Characterization of Irreducible Uncertainty in the Future Energy System

The energy system has an intricate relationship with climate change. Burning fossil fuels for energy has a tremendous impact on global climate, and will continue to do so unless we take preventive steps.

Low or zero-carbon energy technologies such as wind and solar power show great potential to replace fossil-fuel consumption, and will play a major role in curbing the carbon dioxide released into the atmosphere. In the past few decades, investment in these technologies has increased tremendously.

As new energy technologies emerge because of climate change, researchers have tried to model the future evolution of the energy system. Most of these models assume that using many different technologies simultaneously will reduce emissions. But historical evidence suggests that a few technologies tend to dominate energy systems. Such imbalanced distribution happens as a result of different rates of technological maturity, costs, subsidies, market conditions and various path dependencies i.e. all the decisions and outcomes that have shaped the history of the technology.

Part of our research at the CDMC focuses on developing a more detailed way of thinking about the future of the U.S. energy system, about the impacts it may have on the climate system, and the impacts climate policy will have on it in return. At the same time, we want to understand the fundamental uncertainty present in all of these issues.

While we do not expect to be able to predict specific details of the energy system's future, we believe that through historical analysis, technology assessment and policy analysis, we can develop a much better understanding of the factors that are likely to shape that future, as well as the policies that could influence its development.

The researchers involved in this arm of the CDMC plan to study past and present low-carbon technologies, including wind, solar, fuel cells, and carbon storage. Some of their goals are to understand the historical course of evolution of past technologies, to assess situations where government subsidies make sense, and to study the social implications of alternative energy-system structures-centralized versus decentralized, gas versus electricity-based etc.-in the future.

Low-Carbon Energy Systems

Researchers: Inês Lima Azevedo, Engineering and Public Policy, Carnegie Mellon University; Granger Morgan, Engineering and Public Policy, Carnegie Mellon University; Costa Samaras (former affiliate)

In order to avoid the possibly drastic consequences of climate change, large emissions reductions will be necessary. Most of these emissions are linked to our energy systems, largely through the consumption of fossil fuels. Burning fossil fuels for energy has a tremendous impact on global climate, and will continue to do so unless we take preventive steps.

Part of our research at the CDMC focuses on developing a more detailed way of thinking about the future of the U.S. energy system, about the impacts it may have on the climate system, and the impacts climate policy will have on it in return. At the same time, we want to understand the fundamental uncertainty present in all of these issues.

We plan to assess and compare how energy and climate policies and technology choices will affect different economic sectors (residential, commercial, industrial, transportation and the electric sector).

Public Outreach: Cap and Trade is Not Enough: Improving US Climate Policy (March 2009)

Relevant Publications:

"Energy Efficiency and Conservation: A bright idea with solid state lighting?" - I.L. Azevedo, 2007; Proceedings of the European Council for an Energy Efficient Economy Summer Study (ECEEE), La Colle sur Loup, France (La Colle sur Loup, France). [ BibTeX | XML | Full paper ]

"Impact of Battery Weight and Charging Patterns on the Economic and Environmental Benefits of Plug-in Hybrid Vehicles" - C.S. Shiau, C. Samaras, R. Hauffe, J.J. Michalek, January 11-15 2009; 2009 Annual Meeting of the Transportation Research Board, Washington, DC. [ BibTeX | XML | Full paper ]

"Long-term Electric System Investments to Support Plug-in Hybrid Electric Vehicles" - S. Blumsack, C. Samaras, P. Hines, July 20-24 2008; Proceedings of the IEEE Power Engineering Society 2008 General Meeting (Pittsburgh PA). [ BibTeX | XML | Full paper ]

"Plug-in Hybrid Vehicle Simulation: How battery weight and charging patterns impact cost, fuel consumption, and CO2 Emissions" - R. Hauffe, C. Samaras, J.J. Michalek, Auguest 3-6 2008; 2008 ASME Design Engineering Technical Conferences & Computer and Information in Engineering Confere, New York, NY. [ BibTeX | XML ]

"Policies to Promote Plug-in Hybrid Electric Vehicles for Greenhouse Gas Emissions Reductions and Oil Displacement" - C. Samaras, C. Hendrickson, H.S. Mathews, M.G. Morgan, January 11-15 2009; 2009 Annual Meeting of the Transportation Research Board, Washington, DC. [ BibTeX | XML | Full paper ]

"The Transition to Solid-State Lighting" - I.L. Azevedo, M.G. Morgan, F. Morgan, Proceedings of the IEEE, March 2009, 481-510 (ISSN: 0018-9219). [ BibTeX | XML | Full paper ]

The Technical and Economic Feasibility of Solar Photovoltaic Technology

Researchers: Aimee Curtwright, Granger Morgan, Engineering and Public Policy, Carnegie Mellon University

To establish how much we can know about future energy technologies and systems, we need to understand the likely characteristics and performance of currently dominant technologies. We also need to understand the path dependencies of energy systems, how factors such as social choices, R&D investment and policy environments could lead to different plausible technology futures.
In this project, we are focusing on determining the technical and economic feasibility of solar energy technology. We are assessing both current and emerging technologies, with an emphasis on photovoltaic (PV) cells, which are the most common way to harness solar power with semiconductors that convert light energy to electricity.

Various PV technologies are at different stages of maturity and cost competitiveness. Whether or not to pursue improvements through basic research, through advanced engineering design and methods, or through large-scale manufacturing will depend on the assessed maturity and the overall promise of the individual PV technology.

Photovoltaics can contribute significantly to carbon dioxide reductions, but their costs are still unacceptable. We are trying to assess the obstacles in the technology behind PV cells that need to be overcome to lower costs, and at what timescales this would happen. While a lot about solar technology's future is unknown, we want to see what different technology pathways are possible, and evaluate their relative risks and likelihood.

We plan to survey existing literature as well as perform an expert elicitation in the form of a survey for a handpicked group of solar experts in order to evaluate where various PV technologies are headed.

Solar research will not progress without the appropriate funding allocation; we aim to develop a reference guide for the energy policy makers who make research investment decisions. By studying the trends in various technologies and by analyzing their benefits and drawbacks, we can understand what research and policy factors will help the advancement of solar PV technology. This will help us create a concise analysis that could serve as a reference guide.

Public Outreach Materials - 2006 (pdf)

Relevant Publications:

"Expert Assessments of Future Photovoltaic Technologies" - A.E. Curtright, M.G. Morgan, D.W. Keith, Environmental Science & Technology, Vol. 4, No. 24, 2008, 9031-9038. [ BibTeX | XML | Full paper ]

"The Character of Power Output from Utility-Scale Photovoltaic Systems" - A.E. Curtright, J. Apt, Progress in Photovoltaics, Vol. 16, No. 3, 2008, 241-247. [ BibTeX | XML | Full paper ]

Government Investment Decisions for Renewable Energy Technologies

Researchers: Constantine Samaras (former affiliate), Granger Morgan, Engineering and Public Policy, Carnegie Mellon University

The government can influence the development and adoption of renewable energy in a variety of ways-funding technology research; providing tax breaks or subsidies for production, generation, or consumption; providing deployment incentives; and regulatory requirements. The method of intervention used depends on the technology being considered, and its state of progress.

We want to examine a portfolio of renewable energy technologies and perform a technical assessment of which government strategies are most appropriate for each technology. We want to explore the question of when a technology should receive subsidies so that people can adopt it easily and learn from use, and when investments should be made in basic research instead.

We are starting with analyzing the engineering and policy decisions that have resulted in the successful evolution of modern wind energy into the fastest growing, most popular renewable energy source in the world, which will surely play a key role in a low-carbon future.

In the United States, which has the second largest wind market after Germany, wind energy technology is benefiting from the federal government's production tax credits as well as state-level renewable portfolio standards. As a result, wind power is competitive with traditional coal-based electric power generation. The total installed capacity in the U.S. as of December 2004 was 6740 megawatts, enough to power 1.6 to 2 million households a year.

The factors that have led to wind energy's success include technological innovations in wind turbine design influenced by traditional engineering disciplines, as well as gains from learning, specialization, and economies of scale provided by market growth and public policy. We are analyzing trends in wind power development to see which of these factors have led to the greatest reduction in energy costs.

After the wind energy work, we will pursue similar research in solar photovoltaics and biofuels. We plan to develop a practical guide for policymakers who set, analyze, and evaluate alternative energy policy actions, as well as for engineers who design, build, operate, and maintain alternative energy infrastructure, so that we can maximize the successful adoption of these energy technologies.

Public Outreach Materials - 2006 (pdf)

CO₂ Capture from Ambient Air

Researchers: Joshuah Stolaroff (former affiliate), Engineering and Public Policy, Carnegie Mellon University; David Keith, University of Calgary, Canada ; Greg Lowry, Civil and Environmental Engineering, Carnegie Mellon University

Alternative energy sources such as wind and solar power are seeing a slow increase in their share of energy production in the United States . But fossil fuels are still the overwhelmingly dominant energy source in the country. In 2003, renewables accounted for only 6 percent of the total energy consumed in the country. Many experts agree that it's going to be difficult to overcome the inertia involved in our dependence on coal and oil for more than two centuries.

As a near to medium-term solution, carbon capture and storage could contribute to emissions reductions substantially, given the extent of emissions reductions needed to stabilize atmospheric carbon dioxide concentrations. Capturing CO₂ and sequestering it into the earth will reduce emissions while giving us more time to slowly phase out fossil fuels and their associate infrastructure, and thus reduce related social costs.

Nearly all of the current research on carbon capture focuses on capturing CO₂ from point sources such as power plants. These research plans typically involve capturing CO₂ from flue gas, compressing it and transporting it in pipelines to a sequestration site, where it can be stored either by injecting into the ground or some other method.

We are working on a system that can capture carbon dioxide directly from ambient air, a process called air capture. This eliminates the need for a CO₂-transportation infrastructure, since the capture unit can be placed at a favorable sequestration site. In addition, this strategy has the advantage that it can capture emissions from any sector, including diffuse sources such as automobiles.

We have developed a prototype system based on capture using a chemical sorbant that can be regenerated. The land use requirements for this air capture system are potentially very small. All the chemicals involved are inexpensive, abundant and relatively benign, and the processes are all well understood as current industrial-scale practices. Moreoever, it's a system that could be engineered with existing technology and which can be scaled to capture a significant fraction of CO₂ emissions without depleting scarce resources.

According to our initial estimates, the cost for this process turns out to be higher than the cost of capture from point sources. But it is significantly cheaper than other means of reducing carbon emissions from the transportation sector, such as switching to hydrogen powered vehicles.

Public Outreach Materials - 2006 (pdf)

Synthetic Fuel Emissions

More Coming Soon

Public Outreach Materials - 2006 (pdf)