New European legislation scheduled for 2030 will require green hydrogen producers to prove their electrolysers source energy from specifically built' renewables on an hour-by-hour basis.
However, the rules are set to increase the cost of green H2 by more than a quarter, according to a scientific study published in the Energy Policy journal.
It comes as a separate study highlighted the potential for wave energy to reduce the costs of green hydrogen. The offsetting of wave energy with other renewables such as wind and solar can result in a more consistent power profile, and thus support hourly matching requirements.
The EU Delegated Acts on Renewable Fuels of Non-Biological Origin (RFNBOs) ie, green hydrogen and their derivatives allow for monthly matching of green hydrogen production with renewables generation until 2030, when it is due to switch to hour-by-hour temporal correlation.
In other words, producers must prove every hour that their electrolysers have consumed only renewable energy generated within that hour.
Due to the Delegated Act's additionality clause, all the electricity consumed must be generated by renewables projects built specifically to supply power for green hydrogen production.
This is being driven by concerns that renewable H2 production would consume clean electricity that would otherwise have been used by the electricity grid, requiring the network operators to fire up fossil-fuel power plants to make up the shortfall, thus increasing overall emissions.
Researchers in the US and Germany have since published a study assessing the impact hourly temporal correlation and additionality would have on the production costs of green hydrogen. They concluded that hourly correlation or "simultaneity" would increase the cost of green hydrogen by 27.5%, compared to annual correlation, with both scenarios including additionality.
The study titled Flexible green hydrogen: The effect of relaxing simultaneity requirements on project design, economics, and power sector emissions also found that these new requirements could lead to investment in oversized, underutilised assets, increasing cost considerably.
Adding wave energy to the mix
As a consistent and reliable power source, which is offset from other renewables such as wind and solar, wave energy could offer a direct solution to this hourly correlation conundrum.
This is supported by a separate study - Assessing wave energy's value for decarbonizing the steel industry - produced by CorPower Ocean, Instituto Superior Técnico de Lisboa (IST) and a global green steel manufacturer. The research highlights how wave energy will positively impact the creation of green hydrogen in the production of green steel.
In particular, results show that introducing wave energy can help to half the installed capacity required for a 1GW hydrogen electrolyser - and lower the total cost of energy by 26%.
When only using solar and wind energy, the need to cover 90% demand resulted in an energy system of 8.4GW. By comparison, when adding wave energy into the mix, the installed capacity required was reduced by 46% to 4.5GW.
Green hydrogen production - a complex process
Green hydrogen is currently the only solution to decarbonise hard-to-abate sectors, such as steel, cement and the chemical industry, which cannot readily be electrified. Its production requires electrolysers to split water into oxygen and hydrogen using renewable energy.
However, this remains a complex process due to the amount of energy required, while matching the supply and demand for green hydrogen. With nuclear and hydro potential heavily exploited, a broader mix of renewables are needed to support intermittent wind and solar resources, in order to deliver 24/7 carbon free energy.
In conclusion, wave energy emerges as a promising solution to alleviate the perceived cost escalation of green hydrogen. The reliability, consistency, and scalability inherent in ocean energy position it to fill the void, offering a dependable and sustainable power source for green hydrogen production.
