An academic study calculating the costs of creating a net-zero energy system in Europe has found that a new hydrogen network could reduce the need for power grid expansion — which may be necessary due to public opposition to new overhead transmission lines.

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The paper, entitled The potential role of a hydrogen network in Europe”, which was published last week in the Joule journal, calculated that Europe could achieve net-zero emissions without expanding the power grid or creating a hydrogen network, but at a cost of €805bn ($904bn) per year.

But expanding the power grid and building a new hydrogen network — with around two-thirds of the latter reusing existing gas pipes — would save €72bn a year compared to the above figure.

This €733bn is only slightly higher than the roughly €700bn that Europe currently spends on energy system costs, one of the study’s authors Fabien Neumann, an energy systems modeler at the Technical University of Berlin, tells Hydrogen Insight.

The study is based around four scenarios for a net-zero energy system, based on expected technology costs in 2030 and projected energy demand for different sectors: an expansion of the electricity grid, the construction of a hydrogen network, both, or neither.

Building sufficient electricity transmission lines without a hydrogen network would provide a total net benefit of €46-61bn (6.3-8.1%) per year in system costs, from an annual investment of €15.1-37.9bn.

And constructing a new hydrogen network could also reduce net system costs by €12-26bn a year with an annual investment of €3.2-4.6bn (1.6-3.4%), with the highest savings in the scenario with no electricity grid expansion.

“Power grid reinforcements enable renewable resources with higher capacity factors to be integrated from further away, resulting in lower capacity needs for solar and wind,” the study explains. “The electricity grid also allows renewable variations to be smoothed in space and facilitates the integration of offshore wind, resulting in lower hydrogen demand for balancing power and heat and less hydrogen infrastructure (comprising electrolysis, cavern storage, reconversion, and pipelines).

“As a hydrogen network could compensate for the lack of grid capacity to transport energy over long distances, the benefit of electricity grid reinforcements is strongest if no hydrogen network can be developed.”

But it continues: “The hydrogen network offers an alternative for bulk energy transport from the windiest and sunniest regions in Europe’s periphery to low-cost geological storage sites and the industrial clusters in Central Europe with high energy demand but less attractive and more constrained renewable potentials.”

The system cost benefit for a hydrogen network is strongest in a scenario where the electricity grid is not expanded further than today.

“However, even with high levels of power grid expansion, the hydrogen network is still a beneficial structure,” the authors claim.

“Although power grid reinforcements provide higher cost reductions, hydrogen and electricity networks are stronger together.”

The paper explainsthat a hydrogen network can only partially compensate for the lack of grid expansion because of electricity’s greater versatility.

“Hydrogen can only be used directly in a few specialized sectors, and if it has to produced only to be re-electrified later, there will be expensive efficiency losses.”

The study assumes that costs for a new hydrogen pipeline are €250/MW/km and repurposing existing gas pipelines are €117/MW/km, while a new high-voltage transmission line would cost €400/MW/km.

The model also expects that 64-69% of a new hydrogen network would be made up of repurposed gas pipelines — equivalent to a quarter of the current gas grid. And the study does not account for imported volumes of hydrogen or its derivatives, such as ammonia, methanol and synthetic methane.

Additionally, most of the demand for hydrogen in its scenarios will actually be for its derivatives, with limited direct use in steelmaking and heavy-duty transport.

Across all four scenarios, around 2,375TWh of hydrogen (equivalent to nearly 72 million tonnes) is consumed per year.

In the scenario where the grid is not expanded but a hydrogen network is built, an extra 289TWh of H2 a year will be consumed to fuel power and heat.

All scenarios require the vast majority of hydrogen to be produced from electrolysis, with a small proportion (78TWh/year) from steam methane reforming with carbon capture for the two scenarios in which no H2 network is built.

The study predicts electrolyser capacities will scale up to 937-1,250GW across Europe, with the lower end of the range seen in scenarios where the electricity grid is expanded.

It also anticipates that more H2 storage capacity will need to be developed, with cost-optimal capacities between 26-43TWh with a hydrogen network and 21-22TWh without, with similar filling level patterns throughout the year.

“Almost all hydrogen is stored in salt caverns, exploiting vast geological potentials across Europe, mostly in Northern Ireland, England, and Denmark,” the authors write.

The model also predicts that if a hydrogen network is built, there will be net flows from the UK to Belgium, the Netherlands, Luxembourg, Germany and Norway; from the north of Germany to its south; and from eastern Spain to southern France.

Updated to correct a typo in the costs outlined in the 3rd and 4th paragraphs.