There is no single route to reaching net zero, writes Professor Emmanouil Kakaras, who argues that decarbonizing our energy supply will need a range of solutions, including energy storage, which has grown in importance in recent years, alongside the increasing use of renewable energy and the expansion of localized electricity grids.
And yet we still need more storage. In order to keep the world on track to meet the UN Sustainable Development Goals (SDGs) on energy, the sector needs to see double-digit growth, according to the International Energy Agency (IEA), because of its ability to level out the intermittent nature of renewable sources and respond rapidly to fluctuating demand.
Hydrogen is being considered as an option for energy storage, as an alternative to lithium-ion batteries. So, the question that ponders on our mind is whether hydrogen will be the next viable solution for long term storage?
The relationship between hydrogen and renewables – the potential for energy storage
An almost symbiotic relationship is emerging between hydrogen and renewables. As wind turbines and solar PV panels become cheaper, so does the cost of producing green hydrogen from renewables through electrolysis.
Hydrogen offers the potential for energy storage — it complements battery solutions to provide flexibility to the grid, delivering energy on a much larger scale. Hydrogen can harness surplus renewable energy and store it for long durations, to help smooth out intermittency issues, seasonal power supply imbalances and avoid extended periods of wind or solar curtailment.
As mentioned, this is a particular advantage when there are large seasonal variations in the level of electricity generated by renewables and can help capture energy that might otherwise be wasted. For example, hydrogen storage could be used to capture the excess electricity generated by offshore windfarms during the North Sea’s fierce winter winds.
As renewable energy is generated on a use-it-or-lose-it basis, surplus energy is currently either wasted or curtailed by switching off wind turbines, for example. Hydrogen provides a unique storage solution that can utilize this surplus, which produces no CO₂ emissions when combusted.
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Once excess supply of clean energy is converted into green hydrogen, it can power gas turbines and generate electricity as and when required.
This sustainable alternative to natural gas and other fossil fuels can be used to generate baseload backup power during periods of peak energy grid demand. It is also suitable for ironing out short- or long-duration intermittency imbalances associated with renewables when there is too little wind or sun to generate sufficient supply.
Renewable energy can be converted to hydrogen, stored until it is needed, and then reverted to electricity on demand. One of hydrogen’s advantages is its scalability, particularly as an enabler of long-term seasonal storage.
In the western US, for instance, there is often a large renewable energy surplus in the spring, when a combination of strong winds, sunlight and cool temperatures can lead to an excess equal to hundreds of thousands of megawatt hours.
As nodded to previously, it’s a similar situation in the North Sea, where vast offshore wind farms often generate excess energy. There are already a number of projects in development to harness that energy, including the Hamburg Green Hydrogen Hub in Germany, which will produce hydrogen from wind and solar power.
The Hydrogen Council, a global partnership launched at the World Economic Forum Annual Meeting in 2017, says that hydrogen could enable the deployment of renewables by converting and storing more than 500 TWh of electricity.
Crucially, hydrogen also can also help to deliver carbon-free electricity when renewable energy systems (RES) are not producing. This serves to increase security of supply and can help regions such as Europe gain more energy independence in light of geopolitical tensions and uncertainty.
Hydrogen will also bridge regions with high RES potential around the world with industrial centers of energy demand — again, Europe comes to mind.
In order to achieve this, we will have to build a global hydrogen supply infrastructure, in which hydrogen carriers such as ammonia will play an important role by enabling the energy to be transmitted efficiently and safely across long distances.
The Advanced Clean Energy Storage Project
Mitsubishi Power in partnership with Magnum Renewable Development, is building the world’s largest renewable energy storage project, called Advanced Clean Energy Storage Project in Utah in the United States.
Renewable hydrogen will be produced from excess renewable energy and stored in a series of underground salt caverns. One cavern at the Advanced Clean Energy Storage project will store enough renewable hydrogen to provide 150,000 MWh of clean energy storage. The location of the project is important for two reasons.
First, it sits on salt caverns that can be used for compressed hydrogen and compressed air energy storage. Second, it’s being built next to the Intermountain Power Plant, a 1.8GW coal-fired power plant that supplies one-fifth of Los Angeles’ electricity and is due for retirement in 2025.
This location means the project will be able to easily connect with the existing electricity transmission infrastructure. It also potentially removes the need for long-distance hydrogen pipelines, as the Intermountain Power Renewal Project will be adjacent to the Advanced Renewable Energy Storage project.
Large-capacity, long-term energy storage and usage needs are growing as renewables spread. Accelerating decarbonization is required even in industries that face challenges electrifying.
Hydrogen and other clean fuels offer solutions. Creating enough future storage capacity for clean alternative fuels, like green hydrogen, is a crucial step in achieving net zero emissions. Hydrogen can store surplus renewable energy, which can then be used as a clean fuel source to help decarbonize power generation or hard-to-abate sectors like transportation and heavy industry.
Hydrogen can help strengthen security of supply, which goes hand in hand with increased energy independence, particularly in the case of Europe. It will connect those regions with the highest potential for solar and wind with demand centers elsewhere, increasing overall efficiency.
Hydrogen alongside other options will be a key element of decarbonising the energy system as a whole – both as a storage medium for renewable energy as well as a fuel to decarbonise those sectors that cannot be simply electrified.
Professor Emmanouil Kakaras is Director of the Laboratory of Steam Boilers and Thermal Plants at the National Technical University of Athens, and Executive Vice-President of NEXT Energy Business at Mitsubishi Heavy Industries EMEA.
