The First Element Could Be Even More Important
For years EPRI has considered and discussed the potential for hydrogen and the electricity sector to combine in a more integrated energy system. As EPRI continues to broaden its portfolio, some recent and current examples provide a good understanding of the portfolio's scope and direction with respect to energy production, delivery, and use.
Among the options for hydrogen are its potential to serve as: A source of large-scale electricity demand (if produced by electrolysis); Value-added co-product to increase the flexibility of power plants; An energy carrier for decarbonizing hard-to-electrify sectors; An emerging fuel for both distributed (fuel cell) and utility-scale (gas turbine) power generation.
Power-to-Gas Frameworks
In 2014, EPRI published a technology brief looking at the Power-to-Gas or P2G frameworks in which renewable electricity is converted to gaseous fuels such as hydrogen via electrolysis. The brief outlined the potential value of harnessing variable-output renewable energy for producing hydrogen for direct use, or for injection into natural gas storage and delivery networks for use in electricity generation, heating, transportation, and other applications.
In its 2017 review of the Uniper Energy Storage GmbH Power-To-Gas (P2G) Demonstration Projects in Germany, EPRI reported on projects that sought to: Demonstrate the coupling of intermittent surplus renewable energy to the storage capacity of the natural gas grid using conventional alkaline electrolysis cell (AEC) based systems to generate hydrogen, which was then fed into the high-pressure transmission gas grid; and Demonstrate the potential of proton exchange membrane electrolysis cell (PEMEC) technology to generate hydrogen for P2G systems.
Based on these projects, PEMEC technology emerged as the then leader for prospective P2G facilities based on its footprint, efficiency, dynamics, and opportunity for cost reduction. The report emphasized that under the given market conditions, the simple arbitrage model implemented by these projects (purchasing electricity under normal commercial terms) was not a viable economic model. It pointed to the need for other market mechanisms for viable P2G projects to address opportunities for integrating the electricity, heat, transportation, and chemical sectors.
Further EPRI Research
Under a DOE H2@Scale award, EPRI is working with NREL to apply production cost modeling for integrated assessment of the impact of hydrogen technology deployment to overall electricity system operations through functions such as demand response, frequency support, and long-duration energy storage.
Earlier this year EPRI reported on an extensive review of prospects for the large-scale production of hydrogen by water electrolysis. It examined technologies, costs, and economic assessments and reported on electrolyzers' prospective of key performance indicators with respect to capital cost, efficiency, and operating lifetime.
The study found that electrolyzer manufacturers worldwide are actively developing large-scale alkaline and PEM technologies, some of which are close to meeting the efficiency and lifetime requirements for large-scale hydrogen production. Based on the likely performance of emerging PEM and alkaline electrolyzers, the analysis indicates that electricity costs of 2¢/kWh or less will be necessary to produce hydrogen from electrolysis at a cost $2/kg or less.
EPRI's generation and nuclear sectors are exploring how integrated hydrogen production and co-production could increase existing and new power plants' operating flexibility. EPRI's Flexible Plant Operations Program — with U.S. Department of Energy's Light Water Reactor Sustainability Program — is examining the feasibility and potential demonstration of minimizing plant "cycling" by co-producing hydrogen during periods of low demand. EPRI's Advanced Nuclear Technology Program is scoping potential deployment models for hydrogen production from advanced, high-temperature reactors.
EPRI's Generation Sector R&D staff are taking an informed look at what R&D is needed with respect to hydrogen as fuel for power generation. Gas turbines and engines may emerge among the end-use equipment most sensitive to new fuel mixes.
EPRI technology scouting reports have reviewed potential impacts of hydrogen fuel on materials and combustion systems. EPRI projects the need for in-depth research, including case-by-case consideration.
EPRI transportation research is expanding its scope to consider fuel cells. After more than twenty years of significant efforts to develop automotive proton exchange membrane fuel cell (PEMFC) technology, producers of fuel cell electric vehicles (FCEVs) are bringing to market limited numbers of these vehicles. EPRI is interested in understanding the prospects for large numbers of these vehicles to impact electric utility energy supply planning - looking at the next five to ten years and beyond.
EPRI's recently published update concludes that the technology offers competitive performance, but the technology still does not meet the combination of low cost and long life required for broad commercial viability. Uncertainties remain concerning the ultimate potential of PEMFC technology, widespread availability of cost-competitive hydrogen fuel, market segment fit, and overall market potential of FCEVs. Mass production is unlikely before the mid-2020s at the earliest - and then only if all technology life and cost issues are positively resolved and necessary production commitments are made within the next three to five years.
EPRI recently released a brief that examined safety considerations of blending hydrogen in natural gas delivery systems, which presents a range of potential energy benefits. Recent feasibility studies have found that blends of approximately five to twenty percent hydrogen can be accommodated by most networks with little increased risk. EPRI is pointing to opportunities for case-by-base safety/risk assessments to consider the varying characteristics of local/regional gas infrastructure and end-use systems.
