For the first time, TU Delft researchers led by Prof. Fokko Mulder have produced an integrated battery electrolysis system – known as a ‘battolyser’ – that can not only store or supply electricity efficiently as a battery but can also split water into hydrogen and oxygen using electrolysis. This week the first article about it was published Energy & Environmental Science, and a research programme has been awarded funding by the Technology Foundation STW with the support of several companies.
There is an increasing amount of sustainably generated electricity in the form of wind and solar power, but it is not available whenever we want it. Large-scale electricity storage facilities are therefore needed, both for short-term (day and night) and long-term (weekly or seasonal) storage. Batteries are best for short-term storage, whereas artificially produced fuels such as hydrogen are most suitable for long-term energy storage.
‘Electricity and hydrogen have always been regarded as two separate, even competing, solutions for energy storage,’ said Mulder. ‘With the battolyser we have the first integrated battery electrolysis system, which can store and supply electricity very efficiently as a battery, and when the battery is full, it automatically starts splitting water into hydrogen and oxygen using electrolysis. By combining battery technology with electrolysis, we achieve an outstanding overall efficiency of up to 90 percent. The battolyser has also been found to be stable, both in battery and electrolysis mode, even under long, intensive charging, discharging and hydrogen production.’