Most fusion takes I read stop at the milestone. SPARC ignited. ARC broke ground. Google signed a PPA. All good news, but the part that actually matters comes later, when fusion stops being a science story and starts being an electricity story. The interesting question is not whether fusion works. It is what gets cheap when it does.
Two things on that list are worth talking about, because they are usually framed as separate climate problems: fresh water and atmospheric carbon dioxide. Both are, at heart, energy problems in disguise.
Desalination is mostly an electricity bill
Modern seawater reverse osmosis (SWRO) plants consume roughly 2.5 to 4.0 kWh per cubic meter of fresh water produced, with the best plants pushing toward 2.0 kWh/m³. Energy alone makes up 40 to 60 percent of the operating cost of a desalination plant. (Hannah Ritchie, Pumps & Systems)
When Dubai's Hassyan plant came online it set a record contract price of about $0.30 per cubic meter, mostly because it was paired with very cheap power. Most projects still land between $1.00 and $2.50 per cubic meter. (Best Membrane)
Now pencil in cheap fusion. Even pessimistic projections for early commercial fusion plants land around $150 to $200 per MWh, which is 15 to 20 cents per kWh. That is not the interesting number. The interesting number is the longer-term target of $60 to $70 per MWh, roughly 6 to 7 cents per kWh, once a fleet exists and learning curves do their work. (UKAEA cost study)
At 3 kWh per cubic meter and 7 cents per kWh, the energy cost of fresh water from the sea is about $0.21 per cubic meter. That is below current Gulf state contract prices, available anywhere there is a coastline and a fusion plant, with no fuel price volatility and no carbon penalty.
Global installed desalination capacity is already around 91.5 million cubic meters per day across more than 21,000 facilities, growing about 5.6 percent a year. (IDRA, Pollution Solutions Online) Cheap, clean baseload power does not invent desalination. It removes the two reasons most inland and developing-world cities have not built it yet: cost per cubic meter, and the carbon footprint of the electricity feeding the plant.
Direct air capture is almost entirely an energy problem
Direct air capture (DAC) is the other side of the same coin. Current commercial systems consume somewhere between 1,500 and 3,000 kWh of energy per ton of CO2 removed, depending on whose tech you ask about, and the total energy budget including compression and storage can run 1.4 to 4.2 MWh per ton. (Springer / MRS Energy & Sustainability, World Resources Institute)
Today's price tag: $400 to $1,500 per ton, with the leading operators (Climeworks, Carbon Engineering) at or below $600 per ton at their largest plants. The widely cited industry target is around $100 to $150 per ton, which is what climate economists generally agree is "viable at scale." (Mission Zero, IDTechEx)
Energy is the dominant variable in those numbers. At 2,000 kWh per ton and 7 cents per kWh, the electricity cost alone is $140 per ton. At 1,500 kWh per ton you are at $105. The capital and sorbent costs come down with scale and learning, but the energy floor is set by physics, and that floor is exactly where fusion's long-term LCOE target wants to live.
There is a footnote that matters. A gigaton of DAC per year needs roughly 1,400 to 4,200 TWh of clean electricity. The entire US utility-scale generation in 2022 was 4,240 TWh. (WRI) You cannot do this with solar and batteries alone without crowding out everything else on the grid. You need a power source that is dense, firm, and clean. That description fits two things: fission and fusion. Fusion is the one without the waste politics.
What I actually think happens
I do not think the first ARC reactor in Virginia in the early 2030s makes any of this cheap on day one. (CFS announcement) The first units will sell expensive electricity to hyperscalers who care about carbon-free 24/7 power more than they care about the per-kWh number. Google's 200 MW PPA with CFS is exactly that bet.
The interesting decade is the one after. Once a second and third generation of plants exists and unit costs settle into the $60 to $70 per MWh range, the economics of moving water and pulling carbon flip. A coastal fusion plant becomes a desalination cluster. A geothermal-style fusion site in a low-population region becomes a DAC farm. Neither application has to compete with grid loads, because both can soak up power whenever it is cheapest.
The pitch fusion advocates have been making for thirty years is "limitless clean power." That has always been true but slightly off-target. The more useful framing is that fusion is the first energy source that can plausibly make the cost of fresh water and the cost of removing CO2 from the atmosphere drop into the range where governments and corporations actually do them at scale. Not as a moral choice. As a budget choice.
That is the part of the fusion story I will be watching after the ignition headlines fade.
References
- Hannah Ritchie, "How much energy does desalinisation use?"
- Pumps & Systems, "Energy Efficiency in Seawater Reverse Osmosis"
- Best Membrane, "Seawater Desalination Costs & ROI: 2025 Insights"
- UKAEA, "Extrapolating Costs to Commercial Fusion Power Plants"
- International Desalination & Reuse Alliance, "Decarbonizing Desalination and Reuse"
- Pollution Solutions Online, "Global Desalination Capacity Tops 80 Million Cubic Meters Per Day"
- MRS Energy & Sustainability, "Atmospheric alchemy: energy and cost of direct air capture"
- World Resources Institute, "Direct Air Capture: 6 Things To Know"
- Mission Zero, "Debunking the $100 fallacy: what does DAC actually cost?"
- IDTechEx, "Direct Air Capture: Reaching $100 per Tonne of CO2"
- Commonwealth Fusion Systems, "World's First Commercial Fusion Power Plant in Virginia"
- Data Center Dynamics, "CFS hopes to build first grid-scale fusion power plant in Virginia by early 2030s"