Power-to-gas (P2G)—the conversion of electrical power into gaseous energy carriers—is a quickly improving and potentially disruptive energy conversion technology. It offers many of the same services of other energy storage technologies and has the added ability to be stored for long periods in the form of a useful commodity fuel product, hydrogen. The hydrogen economy has had false starts before thanks in part to high costs and infrastructure challenges. P2G is primed for significant growth in coming years as demand for clean hydrogen grows, electrolyzer capital costs fall, and cheap renewable energy bathes the grid. P2G provides a variety of services to the electric grid for renewables integration. While these services can also be provided by most grid-tied storage technologies, P2G has unique attributes that can give it an edge. Seasonal energy storage—of interest in places like California where a record 80 GWh of renewable power was curtailed in the windy and sunny month of March—is an application well-suited for P2G, since long-term storage capacity can be scaled up by adding low tech tanks. Researchers at the University of California, Irvine’s Advanced Power and Energy Program found that hydrogen energy storage systems can have lower capital costs than lithium-ion batteries for discharge durations of more than about 20 hours—a duration easily exceeded in the months-long seasonal storage arena. Electrolyzers can also ramp production up or down on command and maintain that new state for a nearly indefinite period, functioning as a demand response (DR) resource. For example, within seconds, a 10-MW electrolyzer operating at a steady 5 MW can look like a load (by ramping to 10 MW) or a generator (by dropping to 0 MW). ITM Power, an electrolyzer vendor, identifies three value streams in the example of electrolyzers operating on the UK’s National Grid: Electric utilities are gradually beginning to recognize the value P2G can bring to their grid; Navigant Research sees European utilities leading deployment, with Asia Pacific and North American counterparts following. Gas utilities, which are beginning to recognize hydrogen as a potentially significant fuel of the low carbon future, should direct renewable gas research and programs accordingly. A longer-term vision of companies like Engie and others is to generate hydrogen where cheap renewables exist, and export it to demand centers. Ultimately, though, hydrogen end-users could play the most important role in driving P2G in the coming decade. From consumer FCVs to oil refineries, end-users are starting to recognize that generating hydrogen from renewables can be a win-win for markets across the globe.
Renewable Energy World 13th Oct 2017 read more »