The Jacobson Plan: 100% renewable energy in the United States

This week a team led by Stanford Professor of Civil and Environmental Engineering Mark Jacobson presented the latest results of its work on the technical and economic feasibility of moving the United States to 100% renewable energy by 2050. This includes state-by-state assessments and covers all forms of energy: Electricity, transit, heat and industry.

Their conclusion: It can be done. This does not surprise many of us who work in renewable energy; but it’s still, in the immortal words of Joe Biden, a big f***ing deal.

I’m a big fan of Jacobson’s work, and I think this is exactly the conversation that we need to be having at this time. And as someone who has been writing about day-to-day conditions in the solar industry and the transition to renewable energy for five years, I have some friendly critiques of this study.

I have more critical comments on the media coverage of this work, namely the article by Vox’s David Roberts.

80% by 2030

First off, it bears mentioning that while the headline is 100% renewable energy by 2050, I feel that the more radical and exciting conclusion is that we can get 80% of our total energy – again, electricity, transportation and heat – from wind, water power and solar by 2030.

Given that it would dramatically reduce carbon emissions, I’m not so concerned if we burn a little oil and/or gas for the remaining 20%. Also, I will argue that when we reach 80% renewable energy, transforming the next 15-18% of our energy supply is likely to only take five to ten years.

The reason is that by this time, the solar, wind and battery industries will be the energy incumbents. They will subsequently be massive and will have a level of R&D spending, technology momentum and political/economic clout that will enable them to solve some of the thornier remaining problems of the transition much more quickly.

Critiques of approach

I have a number of friendly critiques of this important study. But first, it is fundamental to understand that this is a work by engineers looking at technical and economic factors in a somewhat simplified form with a number of assumptions. It also does not deal with political realities. In his coverage for Vox, David Roberts was right to emphasize these points.

I’ll also note that the study, by focusing on existing conditions and technologies and by using studies that consider the same, is unavoidably subject to a form of incumbency bias. This is true of most major studies of renewable energy, and appears to be the primary reason that forecasts for renewable energy, whether done by the U.S. DOE, the IEA, and even Greenpeace have repeatedly underestimated the rapid growth and cost reduction in solar PV and wind technologies in recent years.

This includes the assumption that there will not be technology breakthroughs, which I consider reasonable and fair. Solar, wind, and battery technologies have evolved slowly over time and are more characterized by incremental improvements than breakthroughs.

I am concerned about the cost assumptions. I’m a little unclear how the study got its estimates for 2050 costs (p.12), given that it cites “electronic supplemental information”. However, the average 2050 technology costs for utility-scale solar PV are higher than current power purchase agreements, while solar PV costs continue to fall rapidly. And while the average costs for delivered electricity cited by Jacobson include “long-distance transmission, distribution and storage”, the cost fall for utility-scale solar PV is assumed to be less than 20% over the next 35 years, and 30-50% for rooftop PV.

Again, while it is hard to comment on these estimates as I am not clear on the assumptions, I think anyone who has seen the ongoing collapse in solar PV costs over the last decade will find these numbers to be extremely conservative.

Likewise, I am puzzled by the costs given for concentrating solar power (CSP, also called solar thermal electric), given that the cost with storage is lower than the cost without storage. And while I’m a big fan of CSP due largely to this ability to incorporate low-cost energy storage, I must openly question the assumptions of cost reduction for solar CSP relative to solar PV, given the very different nature of these technologies.

What does this mean in practice? It means I expect solar PV (with storage) to be a bigger part of the energy mix than the 38% that Jacobson projects.

Similarly, there is the assumption that grid integration will rely on “prioritizing storage for excess heat (in soil and water) and electricity (in ice, water, phase-change material tied to CSP, pumped hydro, and hydrogen)”, limited pumped hydro, and demand response. Jacobson does mention battery storage at the distributed level in homes and businesses, however he does not include grid-scale battery energy storage.

I must refer here to the recent growth in battery storage applications, and the work of analysts who predict a rapid increase in the use of battery storage at all scales. Notably, falling costs for batteries are anticipated with greater economies of scale, driven in part by the electric vehicle and small-scale energy storage industries.

Finally, when Jacobson does look at policy solutions, he limits them to renewable portfolio standards, which are widely deployed at present, taxes and fees on carbon, which are less widely adopted but very popular with American activists, and weak policies like net metering. He does not include feed-in tariffs or other forms of standard offer policies like Value of Solar Tariffs.

Not only have standard offer policies driven the rapid deployment of wind and solar globally, but they are particularly effective for the mass deployment of the distributed solar which Jacobson relies upon for 7.2% of all power needs. The nations in Western Europe which have quickly transitioned to non-hydro renewable energy for significant portions of their electricity supply all used some form of standard offer policy during the periods of most rapid adoption of renewable energy, and I think it’s unrealistic to not include them in projections based on rapid deployment.

On resources

I also have a number of friendly critiques of the assumptions that Jacobson makes regarding resources, some of which I feel to be neither realistic nor reasonable. Topping the list is that while various forms of wind, solar, geothermal, wave and tidal power are included, biomass is explicitly excluded.

Jacobson cites the air pollution side effects of biofuels, and this is a fair critique of incineration in general. He also cites the land use requirements for these technologies. I can personally understand an opposition to woody biomass based on issues with sourcing, questionable carbon calculations, and the risk that whole forests will be turned into fuel for power plants. I can also understand concerns about incineration of municipal solid waste due to concerns about introducing toxins into the air.

However, biomass is broad, and I see no reason to exclude practical and beneficial forms of biomass such as annual crop-based biomass (straw, sugarcane bagasse) and biogas. Both technologies are often integrated into existing agricultural practices, and as such require no additional land use. Furthermore, in the case of sugarcane bagasse, the crop residues used for fuel are burned anyway, so there are no net pollution impacts of efficiently producing power with them.

More importantly, biomass and biogas can be fast-ramping, flexible resources (unlike nuclear power plants), and as such are the sort of generation that you want on hand for periods of low wind and solar output. Including some forms of biomass will be particularly important for states like Louisiana, which has weak onshore wind resources and only moderate solar potential, as well as a strong agriculture industry which can and should be part of the Energy Transition.

An assumption which concerns me far more is that we will account for all externalities of our current power system, including both climate and health impacts. We can and should account for these. But in the real world we won’t, and as such we need to look at cost considerations that do not include externalities.

Associated with this overly idealistic approach to costs is a seeming disregard for some of the conditions of technology deployment. This distorts the report’s findings slightly. For example, we’re never going to deploy any CSP in some of the places that Jacobson includes in his study (Wisconsin, West Virginia, Louisiana, Minnesota, Michigan). This is because the resource intensity is inadequate to make the numbers work, and because we’ll find other, more cost-effective ways to meet peak demand (like batteries).

All in all, these are minor critiques. Again, this is a technical and economic study done by engineers which takes the safe and conservative approach of using existing technologies and conditions. It also does not deal with broader, real-world economic and political issues. But what it does it does relatively well and it’s an important contribution.

Vox falls short

I reserve a sharper critique for the subsequent article written on this study by David Roberts, who covers climate and energy issues for Vox. First, I must note that Roberts covered the findings of this study accurately and without introducing mythologies about renewable energy. This is a low bar, but unfortunately the uncritical repeating of such myths is standard practice for much of the mainstream media.

So while Roberts does a good job of explaining the focus and limitations of the study, he then goes on to state that the plan is unrealistic, based on the current state of the U.S. government. That’s a mistake.

Jacobson’s work proposes several policy options to support the transition, and Roberts notes that taken together, these policy recommendations “represent an unprecedented level of government activism, a skein of incentives, mandates, standards, and laws unmatched in US history”.

He then focuses on one statement in the report: “We do not believe a technical or economic barrier exists to ramping up production of WWS technologies, as history suggests that rapid ramp-ups of production can occur given strong enough political will”, and referencing World War II aircraft production.

Roberts has made a leap of logic here. The study definitely suggests that strong political will is one way that these changes can come about; I don’t read anywhere where it says that this is the only way or sole factor.

Jacobson and the other authors can speak for themselves. What I will say is that if these changes relied solely on the federal government and/or coordinated action between states and the federal government, we would be well and truly screwed. As someone who has covered the growth of renewable energy markets both globally and in the United States, I must explain that the ongoing, rapid growth of renewable energy in this nation is the result of several factors, and that support by the U.S. federal government is the least of these.

The U.S. solar market has more than doubled every two years for the past decade, and in 2014 we put online roughly 7 gigawatts (GW) of PV and CSP capacity, with a peak power output equivalent to seven nuclear reactors. Much of this is driven by state-level mandates. 28 states and the district of Columbia have mandates (renewable portfolio standards or RPS) that utilities procure an increasing share of their power from renewables.

In leading states, RPS policies are becoming more aggressive. Hawaii has increased its RPS to 100% of electricity by 2045, and California is considering adding to its 33% by 2020 mandate to require that utilities source 50% of their power from renewables by 2030.

While important, the progress in these leading, “blue” states will not alone get us there. Fortunately, many “red” states are also embracing renewable energy – a detail you would not know from Roberts’ grim and oversimplified picture of the political landscape for renewables:

“Republicans, who fervently oppose nearly every one of these goals, are expected to control the House of Representative and well over half of the 50 state legislatures.”

Well, in Georgia, a public service commission composed entirely of Republicans backed by a Tea Party group has required that Georgia Power build hundreds of megawatts of solar, and the Republican Governor just signed a bill approved by a Republican-controlled legislature authorizing third-party-owned solar. In Arizona, the son of conservative icon Barry Goldwater leads a group fighting for net metering, which has since expanded to Louisiana. An in the 2012 presidential race, Iowa Senator Chuck Grassley railed against Mitt Romney for attacking the wind energy tax credit.

This emerging split in the Republican Party and American right isn’t the result of Republicans suddenly caring about Climate Change or the environment. It is in part because most of the optimal wind and solar resources in the United States is located in red states, and as these industries grow and gain speed they become important constituents for politicians of any party. And it is in part because the ability to generate your own power with rooftop PV appeals to right-wing ideas about self-sufficiency.

Other trends are even more fundamental. Regardless of national politics, the residential PV market continues to grow consistently, driven by falling costs, even in states that do not have RPS requirements. For larger-scale PV, GTM Research reports that there are 5.5 GW of utility-scale projects that have been contracted by utilities and private companies outside of RPS mandates in the last two years. Some of this was through PURPA, which requires that utilities purchase power from independent power producers if it less than their estimated cost of generation. Some of it is being voluntarily procured by utilities. Either way, it’s being built primarily for economic reasons.

Similarly, the wind industry is booming in the Great Plains and parts of the Midwest, despite the lack of mandatory RPS policies in most of these states. In states like Iowa that have RPS policies, deployment of wind has exceeded RPS targets for all renewable energies.

Roberts’ quick dismissal overlooks all of this, and the bigger picture. As more renewables are deployed and costs come down, not only does political policy support grow, but such support and particularly incentives becomes less important, and solar and wind begin to be deployed for economic reasons.

It would be easy for much of the public to miss this, given that some of the most important signs of these trends have emerged only in the last two years. However, this is Roberts’ beat, so I expect more of him. And I must recommend again that for a larger understanding of how solar PV in particular represents a technology disruption, Roberts should read Tony Seba’s work.

This is not the first time that Roberts’ deserved cynicism about the direction of policy at federal level has translated into being dismissive of prospects for a rapid transition to renewable energy. He has his line, and it is simple. It’s also what the fossil fuel and nuclear industries would like you to think: That rapid deployment of renewables as a solution to the worst effects of Climate Change is unrealistic.

Fortunately for all of us, the future will not ultimately be determined by the opinions of writers at Vox, or any other publication, or the dismal state of politics at the U.S. federal level. Powerful technological and economic factors are driving the shift to renewable energy. The fights over policy are very important, but ultimately they are only about how quickly we accelerate this inevitable shift.



  1. […] applaud Roberts for this, even if I find his analysis to sometimes miss important details, and if I find his choice of sources disappointing, per the latest article. As I did in the last […]

  2. […] discussed my points of concern about the Jacobson report in a previous post; namely that I think it makes the technical challenge more difficult than it needs to be (and more […]

  3. […] discussed my points of concern about the Jacobson report in a previous post; namely that I think it makes the technical challenge more difficult than it needs to be (and more […]

  4. […] we get close to the goal of 100% renewable energy, things may look different, but as I’ve argued before, 80% is the more important […]

  5. […] he cites the work of Stanford Professor Mark Jacobson. I think Jacobson’s work is important, but as I have written before, it is more an academic exercise than a practical roadmap, and as an academic exercise, Jacobson […]

  6. […] modeling experience to know that there were issues with the Jacobson study. When the study came out I welcomed it as an academic work, but noted several of its limitations; I certainly never expected it to be used as a plan for deployment of renewable energy as it is […]

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