Although the installed capacity of hydropower and geothermal energy has increased steadily since 2003, both types of energy saw slower growth in 2011, according to new research conducted by the Washington, DC-based Worldwatch Institute.
A total of 25 gigawatts (GW) of new hydropower capacity was added in 2011—less than in previous years—with China, Vietnam, Brazil, India, and Canada responsible for 75 percent of the added capacity. Some 136 megawatts (MW) of new geothermal power capacity was installed, the vast majority of which came from two major projects: a 90 MW facility in Iceland and a 42 MW plant in Costa Rica.
Global installed capacity of hydropower hit 970 gigawatts (GW), only a 1.6 percent increase from the previous year; while geothermal cumulative capacity reached 11.2 GW, stalling at below one percent for the first time since 2002.
Specifically, although some 150 countries produce hydropower, half of global installed capacity was concentrated in just five nations at the end of 2011. China remained the leader, with 212 GW installed; followed by Brazil (82.2 GW), the United States (79 GW), Canada (76.4 GW), and Russia (46 GW).
The United States continued to be the leader in geothermal capacity, with 3.1 GW; followed by the Philippines (1.9 GW), Indonesia (1.2 GW), Mexico (1 GW), and Italy (0.8 GW).
"Despite the recent slowdown in growth, the overall market for hydropower and geothermal power is increasing—in part because these two sources are not subject to the variability in generation that plagues other renewable energy sources such as wind and solar," said Evan Musolino a research associate with the Worldwatch's Climate and Energy Program. "The greater reliability of hydro and geothermal can thus be harnessed to provide reliable base load power."
During 2011, hydroelectricity represented nearly six percent of primary energy consumption among members of the Organization for Economic Co-operation and Development (OECD)—a Paris-based forum for countries committed to democracy and the free-market economy. It played a more important role in other countries----at a little over seven percent of usage----and these non-OECD nations, including China, accounted for 60 percent of worldwide hydroelectricity consumption. On a regional basis, South America and Central America are most dependent on hydroelectricity, relative to total energy use.
Putting a ‘Damper’ on Growth
Despite the potential of hydropower to generate inexpensive, low-emission electricity, large projects also may involve significant negative consequences. The damming of rivers to create the reservoirs needed for large-scale power generation is severely disruptive to ecosystems and can harm both animal and human populations.
But hydropower continues to be one of the most cost-effective renewable energy generation sources. Typical costs are in the range of 2-13 U.S. cents per kilowatt-hour (kWh) for existing grid-connected hydropower plants and 5-10 cents per kWh for new plants. Micro-hydropower installations (0.1 kilowatt to 1 megawatt)—which typically are used in rural communities that are not yet connected to the national grid—generate at 5-40 cents per kilowatt-hour.
Like hydropower, geothermal resources are highly location-specific. Many countries with strong hydropower potential—including much of Latin America, the Caribbean, and Southeast Asia— have equally impressive geothermal potential. These resources have been exploited for energy generation for over a century, with significant capacity being developed since the mid-1900s.
The costs associated with geothermal power also closely mirror those of hydropower. Varying by geothermal technology, generation costs are in the range of 5.7-10.7 cents per kWh. High capital costs, associated primarily with the expense of drilling geothermal wells and the long lead time for project development, continue to challenge project developers.
Edited by Brooke Neuman