For how long are we going to have to keep talking about the energy transition? Let’s be honest, it can get pretty tiring after awhile – and this has got to be part of why so many people are looking for a quick fix, so we can move on already. “Electrify everything!” is the kind of slogan that fits this mood. Never mind that the technology for electrifying many end uses is not yet available, or that wind, solar and battery power carry a whole host of sustainability issues in their own right. The desire to avoid all the messy compromises around biofuels, carbon capture and the like is so strong that some healthy climate advocates prefer to pretend that none of those technologies are needed.
We are looking for a holy grail to rescue us from the unpleasant reality that over three quarters of the energy used in the US and worldwide still comes from fossil fuels. If that number seems high, it’s because most reporting focuses on electricity generation, where fossil fuels contribute “only” about 60%. The 15-20 point gap between fossil fuel use in power generation versus fossil fuel use overall comes from the fact that electrification of the transportation, industry, residential and commercial sectors is advancing very slowly. Those four sectors gobble up over 60% of the energy used in the US, and all are still heavily dominated by oil and gas.
Hope springs eternal for the perfect energy source, but the physical universe has its own internal logic. The number of primary energy sources available to us is actually very limited – sunlight, radioactivity and geologic heat (itself deriving partly from radioactivity) make up the entire list. All our other energy sources (wind, hydropower, biomass, fossil fuels) depend ultimately on the Sun for their existence. From there, everything devolves to an engineering problem. If we cannot efficiently harness a particular primary or secondary source to deliver energy at scale and reasonable cost, then we move on to something else.
Vaclav Smil, one of our leading energy historians, has exhaustively documented the national, regional and global transition of energy use from the preindustrial era to the present. Smil’s key insight from analyzing the 19th/20th century transition from surface biomass (especially wood) to fossil fuels is that overcoming the inertia of existing energy systems necessarily takes many decades, not just a few years. His extrapolation of this finding to our present-day transition generates a message that conservatives have been more than pleased to adopt as their own: fossil fuels will inevitably still be around for a long time. The desire to defeat this message fuels hopes for a holy grail that will somehow bring about rapid decarbonization, proving Smil wrong.
Conceptually, our present energy transition is divisible into three parts that will be completed under different timetables but overlap in execution: decarbonization of the electricity grid, electrification of end uses across all sectors of the global economy, and removal of long-lived atmospheric carbon dioxide to return the climate to some facsimile of its preindustrial state. The present consensus gives clearly dominant roles to solar and wind power, enabled by decreases in cost from both public subsidies (in the US, primarily via tax breaks) and developing economies of scale. Although today’s statistics still look bleak, the promising future of the electricity grid is clearly visible in the data for new capacity additions. In 2023, the US added 56 gigawatts (GW) of new power to a grid with a total capacity of about 1300 GW, of which 82% came from solar, wind and batteries and only 14% from natural gas. In contrast, all the old electricity generation retired in 2023 (about 15 GW) was fossil fuel powered.
Is it a good idea to depend so much on wind and solar power? The amount of energy storage required on the grid increases with the proportion of intermittent sources, so a grid heavily dominated by solar and wind would demand more investment in batteries and other storage mediums. This raises legitimate concerns about mining of lithium, cobalt and other metals, much of which is presently sourced from other countries where pollution control and attention to social equity are not priorities. We should also note the huge land footprints of solar and wind farms, which generates concerns about ecology and aesthetics, and leads to a great deal of local pushback. These issues increase the vulnerability of both technologies and offer a wedge for advocates of natural gas to make their case for continuing the status quo.
In the US, we are plunging ahead with solar and wind because other good options are scant. Hydroelectric power (6% of grid capacity) cannot expand much because almost all our large rivers are already dammed, and conventional geothermal power (1%) is limited by the low abundance of known sources hot enough to generate the steam needed to drive electricity turbines. Broad opposition to biomass (1%) is driven by the very large land and ecological impacts that would arise from its expansion, and our fleet of aging, large nuclear fission plants (18%) is in slow decline, with an increasing number of facilities requiring repairs and federal bailouts to stay in operation.
To be sure, some are bullish about the potential for conventional power sources to expand their reach. While new hydropower facilities are not an option in the US, there is potential to retrofit existing dams used for other purposes to add a modest amount of new generation capacity, including pumped storage. A related technology, tidal power, received some funding in the 2021 bipartisan infrastructure bill – though the cost and size of projected facilities is formidable, and the DOE has just announced that the money is being targeted to remote areas where the local grids need a boost. Enhanced geothermal systems, a fracking-based approach to broadly tap underground heat (Earthward, Sept. 14), has significant potential but is still very much in an exploratory development phase.
Another prospect for expanding conventional energy technology is offered by small modular nuclear fission reactors (SMRs). The technology here is a well-developed scale-down of large reactors, and the Nuclear Regulatory Commission has approved designs from NuScale, a leading company. The hope is that these reactors – with smaller footprints, safer designs and lower requirements for fissionable material – will catch on as replacements for the existing commercial reactor fleet. This would allow nuclear power to maintain its significant, carbon-free contribution to powering the grid over at least the next few decades. However, the recent, highly publicized cancellation of an SMR project in Utah, caused by tripling of costs over an eight-year development period, has generated a great deal of pessimism about whether the technology can succeed in the marketplace. At this point it is not clear when SMRs might begin operating in the US, although prospects are brighter elsewhere in the world, with the first few projects commencing operation in 2022.
It’s clear enough that none of this looks anything like what holy grail seekers have in mind, but we know that hope dies hard. In fact, a perennial candidate for the holy grail has recently resurfaced: nuclear fusion. After all, if harnessing incoming sunlight has issues, why not create our own little suns right here on earth?
The enthusiastic media response to the Lawrence Livermore National Laboratory’s announcement, in December 2022, that it had achieved “fusion ignition” really highlighted the deep hopes for a solution to the clean energy dilemma. Nuclear fusion, in the Sun and now also under controlled conditions in the lab, is the combination of two light atoms (like hydrogen) to form a heavier atom (helium), producing a huge burst of energy. Getting the reaction to go in the lab involved focusing 192 laser beams on a fusion cell, a process that (needless to say) itself requires a huge amount of energy. “Fusion ignition” means that, after no less than 60 years of effort, LLNL physicists have finally been able to make the process yield a net energy gain. In LLNL’s words, this achievement has “launch[ed] the era of controlled fusion ignition in the laboratory.” Energy secretary Jennifer Granholm called the achievement “one of the most impressive scientific feats of the 21st century,” and many news outlets offered similar assessments. The bipartisan House of Representatives “fusion caucus” has grown rapidly since the announcement, and the Senate is following suit, with plans to announce a similar caucus in the upcoming weeks. Politico reports that, among other actions, the new groups hope to establish an industry-friendly approach to regulation, a timetable for transferring fusion research dollars from basic science to commercialization programs, and a more stable mechanism for continuing funding into the future.
Some members of Congress think that commercialization of fusion power is achievable within eight to ten years, but this is wildly unrealistic given the formidable engineering hurdles that must be surmounted. LLNL has successfully repeated its experiment several times in the past year, but this does not change the fact that, as stated in the peer-reviewed publication describing the data, the achievement still consists only in a “proof of principle that controlled laboratory fusion energy is possible.” An even more sobering reality check is that the actual full energy requirement for the laser facility is 100 times greater than the energy output: only the comparison of direct energy into the fusion target, with the energy produced, yields a positive energy gain. The breakthrough is real, but the practical prospects for commercialization are still just a glimmer on the horizon.
Is this it for energy miracles? Maybe not. Because while we know that the prospects for enhancing geothermal energy supply by fracking pose some very challenging engineering problems, some are asking whether natural underground heat may have generated an overlooked source of clean chemical energy that is just sitting there, ripe for the taking. That is our topic for next week.
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Global energy mix: https://ourworldindata.org/energy-mix
Global electricity production, by energy source: https://ourworldindata.org/electricity-mix
US energy mix: https://www.eia.gov/energyexplained/us-energy-facts/
US electricity generation by source: https://www.eia.gov/tools/faqs/faq.php?id=427&t=3
Vaclav Smil’s book on energy transitions: https://publisher.abc-clio.com/9781440853258/
US electric power capacity additions, 2023: https://www.eia.gov/outlooks/aeo/electricity/sub-topic-02.php
Impacts of wind and solar farms: https://sustainablereview.com/environmental-impacts-wind-vs-solar/
Hydropower expansion potential: https://e360.yale.edu/features/can-retrofitting-dams-for-hydro-provide-a-green-energy-boost
Tidal power challenges: https://climate.mit.edu/ask-mit/why-dont-we-use-tidal-power-more
Tidal power funding: https://www.energy.gov/articles/biden-harris-administration-invests-nearly-16-million-advance-marine-energy-us-1
Enhanced geothermal: https://cleantechnica.com/2023/10/13/geothermal-energy-rising-pros-risks/
US nuclear power industry: https://www.eia.gov/energyexplained/nuclear/us-nuclear-industry.php
Small modular nuclear reactors: https://www.energy.gov/ne/benefits-small-modular-reactors-smrs
Opinion against SMRs: https://www.utilitydive.com/news/nuscale-uamps-project-small-modular-reactor-ramanasmr-/705717/
SMR global development: https://www.statista.com/statistics/1334632/number-of-small-modular-reactor-projects-worldwide/
Lawrence Livermore’s fusion ignition: https://www.llnl.gov/news/ignition
LLNL press release: https://www.llnl.gov/article/49306/lawrence-livermore-national-laboratory-achieves-fusion-ignition
Congressional action on fusion: https://www.eenews.net/articles/fusion-fever-grips-capitol-hill-will-big-funding-follow/
Fusion reality check: https://spectrum.ieee.org/nuclear-fusion-breakthrough-long-road
Fusion experiment: peer-reviewed paper: https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.132.065102