To be more sustainable and produce fewer carbon footprints, the energy-intensive data center industry must turn from conventional fossil energy sources to renewable or low-carbon energy sources. Under such circumstances, will small modular reactors (SMRs) be a promising solution in the coming years?
An SMR, as its name suggests, is a scaled-down nuclear plant. Unlike regular nuclear plants each with an output of at least 1GW, an SMR comes with a capacity of dozens to hundreds of MW. In the past, SMRs were mostly adopted for marine propulsion. It has only recently been used for commercial purposes by nuclear startups. So far, the Russia-based floating nuclear power plant Akademik Lomonosov is the first and only grid-connected case in the world, which is composed of two Russian-made SMRs totaling a capacity of 70MW.
Alan Howard and Vladimir Galabov, analysts at UK-based consulting firm Omdia, indicated in a recent report that SMRs might be a good choice for power supply in large data centers.
Taking computing, thermal management and other assistance systems into consideration, a data center consumes around 125MWh. Assuming that an SMR produces 35MWh, four reactors should suffice. As SMRs are relatively small compared to average nuclear plants, they are suitable for large-scale data centers using more than 100MWh of energy. By contrast, it would be preferable for small data centers to work with local electric companies for power supply.
Speaking of nuclear power, it’s hard not to talk about concerns over nuclear waste and nuclear safety. Howard and Galabov hold that as SMRs are modifications based on previous experience along with their small size, simple design, and safe reaction process, these reactors are less risky. Moreover, SMRs have little need to be “filled up with fuel”. As Omdia indicates, the reactor within a nuclear-powered submarine needs to be refueled every 10 years, with later models only requiring a refuel every 30 to 40 years.
Despite being cleaner than fuel gas and coal, SMRs do produce nuclear waste and require more waste storage space. According to a study conducted by the University of Pennsylvania, molten salt- and sodium-cooled fast SMR designs will increase the volume of nuclear waste in need of management and disposal by 2 to 30 folds.
That being said, SMRs must be commercialized before being applied to data centers. As SMRs for commercial use are still at the introduction stage, it is hard to calculate the ultimate operating cost. Startup NuScale claims that following the commercialization of SMRs in 2050, their levelized cost of electricity (LCOE) will be approximately USD 40–65 per MWh.
As data compiled by the US Department of Energy reveal, the LCOE of fuel gas and onshore wind energy is USD 37 MWh, while that of solar energy is USD 33 MWh. While natural gas prices are expected to increase in the future, SMRs—despite being more expensive now—are free of power generation intermittency and GHG emission problems. Being one of the countries striving to promote SMRs, the United States is estimated to establish SMRs as soon as 2030 and apply them to data centers 10 to 15 years later.
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