EPA Science Matters Newsletter: Breaking Through? Evaluating Technologies for Greenhouse Gas Mitigation (Published April 2014)

EPA modelers develop innovative methods to assess low-carbon technologies.

Image of solar panels and wind mills

Much of the energy we use to power our homes, cars, and industries is also the main source of greenhouse gases (GHG) responsible for global climate change. It follows then, that limiting emissions from the combustion of these energy sources could contribute toward a stable, sustainable environmental future.

Developing new “game changing” technologies and energy sources will be important to mitigate GHG emissions cost-effectively. But how can today’s decision makers identify  technologies with true transformational potential for reducing global climate change over the long term ?  

EPA scientists and engineers are helping answer just that question. They are using sophisticated computer models to support decision makers by comparing potential mitigation technologies in terms of cost, environmental performance, economic impact, and more.

In one such effort, the results of which were recently presented in the journal Clean Technologies and Environmental Policy, EPA physical scientist Dan Loughlin and his research colleagues used an innovative modeling approach tapping the MARKet ALlocation (MARKAL) model to demonstrate a “breakthrough analysis” that researchers can use to identify technologies that can make a true difference in reducing GHG emissions.

MARKAL was created in the late 1970s by Brookhaven National Laboratory scientists to help partner researchers and others wade through the complex and far reaching differences and tradeoffs involved in making decisions and policies related to energy use. Over the next several decades, the model was improved and reworked to support new functionality, and to take advantage of increasing computational power. It is now one of several models that EPA’s own climate change researchers use.

“Breakthrough” in this case refers to a technology that can limit GHG emissions significantly and cost-effectively over the long haul, explains Loughlin. “We developed a methodology to examine the breakthrough potential of energy-related technologies, taking into account the complexities of the entire energy system.”

The researchers focused on MARKAL because of its comprehensive coverage of the energy system, from the importation, production, or manufacture of a particular energy source, right through its distribution and end use by a whole variety of interacting sectors.

“For example, using MARKAL we might ask ‘What would happen if the cost of solar photovoltaic technology goes down to 20 cents per kilowatt hour? Would it penetrate the market and yield significant reductions in GHG? Using MARKAL this way allows us to incorporate important multi-sectoral interactions in our analysis that would not be possible with less powerful tools,” says EPA engineer William Yelverton, who contributed to the breakthrough technology approach. 

To demonstrate how such an approach could be used to support greenhouse gas mitigation decisions, Loughlin, Yelverton, and their EPA colleague Rebecca Dodder focused on a breakthrough analysis of utility-scale solar photovoltaics (PV). Their calculations suggest, for instance, that an 80% drop in the price of photovoltaics would lower the cost of cutting carbon dioxide emissions in the United States in half by $270 billion—potentially making it a technology breakthrough.

The research team plans to use this approach to evaluate and compare the breakthrough potential of additional energy technologies.

In their paper, they and their coauthors write: Fortunately, as a society, we have shown a great ability to innovate. Technology breakthroughs have led to putting humans on the moon and to downsizing electronics so that the smart phones in our pockets are more powerful than the supercomputers of several decades ago. Similar breakthroughs in low- and zero-carbon energy technologies will be needed to meet GHG mitigation goals identified as being necessary by the IPCC [Intergovernmental Panel on Climate Change]. This need raises important questions, such as ‘What constitutes a breakthrough?’ and ‘Where would breakthroughs be achieved most readily and most cost effectively?’

Together, EPA researchers Loughlin, Yelverton, Dodder and their partners are working to answer those questions, and help provide the science and tools needed to address global climate change.

Developing Models and Tools to Meet Climate Challenges

Now used by some 77 different institutions in 37 countries, MARKAL is one of several models that EPA’s own researchers are using in innovative ways to provide the information and tools needed to identify and address the challenges of climate change. Other examples of EPA climate change methods, models, tools, and databases follow:


    EPA scientists are developing GLIMPSE, a software tool that will help policymakers consider synergies and tradeoffs among different policy options intended to protect human health and curb the production of pollutants that contribute to global climate change.

    Modelers built the tool by combining a global chemical transport model for pollutants, a model simulating the effects pollutants have on solar radiation, and an energy system model.

    “The complexity of simultaneously addressing air pollution and climate change demands that policies take into account the full context of the problem,” explains EPA scientist Dr. Rob Pinder, who is leading GLIMPSE.

  • The Greenhouse Gas Mitigation Options Database and Analysis Tool

    EPA scientists are cataloging hundreds of low-carbon technologies that could potentially be used to help reduce greenhouse gas emissions in the Greenhouse Gas Mitigation Options Database (GMOD) and Analysis Tool. The tool focuses on technology options for the power, cement, and pulp & paper industries (among the most energy-intensive).

    “The goal of GMOD is to help stakeholders make intelligent decisions about how to lower carbon footprints within the limits of technology,” says EPA chemical engineer Frank Princiotta. “The literature is full of information on these technologies—this model provides a way to assess them objectively and consistently.”

  • Integrated Climate and Land Use Scenarios (ICLUS)

    How will dynamic and related changes in population density, land use, and economic development impact future climate change scenarios? EPA modelers have developed the Integrated Climate and Land use Scenarios model to support impact assessments that answer these and other questions, and identify opportunities that will increase the resiliency of communities and natural systems.

    Researchers built the tool to address the broad research objective of understanding the effects of future interactions between climate and land use change in the United States. EPA global change scientists used the tool extensively in their report Land-Use Scenarios: Housing-Density Scenarios Consistent with Climate Change Storylines, and ICLUS data supports the National Climate Assessment.

  • Downscaling Global Climate Models

    EPA atmospheric modelers are working on large-scale, world-wide models and adapting them for use on more local, regional scales. Through a process called “downscaling,” they are developing techniques to produce current and future climate scenarios for the contiguous U.S.

    “Downscaling allows us to focus on the impacts of climate change within a target region, state, city, or watershed, and especially to address the impacts of extreme events with greater detail,” notes EPA physical scientist Tanya Otte.

    The work is building the capability for researchers to assess the impacts of climate change on air quality, human exposure and health, and ecosystems at smaller geographic scales.

    • Regional Climate Downscaling

Related Resources

  • Climate Change Research
  • Climate Change Adaptation and Mitigation
  • MARKAL Technology Database and Model - a data-driven, energy system optimization model. Given the structure of the energy system to be modeled and data to characterize each of the technologies and resources used, MARKAL then calculates the least costly set of technologies over time to satisfy the specified demands, subject to various user-defined constraints. Outputs of the model include a determination of the technological mix at intervals into the future, estimates of total system cost, energy demand (by type and quantity), estimates of criteria and GHG emissions, and estimates of energy commodity prices.
  • Methods, Models, Tools and Databases for Exposure Research: Climate Change