50 years ago, a Stanford Research Institute report titled ‘Sources, Abundance, and Fate of Gaseous Atmospheric Polluters’ was the first to officially suggest that “rising CO2 levels could bring about climatic changes like temperature increases, melting of ice caps and sea level rise.” After the most heavily polluting half century in human history we now know that to be true.

In a 2014 report, the International Energy Agency estimated that the world needs to spend $359 trillion between then and 2050 to avoid catastrophic climate change - that’s almost $11 billion per year. Global investment to address climate change that year was estimated at $388 billion, that figure increased to a record $437 billion in 2015, before dropping to $383 in 2016. Figures were more positive in 2017 with $410 billion but still 25 times less than we should be spending to “save the world.”

To address this, a group of the world’s richest people joined forces to create Breakthrough Energy Ventures (BEV) an investment fund to support technologies capable of cutting global carbon emissions by at least 500 million metric tons annually. The group, which includes big names like Bill Gates, Jeff Bezos, Jack Ma, Mukesh Ambani, and Richard Branson, have described their strategy as “patient capital,” as they accept they may not see financial returns for 20 years or more.

BEV assembled a team of experts to assess which methods offered the most promise for tackling greenhouse-gas emissions, and in 2018 they announced the first two startups that will receive investment. Form Energy and Quidnet Energy are both focused on energy storage but each uses a completely different approach. Neither is developing lithium-ion batteries that currently dominates the energy storage market. While the cost of lithium-ion has dropped from $1,000/kWh in 2010, to $200/kWh in 2017, it is expected to bottom out at about $100/kWh, not low enough to bring about zero carbon societies.

Quidnet Energy’s approach uses water but not the traditional method of damming rivers and filling reservoirs, which is limited by geography, displaces people and has implications for local ecosystems. Instead Quidnet uses excess power to forcibly pump water into underground shale rock formations and abandoned oil-and-gas wells, when power is needed the pressure is released and the water spews out with enough force to run turbines and create electricity at highly economical rates. Quidnet will use the $6.4 million raised through BEV and Evok Innovations on more field trials to develop the technology.

Form Energy makes batteries and we don’t know a whole lot more than that. The three founders have very impressive resumes however: Ming Chiang is an MIT professor who has already founded five battery companies; Ted Wiley previously co-founded battery firm Aquion Energy; and Mateo Jaramillo, who created Tesla’s energy-storage group. “If I were to create a battery company today, I would want the three founders of Form Energy in my team,” says Venkat Viswanathan, a battery expert at Carnegie Mellon University.

Wiley disclosed that Form is working on two types of battery, and in a 2017 paper Chiang confirmed that one of them is a “sulfur-flow battery.” In the same paper Chiang claimed that the technology could achieve “the lowest chemical cost to our knowledge of any rechargeable battery: less than $1/kWh,” which would rise to $10/kWh with the cost of infrastructure, 10 times lower than the cheapest conceivable lithium-ion battery.

Form Energy has raised $11 million to date. An initial $2 million from MIT’s Engine Fund and then $9 million from BEV, along with Prelude Ventures and several small investors. “Thanks to lithium-ion batteries, storing energy for less than a day is a solved problem,” says Wiley. “Our goal is to find solutions to store energy for weeks, months, and maybe even across seasons at a fraction of the cost of current technology.” Storing summer solar for use in dark winter months would be a hugely significant development for the energy sector.

For now, however, day-use lithium-ion is still the leading established technology, and another well known billionaire has been pushing adoption of the battery technology for homes, buildings and utilities. Elon Musk used a portion of the wealth he gained selling Paypal to found Tesla Motors, which rose to fame as an electric vehicle manufacturer. With an extensive battery manufacturing infrastructure setup for vehicles and his large stake in solar power firm Solarcity, Musk began producing stackable, stationary batteries.

In 2016 ‘Tesla Motors’ was renamed ‘Tesla’ suggesting the energy side of the business was gaining significance. Then, in a shareholder meeting last week, Musk described dealing with the slowing vehicle sales as “the most excruciating, hellish few months I think I’ve ever had.” However, Musk also announced that Tesla had hit the milestone of deploying 1 gigawatt-hour (GWh) worth of energy storage, which represents a just under half of all of the stationary energy storage deployed globally last year. Musk expects to deploy another GWh worth of energy storage within a year, potentially redefining Tesla as an energy company as much as it is a car manufacturer.

“The rate of stationary storage is going to grow exponentially. For many years to come each incremental year will be about as much as all of the preceding years, which is a crazy, crazy growth rate,” Musk said. Bloomberg New Energy Finance estimates that 7.4 GWh of battery storage projects were installed globally by the end of 2017, they predict that figure will rise to 12.1 GWh by this year and then 17.5 GWh by 2019.

Energy storage was long touted as the missing piece of the energy puzzle. It reduces greenhouse-gas emissions by facilitating the use of renewable energies like solar and wind, which generate excess power when the sun shines and the wind blows. According to these billionaires and the experts they hire, capturing that excess energy for later use is the key to slowing climate change. While more must be done, right now it is their sizable sums of money making the world go green.