This December marks the tenth anniversary of the Paris Agreement. When world leaders gathered in 2015, the agreement set ambitious targets to limit global warming to well below 2°C, preferably to 1.5°C, above pre-industrial levels. Whilst we’re still a distance away from achieving those goals, it’s also true that the past decade has delivered important progress in the technologies needed to get us closer. Battery Energy Storage System (BESS) stands as one of the most significant examples explains Aazzum Yassir, Director of Technology and Operations at Pulse Clean Energy.
Meeting the Paris targets required a six-fold increase in global energy storage capacity. At the time, deploying battery energy storage was an expensive gamble few were willing to take. Today, after spending a decade navigating this sector, I can say with certainty that battery storage has become infrastructure we simply cannot do without.
Why storage became essential
Storage became essential because renewables became dominant, and the physics of the grid demanded a solution. You cannot run a grid on 80% renewable penetration without storage. Without it, the future grid will not work and we would be curtailing vast amounts of renewable generation because the grid cannot absorb it, or we would be running gas plants as expensive backup. Storage captures energy when generation exceeds demand and releases it when the situation reverses.
In the early days, we were chasing innovation funding from Ofgem and competing for Enhanced Frequency Response contracts. The business case was marginal at best. Today, we are stacking revenues across multiple services – the revenue streams proven and the technology investable. At Pulse Clean Energy, we recently secured a £220 million green finance deal, representing a major vote of confidence in the sector, which enabled the National Wealth Fund to step back from the support it had previously provided us.
From risk to reward
A decade ago, storing 1 MWh of energy cost £800 per kWh. Fewer than ten suppliers existed globally. The technology was bespoke, expensive, and largely unproven at scale. Fast forward to 2025, costs have reduced to under £110 per kWh, over a hundred suppliers are competing, and the UK is forecasting a 900% increase in storage capacity by 2050. An amalgamation of forces drove this transformation. Research in cell chemistry unlocked improvements in energy density, allowing us pack far more energy into the same physical footprint. The industry’s learning rate of roughly 18% means that for every doubling of installed capacity, prices drop accordingly.
We have also witnessed a shift from expensive lithium-ion chemistries like Nickel Manganese Cobalt (NMC) and Nickel Cobalt Aluminium (NMA) to Lithium Iron Phosphate (LFP), which uses cheaper, more widely available raw materials with longer operational life and improved ESG characteristics. Together, these advances have made batteries more investable at scale.
The future grid
Looking ahead, the challenge becomes clearer and more urgent. The UK’s population is projected to grow from 70 million to 80 million by 2050. Peak demand will surge from 58GWn today to 144GW. Annual consumption will nearly triple from 290TWh to 800TWh. And to manage all of this, storage power capacity needs to climb from 10GW today to 90GW.
In the last ten years, we have leapt from a centralised system where energy flowed in one direction, from large power stations to end users, to a much more distributed network where power flows in multiple directions simultaneously.
As this network matures further, grid-scale batteries will be asked to provide an ever-expanding menu of services. Now we need inertia provision to stabilise the grid as thermal plants retire and short-circuit contribution to maintain fault levels. We also need voltage control to manage power quality and black start capabilities to restart the network in the event of a large-scale power outages.
And, as I reflect on where I began in the sector delivering the first large scale BESS in Europe back in 2015, I am reminded of how far we have come and how much further we need to go to ensure the long-term benefits reach the final consumers.
In 2015, at a conference, I coined the phrase that BESS were the Swiss army knife of the grid, capable of multiple jobs. A decade on, that analogy no longer does justice to how far the technology has evolved. Whilst a Swiss army knife is undeniably useful in a pinch, it’s no replacement for dedicated tools like a screwdriver. Batteries, by contrast, have proven themselves not just capable of delivering many services, but in most cases can do so cheaper and more effectively than any other technology available to grid operators. BESS is has become the complete toolbox.
The Paris Agreement set ambitious targets. Battery storage is proving that we can meet them. The last ten years demonstrated what is possible. The subsequent decade will determine whether we actually do it.
