Expert touts hydrogen as viable energy source in push to slash carbon emissions

Anaheim, California:

In the move towards a decarbonised economy, hydrogen is being considered as a renewable energy storage option.

Burns & McDonnell senior development engineer Megan Reusser said when thinking about energy storage options, batteries – whether lithium-ion or flow – are often the first solution that comes to mind.

“However, when coupled with a gas turbine generator or a fuel cell, hydrogen may be a viable option of energy storage for electric utility companies. Utilities should consider storing hydrogen, delivered via truck to the site, or if feasible, generating their own and storing on-site,” she said during an educational session at North America’s largest renewable energy event, RE+, on September 21.

Reusser reasoned that hydrogen energy storage can be considered as a “giant battery”.

There are three major storage options for hydrogen, namely, compressed gas storage, liquid hydrogen storage and geological underground storage.

“Hydrogen can be stored via multiple methods for use as a transportation fuel, power source, process feedstock or other applications. It may even offer greater flexibility for storage duration and capacity than lithium-ion batteries, benefiting producers and consumers,” Reusser explained.

She shared that the primary reason the renewable sector needs energy storage is because of the excess energy available.

KEY REASON FOR ENERGY STORAGE

“Additionally, [with] the variability of the renewables – as the sun shines at different grades, as well as the wind, we could see fluctuations in the amount of power that is being generated, so having energy storage to manage that variability is another key reason for energy storage,” she said.

Grid stabilisation and time-of-use charges are other reasons individuals and companies may want to store energy.

She explained that in times of peak demand, users may pay higher rates for using electricity, so opting to store energy and utilise it at that time makes economic sense.

“Long duration is the final reason for wanting to store energy. As we saw with some of the storms that happened in the last couple of years, where power was unavailable for days at a time, having long-duration, stored-up energy is going to be crucial to ensuring that everyone has safe and reliable energy,” Reusser said.

She compared battery and hydrogen storage using the following categories: storage duration, efficiency, cost and commercial availability.

For storage duration, hydrogen was considered “unlimited”, while batteries had a minimum of 30 minutes and a maximum of eight hours of storage time.

When compared for efficiency, hydrogen had a round-trip efficiency of 25 to 40 per cent, while batteries had an 88 per cent efficiency.

Round-trip efficiency is the percentage of electricity put into storage that is later retrieved. The higher the round-trip efficiency, the less energy is lost in the storage process.

In terms of cost, the capital cost for hydrogen is $1,000 per kWh and $450 to $500 per kWh for batteries.

Lastly, batteries are widely available in the commercial market, while there is a growing market for hydrogen.

“Ultimately, both of them are very flexible solutions. They can both be fast responding to changes in renewable energy and they can both work collaboratively with renewable energy,” she remarked.

She said various factors must be considered to determine the right energy storage solution, specific to project requirements.

judana.murphy@gleanerjm.com