Deep Decarbonization Study Reveals Multiple Pathways to Carbon Goal

A few weeks back, we posted a story describing the substantial amount of technology that is ready and able to confront the looming climate challenge. The article contained a sizable list of technologies on both the supply and demand side of the energy equation. It pointed out that solar and wind are already less expensive than coal in most places and described the 10 winners of the 2015 U.N. Climate Solutions Award.

A similar, but far more comprehensive, study was released last week by the Deep Decarbonization Pathways Project (DDPP). The report, which was developed by Energy and Environmental Economics (E3), in collaboration with researchers at Lawrence Berkeley National Laboratory and Pacific Northwest National Laboratory, consists of two volumes.

The first volume, Pathways to Deep Decarbonization, describes “the technology requirements and costs of different options for reducing U.S. greenhouse gas emissions 80 percent below 1990 levels by the year 2050.” Dr. Dan Lashof, chief operating officer of NextGen Climate America, one of the sponsors of the research, said: “This is by far the most rigorous and detailed study of what it will take to achieve a transition to clean energy in the United States. It demonstrates that a climate-friendly transformation of our energy system is not only achievable, it would increase our prosperity, protect our environment and strengthen our national security.”

The report describes an in-depth analysis of various energy scenarios, based on a simulation of the national power system with resolution down to hourly supply and demand for the years up to 2050. The research was directed at the following four questions:

1. Is it technically feasible to reduce U.S. GHG emissions to 80 percent below 1990 levels by 2050, subject to realistic constraints?


2. What is the expected cost of achieving this level of reductions in GHG emissions?


3. What changes in energy system infrastructure and technology are required to meet this level of GHG reduction?


4. What are the implications of these technology and infrastructure changes for the energy economy and policy?

The analysis identified four distinct scenarios, namely high renewable, high nuclear, high CCS (carbon capture and storage) and mixed case, that all met the criteria of reducing overall overall net GHG emissions to no more than 1,080 million metric tons of CO2 equivalent (MtCO2e), and fossil fuel combustion emissions of no more than 750 MtCO by the year 2050. Each scenario followed a distinctly different path. The model also demonstrated the ‘technical feasibility of reducing net non-energy and nonCO2 GHG emissions to no more than 330 MtCO2e by 2050, including land use carbon cycle impacts from biomass use and potential changes in the forest carbon sink.”

The median cost of these scenarios, with some degree of uncertainty, was just over $300 billion or 0.80 percent of U.S. GDP. That is roughly half of the 2015 military budget. These costs did not include the numerous net non-energy benefits such as reduced health care costs due to less pollution (which are estimated by the EPA to reach a level of $65 billion by 2020) or any of the other many costs of climate change, such as responding to increased levels of catastrophic weather events, which, though nearly impossible to quantify, are expected to be substantial.

Substantial infrastructure changes will be required in three areas: highly efficient end-use of energy in buildings, transportation and industry; decarbonization of electricity and other fuels; and fuel switching of end uses to electricity and other low-carbon supplies. All of these changes, across all sectors of the economy, will be required to meet the target of an 80 percent GHG reduction below 1990 levels by 2050.

These scenarios indicate a shift of the transportation energy supply toward either electrification or the use of fuels, such as hydrogen, that are produced by electricity.

What this entails will be nothing less than a doubling of the electricity supply by 2050, while at the same time reducing its carbon intensity to 3 to 10 percent of its current level. It would further require an average vehicle fuel economy in excess of 100 miles per gallon and a shift of 80 percent of vehicles away from combustion engines.

These are severe shifts which will not be easy to achieve, though, as the study shows, they are clearly possible. The analysis is necessarily conservative in that it cannot see around technological corners, and in fact does not include advancements already being demonstrated in third- and fourth-generation biofuels, as well as dramatic improvements in engine technology such as those being studied at Oak Ridge National Labs. The ability to safely include a higher level of liquid fuels will reduce the demands on the electric generation infrastructure.

The fourth question is the subject of the second volume, Policy Implications of Deep Decarbonization in the United States. That report provides a roadmap for what policy makers at the national, state and local levels need to do to enable a low-carbon transition. It describes how businesses and whole regions could benefit in an energy economy where the dominant mode shifts from purchasing fossil fuel, with historically volatile prices, to investment in efficient, low-carbon hardware, with very predictable costs.”

The report provides policy makers and businesses with a detailed understanding of what deep decarbonization will actually require in terms of scale and timing of investment, rates of technology adoption, distribution of costs and benefits, and risks associated with different options.

It will facilitate a policy discussion that can move beyond emissions targets to the required end state of an energy system that can meet those targets.

Finally, it provides a new lens on analytical approaches and policy prescriptions in the energy and climate domain, with the key question being whether and under what conditions they are effective in driving an energy system transformation. Some of the policy guidance in this report is not yet on the policy radar.

Image courtesy of USDPP