Renewable Hydrogen

In its transition to net zero, it is essential that the UK now invests in the technologies of the future. Hydrogen can be used for the decarbonisation of many sectors of the UK’s energy system such as industrial clusters, transport modes including heavy-goods vehicles, trains, buses, manual handling equipment and maritime applications as well as the gas grid.

However, most of the hydrogen used today comes from fossil fuels and there are upstream emissions associated with its production. Zero carbon hydrogen production options are now needed at scale to ensure hydrogen can fulfil its potential.

Gigastack’s answer to this urgent need is renewable hydrogen. Renewable hydrogen is increasingly recognised as a vital component of the UK’s energy future and the decarbonisation of the whole energy system. It is produced by splitting water into oxygen and hydrogen in an electrolyser using renewable electricity – from a wind farm for example. This ensures there are no emissions associated with this type of production. To date, renewable hydrogen has helped to decarbonise small passenger car and bus fleets as well as small scale gas grids through demonstration projects. Scaling this to decarbonise industry, larger fleets and the UK’s gas networks requires:

  • The next generation of electrolyser stack – to reduce the underlying cost of manufacture
  • Electrolyser manufacturing capacity – to reduce costs through economies of scale
  • Wind farm – electrolyser synergies – to increase overall system efficiency and ensure as low as possible a price for input electricity

All of which are under development in Gigastack. The Hydrogen Council, a global initiative of leading energy, transport and industry companies, forecasts that the cost of electrolysis is expected to come down significantly to become competitive with blue hydrogen (from reformation with CCS) and even methane.

Large scale electrolysis will also support the UK’s wider transition to a cleaner energy system. Balancing the UK’s electricity supply within a system with an increasing proportion of weather-dependent generation and ever-changing consumer behaviour is becoming increasingly challenging. Renewable hydrogen can support renewable electricity generation over short time frames by responding to changes in demand in sub-second time. This is possible for dedicated assets, such as Hornsea, as well as the wider UK electricity network and can minimise consumer exposure to variability. Renewable hydrogen also supports inter-seasonal energy variation by flattening demand and supply curves using long-term storage. This increases the security of our energy supply in an increasingly variable future. Renewable hydrogen is vital for the scaling up of renewable generation capacity and the UK Government’s vision for 40GW of offshore wind by 2030.

Benefits of Renewable Hydrogen

Carbon emissions from electrolytic hydrogen are only associated with the carbon intensity of the electricity used to produce it. Where renewable electricity is used to split the water (as in Gigastack), the hydrogen product is termed renewable hydrogen – the carbon emissions are zero.

The hydrogen from an electrolyser is inherently pure, which means it can be used directly in even sensitive applications such as the low temperature fuel cells used in hydrogen fuelled cars and buses.

Hydrogen production from polymer electrolyte membrane (PEM) electrolysers is inherently flexible. This means that; (i) the electrolyser can respond to changes in the setpoint in sub-second time frames, allowing it to follow the generation profile of variable renewable energy sources; (ii) the asset can operate at a wide variety of load factors; and (iii) the 5MW modular stack design enables the electrolyser to be built at a variety of capacities to suit the use case.

The only resources required to produce electrolytic hydrogen are water and electricity. An increased UK portfolio of electrolysers would decrease our dependency on imports of foreign natural gas and, thereby, increase the security of our national energy supply.


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