Megadams: A Technology We Should Continue to Use Today – Blog Post 6 - September 16

            This week in The Energy Reader, I read a short argument by Juan Pablo Orrego about the false solution of megadams.  Although Juan Orrego crafted a good argument, I disagree with many of the points he made, including his final conclusion that megadams should not really be used at all. 

            Orrego’s biggest argument, along with most people who do not like dams, is that dams destroy ecological areas.  They prevent the normal flow of water downstream, which causes variations in oxygen content, temperature, and sediment flow.  These sediments contain organic and inorganic materials that are essential to downstream ecosystems.  Orrego extended the argument by pointing out a common idea in environmental science: everything affects everything.  The ecologically damaged stream can affect other nearby ecosystems that depend on the stream, such as estuaries and even the ocean, which damages those ecosystems as well.  Some technological advancements can help to lower these impacts though, such as by sediment flushing.  Sediment flushing opens up lower parts of the dam temporarily so that sediments can flow downstream.  This can be good for the dam operator because it prevents the reservoirs from filling in.  The environment may benefit from these sediments, depending on the rate at which they are released from the dam (Sumi 1).  

            Although all of this is true, I still support megadams to the fullest.  Many of the problems with megadams are fixable, or are minimal in comparison to other methods of generating electricity.  Orrego debates the idea that hydroelectric megadam technology is a “clean, abundant, renewable, and cheap source of energy” (The Energy Reader 180).  He claims that these assumptions are ideological and not descriptive of what really happens.  The energy return on investment for hydropower is generally between thirty and forty to one, which is very good and means that the energy can be sold for cheap (The Energy Reader 108).  Although people nearby the dams may pay expensive price for electricity in his experiences, this is probably because of greedy megadam companies, not because of the technology.  Powerful companies taking advantage of poorer countries and poorer people is not specific to hydropower, but is common to most industries, so this is not a good reason to specifically disincentivize megadams.  To further debate Orrego’s claim, I would argue that megadams are definitely renewable because they rely on a constant stream of water to power them.  Additionally, I would argue that they are clean because although it takes a lot of resources and fossil fuels to build the dam, it lasts a long time and takes close to no further input of fossil fuels after it is built.  This is a lot cleaner than mining for coal every time it is needed, transporting it across the country, and then burning it day and night. 

            Orrego also makes comments on how megadams can change the climate.  He argues that megadams can release millions of tons of methane per year due to the putrefaction of organic matter caused by the formation of a new reservoir.  It is true that bodies of water emit methane because water does not have much oxygen in it so decomposers use more anaerobic respiration, which releases methane.   I hypothesize that because there is more water upstream, there is less downstream; therefore, maybe downstream of the reservoir there is less methane release than usual, which would balance out the extra methane released by the reservoir.  Additionally, fossil fuels release tons of methane and carbon dioxide as well, so I do not find climate change a reason to disincentivize megadams right now because they are not bad in comparison to using fossil fuels for electricity generation. 

            In conclusion, although Orrego gives a decent argument on why megadams should not be supported, I strongly disagree with him.  The hydroelectric megadams have a good energy return on investment, are renewable, and provide energy locally for a long time period.  I feel confident that they are better for our climate than fossil fuels because fossil fuels need to be found, processed, delivered, and burned each time they are used, yet megadams are a one-time set-up with minimal costs afterwards, by comparison.  Additionally, the problems with ecosystem disruption can be aided by new technologies that help allow sediments through, such as sediment flushing techniques.  Overall, megadams are a much better technology for generating electricity than today’s major alternatives.