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Oct 22, 2013

Lunch & Learn with RMI:

Is a Rapid Transition to a Low-Carbon Energy System Feasible?


RMI periodically hosts “Lunch & Learn” sessions—internal professional development opportunities that help keep our staff abreast of the latest research, technology, and ideas. In this periodic series, we pay it forward.

Our Boulder office recently welcomed Alexander MacDonald, Ph.D., chief science advisor for NOAA’s Office of Oceanic and Atmospheric Research and director of the Earth System Research Laboratory. MacDonald and his team presented their research on how weather patterns affect renewable generation—specifically wind and solar.

MacDonald began his team’s talk with a bold statement: “2050 is too late [for the U.S. to get off of fossil fuels].” RMI’s Reinventing Fire maps a pathway for achieving an economy driven by efficiency and renewables rather than by oil, coal, and nuclear energy by 2050, so as you might imagine, that statement got our attention!

Team members presented their research on how weather patterns affect renewable generation and the feasibility of transitioning off fossil fuels. They also discussed data gathering, model building, and scenario testing. Accurate and detailed weather and electric load data was critical for the NOAA study, known as NEWS (Nation-scale Energy from Wind and Solar). NOAA started with three years of hourly wind and solar data and collected electric load data concurrent in time with the weather data to assess geographies and times of unmet need and surplus availability. Next, NOAA developed a power system simulator that can model all power-producing technologies and associated infrastructure. The minimization of cost, constrained by several requirements including the requirement to meet load every hour, is the primary function of the simulator. So, the system determines the lowest-cost system-wide generation and transmission portfolio given a set of input assumptions and scenario to meet the defined load.

On the surface, this work may sound similar to NREL’s Renewable Electricity Futures Study, which was based on the familiar ReEDS model. But though there are some similarities—and the studies come to intriguingly similar conclusions—there are also important differences. For example, REFS used 17 “time slices” to describe annual weather variability, while NEWS incorporated 26,000 hours’ worth of accurate wind and solar weather data from over the course of a three-year period. Reciprocally, REFS used 134 nodes to model a national transmission system, while NEWS used 32 nodes. In the words of ESRL’s Adam Dunbar, “NEWS emphasizes accuracy and resolution of weather over transmission. I would say that REFS gets closer to an engineering-level treatment of transmission at the expense of realistic weather.” Both, of course, have value.

So, why this approach?

Combining sophisticated weather analysis, power plant generation capabilities, economic considerations, and the meeting of electricity needs (load) is easy. Long-term energy supply modeling often looks at projected annual generation totals in order to meet annual load, annual renewable energy generation capabilities (annual “capacity factors”), and general variability considerations. But you don’t want to meet the energy needs on an average basis; you have to meet it very much moment by moment (reasonably modeled at hourly granulation) in order to fulfill first-world reliability expectation. While NOAA can’t accurately predict the weather in a specific hour a month from today, its top-of-the-line weather modeling allows for reasonable example hours over a long duration and changing energy infrastructure. That’s the real “secret sauce” that NOAA’s added to modeling the long-term, U.S. electrical system.

NOAA’s results

You will have to wait to hear the full conclusions of the study, since NOAA is in the process of publication. What we can share is that given the scenarios tested, NOAA has found economically viable solutions for a rapid transition off fossil fuels, with a few critical conditions for implementation. These conditions include realizing or surpassing DOE wind and solar cost goals, a national high-voltage DC transmission system, and specific regulatory, legal, and financial systems that enable this type of national solution. Perhaps most importantly, the research shows a scenario for a drastic reduction in carbon emissions—up to 90 percent by 2030 compared to 2010 levels (dependent on pricing and balance area size).

Q&A with the project team

MacDonald was joined by CDR Adam Dunbar, associate director of NOAA’s Earth System Research Laboratory; Christopher Clack, Ph.D., researcher scientist at the University of Colorado at Boulder’s Cooperative Institute for Research in Environmental Sciences; and Melinda Marquis, Ph.D., renewable energy program manager at NOAA’s Earth System Research Laboratory.

RMI: In your presentation, MacDonald mentioned being inspired by Soft Energy Paths, by RMI’s chief scientist and cofounder, Amory Lovins. Can you talk a bit about how this publication and perhaps other publications from RMI have inspired or been utilized in your work?

NOAA: Soft Energy Paths started me thinking more about the role of energy in both the economy and the environment. About a year after we began this project, Reinventing Fire was released. I was very happy to see the broad and comprehensive approach RMI took to the problem and felt that our quantitative treatment of the weather-driven renewable electric portion had the potential to really validate many of the points made in the book.

RMI: What role does innovation play in your work?

NOAA: The Earth System Research Laboratory is NOAA’s largest research facility. Our research is mission oriented, meaning we are focused on improving NOAA’s products and services—which include weather forecasts and assessments of climate impacts. While some improvements are predictable, such as the expectation to benefit from improving supercomputer capability, other advances are not. The willingness to try new approaches is essential in research—even applied research.

RMI: What is the most surprising/interesting thing happening in your work right now?

NOAA: Using today’s costs for wind and solar power plants, our energy system modeling yielded a penetration that is almost identical to today’s actual level. Even though we have non-economic policy influences such as renewable portfolio standards (RPS), we were somewhat surprised at how close we currently are to economic efficiency with respect to wind and solar. Keep in mind that the very low penetration (~5 percent) we currently have installed is not reliant on large-scale transmission. To efficiently break into high-penetration scenarios, it is clear that a much improved transmission capability is necessary.

RMI: What keeps you optimistic about our energy future?

NOAA: We feel the work we have done on this project shows that renewable energy sources (wind and solar) can be a very large part of powering our modern way of life, and in fact will be most economically efficient if U.S. cost targets are achieved for wind and solar technologies. Everyone is starting to understand that we do not need to burn millions of years of fossil carbon to power a healthy economy—there are plenty of renewable resources to take its place.

The road ahead

If this piqued your interest, stay tuned for upcoming publications on this research. NOAA’s ESRL has a technical article on this work submitted and under review at the International Journal of Electrical Power & Energy Systems, and two other articles possible for publication at a later date.

Meanwhile, NOAA’s early results are certainly encouraging in terms of realizing Reinventing Fire’s larger carbon reduction goals and movement toward renewable generation. While Reinventing Fire lays out a number of electricity cases for an electrical system with 80-percent-lower carbon emissions in 2050, RMI specifically works toward the Transform case, which details a significant transformation to use of distributed generation, in conjunction with a substantial expansion of utility-scale renewable generation. NOAA’s early conclusions on the need for a substantial transmission evolution (and the large costs that forebodes) with increased renewable energy hopefully can be moderated by improved grid management and generation at the distribution level.

Image courtesy of shutterstock.com

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