Analysis of a hydrogen refuelling station operating in the electricity market with wind power

Hydrogen refuelling stations have the ability to generate hydrogen at times when there is no vehicle demand by using on-site hydrogen storage. This ability can allow them to optimise their time of production of hydrogen for a given purpose. This could be to take advantage of price variations in the electricity market, or to help with integrating renewable energy sources. An optimisation routine has been developed to analyse the performance of a hydrogen refuelling station for these purposes. The electrolyser is modelled as having a minimum turn down ratio below which it cannot operate, resulting in a mixed integer nonlinear programming problem. The performance of a hydrogen refuelling station, located at the advanced manufacturing park in Rotherham has been simulated. The effect of operating the electrolyser to optimize operation in the electricity network, as well as reducing wind curtailment in a grid constrained scenario is determined.
It is found that the optimisation routine is capable of increasing profits when operating in the market, but this is dependent on various factors such as the level of hydrogen demand and wind power. Increasing the number of cars refuelled per day increases the electrolyser utilisation as shown in figure 1a, but this limits the ability of the electrolyser to take advantage of electricity price variations.
Figure 1: a) effect of number of cars refuelled daily on electrolyser operation and hydrogen demand not met. b) Power transfer between refuelling station and grid for two different optimisation methods. [1]
Figure 1b shows the power transfer between the refuelling station and the grid for a market and non-market optimisation. In the market optimisation the electrolyser operates to take advantage of price fluctuations, resulting in the different pattern of power transfer seen in figure 1b. Utilising hydrogen demand and storage can help in supporting the grid to integrate renewable energy sources, both when the renewable resource is on-site, and when it is distributed throughout a distribution network [2].
References
[1] Carr, S., Zhang, F., Liu, F., Du, Z. and Maddy, J Optimal operation of a hydrogen refuelling station combined with wind power in the electricity market, International Journal of Hydrogen Energy, In press
[2] Carr, S., Premier, G.C., Guwy, A.J., Dinsdale, R.M. and Maddy, J., 2014. Hydrogen storage and demand to increase wind power onto electricity distribution networks. International Journal of Hydrogen Energy, 39(19), pp.10195-10207.