To reduce its dependence on fossil fuel imports, Central America has embraced alternative energy in recent decades. Non-fossil fuel resources now account for 64.9 percent of electricity capacity in the region. But the largest source of this renewable energy—hydropower—cannot only be considered clean energy. Hydropower accounts for 51.6 percent of the region’s installed power capacity, supplying – with over 20,000 gigawatt-hours per year, more than all other energy sources combined. Although hydropower is “renewable” to the extent that the water resource is regenerated through hydrological and climate cycles, the damming of rivers has major social and environmental impacts.

These impacts are frequently overlooked because hydropower can be one of the least expensive sources of electricity. After relatively high initial upfront costs, there are fewer recurring risks than fossil-fuel based energy. Hydropower also serves an important role in a stable energy supply because it provides baseload power that can be ramped up or down on demand, unlike more variable renewable energy sources such as wind that depend on favorable weather conditions.

Costa Rica currently derives over 90 percent of its electricity from renewable sources, 76 percent of this from hydropower. Political leaders in the country have praised large-scale hydro because of the economic development and energy security benefits it can provide. In 2011, the 134 megawatt (MW) Pirris Dam was brought online to address rising domestic electricity demand and further reduce Costa Rica’s petroleum fuel imports.

Large hydro’s heavy footprint

Proponents of large hydropower often portray the technology as “green.” The evidence, however, suggests a more mixed picture. One report indicates that dammed reservoirs in tropical regions produce as much as 4 percent of total human caused greenhouse gas emissions. The methane released from decomposing organic material in reservoirs would otherwise be stored in carbon sinks such as topsoil, forests, rivers, or oceans. Building hydroelectric facilities also requires large amounts of carbon-intense concrete, steel, and other materials.

In many cases, dams fundamentally change the chemical and mineral composition of a watershed, affecting micro-organisms, plants, insects, fish, reptiles, amphibians, birds, and mammals. Habitat loss is the leading cause of species extinction worldwide, and in some cases, dams have been responsible. The human caused sixth mass extinction that is now expected to be underway is among the most critical environmental concerns of our era. Conservative estimates are that globally, at least 10,000 species go extinct each year. The protection of ecosystems, including river systems, is a critical challenge facing biodiverse tropical regions such as Central America.

Hydroelectric dams can also result in the displacement of people who occupy land in the flood zone of a reservoir, and can affect the lives of those living downstream by fundamentally changing a river’s natural cycles. In China, dams have displaced millions of people. The world’s largest hydroelectric project, the Three Gorges Dam, displaced 1.2 million people—the residents of three cities, 140 towns, and 1,350 villages.

Opposition to dams in Central America

In Central America, the concerns are similar on a smaller scale. Costa Rica’s El Diquís project has been in the spotlight of controversy since 2006. The proposed 631 MW hydroelectric plant would displace more than 1,500 people and submerge hundreds of kilometers of mangroves and other fragile ecosystems. In March 2011, with legal support from human rights groups, the Terraba indigenous community filed a lawsuit against the Costa Rican state utility, ICE, to protest the project. Concerns and recommendations have also been expressed by the UN Special Rapporteur on indigenous rights.

Also controversial is the proposed 100 MW dam on the Patuca River in Honduras, which has been on the table since 2006. Here too, opponents—including the indigenous Tawahka, Pech, and Miskitu peoples; the Afro-Honduran Garifuna; and human rights organizations such as Cultural Survival— have formed a movement to prevent what would be a series of three dams in the Mesoamerican Biological Corridor, one of Central America’s most diverse expanses of wilderness.

In both instances, opponents to the dams have cited the International Labor Organization’s Convention on the Rights of Indigenous Peoples, as well as potential environmental impacts. If these projects continue as planned, Costa Rica’s El Diquis dam, the largest hydro facility in Central America, could break ground as soon as 2013 and be commissioned in 2016. Meanwhile, the effects on Honduras’s previously undammed Patuca River are only beginning to be understood through science and by learning from people who have lived along the river for thousands of years.

Small hydropower alternatives

Not all forms of hydroelectricity are as controversial as conventional large dams. For example, some types of small-scale power stations—typically less than 10 MW in capacity—provide an uninterrupted branch of the river that bypasses the dam to enable fish, insects, and other species to navigate the river for spawning and other purposes. Also, some dams are required to turn off their turbines during fish migration. Other dam efforts try to mimic seasonal flow variations that trigger the spawning in fish and natural environmental processes, or they take into account the silt and mineral composition of a healthy flowing river and try to release the same amounts. However, this often proves difficult.

Public opposition has successfully averted proposed hydroelectric dam projects in Central America in the past. In 2001, indigenous and local community protests, as well as assessments of the river’s recreational value, prevented development of a 40 MW facility on the Cangrejal River in Honduras, and plans for the project have been put on hold.

Community activism, legal support, and international attention are pushing countries to look toward alternatives to large hydropower. But the success of other renewable energy options depends on a stable and consistent political framework, effective policy administration, and a financial climate that encourages investment in renewables and the appropriate infrastructure. In Central America, alternatives are gaining ground, and the region is in the position to add up to 130 MW of geothermal energy in 2012. Significant wind power installations also exist in four of the seven countries, although much more could be done to embrace sustainable energy options.

The Worldwatch Institute is currently prioritizing energy planning in Central America that incorporates new and sustainable energy sources such as wind, solar, geothermal, and biomass. The Institute’s Climate & Energy initiative in Central America is spearheading these efforts in collaboration with the Energy and Environment Partnership of Central America as well as policy and energy experts from the Central American Institute for Business Administration, based in Costa Rica and Nicaragua.

This blog was first posted in WorldWatch Institute website