The solar panels are producing. The building is using less than they generate. Selling the surplus brings little value, or the export limit has already been reached.
What else could that electricity do?
For a site that consumes hydrogen, one possibility is to use it for electrolysis and keep the resulting gas for later. This is a practical connection to the work we are doing at HydroCharge: local production, compression, storage and refueling for smaller hydrogen users.
The attraction is easy to see. A laboratory or business could investigate producing hydrogen when electricity is available on favourable terms, rather than buying all of its gas through deliveries. Production and use would not have to coincide, provided there is enough storage and time to replenish it.
Low electricity prices can improve the case for local hydrogen production. The comparison should include the site’s full electricity costs, alongside the electrolyzer, supporting equipment and maintenance. This gives a practical view of how favourable operating hours could contribute to the cost of the hydrogen supplied.
It also matters what would otherwise happen to the electricity. Surplus generation might still be sold. Using it locally then means giving up the value of that sale. Is it or high or a low price? Alternatively, an export constraint might force production to be reduced. In that situation, an additional local use could allow some generation to continue, subject to the installation’s technical limits. Those are different opportunities and should be evaluated separately.
Cheap hours need to become useful hydrogen
The first thing to establish is where the hydrogen will go. A site with an existing gas requirement has a concrete basis for comparison: its current supply, the timing of its consumption and the conditions the application requires. Matching production to that need gives low-cost electricity a useful purpose.
Next comes the operating schedule. How often is favourable electricity available, and for how long? Does that window arrive before the hydrogen is needed? Can the equipment produce enough during it, and is there room in storage?
The DOE’s H2NEW programme examines opportunities created by changing electricity prices, curtailed power and integration with renewable generation. For an individual site, its own records can help identify a suitable operating pattern. Looking beyond a few exceptionally cheap hours helps balance electricity savings with equipment utilisation and the amount of hydrogen needed.
A broader operating schedule may prove more useful. It is worth comparing operation during the very cheapest periods with production at other times that still offer reasonable costs and keep the required reserve available. The decision should account for the equipment’s permitted operating range and the electricity used by compression and other supporting components.
HydroCharge provides a basis for exploring this at a smaller scale.
Some users may also want to turn the stored hydrogen back into electricity, extending its role within the local energy system. This would involve a fuel cell and supporting equipment, with conversion losses included when comparing the available ways of using or storing the electricity.
For a business already needing hydrogen, the starting point can be simpler: compare local production with the gas it currently buys. The value lies in supplying that need, potentially using electricity that earns little from export or would otherwise remain unavailable because production is curtailed.
DOE H2NEW — Electrolyzer Integration and Optimization
US Department of Energy — Systems Development and Integration Energy Storage and Power Generation