Role of hydrogen in resolving electricity grid issues

• Electrolytic hydrogen production can help to resolve electricity grid issues.
• The nuclear power plants load following and balancing mechanism can be addressed.
• The costs depend on the size of the electrolysers and the type of storage.
• The utilization rate of the available electricity is a major determiner of the cost.
• Specific layouts lead to production costs that fit into the hydrogen energy market.

Hydrogen seems to offer a credible way of storing energy, which can easily be restored as electricity. Its flexible production via electrolysis also means that it can also be used to help balance the electrical system. All in all, hydrogen's potential for energy integration (electricity-hydrogen) makes it an interesting option. This study assesses the effect of combining the hydrogen system with the electrical system. Two aspects coupling hydrogen with electricity are therefore examined within the French context: 1) load following with nuclear power plants (NPP), and 2) the balancing mechanism (BM). The HOMER simulation software developed by NREL in the US was used to do this. The analyses herein show that the costs of producing hydrogen via electrolysis – as compensation for load following with NPPs – are very variable and basically depend on the size of the electrolysers and the type of storage, plus the utilisation rate of the available electricity. Several configurations were studied taking each reactor in the plant separately. Costs varying from €3.0 to €4.5/kg were obtained when the salt cavern storage technique was used and the price of electricity was disregarded. These costs are lower than for the whole group (€7.2/kg). From the point of view of balancing the overall electrical system, an assessment of the relevance (quantities, costs) of hydrogen production has been considered at least as concerns the balancing mechanism. Hydrogen production offers the possibility of better managing the electrical system, while offering the opportunity for lower production costs by better exploiting the available electricity. Overall, losing approximately 50% of the electrical power can reduce the cost (excluding the price of electricity) by a factor of 4 from €9.7 to €2.4/kg, which is considerable. As regards the overall BM cases, hydrogen production costs obtained can be similar to the reference costs (ca €0.9/kg excluding the electricity price), while replacing the major part of the balancing mechanism. In any case, a compromise must be reached between the quantity produced and the cost of production. Yet investments could prove to be significant, as could the resulting hydrogen productions, with both strongly depending on stakeholder strategies.The results of this study show that combining the hydrogen production chain with the electrical system could be a very relevant option.