Energy storage: generation’s forgotten twin

In recent years, the conversation around renewable energy sources has grown broader and louder. Although wind, solar, and their lesser-known cousins do not (yet) represent a majority of energy generation in the vast majority of countries, they form an increasingly significant part of the grid’s energy mix. Indeed, in 2017 – and for the first time in its history – Britain generated more of its electricity from renewable and nuclear sources than from gas and coal.

Great news. Onwards and upwards! But there’s a small hitch… Renewable energy is famously intermittent. The wind blows when it feels like it and, to the ire of many British beachgoers, the sun shines any time other than when you want it to. Ok, some renewable energy sources such as hydro are more predictable but let’s focus on the intermittent side of things for now.

Because of our historic dependence on ‘predictable’ conventional generation, we often overlook a critical component of energy provision in the next 10… 20… 100 years: storage. All too often, energy generation and storage are unhelpfully divorced from one another. Yet, we will never successfully achieve a renewable future without realising an equivalent investment in, and evolution of energy storage technologies. The yang to generation’s yin, if you will.

It is only really since the advent of Tesla that the world has started to think seriously about energy storage (good Tesla). We have been talking solar panels and wind turbines for several decades. Storage has some catching up to do. Indeed, it is the automotive industry which is really driving the flow of investment into energy storage technologies. This is also why many people are limited to thinking that ‘storage equals batteries’ (bad Tesla), predominantly lithium-ion. Yes, I know we use the same chemistry in the batteries that power our phones, laptops, etc. but this isn’t the coalface of chemical battery innovation.

The potential problem with this battery-focused view is that it will not be the best storage technology in all situations. Lithium-ion isn’t even that good: it doesn’t store that much energy, it’s expensive, and it’s not entirely safe. You can pick figurative holes in all batteries, all technology types, but my fundamental point is that this is not a ‘one size fits all situation’.

For example, a remote monitoring sensor requires short, large bursts of power that might be provided by a supercapacitor. Electric vehicles of the future might run on fuel cells, instead of batteries. And grid-scale renewable generation will need to be paired with grid-scale storage which could take the form of giant flywheels, compressed air energy storage in vast underground caves, or something we simply haven’t invented yet.

Successful innovation leaders will remain agnostic as to what future storage solutions will be required by each industry and application. My point is that, by focusing on batteries, we may limit the development potential of other technologies, some of which could be essential to our energy future.

Secondly, and to go back to where I started, we will need a myriad of solutions to support the energy transition to a cleaner, renewable grid. Unless we re-establish the critical link between storage and generation, innovation in the former will continue to lag behind. In practical terms, we will produce all the energy that we could possibly want from the sun and the wind, but it will have nowhere to go.