decreases the need for multiple reservoirs in one plant (additional energy sources means less water storage for future use), additionally decreasing spending, natural habitat destruction, reservoir water evaporation, and the alteration of water flow (Pfister, 2016). According to Stephan Pfister, if this 60% of methane emissions were to be captures from each hydropower plant, “19% of total methane emissions could be saved, which would reduce the overall carbon footprint of global hydropower by 8%.” This method can also be followed by other renewable energy sources, such a wind or solar power, which would decrease emissions and carbon footprint even more (Pfister, 2016). In fact, this method has already been put into practice. In 2003, BMW Manufacturing Corporation began recycling methane emissions produced from a landfill in Palmetto for additional energy use to power four of their turbines. As a result, BMW has powered 25% of their energy needs with recycled methane gas and has reduced their carbon footprint by 55,000 tonnes of carbon dioxide that was originally produced before integrating this method (GreenBiz Editors, 2003). An additional method of reducing methane emissions on an equally effective scale can be through preventing reservoir eutrophication, or mass of nutrients, for algae and other organisms to absorb and as a result produce more methane than they would in natural bodies of water (Deemer, 2016). One way to do this would be to place new reservoirs upstream, where only a small amount of a river is collected and ran through the turbine, and the flow is continued as normal downstream instead of collecting at the bottom. As well, decrease of overall surface area of reservoirs can greatly reduce rot of vegetation, and instead an increase total depth can take place to collect an abundance of water. (Mission 2017, 2017) The wide and often-shallow reservoirs that reside at the bottom of plants collect nutrients and algae, and cover a larger surface area of submerged vegetation, ultimately resulting in massive rot and an abundance of methane gas. Not only this, but the relocation of reservoirs to upstream or in gorges would greatly impact other environmental issues in hydro plants, such as flooding issues due to low level reservoirs overflowing and causing groundwater flooding and release of deoxygenated water downstream. Upstream reservoirs located in deep gorges would greatly reduce this, as river levels would be lowered, and would also reduce the rate of decay from nearby forests and other plant life from flooding, as forest decay greatly contributes to methane production as well. Reservoirs located upstream also maintain oxygenated water, as they do not produce nearly as much methane as a downstream reservoir, which holds a mass amount of methane gas produced at the bottom due to plant decay, resulting in a dramatic decrease of oxygen. (Mission 2017, 2017)
Overall, the concept of hydropower is much more dependable than other types of renewable energy. But at its current standpoint, it is not entirely sustainable. However, in using these methods, the methane emissions that hydropower plants and their reservoirs produce can be greatly decreased, making them much more sustainable and eco-friendly, and may very well become the future of all energy production on a global scale.