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Geothermal power, which uses the Earth's natural heat to produce electricity and heating services, is increasingly being recognized as a valuable resource by policymakers (Source: Energy Conservation Future).

Hydropower and geothermal technologies are some of the oldest and longest-standing renewables in use today. In 2011, the total capacity and use of both technologies continued to increase. The two technologies, however, are at very different stages of deployment. By year-end 2011, global installed capacity of hydropower reached 970 gigawatts (GW), roughly 2.5 times greater than capacity of all other renewable power sources combined. By contrast, geothermal installed capacity reached a new high of 11.2 GW as of year-end 2011. While overall capacity continued to increase, consumption growth slowed for both technologies compared to recent years with each growing at reduced rates not seen since the early 2000s.

The majority of geothermal power is found in a select group of countries, although capacity has now been developed in 24 countries worldwide. The United States continues to lead all others, accounting for 28 percent of geothermal power capacity. Beyond the U.S., only three other countries had over 1 GW of capacity installed as of May 2012. Geothermal is increasingly attracting the attention of policymakers and project developers with new projects under development or consideration in an additional 70 countries. Though expanding, geothermal sources accounted for less than 1 percent of global electricity production in 2011.

By contrast, hydropower represents slightly above 6 percent of total primary energy use and 15 percent of electricity production worldwide. China, Brazil, the United States, Canada, and Russia are the global hydropower leaders, together accounting for over 50 percent of all installed capacity. China, Vietnam, Brazil, India, and Canada accounted for 75 percent of all new installations, with China alone representing nearly half of all new capacity added in 2011.

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energy, geothermal, hydropower, renewable energy, Vital Signs Online

Recent legislative proposals in a number of states across the country have reignited the debate over how  ‘sustainable’ hydropower actually is,  and if it is truly emissions free. California’s Assembly Bill 1771, which was rejected in the state legislature this past April, would have allowed large hydropower facilities to contribute toward state Renewable Portfolio Standards (RPS). As a growing number of states establish increasingly ambitious targets for shares of energy production from renewable sources, there has been ongoing discussion about what types of hydropower should be included in these RPS schemes.

In the United States, state regulators divide hydro into two categories – small and large – depending on the facility’s installed generating capacity. For example, California considers any facility with at least 30 megawatts (MW) of capacity to be ‘large hydro’. Currently, utilities in most states can count only ‘small hydro’ toward RPS targets.

Zipingpu Dam in China's Sichuan Province

California’s Assembly Bill 1771 is neither the first nor the only proposal of its kind. As states that have implemented RPS programs scramble to reach their renewable energy targets, the movement to count large hydro towards these goals has gained momentum.  Similar bills have been proposed in California in the past, as well as in Minnesota. North Dakota currently counts all hydropower in its RPS, including power imported from Manitoba, but stipulates that large hydro facilities must have been placed in service on or after Dec. 31, 2010. Wisconsin will allow utilities to count hydropower from large facilities starting in 2015. 

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carbon sinks, hydropower, large hydro, low-carbon, renewable energy, renewables, small hydro, sustainability

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.

The 134MW Pirris Hydroelectric Dam in the Southern part of San Jose province, Costa Rica

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.

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Central America, hydropower, Low-Carbon Development, renewable energy, small hydropower

In a previous blog, I discussed the value of pumped-storage hydro systems, especially when it comes to integrating intermittent renewable energies like wind and solar into a power system. However, traditional pumped-storage hydro systems require two reservoirs of fresh water (one upper and one lower), which are not always available at locations that might otherwise benefit from an energy storage system. An exciting technology that tackles this problem – requiring only one on-land reservoir – and that has gained recent momentum is seawater pumped-storage hydro.

An aerial view of the seawater pumped-storage hydro system on Okinawa Island (Source: wastedenergy.net)

Seawater pumped-storage hydro works similarly to traditional systems. Excess electricity from fossil fuel, nuclear, or renewable energy power plants is used during periods of low power demand to pump water uphill to be stored in reservoirs as potential energy. Then, when demand peaks the reservoirs are opened, allowing water to pass through hydroelectric turbines to generate the electricity needed to meet power demand. The main difference for seawater pumped-storage is that instead of having a lake, river, or some other source of fresh water serve as the lower reservoir, these systems pump salt water uphill from the ocean to a land reservoir above. This lowers the system’s fresh water footprint and greatly expands the potential for pumped-storage hydro worldwide because seawater pumped-storage is much less site-specific than traditional systems.

There is currently one seawater pumped-storage hydro system operating in the world, on the northern coast of Okinawa Island, Japan. The system began operation in 1999 and has the potential to generate up to 30 megawatts (MW) of power. The hydropower plant has a total head – the vertical distance, or drop, between the intake of the plant and the turbine – of 136 meters and the upper reservoir is located just 600 meters from the coast.

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Caribbean, energy storage, hydropower, Innovation, pumped-hydro storage, renewable energy, wind power

Mr. Gerald Lindo is a Senior Energy Engineer with the Ministry of Energy & Mining in Jamaica

From left to right: Fitzroy Vidal, Senior Director, Energy, Ministry of Energy & Mining; Honorable Laurence Broderick, MP; Mark Konold, Caribbean Energy Roadmap Project Manager, Worldwatch; Gerald Lindo, Senior Energy Engineer, Ministry of Energy & Mining

On September 19th, a group of engineers met in Kingston, Jamaica during the Annual Conference of the Jamaica Institute of Engineers (JIE) to discuss the future of Jamaica’s energy sector. This year, the first two days of the week-long event were devoted entirely to discussing the country’s energy challenges and the way forward. The Principal Director of the Energy Division in Jamaica’s Ministry of Energy and Mining (MEM), Mr. Fitzroy Vidal, gave one of the keynote speeches detailing Jamaica’s National Energy Policy (NEP) and the progress towards its implementation.

It was a brisk and upbeat meeting, and Mr. Vidal’s speech was well received. Questions abounded on the direction of Jamaica’s energy sector and on the proposed considerations of innovative green technology solutions aimed at ensuring the country’s energy security and long term sustainability. However, underneath the cordiality and spirit of the conference was a smouldering worry, an elephant in the room: the tremendous price that Jamaicans pay for electricity.

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Caribbean, energy efficiency, feed-in tariffs, hydropower, Jamaica, renewable energy, solar power, wind power

Worldwatch researchers recently returned from Haiti as a part of the Energy Roadmaps for the Caribbean Project. One exciting idea that grew out of our meetings with government, utility, and private sector officials is the potential for wind and pumped-storage hydro systems on the island of Hispaniola.

A wind and pumped-storage hydro system is an old technology with a new twist, and it is a technology that is being explored on several small islands around the world.

A model of the wind and pumped-storage hydro system on El Hierro (Source: ThomasNet News and Gorona del Viento El Hierro)

For the past half century, countries including the United States have used excess electricity from fossil fuel and nuclear power plants during periods of low power demand to pump water uphill to be stored in reservoirs as potential energy. Then, when demand peaks the reservoirs are opened, allowing water to pass through hydroelectric facilities to generate the needed electricity to meet power demand.

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Caribbean, developing countries, emissions reductions, energy security, Green Technology, Haiti, hydropower, Innovation, low-carbon, renewable energy, wind power

China appears to be heading for its worst power shortage since 2004, putting pressure on already struggling industries and strained livelihoods due to restricted energy access. The 26 provinces served by the State Grid Corp of China could face a combined power shortage of 30 gigawatts (GW) this summer. Central, southern, southwestern and eastern provinces introduced power use restrictions and rationing in late March, well ahead of the summer peak demand season, fueling concerns that shortages could worsen and spread to other regions.

Source: China Daily

Jiangsu, Henan, Zhejiang, Guangdong and Hubei provinces are most susceptible to electricity shortages this summer. Jiangsu province alone is expected to face an 11 GW gap between available power supply and expected demand, accounting for 37 percent of the country’s total shortage. Due to power use restrictions and rationing, many factories in the export-oriented eastern provinces have been forced to significantly reduce output, or instead meet their power demands with costly diesel generators.

The recent financial difficulties faced by China’s power companies caused the thermal power supply slump driving these severe shortages. This is particularly true of coal-fired power plants, which provide more than 70 percent of the country’s generation capacity. According to the 2010 Annual Report of the State Electricity Regulation Commission (SERC), the overall deficits for China’s five major thermal power companies (China Datang Corp., China Guodian Corp., China Huadian Group,  China Huaneng Group and China Power Investment Corp.) exceeded 60 billion Yuan ($6.23 billion) from 2008 to the end of 2010. In May 2011 alone, these “big five” lost 12.16 billion Yuan ($1.88 billion).

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China, drought, electricity, energy roadmap, energy supply, hydropower, low-carbon, nuclear, power shortage, renewable energy, solar, sustainable development, wind

When it comes to clean power, can you have too much of a good thing? The answer, at least in the U.S. Pacific Northwest, is yes. The Bonneville Power Authority (BPA), the federal agency that operates 15,000 miles of transmission lines and 31 hydroelectric dams in Washington, Oregon, Idaho, and parts of five other states, recently proposed a slight adjustment to its dispatch rules – the rules that determine the priority with which different power generators are deployed. (See Figure.) BPA now hopes to achieve a more harmonious coexistence between two renewable sources of electricity: wind and hydroelectricity.

Transmission System and Federal Dams in the Bonneville Power Administration

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endangered species, grid integration, hydropower, renewable energy, United States, wind power