Google isn’t alone in eyeballing nuclear power as an energy source for massive datacenters. In September, Ars reported on a plan from Microsoft that would re-open the Three Mile Island nuclear power plant in Pennsylvania to fulfill some of its power needs. And the US administration is getting into the nuclear act as well, signing a bipartisan ADVANCE act in July with the aim of jump-starting new nuclear power technology.
AI is driving demand for nuclear
In some ways, it would be an interesting twist if demand for training and running power-hungry AI models, which are often criticized as wasteful, ends up kick-starting a nuclear power renaissance that helps wean the US off fossil fuels and eventually reduces the impact of global climate change. These days, almost every Big Tech corporate position could be seen as an optics play designed to increase shareholder value, but this may be one of the rare times when the needs of giant corporations accidentally align with the needs of the planet.
Even from a cynical angle, the partnership between Google and Kairos Power represents a step toward the development of next-generation nuclear power as an ostensibly clean energy source (especially when compared to coal-fired power plants). As the world sees increasing energy demands, collaborations like this one, along with adopting solutions like solar and wind power, may play a key role in reducing greenhouse gas emissions.
Despite that potential upside, some experts are deeply skeptical of the Google-Kairos deal, suggesting that this recent rush to nuclear may result in Big Tech ownership of clean power generation. Dr. Sasha Luccioni, Climate and AI Lead at Hugging Face, wrote on X, “One step closer to a world of private nuclear power plants controlled by Big Tech to power the generative AI boom. Instead of rethinking the way we build and deploy these systems in the first place.”
With the plunging price of photovoltaics, the construction of solar plants has boomed in the US. Last year, for example, the US’s Energy Information Agency expected that over half of the new generating capacity would be solar, with a lot of it coming online at the very end of the year for tax reasons. Yesterday, the EIA released electricity generation numbers for the first five months of 2024, and that construction boom has seemingly made itself felt: generation by solar power has shot up by 25 percent compared to just one year earlier.
The EIA breaks down solar production according to the size of the plant. Large grid-scale facilities have their production tracked, giving the EIA hard numbers. For smaller installations, like rooftop solar on residential and commercial buildings, the agency has to estimate the amount produced, since the hardware often resides behind the metering equipment, so only shows up via lower-than-expected consumption.
In terms of utility-scale production, the first five months of 2024 saw it rise by 29 percent compared to the same period in the year prior. Small-scale solar was “only” up by 18 percent, with the combined number rising by 25.3 percent.
Most other generating sources were largely flat, year over year. This includes coal, nuclear, and hydroelectric, all of which changed by 2 percent or less. Wind was up by 4 percent, while natural gas rose by 5 percent. Because natural gas is the largest single source of energy on the grid, however, its 5 percent rise represents a lot of electrons—slightly more than the total increase in wind and solar.
Enlarge/ US electricity sources for January through May of 2024. Note that the numbers do not add up to 100 percent due to the omission of minor contributors like geothermal and biomass.
John Timmer
Overall, energy use was up by about 4 percent compared to the same period in 2023. This could simply be a matter of changing weather conditions that require more heating or cooling. But there have been several trends that should increase electricity usage: the rise of bitcoin mining, the growth of data centers, and the electrification of appliances and transport. So far, that hasn’t shown up in the actual electricity usage in the US, which has stayed largely flat for decades. It could be possible that 2024 is the year when usage starts going up again.
More to come
It’s worth noting that this data all comes from before some of the most productive months of the year for solar power; overall, the EIA is predicting that solar production could rise by as much as 42 percent in 2024.
So, where does this leave the US’s efforts to decarbonize? If we combine nuclear, hydro, wind, and solar under the umbrella of carbon-free power sources, then these account for about 45 percent of US electricity production so far this year. Within that category, wind and solar now produce more than three times hydroelectric, and roughly the same amount as nuclear.
Wind and solar have also produced 1.3 times as much electricity as coal so far in 2024, with solar alone now producing about half as much as coal. That said, natural gas still produces twice as much electricity as wind and solar combined, indicating we still have a long way to go to decarbonize our grid.
Enlarge/ When you look at the generating facilities that will be built over the next 12 months, it’s difficult not to see a pattern.
Still, we can expect solar’s productivity to climb even before the year is out. That’s in part because we don’t yet have numbers for June, the month that contains the longest day of the year. But it’s also because the construction boom shows no sign of stopping. As noted here, solar and wind deployments are expected to dwarf everything else over the coming year. The items in gray on the map primarily represent battery storage, which will allow us to make better use of those renewables, as well.
By contrast, facilities that are scheduled for retirement over the next year largely consist of coal and natural gas plants.
High-assay low-enriched uranium (HALEU) has been touted as the go-to fuel for powering next-gen nuclear reactors, which include the sodium-cooled TerraPower or the space-borne system powering Demonstration Rocket for Agile Cislunar Operations (DRACO). That’s because it was supposed to offer higher efficiency while keeping uranium enrichment “well below the threshold needed for weapons-grade material,” according to the US Department of Energy.
This justified huge government investments in HALEU production in the US and UK, as well as relaxed security requirements for facilities using it as fuel. But now, a team of scientists has published an article in Science that argues that you can make a nuclear bomb using HALEU.
“I looked it up and DRACO space reactor will use around 300 kg of HALEU. This is marginal, but I would say you could make one a weapon with that much,” says Edwin Lyman, the director of Nuclear Power Safety at the Union of Concerned Scientists and co-author of the paper.
Forgotten threats
“When uranium is mined out of the ground, it’s mostly a mixture of two isotopes: uranium-238 and uranium-235. Uranium 235 concentrations are below one percent,” says Lyman. This is sent through an enrichment process, usually in gas centrifuges, where it is turned into gaseous form and centrifuged till the two isotopes are separated from each other due to their slight difference in their atomic weights. This can produce uranium with various levels of enrichment. Material that’s under 10 percent uranium-235 is called low-enriched uranium (LEU) and is used in power reactors working today. Moving the enrichment level up to between 10 and 20 percent, we get HALEU; above 20 percent, we start talking about highly enriched uranium, which can reach over 90 percent enrichment for uses like nuclear weapons.
“Historically, 20 percent has been considered a threshold between highly enriched uranium and low enriched uranium and, over time, that’s been associated with the limit of what is usable in nuclear weapons and what isn’t. But the truth is that threshold is not really a limit of weapons usability,” says Lyman. And we knew that since long time ago.
A study assessing the weaponization potential of uranium with different enrichment levels was done by the Los Alamos National Laboratory back in 1954. The findings were clear: Uranium enriched up to 10 percent was no good for weapons, regardless of how much of it you had. HALEU, though, was found to be of “weapons significance,” provided a sufficient amount was available. “My sense is that once they established 20 percent is somewhat acceptable, and given the material is weapons-usable only when you have enough of it, they just thought we’d need to limit the quantities and we’d be okay. That sort of got baked into the international security framework for uranium because there was not that much HALEU,” says Lyman. The Los Alamos study recommended releasing 100 kg of uranium enriched to up to 20 percent for research purposes in other countries, as they didn’t think 100 kg could lead to any nuclear threats.
The question that wasn’t answered at the time was how much was too much.
Enlarge/ Jürgen Trittin, member of the German Bundestag and former environment minister, stands next to an activist during an action of the environmental organization Greenpeace in front of the Brandenburg Gate in April 2023. The action is to celebrate the shutdown of the last three German nuclear power plants.
One year ago, Germany took its last three nuclear power stations offline. When it comes to energy, few events have baffled outsiders more.
In the face of climate change, calls to expedite the transition away from fossil fuels, and an energy crisis precipitated by Russia’s 2022 invasion of Ukraine, Berlin’s move to quit nuclear before carbon-intensive energy sources like coal has attracted significant criticism. (Greta Thunberg prominently labeled it “a mistake.”)
This decision can only be understood in the context of post-war socio-political developments in Germany, where anti-nuclearism predated the public climate discourse.
From a 1971 West German bestseller evocatively titled Peaceably into Catastrophe: A Documentation of Nuclear Power Plants, to huge protests of hundreds of thousands—including the largest-ever demonstration seen in the West German capital Bonn—the anti-nuclear movement attracted national attention and widespread sympathy. It became a major political force well before even the Chernobyl disaster of 1986.
Its motivations included: a distrust of technocracy; ecological, environmental, and safety fears; suspicions that nuclear energy could engender nuclear proliferation; and general opposition to concentrated power (especially after its extreme consolidation under the Nazi dictatorship).
Instead, activists championed what they regarded as safer, greener, and more accessible renewable alternatives like solar and wind, embracing their promise of greater self-sufficiency, community participation, and citizen empowerment (“energy democracy”).
This support for renewables was less about CO₂ and more aimed at resetting power relations (through decentralised, bottom-up generation rather than top-down production and distribution), protecting local ecosystems, and promoting peace in the context of the Cold War.
Germany’s Energiewende
The contrast here with Thunberg’s latter-day Fridays for Future movement and its “listen to the experts” slogan is striking. The older activist generation deliberately rejected the mainstream expertise of the time, which then regarded centralised nuclear power as the future and mass deployment of distributed renewables as a pipe dream.
This earlier movement was instrumental in creating Germany’s Green Party—today the world’s most influential—which emerged in 1980 and first entered national government from 1998 to 2005 as junior partner to the Social Democrats. This “red-green” coalition banned new reactors, announced a shutdown of existing ones by 2022, and passed a raft of legislation supporting renewable energy.
That, in turn, turbocharged the national deployment of renewables, which ballooned from 6.3 percent of gross domestic electricity consumption in 2000 to 51.8 percent in 2023.
These figures are all the more remarkable given the contributions of ordinary citizens. In 2019, they owned fully 40.4 percent (and over 50 percent in the early 2010s) of Germany’s total installed renewable power generation capacity, whether through community wind energy cooperatives, farm-based biogas installations, or household rooftop solar.
Most other countries’ more recent energy transitions have been attempts to achieve net-zero targets using whatever low-carbon technologies are available. Germany’s now-famous “Energiewende” (translated as “energy transition” or even “energy revolution”), however, has from its earlier inception sought to shift away from both carbon-intensive as well as nuclear energy to predominantly renewable alternatives.
Consecutive German governments have, over the past two and a half decades, more or less hewed to this line. Angela Merkel’s pro-nuclear second cabinet (2009–13) was an initial exception.
That lasted until the 2011 Fukushima disaster, after which mass protests of 250,000 and a shock state election loss to the Greens forced that administration, too, to revert to the 2022 phaseout plan. Small wonder that so many politicians today are reluctant to reopen that particular Pandora’s box.
Another ongoing political headache is where to store the country’s nuclear waste, an issue Germany has never managed to solve. No community has consented to host such a facility, and those designated for this purpose have seen large-scaleprotests.
Instead, radioactive waste has been stored in temporary facilities close to existing reactors—no long-term solution.
Just before the holiday break, the US Energy Information Agency released data on the country’s electrical generation. Because of delays in reporting, the monthly data runs through October, so it doesn’t provide a complete picture of the changes we’ve seen in 2023. But some of the trends now seem locked in for the year: wind and solar are likely to be in a dead heat with coal, and all carbon-emissions-free sources combined will account for roughly 40 percent of US electricity production.
Tracking trends
Having data through October necessarily provides an incomplete picture of 2023. There are several factors that can cause the later months of the year to differ from the earlier ones. Some forms of generation are seasonal—notably solar, which has its highest production over the summer months. Weather can also play a role, as unusually high demand for heating in the winter months could potentially require that older fossil fuel plants be brought online. It also influences production from hydroelectric plants, creating lots of year-to-year variation.
Finally, everything’s taking place against a backdrop of booming construction of solar and natural gas. So, it’s entirely possible that we will have built enough new solar over the course of the year to offset the seasonal decline at the end of the year.
Let’s look at the year-to-date data to get a sense of the trends and where things stand. We’ll then check the monthly data for October to see if any of those trends show indications of reversing.
The most important takeaway is that energy use is largely flat. Overall electricity production year-to-date is down by just over one percent from 2022, though demand was higher this October compared to last year. This is in keeping with a general trend of flat-to-declining electricity use as greater efficiency is offsetting factors like population growth and expanding electrification.
That’s important because it means that any newly added capacity will displace the use of existing facilities. And, at the moment, that displacement is happening to coal.
Can’t hide the decline
At this point last year, coal had produced nearly 20 percent of the electricity in the US. This year, it’s down to 16.2 percent, and only accounts for 15.5 percent of October’s production. Wind and solar combined are presently at 16 percent of year-to-date production, meaning they’re likely to be in a dead heat with coal this year and easily surpass it next year.
Year-to-date, wind is largely unchanged since 2022, accounting for about 10 percent of total generation, and it’s up to over 11 percent in the October data, so that’s unlikely to change much by the end of the year. Solar has seen a significant change, going from five to six percent of the total electricity production (this figure includes both utility-scale generation and the EIA’s estimate of residential production). And it’s largely unchanged in October alone, suggesting that new construction is offsetting some of the seasonal decline.
Enlarge/ Coal is being squeezed out by natural gas, with an assist from renewables.
Eric Bangeman/Ars Technica
Hydroelectric production has dropped by about six percent since last year, causing it to slip from 6.1 percent to 5.8 percent of the total production. Depending on the next couple of months, that may allow solar to pass hydro on the list of renewables.
Combined, the three major renewables account for about 22 percent of year-to-date electricity generation, up about 0.5 percent since last year. They’re up by even more in the October data, placing them well ahead of both nuclear and coal.
Nuclear itself is largely unchanged, allowing it to pass coal thanks to the latter’s decline. Its output has been boosted by a new, 1.1 Gigawatt reactor that come online this year (a second at the same site, Vogtle in Georgia, is set to start commercial production at any moment). But that’s likely to be the end of new nuclear capacity for this decade; the challenge will be keeping existing plants open despite their age and high costs.
If we combine nuclear and renewables under the umbrella of carbon-free generation, then that’s up by nearly 1 percent since 2022 and is likely to surpass 40 percent for the first time.
The only thing that’s keeping carbon-free power from growing faster is natural gas, which is the fastest-growing source of generation at the moment, going from 40 percent of the year-to-date total in 2022 to 43.3 percent this year. (It’s actually slightly below that level in the October data.) The explosive growth of natural gas in the US has been a big environmental win, since it creates the least particulate pollution of all the fossil fuels, as well as the lowest carbon emissions per unit of electricity. But its use is going to need to start dropping soon if the US is to meet its climate goals, so it will be critical to see whether its growth flat lines over the next few years.
Outside of natural gas, however, all the trends in US generation are good, especially considering that the rise of renewable production would have seemed like an impossibility a decade ago. Unfortunately, the pace is currently too slow for the US to have a net-zero electric grid by the end of the decade.
