Mitigation

Achieving the 50- to 80-percent reduction in greenhouse gas (GHG) emissions that scientists say is needed to avoid the worst effects of climate change will not be easy. It will require action across all sectors of the economy, as well as a revolution in the way people think about and use energy. Cost-effective opportunities exist today for starting the world on a path toward lower emissions—and there are a number of emerging technologies that hold enormous promise for delivering significant emission reductions in the future. The successful development of these technologies will require substantial new investments in research, incentives for producers and consumers, and emission reduction requirements that drive innovation.

While there is no single, silver-bullet technology that will deliver the reductions in emissions that are needed to protect the climate, a variety of solutions that mitigate GHG emissions are available today. Learn more about these and other emerging technologies below.

Facts:

Mitigating Emissions from the Electricity Sector. The electricity sector produces 38% of U.S. carbon dioxide (CO2) emissions. Most of the electricity generated by the sector is used in the nation’s homes, offices and industrial structures to power everything from heating and cooling systems to lights, computers, refrigerators and cell phones. Viable options for reducing emissions from electricity exist in the electric power sector as well as the building sector. These options include the following:

  • Improved Efficiency. Technologies are available today to produce electric power and heat more efficiently using both fossil fuels and renewable energy. Power plants using the Integrated Gasification and Combined Cycle (IGCC) process, for example, deliver efficiency gains along with reductions in air pollution by converting coal into a cleaner-burning gas. Additional efficiency gains can come from advanced technologies for other fuel sources in power plants, including natural gas and biomass.

    Learn more at the Center for Climate and Energy Solutions.
     

  • Renewable Energy . Renewable energy harnesses the power of the wind, the sun, water, tides and other forces to produce electric power. Agricultural “biomass” products also can be used to generate electricity and heat when combusted with coal. Renewables offer the potential to generate electricity without producing GHGs—or producing very little when compared to traditional energy sources.
    • Most renewable resources can be harnessed on a large-scale basis (for example, via wind farms or large geothermal fields) or in more “distributed” forms (for example, by placing solar panels on rooftops).
    • Although larger-scale renewable energy can be cost-competitive with other forms of conventional electricity in some cases, renewables still account for less than 10% of overall electricity production in the U.S.
    • Renewable Portfolio Standards (RPS’s), which require generators to produce a specified share of power from renewable sources, are a great way to expand the use of renewable energy.  Over half of the 50 United States currently have mandatory RPS’s. Check out this map to find renewable portfolio standards in your state.
    • Other options for expanding the use of renewables include consumer rebates and other government incentives as well as further support for research and development to advance the technologies and lower their costs.

    Learn more about renewables in the Energy section.
     

  • Carbon Capture and Sequestration. As noted above, IGCC power plants can convert coal into a gas that produces substantially fewer pollutants when burned; the IGCC process also allows for the relatively easy “capture” of carbon for long-term storage in underground geological formations.
    • The United States has built demonstration plants using carbon capture and sequestration (CCS) technologies, and at least two commercial IGCC plants and one commercial CCS plant are currently being planned.
    • CCS involves the separation of CO2 from other gases emitted in the coal combustion or gasification process and the injection of the CO2 deep underground into geological formations.
    • The United States has the geological capacity to store the emissions from its coal-fueled plants in depleted oil and gas reservoirs for several decades.
    • Capacity in other geological reservoirs is estimated to be in the hundreds of billions of tons (500 billion tons of capacity), enough to store current levels of domestic emissions for over 300 years.

    Learn more about coal and CCS at the Center for Climate and Energy Solutions.
     

  • Nuclear Power. Nuclear power currently provides roughly 20 percent of U.S. electricity with virtually no associated greenhouse gas emissions. Yet, for nuclear power to play a more prominent role in U.S. efforts to address climate change, the industry needs to overcome several important hurdles, including concerns about the cost of nuclear-generated electricity; concerns about nuclear waste disposal; and proliferation in other countries.
    • No new nuclear plant has been ordered in the United States since 1979, although groups of companies are currently pursuing applications for new plants.
    • There are 104 nuclear power plants in the U.S., with a combined total of over 100 million kWh installed capacity. Read more at the Energy Information Agency.
    • The increase in nuclear capacity and improved efficiency at nuclear power plants since 1993 represents one-third of voluntary CO2 reductions from U.S. industries. In 2007, nuclear energy accounted for about 74% of U.S. emission-free generation. Read more at the Nuclear Energy Institute.

    Learn more about nuclear energy in the Energy section.
     

Mitigating Emissions from the Building Sector. GHG emissions from the building sector result primarily from the use of power-hungry items such as lighting fixtures, appliances, and heating and cooling systems. Cost-effective technologies for reducing emissions from buildings are readily available, but they often can’t compete in the marketplace. Options for reducing emissions from buildings include the following:

  • Efficiency. There are many ways to increase the overall energy efficiency of buildings. From more efficient lighting and instantaneous hot water heaters to EnergyStar®-certified products and better insulation, consumers and businesses have an array of cost-effective options for limiting their energy use and boosting efficiency. Learn more about building efficiency in the At Home section.
  • On-site Power Generation. GHG emissions from the electricity and building sectors also can be reduced through on-site power generation using renewables and other climate-friendly energy resources. Examples include rooftop solar panels, solar water heating, small-scale wind generation, stationary fuel cells powered by natural gas or renewable hydrogen, and geothermal heat-pumps.
    • Expanding the use of renewable and climate-friendly energy sources—which will ultimately reduce costs—may require new incentive programs such as consumer rebates and tax credits. Building standards (such as LEED™certification) also can help.
    • In addition, combined heat-and-power (or cogeneration) plants, rather than wasting the excess heat generated in the course of producing electricity, capture it for use in heating homes and industrial sites.

Learn more about mitigation options for the electricity sector at the Center for Climate and Energy Solutions.

 

Mitigating Emissions from the Transportation Sector.  After the electricity or buildings sector, transportation is the second largest source of GHG emissions in the U.S., primarily CO2 produced by cars and trucks. The ways in which we move from place to place are responsible for almost one-third of U.S. CO2 emissions, and nearly a quarter of emissions around the world. Reducing greenhouse gas emissions from transportation can be accomplished in a number of ways.  Among the options:

  • Short-Term Options. One recent study found that commercial (and cost-effective) technologies exist right now to increase fuel economy and/or reduce tailpipe greenhouse gas emissions by as much as 25 percent. These options include:
    • Energy Efficiency - In the U.S., the average fuel economy of all cars and light trucks sold today is no better than it was in the early 1980s. Optimizing fuel efficiency is essential to mitigating the effects of emissions from transportation.
    • Fuel Blending - Corn-based ethanol is currently the dominant biofuel in the United States. Blending of ethanol and other biologically-derived fuels with gasoline creates fewer emissions from vehicles that are able to operate on this “flex fuel”.
    • Advanced Diesels and Hybrid - Diesels and hybrids use different engines than the standard internal combustion engine; diesels also use different fuels. These technologies both offer significant improvements in fuel economy and because they use less gas, they produce fewer GHG emissions when compared to other cars and trucks. When both technologies are combined in a diesel hybrid vehicle, it can yield a 65 -percent reduction in GHG emissions per mile.
  • Longer-Term Options - Ultimately, reducing emissions from cars and trucks to a level where they pose a minimal risk to the climate will require a shift away from petroleum-based fuels. Among the most promising alternatives:
    • Biofuels - While corn-based ethanol can reduce emissions by as much as 30% for every gallon of traditional fuel replaced, cellulosic ethanol and sugar-cane-based ethanol may enable reductions of up to 100%.  Biofuels have the potential to offset 10-24% of current U.S. GHG emissions.
    • Electric Cars - Advances in battery storage are needed to make electric cars more viable but another option is the “plug-in” hybrid, a gas-electric vehicle that can be charged at home overnight. Even using the current U.S. mix of electricity sources to charge the vehicles, plug-in hybrids can achieve significant reductions in emissions compared to traditional vehicles, and even traditional hybrids.
    • Hydrogen - Hydrogen fuel cells, long a staple of the U.S. space program, produce power by combining oxygen with hydrogen to create water. Technological advances and reductions in the costs associated with the use of fuel cells could lay the groundwork for a hydrogen-based transportation system in the decades to come.

Learn more about mitigation options for the transportation sector at the Center for Climate and Energy Solutions.