A Comparison between Hydroelectric Energy and Solar Energy

AComparison between Hydroelectric Energy and Solar Energy

AComparison between Hydroelectric Energy and Solar Energy

Theavailability and the impact of different sources of energy arecontroversial issues that are highly debated in the modern world.Over the years, the world economy has depended on fossil fuels thatare widely used for industrial and domestic purposes. Fossil fuelsare non-renewable sources of energy that are formed from deposits ofanimals and plants that were progressively buried deep within theearth and converted into hydrocarbons by high temperatures andpressure (Milici, 2009). Coal and crude oil are the most widely usedtypes of hydrocarbons in the world. It is estimated that coalcontributed about 30.1 % of the primary energy in the world and 40 %of the global electric energy, where the United States uses coal toproduce 39 % of its national grid (U.S. Energy InformationAdministration, 2015). In addition, the United States has about 240million registered vehicles where about 97 % of them are powered bypetroleum products (Association for Convenience and Fuel Retail,2015). Although fossil fuels make a significant contribution to theglobal economy, they are responsible for the global warming and otherenvironmental impacts that are endangering human survival in themodern world. In addition, fossil fuels cause smog that in turncauses different health problems, including respiratory diseases.

Thenegative impacts of fossil fuels have forced the stakeholders in theenergy sector to explore and exploit alternative sources of energy.Alternative energies refer to any source of energy that cansubstitute fossil fuel and address the negative impacts (such asenvironmental pollution) of fossil fuels (Merewether, 2003). Most, ifnot all, known alternative energies are renewable and includehydroelectric, solar, and wind energy. Solar energy is obtained fromthe sun and can be used in different ways, including heating,generating electricity, and cooking. Wind energy is obtained from thewind and it is used to drive the turbine that produces electricity.Hydroelectric energy is acquired when moving water is used to rotateturbines that in turn produce electricity. These sources of energyproduce a small quantity of greenhouse gases compared to fossilfuels. This paper will compare and contrast hydroelectric and solarenergy with the objective of determining which one has a greaterpotential for the United States.


Usagein the U.S

Hydroelectricenergy is among the widely used renewable energies in the UnitedStates and the state of Washington in particular. About 70 % ofelectricity used in the state of Washington is generated from hydropower stations compared to the national average of 6 % (ACFR, 2015).Apart from the wide usage, the state of Washington produces a largeproportion of the national hydroelectric energy. According to U.S.Energy Information Administration (2015) Washington produces about 29% of the U.S. hydroelectric energy. The State of Oregon is ranked thesecond after Washington in terms of the quantity of hydroelectricgeneration and consumption. Oregon produces near 70 % of its energyfrom hydroelectric power stations, which has resulted in the lowprice of electricity compared to the national average (U.S. EnergyInformation Administration, 2015). The government estimates that theU.S. still has about 65 GW of hydroelectric energy that is stilluntapped (U.S. Energy Information Administration, 2015). Therefore,hydroelectric is a renewable source of energy that can address thecurrent U.S. energy-related challenges.

Infrastructureand generation process

Thelarge scale production of hydroelectricity begins with theconstruction of dams. The dam straddles the river, where watercollects on the upstream to form a reservoir. The dam is fitted withturbines, rotators, and the generator at the outlet section. Dams areusually constructed in strategic located where blocking of a liver isexpected to result in the accumulation of water on the upstream. Thedam plays the role of converting kinetic energy of the river intopotential energy (EDF Energy, 2015). The weight of the reservoirpushes water through penstock, where the waters spin the turbines,converting the kinetic energy of water into mechanical energy. Theturbines rotate the generators, which converts mechanical energy intohydroelectric energy. The energy can then be transmitted tocommercial and domestic facilities where it is consumed.


Hydroelectricpower has many benefits that attract its usage in the modern world.Large scale dams produce large quantities of electricity once theyare completed. In addition, these dams give a promise of reliablesource of energy as long as the source of water (the river) continuessupplying water throughout the year (International HydropowerAssociation, 2000). Hydroelectric energy is also inexpensive toproduce. On average, it is estimated that hydroelectric power plantsproduce each kWh at 2-4 cents (IHA, 2000). Moreover, hydroelectricpower plants produce less greenhouse gases because these plants havea small carbon footprint of 10-30 grams of carbon dioxide per kWhgenerated (IHA, 2000). Additionally, the economic benefits ofhydroelectric source of energy exceed costs because dams and otherinfrastructure are cheap to maintain.

Limitationsof hydroelectric energy

Productionof hydroelectric energy requires the construction of large dams,which results in the destruction of the ecosystem. For example, damsblock flowing rivers, which in turn disrupts the movement of marineorganisms, including fish (Clemons, 2009). In addition, constructionof dams results in encroachment of large pieces of land, whichcontributed towards environmental pollution of disruption ofbiodiversity. Moreover, most of the machines used in the constructionof hydroelectric dams use fossil fuels that are responsible foremission of greenhouse gases. Although the low maintenance of damsincreases the desirability of hydroelectric power, the high cost ofinstallation may reduce the nation’s capacity to exploit itshydroelectric energy potential. For example, a 5 kWh projects costabout $ 153,000 and an infrastructural installation cost of $ 30,000(Hydro and Wind Company, 2015). Therefore, the high cost ofinstallation, environmental pollution, disruption of the ecosystem,and the need for locating dams near the river are the major limitingfactors for the generation of hydroelectric energy.


Usagein USA

Intotal, U.S.A generates 17,500 MW of energy from solar, which isdistributed to over 3.5 million homes (Solar Energy IndustryAssociation, 2015). The state of Washington is ranked in the list ofstates that uses large amounts of solar energy. It is estimated thatWashington produces 39 MW of electricity from solar energy annually,which is supplied to about 5,800 homes (Solar Energy IndustryAssociation, 2015). Washington has been making heavy investments toincrease the amount of solar energy that is produced annually, whereit invested about $ 48 million in the year 2014 (Solar EnergyIndustry Association, 2015). The state of Oregon is ranked number 25nationally because it generates about 84 MW of solar energy annually.This energy is supplied to 10,000 homes. The state of Oregon invested$ 28 million in solar energy projects in 2014 (Solar Energy IndustryAssociation, 2015). The heavy investments that states are making inthe solar energy projects suggest that the desirability of this typeof energy is increasing with time.

Infrastructureand generation process

Solarenergy is mainly harvested using solar panels that are divided intomany photovoltaic cells. These cells absorb photons (particles ofsunlight) where the energy released during the process of absorptionis converted in cells into an electric current (Chinnammai, 2013).Solar cells are made using semiconductors (silicon) and given eitherthe positive of the negative charge. When the sunlight hit thesecells, electrons are displaced from the semiconductor. The positiveand the negative charges are then controlled using some cable. Asingle cell cannot generate substantial amount of energy and thisnecessitated the connection of multiple solar cells that are mountedtogether to form the panel. The electric current that is collectedfrom different cells is then directed to an inverter that turns thedirect current to alternating current for transmission or usage.


Solaris a renewable and non-polluting source of electric energy. It doesnot require the use of fuel or radioactive materials to run the solarsystem and this reduce the chances for emission of greenhouse gases(such as sulfur oxide and carbon dioxide) and harmful radiations(Chinnammai, 2013). In addition, solar is a convenient and flexiblesource of energy because solar panels can be installed in any placeas long as the cells can be stricken by sun rays. Technologicaladvances have also enabled scientists to manufacture small solarpanels that are highly portable. The high portability increases theusefulness of solar systems in remote areas. Solar energy can also beregarded as a relatively reliable source of energy because a currentwill be produced as long the solar exists. Moreover, solar panels donot require maintenance and can remain efficient for many years(Chinnammai, 2013). This implies that the initial cost ofinstallation can be recovered in the long run. Additionally, solarpanels do not require a lot of technical expertise and time toconnect. After purchasing the solar system, one needs to set thepanel to in the direction of sunlight and start using electricity.

Limitationsof solar power

Althoughsolar panels do not require a lot of maintenance costs, the highprice of these panels increases the initial cost, which in turnreduces the economic benefits of generating solar energy. Therefore,the high initial cost discourages people and government agencies fromgenerating solar energy (Chinnammai, 2013). Usage of solar energy isassociated with minimal emission of greenhouse gases, but the processof manufacturing the solar panels contributes towards environmentalpollution. In addition, the material used to manufacture photovoltaiccells is made up of toxic materials that include silicon, lead,mercury, and cadmium (Chinnammai, 2013). Most of these materials arecarcinogenic and pollute the environment when these cells aredisposed off irresponsibly. Moreover, solar energy is highlydependent on weather conditions and times of the day. For example,solar energy may not be generated at night or during cloudy periods.This reduces the reliability of solar energy. The most efficientsolar panels harness up to 80 % of solar energy, but they are moreexpensive (Chinnammai, 2013).

Comparingand contrasting


Bothhydroelectric energy and solar energy are considered to beenvironmentally friendly because they are not associated with theemission of greenhouse gases. However, the argument of theenvironmental friendliness of the two sources of energy is determinedusing emission that is measured starting from the point at which allinfrastructures have been installed. In other words, the usage ofsolar energy and hydroelectric power does not emit greenhouse gases(Chinnammai, 2013 and IHA, 2000).

Althoughthe usage of hydroelectric energy and solar energy does not result inemission of greenhouse gases, most of the pre-installation andinstallation operations emit substantial amounts of greenhouse gases.For example, it is estimated that the construction of hydroelectricdams and installation of other infrastructure has a total carbonfootprint of between 10 and 30 grams of carbon dioxide for everykilowatt per hour that is generated (IHA, 2000). Most of thesegreenhouse gases are emitted by heavy machines used to constructhydroelectric dams. The process of harnessing solar energy, on theother hand, pollute environment during the production of solar panelsand solar cells. These equipments are produced in industries that usefossil fuels and emit greenhouse gases. According to Mulvaney (2014)the carbon footprint of solar energy is about 72 grams of carbondioxide for every kilowatt per hour of energy that harnessed. Apartfrom greenhouse gases production of solar cells involves severalchemicals (such as silicon) that pollute the environment and endangerhuman life (Mulvaney, 2014). Therefore, low-carbon emission does notnecessarily mean zero-emission.


Theprocesses of generating electricity from hydropower plants and solarenergy systems differ in terms of convenience and location.Hydroelectric dams must be constructed in certain sections of largerivers to in order to ensure that they produce the desired amount ofenergy (IHA, 2000). This limits the flexibility and convenience ofhydroelectric energy because a dam cannot be constructed anywhere.Solar energy, on the other hand is more convenient and flexible. Thisis because solar panels can be installed in any located as long as itcan be hit by solar rays. In addition, the fact that technologicaladvances have facilitated the production of smaller solar panels haveincreased flexibility of the use of solar energy since the smallsolar panels can be transported easily (Clemons, 2009).

Thepost-installation impacts of the two energy systems indicate theirdifferences. Solar panels have a limited impact, if any, during theirusage. Hydroelectric dams, on the other hand, have significantimpacts on the ecosystem, even after the construction andinstallation of equipments (such as turbines and generators) iscompleted. For example, these dams block the liver, thus affected thefree movement of aquatic organisms. Research indicates that fish thatattempts to pass through the outlets of hydropower dams are injuredby rotating turbines where most of them die (Cada, 2008). Othersources of injuries sustained by aquatic organisms include highturbulence of water and grinding as these organism passes throughnarrow tunnels. Therefore, the impacts of hydroelectric dams arefelt even during usage.

Thetwo sources of energy also differ in terms of the amount of moneyspent to produce each unit of energy. The cost of producinghydroelectric power is estimated to be 0.85 cents for every kilowattper hour on average, while the cost of producing solar energy rangesbetween 18 and 30 centers per kilowatt per hour of energy (U.S.Department of Energy, 2014). Hydroelectric energy is cheaper toproduce compared to solar energy.

Thereliability of solar energy and hydroelectric power is another sourceof difference between the two sources of energy. Hydroelectric damsare stable and tend to produce a constant amount of energy as long asthe river that supply the dam water remains does not dry up (IHA,2000). This increase the reliability of hydroelectric power comparedto other sources of energy. Solar panels, on the other hand, are notstable and cannot be considered as reliable sources of energy. Thisis because the energy production capacity of solar panels is highlyinfluenced by weather conditions. For example, the energy productioncapacity reduces during the cloudy periods and increases during thesunny periods (IHA, 2000).

Differentstates of the United States have different hydroelectric and solarenergy production capacities. A comprehensive survey of thehydroelectric energy resources in the United States indicated thatabout 49 states have the potential to generate hydroelectric powerwith about 5,667 sites (Grigsby, 2012). Some states have exploitedpart of their hydroelectric resources while others have not. Intotal, the U.S. states generate about 30 GW while 96 GW ofhydroelectric energy remains untapped. All states have the capacityto generate solar energy, but all states produce total only 20 GHs ofsolar energy annually (The White House, 2014).


Hydroelectricityis one of the renewable sources of energy that address theenvironmental concerns associated with the use of fossil fuels.Washington and Oregon are the leading producers of hydroelectricenergy. Hydroelectric energy is environmentally friendly and has acarbon footprint of 10-30 grams of carbon dioxide for every kWh ofenergy. However, there are several limitations that reduce theutilization of hydroelectric energy. These limitations include thehigh cost of constructing dams, disruption of ecosystems, andemission of greenhouse gases during the construction of dams.

Differentstates of the United States have been making heavy investment toincrease the amount of solar energy they produce annually. Solar is anon-polluting source of energy that is provided by nature, but solarpanels are required to harness it. Solar panels can be transportedand installed in any location provided that they are hit by sun rays.However, the usage of solar energy is limited by the high cost ofpurchasing solar panels, environmental pollution during the processof manufacturing solar panels, and inefficiency of solar panels inharnessing solar energy.

Outof the two major types of renewable energy analyzed in the presentstudy, hydroelectricity has the greatest potential in the modernsociety. Hydroelectric energy has a lower carbon footprint (10-30grams of CO2 per kWh) compared to the carbon footprint of solarenergy, which is 72 grams CO2 per kWh. Investing more inhydroelectric energy will reduce the amount of greenhouse gasesemitted into the atmosphere and resolve the issue of global warming.In addition, the cost of producing each unit of hydrocarbon is lessthan the cost of producing energy from other sources. It costs only0.85 cents to produce kWh of energy from hydroelectric dams.Therefore, hydroelectric projects are cost effective and benefitsexceed the cost. Most importantly, hydroelectric dams produce arelatively constant amount of energy, which increase the reliabilityof hydroelectric energy.


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