One of the biggest obstacles in the adoption of renewable energy has been providing a consistent supply. The two biggest forms of generation, wind and solar, rely upon the prevailing weather conditions and even the time of day, meaning that renewable energy storage solutions are essential. These work alongside the generation, helping to supply changes in demand and ensuring that something as simple as a passing cloud doesn’t leave people without power.

The dominant form of energy storage has been the humble battery. Familiar to everyone, whether as the small cylinders that power their devices or the integrated batteries in phones and laptops, these are simply scaled up when used alongside renewable energy generation. The most common batteries are lithium-ion (most common for household uses), but other types of battery, like lead-acid and nickel, are also used.

The difficulty with battery energy storage is the batteries themselves. At almost every stage of their life, they come with a cost. Extracting the chemicals used in their manufacture causes environmental damage and is frequently criticized for its human cost. They are slow to charge, and the efficiency of chemical batteries slowly degrades, meaning they last only a few years before requiring replacement. And disposal of the hazardous chemicals again comes with a significant financial and environmental cost.

The use of batteries for renewable energy storage means that, when considered as a whole, renewable power is not as good for the environment as it might seem—just less polluting than the fossil fuel alternatives.

The most promising alternative to batteries is kinetic energy storage. In many ways, this is a rediscovery rather than an innovation; kinetic storage has been commonly used from the industrial revolution onwards. Only in more recent times have batteries come to dominate.

Kinetic solutions offer several advantages over batteries. Rather than needing chemical reactions from potentially harmful chemicals, kinetic energy relies on some fundamental physics. Perhaps the simplest example is the humble flywheel, which can be turned into an incredibly efficient energy storage device.

Anyone who has played with a spinning top will understand the basics. Essentially, the faster the initial spin, the longer it will last, and those who have used different tops will know that things like the size and weight also have an impact. The spinning top is a simple example of how a large initial input of power is stored and then released over a period of time. Using a flywheel as a renewable energy storage solution is a bit more complex, but not much!

Amber Kinetics started developing flywheel energy storage in 2008 and have become the world leaders in the field, with their scalable installations powering homes in the United States and industry in China. Their units work on the same theory as that spinning top, using surplus energy when generation is high to rapidly spin their flywheels. Their units, like the all-steel M32, house an efficient flywheel that retains as much power as possible, generating a reliable 8kW output for four hours. Highly scalable, it can be used both as part of the power generation and distribution network or commercially to manage self-generated power.

The M32 is currently the industry’s only long-term kinetic energy storage system, making non-battery renewable energy storage viable for the first time. Manufactured to be 100% recyclable, it also means that renewable energy is no longer a trade-off between the harm of fossil fuels against the harm of battery manufacture and disposal. And as the climate crisis becomes increasingly urgent, Amber Kinetics’ renewable energy storage solutions might well be the key to unlocking reliable, large-scale, renewable energy production.