Hydropower is the conversion of falling or moving water into mechanical energy to generate electricity. Hydropower installations around the world account for the largest share of renewable electricity produced globally at around 55%, and hydroelectric dams account for nine of the ten largest power producing facilities on Earth. Since the first hydropower facility came online in Appleton, Wisconsin, USA in 1882, producing power from hydraulic sources has become a powerful tool to stabilize national and regional power grids, complement existing power production infrastructure, reduce greenhouse gas emissions, and the industry has seen a great deal of technological advances which allow hydropower facilities to reduce environmental impacts and expand the opportunities for its use.
Scale of Resource
It is estimated that there is a potential hydropower resource of around 70GW in Peru, which means that present infrastructure is merely 7.4% of the total potential. MSc is a strong proponent of utilizing existing reservoirs to develop additional hydropower capacity.
The most prominent form of hydropower utilized globally and in Peru is through the construction of dams to create upstream reservoirs or artificial lakes. These reservoirs are then funneled into a generating plant where turbines convert the moving water into mechanical energy before the water moves downstream. The Itaipú Dam, a joint venture between Paraguay and Brazil constructed on the Paraná River, is an example of a very large-scale hydropower facility (image below).
Important aspects of dam construction and the consequent formation of a reservoir to keep in mind are the flooding of upstream ecosystems, the greenhouse gas emissions as result of decaying biomass in the reservoir zone, the obstruction of river and stream sediments at the dam location, evaporation of fresh water from the reservoir, and the disruption of riverine lifecycles, among others. For these reasons, it is important to weigh the pros and cons of dam construction for the purposes of generating power against the costs and benefits of other renewable energy sources.
Another hydropower technology that carries fewer environmental risks but reduces power generation flexibility is run-of-the-river (ROTR). ROTR utilizes the movement of water through a generating plant without the use of a substantial reservoir. While these facilities often do not generate as much power as a conventional dam with reservoir, ROTR can protect critical characteristics of a riverine system while providing non-baseload power.
Given the large investment required for hydropower construction, the vast majority of hydropower facilities are in capacity scales of megawatts or even gigawatts. This means that entities like large electric power providers, regional and national governments, and some large industries like mining are the primary drivers of hydropower development. Still, hydropower can serve as a reliable baseload power generator to supplement the existing power grid and provide additional energy resilience.
Below is an image of the powerhouse of the Prairie du Sac Hydroelectric Dam along the Wisconsin River; a 31MW facility in operation for more than 100 years.
Though less common, small-scale hydropower systems can provide power for homes and small businesses. These projects often do not present environmental challenges on the scale of large, utility-scale hydropower facilities. Small ROTR systems, as well as systems with limited utilization of am artificial reservoir, can be assembled at comparative cost to other small-scale renewable energy systems as long as a source of reliable (preferably year-round) moving water is near the energy end-user.
Tidal and Wave
Hydropower is also becoming a generating asset for coastal communities without riverine systems. Tidal power systems convert the movement of water as a result of the Earth’s gravitational interaction with the moon and sun into mechanical energy for power generation. As the tides are easier to predict that wind patterns and cloudy days, tidal power can offer additional reliability to energy networks or smart-grids.
Wave power is exactly as it sounds; the utilization of wave energy to generate electricity. While not widely utilized, wave power can be useful in circumstances where particular coastal geography and nearby communities coexist. Wave power systems often utilize buoys and fins at or near the surface of coastal ocean waters to convert waves into mechanical energy. Peru and Chile offer the greatest potential in Latin America for wave energy utilization.
As of 2016, Peru had 5,189MW of installed hydropower capacity that generated 24.17TWh of electricity, 47% of the country’s total electricity production. There are 178 operational hydropower facilities in Peru with installed capacities ranging from .5MW to 1,008MW. The three departments of the country with the highest installed capacity in hydropower are Huancavelica (1,533.6MW), Lima (1,188.8MW) and Huánuco (456.7MW).
According to one study, the cost per kW of installed capacity of a new hydropower construction can vary widely from $1,050/kW to more than $7,000/kW. However, adding additional capacity to existing dam infrastructure could cost as little as $500/kW in certain site-specific contexts, a dramatic cost savings. Therefore, Peru, which operates several facilities older than 40 years, should concentrate on efficiency improvements and modernization upgrades for existing hydropower facilities before planning new construction.
 Renewable Energy Policy Network for the 21st Century – Renewables 2016: Global Status Report – http://www.ren21.net/wp-content/uploads/2016/06/GSR_2016_Full_Report_REN21.pdf
 Gunn, Kester; Stock-Williams, Clym.: “Quantifying the global wave power resource” – https://www.sciencedirect.com/science/article/pii/S0960148112001310
 MINEM Perú – Anuario Estadístico de Electricidad 2016, Chap 3 – http://www.minem.gob.pe/_estadistica.php?idSector=6&idEstadistica=11738
 MINEM Perú – Anuario Estadístico de Electricidad 2016, Chap 2 – http://www.minem.gob.pe/_estadistica.php?idSector=6&idEstadistica=11738
 International Renewable Energy Agency: Renewable Energy Technologies: Cost Analysis Series – Hydropower – https://www.irena.org/documentdownloads/publications/re_technologies_cost_analysis-hydropower.pdf