The Value of Ancillary Services for Electrolyzers

While renewable hydrogen production is envisioned as the main business for electrolyzers, the provision of frequency-supporting ancillary services to the power grid can be seen as their potential by-products. This can generate additional revenue streams for electrolyzers, accelerating their integration by making them more financially attractive. This paper conducts a value analysis for an electrolyzer in Denmark. We develop a mixed-integer linear optimization model, wherein the physical characteristics of the electrolyzer are accurately captured. This model enables the electrolyzer to make informed bidding decisions in the day-ahead electricity as well as the frequency containment reserve (FCR) and the manual frequency restoration reserve (mFRR) markets. %For modeling the activation of mFRR services in the bidding stage, we suggest pragmatic approaches. By carrying out an ex-post analysis based on historical activation, we provide lower and upper bounds for the profit of the electrolyzer, such that the true profit could lie in between depending how activation has been modeled in the bidding stage. We find that an electrolyzer in the Danish bidding zone DK1 could have earned 57\% more in 2021 by proving ancillary services, while this profit increase in both bidding zones DK1 and DK2 for 2022 could have been drastic.