Breakthrough Energy Ventures, the Bill Gates–backed $1 billion fund announced in late 2016, has finally made its inaugural investments into a pair of promising energy storage startups.

The fund, established to make long-term investments into the technologies necessary to transition to clean energy, has provided $9 million to Form Energy (focused on developing aqueous sulfur–based flow batteries) and joined a $6.4 million funding round for Quidnet Energy (offering a twist on pumped hydroelectric, the company is pumping water down into either abandoned or freshly dug wells)

This investment is noteworthy, as energy storage is costly and takes a long time to develop – many conventional investors are looking for quicker returns and have had their fingers burnt by investing in clean tech.

BEV however, have set out to be both patient and risk tolerant, willing to invest in companies “even if they may not provide returns on investment for up to 20 years. Their $1 billion fund is “patient capital,” to be invested in only companies working on technologies capable of cutting global carbon emissions by at least 500 million metric tons annually, even if they may not provide returns on investment for up to 20 years.

With this approach, the choices Gates et al make will likely shape how other think about energy innovation. Global investment in renewables now outpacing fossil fuels and storage will become an ever-more pressing issue. It’s great to see a fund doing its utmost to support the technologies that can overcome the biggest limitation of modern renewable power: solar panels and wind turbines can only generate energy when the sun is out, or the wind is blowing.