Costa Rica is hoping that the Reventazón Hydroelectric Dam, the largest in the region, will assuage its high energy costs while preserving the country's dedication to clean energy generation.

Rising up in the middle of the Reventazón River Canyon in the Caribbean region of Costa Rica is a massive concrete structure that once completed will stand as the largest hydroelectric plant in the entire region of Central America. The Reventazón Hydroelectric Project, the second-largest infrastructure project in Central America behind the Panama Canal, will upon completion add 305.5MW of electricity to the national power grid. Representing 12% of the country's total current power capacity, the new hydroelectric plant will generate the energy equivalent to the average consumption of 525,000 households. The dam, surrounded by lush forest and small farms 100km east of San José near the town of Siquirres, will bring the country one step closer to its goal of operating a 100% renewable energy matrix. Reventazón has four generating units, each with a capacity of 73MW, plus an additional turbine installed in the central ecological compensation system with a 13.5MW capacity.

The actual infrastructural components of the project will be carried out by the Costa Rican Electricity Institute (ICE) and are valued at USD1.379 billion. In a country as small as Costa Rica the colossal dimensions of the finished project are sure to impress, as the dam will create a water surface area of 700ha. The construction of the facility called for 29,000 tons of steel and 760,000 cubic meters of concrete, enough to lay a 195km four-lane road. The megaproject consists of 12 individual incremental components, such as the power substation, which became operational in January 2016. Among its main physical installations are the concrete dam, spillway, waterproofing surface, water intake channel, discharge background, headrace tunnel, pressure pipe, surge tank, main control station, central ecological compensation, and electrical substation. The construction of Costa Rica's largest ever infrastructure project has been made possible thanks to the "mole men," a term of endearment used to refer to the workers of the Costa Rican Electricity Institute (ICE) responsible for digging tunnels for power projects. The mole men were divided into several groups in order to maintain progress on the project for 24 hours a day, 365 days a year.

When a project of this magnitude is undertaken, there are inevitably some controversial aspects to be addressed, and in a country like Costa Rica those concerns center primarily on environmental responsibility. Some activists have addressed the potential negative externalities of power station in an attempt to minimize its environmental impact. The position of these groups is that filling the dam of Reventazón could generate instability and landslides along the slopes of the river, a threat to the viability of the project as well as the surrounding ecosystem. Some local residents have also complained that the ICE extracted materials from the river bottom without the proper permits.

With most of the country supporting the development of more hydroelectric projects, the government has taken some serious actions to preserve the rivers. President Luis Guillermo Solis signed an agreement in 2015 to protect the Pacuare and Savegre rivers from hydroelectric intervention, as the reputation of both rivers' rapids attracts a great deal of tourists and adventure seekers. However, the government has been clear that it does intend to build more dams; another project even larger than Reventazón, El Diquís, has been proposed near Buenos Aires, located in the southern area of Costa Rica. The signing of the Diquís project has been pending for many years due to a dispute between the ICE and local indigenous groups who claim that they never gave their consent to the state to construct the dam. If the ICE ultimately moves forward with the project, Diquís' 652MW output would more than double that of Reventazón.