The Na+ Solution: How Sodium-Ion Batteries Could Reshape Renewables

It is well known within the renewable energy industry that solar and wind sources are emerging as the cheapest forms of electricity, though their inherent variability challenges grid stability in the UK. However, sodium-ion batters are revolutionising energy storage, potentially providing the capability for power grids to run on 100% renewable energy. 

Whilst sodium-ion batteries operate on similar principles to their lithium-ion counterparts, there are key performance differences. Sodium compounds are synthesised from seawater and limestone, creating a silvery, soft alkaline metal offering a game-changing energy storage solution. 

Sodium-ions are larger and heavier than lithium-ions, meaning they have a lower energy density. This is not to say that the advantages of sodium-ion batteries are not compelling. Sodium is the 7th most abundant element in the world, around 1,200 times more common than lithium, translating to a more sustainable and cost-effective option. In fact, once economies of scale are aligned, the bill of materials for sodium-ion batteries is expected to be 20-30% lower than lithium-ion batteries.  

Sodium-ion batteries are the safer choice, with a higher flash point making them less prone to ignition. They can be transported with terminals directly connected and voltage at zero which eliminates the need for unnecessary and costly safety measures. They are also less toxic and much easier to recycle than lithium-ion batteries.  

Additionally, sodium-ion batteries offer fast charging and discharging capabilities, also allowing for 100% discharge which is impossible with lithium-ion batteries. Grid-scale storage means a varied climate, sodium batteries are the perfect option given they perform well at low temperatures.  

This said, high manufacturing costs are a challenge due to low production volumes, and the technological development lags behind lithium-ion batterie3s in terms of lifespan and energy density. Promising ongoing research is beginning to address these limitations, constant improvements are to be expected. 

Sodium-ion batteries are a malleable solution for the renewable energy industry, offering grid-scale storage which may revolutionise our ability to balance supply and demand from different renewable sources. There’s also potential for use in electric vehicles, driving down costs in a rapidly growing industry. Home energy storage systems are another possible application, allowing households to maximise their use of rooftop solar power. 

In the UK, we are ideally positioned to lead in this emerging field. Major firms are already utilising sodium-ion technology at plants in Sheffield, Thurso, and Caerphilly. These batteries are forecasted to account for 23% of the stationary storage market by 2030, presenting job creation opportunities and economic growth in the UK’s renewable energy market. 

It won’t be a simple revolution; the present lack of a developed supply chain means cells are only produced in small batches. Fortunately, most sodium battery manufacturing processes are similar to those used for lithium batteries, allowing the new technology to benefit from existing knowledge and infrastructure. Retrofitting a lithium-ion plant for sodium-ion production could require as little as 10% additional capital expenditure. There is still a long way to go in improving the performance of sodium-ion batteries and driving down costs, which will require focused innovation.   

Finally, sodium-ion batteries present a transformative opportunity for the renewable energy industry. There may be obstacles, but the potential benefits in terms of cost, sustainability and safety are worth the effort. UK renewable energy companies have the capacity to lead in this emerging market through sensible investment, positioning themselves at the forefront of a revolution in energy storage - one that could play a crucial role in enabling a 100% renewable energy future.