One of the main drawbacks of wind power is the variability in power output. CREAS believes that combining green hydrogen production technology with wind power will help to solve this problem and lead to a new era of accelerated expansion in wind power investment in Northern Europe.
Wind Energy is one of the UK’s main renewable energy resources – 54% of UK total renewable energy was supplied by wind in 2019 – supplying 20% of the UK’s electricity generation. Offshore wind power has many positives aspects including a higher power yield per MW installed capacity than equivalent turbines located onshore, more stable wind conditions and generally less disturbance of wildlife. In October 2020, Boris Johnson pledged that offshore wind farms will generate enough electricity to power every home in the UK by 2030. This pledge begs the question: how does he plan on reaching this milestone, especially with the problems that we currently experience due to variability of output?
To reach the goal of 40GW of offshore wind power capacity by 2030, the government have set aside £160 million to go towards upgrading ports and factories for building turbines to help the country “build back greener” after COVID-19. This finance resource offers huge opportunities for the renewable energy sector in the UK and CREAS believes that some of this money should go towards improving efficiencies by addressing the output variability issue.
Tractebel Overdick and Tractebel Engineering, both part of energy major Engie, have developed a power-to-gas offshore platform concept that would convert offshore wind energy to green hydrogen out at sea.
This platform concept, seen in the main image, combines the positives of offshore wind power with green hydrogen generation. Instead of transporting the electricity generated by the wind turbines to shore, potentially causing congestion in the electricity grid at times, the hydrogen is produced via electrolysis onsite, and green hydrogen is piped to shore, ready to be used for a number of potential applications, including transportation and other hard to abate sectors, such as domestic heating and heavy industrial sectors, such as cement and steel manufacturing.
The main benefit of converting the offshore wind power to hydrogen is that the hydrogen is a flexible ‘store’ of the energy. This is valuable in situations when power supply outweighs demand, as normally this energy would just be curtailed (‘lost’) in order to not overload the grid. The graph below displays an example of offshore wind power generation variations throughout the year to highlight the inherent day-to-day, month-to-month and seasonal variations in wind power generation.
The platform would take the excess electricity in times of high generation, in this case, winter months, to power the electrolysis to make hydrogen. The following graph presents how this hydrogen production could vary month-to-month throughout the year for a 30 MW electrolyser system. Hydrogen production is naturally highest in the winter months in line with the higher generation of power from the wind turbines and hydrogen storage can buffer demand versus lower hydrogen generation / wind power in the summer months.
Stored hydrogen can be used as a gas fuel for transport or heating buildings and in times of lower wind power generation such as July, hydrogen can be drawn from storage to balance supply and demand.
This technique supports assurance of energy security by correcting for seasonal or daily fluctuations in power output, and also allows greater efficiency in the use of the renewable energy, therefore, reducing use of non-renewable energy.
CREAS believes that a portion of this £160 million set aside by the government should go towards initiatives such as this one from Engie to help evolve the offshore wind sector. It is initiatives that prioritise managing variability through increasing efficiency like these that will help the UK government to reach their goal of 40GW wind power production by 2030.
Abigail Clarke, Environment and Sustainability Consultant
Abi is a talented consultant who is passionate about the environment and finding ways to meet the world’s energy supply demands through sustainable means. She works closely with our clients to help bring their projects to life.