As the world races towards a net-zero future, the role of hydrogen in the energy transition is emerging as nothing short of critical. In a recent study, the London-based Royal Society emphasized that hydrogen will play a pivotal role in ensuring a net-zero electricity system for Britain, asserting that no other energy storage method can provide the scale of backup power needed.
This revelation comes after 37 years of meticulous weather data analysis, aimed at deciphering the energy storage requirements for a future British national electricity system primarily reliant on wind and solar power. The study dives deep into various types of storage and demand-reduction methods, evaluating their feasibility and costs.
The Royal Society’s report, aptly titled “Large-scale electricity storage,” unveils staggering numbers. To achieve its legally binding net-zero target, Britain will need up to 100 terawatt-hours (TWh) of energy storage by 2050. To put this into perspective, it’s enough to power a quarter of the country’s current electricity demand or equate to 5,000 replicas of the UK’s largest pumped hydro plant at Dinorwig in Wales.
Why hydrogen, you might ask, when it has a relatively poor round-trip efficiency of about 41%? The answer is simple: scale. Other technologies, including batteries and pumped hydro, fall woefully short of offering the colossal energy storage capacity required.
However, here lies the challenge: these caverns, vital for hydrogen storage on such a scale, are not financially justifiable without government support. It’s a complex puzzle, but one that must be solved if Britain is to meet its net-zero goals.
The report underscores a growing energy demand. By 2050, the demand for electricity is set to double, driven by electrification in heating, transport, industrial processing, and more. Wind and solar power, while cost-effective, are volatile and fluctuate over decades. Hence, they necessitate large-scale energy storage or alternative power sources.
While hydrogen storage is the primary focus of the report, it explores alternative options. Baseload nuclear power, fossil gas with carbon capture and storage (CCS), and bioenergy (with or without CCS) are considered capable of meeting some of the demand. However, these solutions come with hefty price tags or are heavily reliant on uncertain factors.
The Royal Society recommends immediate action on constructing large-scale green hydrogen storage facilities. Other countries have already embarked on this journey, and Britain cannot afford to lag behind. Constructing such caverns will provide insights into hydrogen costs and set the nation on a path towards cost reduction through learning. However, this necessitates government financial support, as the commercial viability of large caverns remains questionable.
To ensure Britain’s lights stay on during periods of low wind and solar, approximately 60-100 TWh of hydrogen storage, equivalent to 1.8-3.0 million tonnes of H2, will be needed. Achieving this requires roughly 30 GW of electrolysers and 60 GW of dedicated renewable energy.
While the focus is on hydrogen, the report explores a wide range of energy storage options, including batteries, compressed air energy storage, thermal energy storage, ammonia, and synthetic fuels. Vehicle-to-grid storage, where electric vehicles can contribute to the grid’s flexibility, is also explored as a valuable asset.
The Royal Society’s report paints a picture of Britain’s energy future. Wind and solar, supported by hydrogen storage and possibly some batteries, can deliver electricity at an average cost of £52/MWh to £92/MWh ($65-115/MWh) in 2021 prices by 2050. While the figures may seem steep compared to the previous decade, they are essential for a sustainable, net-zero future.
Combining hydrogen storage with advanced compressed air energy storage (ACAES) could reduce costs by up to 5% or more, depending on various factors. Similarly, utilizing energy storage alongside fossil gas with CCS could also lead to significant cost reductions.
In conclusion, the Royal Society’s report sends a clear message: hydrogen is not just a part of Britain’s net-zero future; it’s the linchpin. To achieve its ambitious climate targets, Britain must act swiftly to build the necessary hydrogen storage infrastructure. The road ahead is challenging, but the benefits for a sustainable future are immeasurable.