$7.5 Trillion to Decarbonize, and Nobody Wants to Pay

Decarbonizing the global economy would cost roughly $7.5 trillion — about 5 percent of global GDP — according to an artificial-intelligence estimate commissioned by Breakthrough Energy and presented by the network's chief technical officer, Eric Toone, at the MIT Energy Initiative's annual research conference, Energizing@MIT.

Toone, who oversees the technological roadmap at Breakthrough Energy and serves as managing partner of its venture arm, Breakthrough Energy Ventures, framed the problem in blunt terms. Fossil fuels supply 80 percent of global energy use, and coal alone generates 35 percent of the world's electricity. Prosperity drives demand; demand drives emissions.

"Energy is how we make things … build and heat our homes … grow and prepare our food. So, energy is prosperity," Toone said. He noted that income and electricity consumption climb together across countries, and that no high-wealth, low-energy-use nations exist.

What does the cost estimate leave out?

Toone's second question was the uncomfortable one: what are people willing to pay? His answer was not encouraging. Observed behavior "when nobody's looking" shows that even wealthy consumers in OECD countries will not pay a green premium at all. The task, therefore, is to decarbonize at zero additional cost.

"Of course we can decarbonize. It's not hard to do. The question is: How much will it cost?" he said.

Breakthrough Energy was founded in 2015 by Microsoft's Bill Gates to erase exactly that premium. It began with a $1 billion venture fund, raised roughly $5 billion more, and has deployed about $3 billion across some 140 companies.

Where is the capital going?

The portfolio targets the highest-emitting material streams first. Cement alone accounts for 8 percent of global emissions, a figure set to grow as emerging economies build.

• Brimstone mines an alternative critical raw materials source that carries a lower concentration of today's conventional cement feedstock but also yields valuable metals, including aluminum.
• Ecocel is exploiting a recent discovery: controlling cement particle size enables more effective packing and cuts the total cement required.
• CarbonCure Technologies injects carbon dioxide into cement as it is poured, producing a harder material and a 10 percent reduction in total cement demand.
• Luxwall manufactures windows as insulating as walls, sized for conventional frames. One commercial building recorded 30 percent energy savings after installation. Toone called the product the "new LED bulb."

How do you move and store intermittent power?

Solar and wind rank among the cheapest generation sources but do not run on schedule. Breakthrough's answers split into transmission and storage.

• TS Conductor builds transmission wire with a solid core that resists sagging and vegetation contact. "That means I can put up to three times as much energy down an existing transmission corridor," Toone said.
• VEIR, founded by a MITEI Energy Scholar, uses superconducting cables that carry 10 times the power of an existing corridor.
• Form Energy, an MIT spinout, develops iron-air batteries capable of storing power for a month or longer.

Two firm-power plays round out the portfolio. Fervo Energy, applying drilling advances from fracking, is building the Cape Station plant in southwest Utah — the world's first large-scale geothermal facility, already generating 500 megawatts continuously. Commonwealth Fusion Systems, an MIT startup, is developing high-temperature superconducting tapes that generate the magnetic fields needed to contain fusion plasma.

Stoke Space Technologies is building reusable rockets to attack the launch costs that have long stalled space-based solar. "If I go to space, the sun always shines," Toone said.

What happens next?

If these technologies succeed, Toone put the cost of decarbonizing the world economy at $3.5 trillion — half the initial estimate. Breakthrough's $5 billion sits inside a much larger pool: roughly $220 billion invested in clean technology over the same period, with venture capitalists contributing about $2.5 trillion.

The decisive constraint, in Toone's view, is infrastructure turnover. The world must replace an enormous installed base, and new technologies must deploy in the developing and emerging world now, before a second round of stranded assets is built.

"We can absolutely develop new technologies that provide the exact same service, but at zero carbon," he said. The milestone to watch is whether the green premium reaches zero before that second infrastructure wave hardens.