A venture backed by Bill Gates has unveiled small-scale nuclear power-plus-storage technology designed to work alongside wind and solar to provide continuous zero-carbon power.

TerraPower, co-founded by the Microsoft billionaire in 2008, launched its Natrium system in conjunction with GE Hitachi Nuclear Energy, combining a “cost-competitive” nuclear reactor with molten-salt thermal energy storage to be deployed on power networks “with high penetrations of renewables”.

The combined 345MW sodium fast-reactor and storage element can operate at 500MW for up to five and a half hours allowing the system to “follow daily electric load changes and help customers capitalise on peaking opportunities driven by renewable energy fluctuations”, according to US-based TerraPower.

Power system operators will be able to boost their revenues by up to 20% by deploying the system on networks, it claimed.

Major US utility operators PacificCorp – owned by Gates’ fellow tycoon Warren Buffett and Duke Energy have “expressed their support” for the commercialisation effort, according to TerraPower. Both are major investors in wind and solar power in the US.

TerraPower gave few further details of Natrium when announcing its launch, but claimed its “novel” architecture radically simplifies previous designs, reduces complexity and costs, and will be available as soon as the late-2020s “making it one of the first commercial advanced nuclear technologies”.

The Gates-backed venture is the latest example of the nuclear sector innovating for deployment options on a smaller, more flexible scale than the giant multi-gigawatt power plans that have become the focus of opposition on both cost and safety grounds.

The UK’s Rolls-Royce said earlier this year its small modular reactor (SMR) technology will be able to match wind and solar on power cost by deploying systems at about 440MW.

However, the nuclear systems will be competing in an increasingly crowded space of technologies seeking to provide firming for intermittent renewables, ranging from advanced batteries to other storage options such as liquid-air, hot rocks and even aluminium – christened 'Baldies' in Recharge coverage of the sector.

Gates himself is also involved in longer-term efforts to support nuclear fusion research as a potential “magic bullet” for unlimited zero-carbon power.