Renewable Gas, Hydropower, and Geothermal: What is the role of these often overlooked renewable resources?

The Environmental and Energy Study Institute (EESI) hosted a Congressional briefing to discuss several renewable energy resources which often do not receive much attention and yet are in plentiful supply across the United States: renewable gas, hydropower, and geothermal. Each of them can provide baseload electricity, and each of these renewable energy resources comes from a variety of sources and can deliver energy through a variety of energy technology applications. The briefing explored the status of these resources, how they are used and why, and what the market drivers are for them.

Renewable gas (also called biogas) is a carbon-neutral fuel that can be produced from a host of renewable and sustainable biomass sources, including woody biomass, crop residuals, energy crops, and food wastes. Capturing renewable gas from landfills and wastewater treatment facilities also offers substantial greenhouse gas reductions by avoiding methane emissions from these sources. Using such wastes averts a problem and, in turn, provides energy and creates a new revenue stream. Renewable gas is interchangeable with natural gas and compatible with pipelines used to transport and distribute natural gas. It is a highly versatile energy source and can be used in homes, businesses, manufacturing, heavy industry and electricity production – and as an alternative fuel for transportation.

Hydropower currently provides eight percent of total US electricity generation and nearly 2/3 of all renewable electricity generation. A reliable and affordable resource, hydropower has enormous untapped potential. Tens of thousands of megawatts of conventional hydro, pumped storage, and marine and hydrokinetic projects are under development across the country to provide baseload power as well as ancillary grid services as significant amounts of variable resources are integrated into the grid. Nearly 2,000 companies from coast to coast are part of the US supply chain for this growing industry.

Geothermal energy uses the heat of the earth to generate baseload electricity as well as to provide heat for direct use in buildings, greenhouses, spas, homes, etc. While the hot temperatures required for power generation are found primarily in the West, geothermal heating/cooling systems are used across the country in rapidly growing numbers. While the industry has seen very significant growth, the potential is enormous.

Renewable Natural Gas

• Renewable natural gas is a carbon-neutral fuel produced or captured from renewable, sustainable biomass sources, landfills or wastewater treatment facilities. According to Kathryn Clay, executive director of the American Gas Foundation, renewable natural gas can reduce carbon emissions, thereby moving it beyond carbon-neutral, into carbon neutral+ territory.
• Renewable natural gas is particularly versatile, as it can be used for transportation, electricity generation and heating.
• Renewable natural gas could meet demand for between 4-10 percent of natural gas usage. If one used all available feedstocks throughout the nation, one could produce 9.5 quadrillion Btus per year, enough to power 80 million households. In addition, greenhouse gas emissions would be reduced by up to 146 million tons of CO2 per year (the amount produced by 29 million cars).
• It is a 50-state renewable energy resource that could potentially create up to 250,000 jobs in the energy and agricultural sectors.
• Renewable natural gas is fully compatible with the existing energy infrastructure (consisting primarily in 2.4 million miles of pipeline).
• According to the California Air Resources Board, renewable gas is currently the lowest carbon transportation fuel available.
• Over 22 models of light-duty natural gas vehicles are currently available in Europe.

Hydropower

• Hydropower represents 63 percent of all renewable energy production in the United States, nearly 8 percent of the country’s total power generation.
• According to the National Hydropower Association’s director of government affairs, Jeffrey Leahey, hydropower avoided approximately 196 million metric tons of carbon pollution in the United States in 2009, equivalent to the emissions produced by 38 million cars.
• There are 80,000 dams throughout the United States, only 3 percent of which generate power. Clearly, there is enormous potential for growth. Indeed, with the right policies in place, the United States could add 60,000 MW of new hydro capacity by 2025.
• Much of this new capacity would be in the shape of pumped storage, which works in conjunction with intermittent renewables (such as solar and wind energy) to ensure a constant supply of power: when running, wind turbines or solar panels pump water into a reservoir, which can later be used to drive water turbines, generating electricity even if there is no wind or sun. The United States currently has more than 20 GW of pumped storage capacity, distributed throughout the country. Developers have proposed an additional 31 GW.
• By 2025, the hydropower industry could potentially create 1.4 million jobs. Regions with major growth opportunities include the Rust Belt and the lower Mississippi states, which are already home to hundreds of hydro supply chain companies.
• In order to fulfill this potential, hydropower needs a more efficient, expedited regulatory process. National Clean Energy Standards and Renewable Electricity Standards, R&D support and economic incentives (such as Production Tax Credits –PTCs– and Clean Renewable Energy Bonds –CREBs–) would also help.

Geothermal

• Fact: the ground is boiling hot 20,000 feet under Washington D.C. (the deepest oil wells reach 38,000 feet down).
• Geothermal plants are an excellent baseload (24-7) technology, since their output is not affected by external factors.
• In 2012, 3,187 MW of geothermal power was produced in 9 states, mostly in the West.
• Over 147 projects under development could potentially add more than 5,000 MW, in effect tripling U.S. geothermal power production. The industry estimates that 11,592 MW – 89,743 MW of hydrothermal power in 13 western states remains to be developed.
• New technologies, such as binary air-cooled systems, allow lower temperature geothermal sources to be tapped for effective power production.
• With its significant risks and long lead times, the geothermal industry would benefit from government policies that better match its needs (such as tax incentives that last at least as long as it takes to build a new plant, and research support that is less erratic). At present, there is a large mismatch between incentives and lead times (it takes 4-8 years to permit and build a geothermal power plant). According to Karl Gawell, executive director of the Geothermal Energy Association, State and Federal Renewable Standards are a key driver for geothermal deployment.
• Twenty-two countries built new geothermal power plants between 2005 and 2010. With such strong global growth, America must preserve its expertise in geothermal technology. Today, the United States exports more geothermal know-how and equipment than it imports, and there are significant future market opportunities: as of 2010, 70 countries had geothermal projects under consideration, a 52 percent increase since 2007.