Until there's a reliable way of storing renewable energy for when it's actually needed, they say, fossil fuels will keep plugging the gaps. Lithium-ion batteries - the kind in phones and electric cars - work well at small scale but aren't ideal for storing energy at grid level. So O'Connor wrote what he described as an "Ikea-style" instruction manual and sent the Queen's cell design to research groups around the world. "By distributing the Queen's cell around the world, we have been able to lead a large, international research study," Bailey said. "The work is helping to accelerate breakthroughs in long-duration energy storage and advance the transition away from fossil fuels."