By George Harvey
In May of 2015, at team from Stanford University led by Dr. Mark Z. Jacobson published a paper, “100% clean and renewable wind, water, and sunlight (WWS) all-sector energy roadmaps for the 50 United States” (Roadmaps). (http://bit.ly/stanford-fossil-free) The Roadmaps provide formulas for each state to get to 100% freedom from use of polluting energy sources using resources available to that state.
Jacobson’s paper was especially notable for several reasons. While it provided a mix of WWS that would work for each state to get entirely off of fossil fuels, it went further, showing how to eliminate use of carbon-based combustion and nuclear fission altogether. Not only were coal and natural gas not to be used, regardless of carbon capture, but neither were bio-mass and bio-fuels.
The Roadmaps envision efficiency-driven reductions in energy demand among states by a mean of about 39.3% by 2050. All energy would be electric, with onshore wind providing about 30.9%, offshore wind about 19.1%, utility-scale photovoltaics (PV) about 30.7%, rooftop PVs about 7.3%, concentrating solar with storage about 1.25%, hydroelectric power about 3.01%, wave power about 0.37% and tidal power about 0.14%.
Batteries and hydrogen fuel cells are given as the preferred power technologies for most vehicles, with some powered by cryogenic hydrogen. Heating buildings and water, along with cooking, are to be from heat pumps, resistance heaters, and induction heaters. The paper says, “High-temperature industrial processes will be powered by electric arc furnaces, induction furnaces, dielectric heaters, and resistance heaters and some combusted electrolytic hydrogen.”
The goal of Jacobson’s paper is not merely to stop climate change caused by specific types of pollution. It is to reduce all pollution to a bare minimum, addressing not only climate problems, but those producing other issues for both our health and our environment. Dr. Jacobson told us, “Our goal is to solve the air pollution problem simultaneously with the climate problem and to minimize catastrophic risk at the same time.”
The paper gives reasons for avoiding bio-fuels; the most important, that they actually do not reduce pollution. Similarly, nuclear power has environmental effects and dangers that have never been addressed, long-term waste storage being one example.
Though this paper is two years old, we are revisiting it because of attacks that have been mounted on it in the past several weeks. The first of these is an evaluation by Christopher Clack and a score of other scientists, “Evaluation of a proposal for reliable low-cost grid power with 100% wind, water, and solar” (Evaluation). (http://bit.ly/fossil-free-evaluation) It took issue with much of what was found in Jacobson’s paper.
I found the “Evaluation” disturbing for what I see as sloppy unprofessionalism. For example, its abstract contains this sentence, supported by two references: “A number [sic] of studies, including a study by one of us, have concluded that an 80% decarbonization [sic] of the US electric grid could be achieved at reasonable cost.” But the main body of the Evaluation contains this statement, without any citation to support it: “With all available technologies at our disposal, achieving an 80% reduction in GHG emissions from the electricity sector at reasonable costs is extremely challenging, even using a new continental-scale high-voltage transmission grid. Decarbonizing the last 20% of the electricity sector as well as decarbonizing the rest of the economy that is difficult to electrify (e.g., cement manufacture and aviation) are even more challenging.”
Unfortunately, the Evaluation was taken by a segment of the press as a condemnation of the whole idea of getting to 100% renewable energy. The pro-fossil fuel press gave the impression that somehow the Evaluation was all the better because of the sheer number of scientists who were named as co-authors, despite the fact that some of them had no credentials in energy or climate science, or seemed to have conflicts of interest.
Dr. Jacobson responded to the Evaluation with a letter, “The United States can keep the grid stable a low cost with 100% clean, renewable energy in all sectors despite inaccurate claims,” in the same publication that published both it and his original paper. (http://bit.ly/Jacobson-response-letter) He also gave us a detailed, line-by-line response. (http://bit.ly/jacobson-evaluation-line-by-line) In some ways, the line-by-line response is a very much more interesting read than the original paper. One way is that it evaluates objections that have arisen.
My own assessment of Dr. Jacobson’s original paper is that, at the age of two years, it is a little out of date, because of steep declines in solar power and, more to the point, battery storage since it was published.
In addition, I think that it does not address the possibilities of bio-digesters, which the National Renewable Energy Laboratory said, in 2013, could replace 40% of our demand for natural gas. The waste producing the gas has to be dealt with one way or another, and, in keeping with Dr. Jacobson’s standards, could be used in fuel cells. (It could also be used as a replacement for some fossil fuels as a feedstock for other chemicals.)
Another minor issue I would mention is that ammonia, which is carbon-free, can be used as a fuel. A number of technologies have been developed for clean manufacture of ammonia. While ammonia can be burned directly, and has been used in the past to power buses with internal combustion engines, it also has the advantage that it can be used as a fuel for fuel cells, because it can be used to store much larger quantities of hydrogen than can be kept as a gas in tanks of the same volume.
A recent article of mine, listing alternative sources of energy, was published at CleanTechnica.com, “Getting the Last 20% Of Our Energy from Renewables.” (http://bit.ly/getting-the-last-20) In it, I listed a number of technologies that could fill in for fossil fuels in what are currently difficult places.
Given two years’ hindsight, I would argue that Roadmaps was, if anything, a bit too conservative. I think we have made scientific and technological progress Dr. Jacobson did not envision.
In his email, Dr. Jacobson also said, “We have a paper for 139 country roadmaps … coming out the first week of August in the journal, Joule.” We might all look forward to seeing that.
Note: Since this was written, the new paper has appeared. It can be found at: