Hydrogen has long held promise as an energy carrier, though electrolyzer and fuel cell technologies have so far not broken into the mass market—largely due to high costs and infrastructure challenges. As those technologies continue to get cheaper and more efficient, they present intriguing possibilities for hydrogen in one unexpected application: microgrids.
Microgrids, whether grid-tied or remote, rely on local power generation. While solar PV, wind, and other renewables capture many headlines, fossil-fueled distributed generation (DG) accounts for more capacity than any other—40% of the total—among the microgrids tracked in Navigant Research’s Microgrid Deployment Tracker 2Q17. Fossil-fueled DG is often selected since it can provide dispatchable power for long periods and can generally store energy-dense fuel onsite. These facts also hold true for hydrogen. For longer duration storage, hydrogen often outperforms batteries by a significant margin without the emissions associated with fossil fuels.
Emerging business models are setting the stage for hydrogen to play multiple and significant roles in microgrids. Some of these business models are briefly described below.
Remote Microgrids: Hydrogen Displacing Diesel
A new Chilean microgrid developed by Enel, with support from Electro Power Systems (EPS), is showing that hydrogen can fill the same role as diesel, but without the emissions associated with the latter. Remote microgrids have historically depended on diesel gensets, often because many days’ worth of fuel can be stored onsite. While batteries are generally too expensive for multiday storage durations, hydrogen tanks can be easily scaled, independent of the peak power demand.
According to EPS, this type of model is quickly becoming commercially viable. Some reasons include capital and operating cost declines, tighter emissions regulations across the globe, and an eagerness to bypass the diesel value chain across hazardous terrain in remote areas.
Microgrids Exporting Hydrogen
The developers of the Stone Edge Farm microgrid in California had a challenge: despite having excess onsite electricity production from PV and other sources, they faced hurdles in exporting that power in an economically viable way. For example, some of the hurdles to exporting into the California Independent System Operator (CAISO) market include reaching the minimum threshold of 0.5 MW and meeting the ISO’s resource implementation requirements, which include building an onsite meteorological station and control platform. Since these presented significant barriers, the developer looked to another product to export from the microgrid: hydrogen. A bank of onsite electrolyzers turns excess electricity into hydrogen, which then fuels the onsite Toyota Mirai fuel cell vehicles and can also feed the microgrid’s fuel cell bank to generate power.
Islands: Hydrogen as Local Energy Commodity
Many islands are dependent on diesel fuel for both transport and electricity, since it has historically been the cheapest large-scale energy carrier available. However, in places like Hawaii, the appeal of hydrogen is growing thanks to concern over climate change and a growing need to store the high output of intermittent renewables—often using power-to-gas schemes (for more information, see Navigant Research’s Power-to-Gas for Renewables Integration report). In addition, the captive nature of the vehicles helps alleviate the infrastructure problem since relatively few stations are needed. ENGIE, a member of the Hydrogen Council, has been bullish on hydrogen as a future fuel. The company is helping to build an island microgrid based around hydrogen technologies near Singapore. More projects are sure to be announced as the technologies continue to improve.
Thanks to cheap renewables and improving electrolysis technology, hydrogen’s outlook is getting better. Due to the challenges with major fueling infrastructure rollouts, Navigant Research anticipates that hydrogen development will be focused in small geographic areas through 2020. Fitting, then, that hydrogen should find a foothold on the small scale of microgrids.