As hydrogen-powered vehicles penetrate the market, fuel pathway energy requirements (including electricity for production, liquefaction, and compression of hydrogen) place new demands on the electricity system.  Depending on the timing of these demands, hydrogen pathways could add to peak electricity demand, further distorting demand curves and requiring additional costly and inefficient generation capacity.  Or, they could serve to “load-level” electricity demand curves, improving the efficiency and reliability of electricity supply and potentially enabling increased penetration of intermittent renewable resources.

To understand the complex interactions between hydrogen-based transportation and the electricity system, we have developed fuel demand scenarios for California and a dispatch model that simulates the composition of the electricity grid on an hourly basis.  The dispatch model allocates generation according to a set of rules that governs which power plants are used to meet demands.  This allows us to conduct a scenario analysis of cost, greenhouse gas emissions, and resource impacts associated with different hydrogen supply pathways in California.

This study extends work presented last year at the NHA conference (McCarthy, et al, 2007) in two critical dimensions.  First, we include electricity-sector costs, which allows us to compare alternatives on an economic basis.  Second, we implement a stochastic representation of power plant availability.  The previous paper treated the availability of thermal power plants deterministically and used exogenously-defined profiles for intermittent wind, hydroelectric, and imported power generation.  Here, we improve upon the representation of these generation resources.  Unscheduled maintenance at thermal power plants and the availability of wind power (a function of hourly wind speed) are now represented as stochastic processes.  Hydroelectric generation and imported power are represented as a function of hourly electricity costs and the availability of other power plants.  We perform Monte Carlo simulations to develop probabilistic results for several hydrogen fuel and electric vehicle pathways.