The U.S. Department of Energy (DOE) and its national laboratories have been studying the benefits and uses of hydrogen, dubbing their findings the “hydrogen at scale” (H2@Scale) initiative. Hydrogen’s value lies in its ability to provide benefits across multiple sectors and in decoupling energy conversion from energy storage, unlike conventional batteries. Hydrogen allows you to couple and decouple multiple sectors from power generation in unique ways and serves as an enabler for many applications. The H2@Scale initiative is aimed to tap into those added-value features hydrogen can offer in a larger-scale energy system.
We are only beginning to understand the potential value of hydrogen to our evolving energy sector. Research and development over the past 15 years have helped unlock building blocks of information that can take us beyond the typical uses of hydrogen today: backup stationary power and petrochemical refinement. The H2@Scale Initiative is aimed at tapping into that added-value that hydrogen can offer in larger scale energy systems.
History of hydrogen
Hydrogen is already an essential industrial feedstock, with more than 10 million metric tons produced annually in the U.S., primarily for the petrochemical industry (e.g. oil refining and ammonia). Industrial demand for hydrogen is expected to steadily grow due to both existing processes, such as petrochemical refining, as well as the growth of new applications, such as the use of hydrogen in ironmaking. Approximately 95 percent of hydrogen produced in the U.S. is generated via reforming of natural gas.
Another approach to hydrogen production is electrolysis, wherein electricity is used to split water into high purity hydrogen and oxygen. Today, electrolyzers are used when natural gas is not available, steam methane reforming is not practical, or where high levels of hydrogen purity are needed such as semiconductor or fuel cell applications.
Using hydrogen to power fuel cells is another established technology, particularly where emissions, reliability, maintenance costs, and/or quiet operation are concerns. Fuel cells generate electricity from hydrogen and oxygen without combustion, which enables high efficiencies and near-zero life cycle emissions for a range of technologies. The largest markets for fuel cells are in stationary power, backup power, and material handling equipment. These markets have recently seen steady growth; nearly 65,000 fuel cells were shipped worldwide in 2016, representing more than double the capacity of shipments in megawatts compared to 2014.
H2@Scale framework
The premise of the H2@Scale concept is that energy that is intermittently available like renewables, or baseload plants like nuclear, can be leveraged to economically produce hydrogen for consumers. Hydrogen’s potential as an “energy intermediate” is unique because its production can utilize either electricity or heat, or both, and because at least one hydrogen production technology, electrolysis, has already demonstrated the ability to produce hydrogen rapidly in response to fluctuations in power supply. This ability to cycle gives electrolyzers a value proposition to the power grid, which requires “responsive load” to rapidly consume energy when power supply exceeds demand. “H2@Scale” lays a framework for the potential wide-scale production and utilization of hydrogen. It address key issues such as enabling grid resiliency, energy security, cross-sector efficiency improvements, and emissions reductions.
H2@Scale will enable innovations to utilize hydrogen as a large-scale energy carrier, coupling power generation, the grid, and hydrogen consumers to lower the cost of both baseload plants (e.g., nuclear and coal) and intermittent renewables (e.g. solar and wind), enable grid resiliency, and avoid curtailment. Hydrogen is already stored and distributed throughout the country via large-scale infrastructure, including over 1,600 miles of hydrogen pipelines, eight liquefaction plants, and three geologic caverns (with capacity for storage of thousands of metric tons of hydrogen). Growing consumers of hydrogen include production of gasoline and diesel, fertilizer production, and fuel cell vehicles that run directly on hydrogen as well as stationary/back-up power. Additionally, hydrogen production can become a revenue stream for power generation. Research and development efforts in these areas include modular, scalable concepts for dispatchable hydrogen production, delivery and storage, liquefaction, and use in innovative processes, such as ironmaking.
Grid Management
The U.S. electric grid is experiencing a growing need for technologies that can ensure stability when demand outweighs supply and vice versa. The need for these grid services to manage electricity flow will only increase as more unpredictable power generators like wind and solar are deployed.
Electrolyzers can use their capacity as a form of ’responsive load’, to increase power and produce hydrogen when electricity generation exceeds demand, and decrease power when demand exceeds generation. Their sub-second response times have been validated by DOE national labs.
If electrolyzers were integrated with the grid in a manner where they turn on and consume power during hours of the day when power supply is in excess, like wind at night, they could support grid stability while accessing low-cost power that enables economic hydrogen production. Similarly, electrolyzers can also be integrated with baseload generators, such as nuclear power, that are currently financially challenged due to natural gas abundance. Baseload generators are not designed to fluctuate output rapidly throughout the day, and consequently have difficulty staying online during days when electricity demand is low and significant hours are unprofitable. Hydrogen and also offer higher capacity (gigawatt scale) energy storage, with fewer geographical constraints than pumped hydro or compressed air storage, and at lower costs compared to battery storage over many days.
Transportation
There are now roughly 2,500 commercial fuel cell cars on the road, with projections for over 40,000 fuel cell electric vehicles (FCEVs) on the road by 2022. These cars offer completely zero tailpipe emissions and a 300-mile range of over 60 miles per gallon gasoline equivalent, and can be refueled in a few minutes. In recent years, fuel cells have also begun penetrating the markets for medium- and heavy-duty transportation. In 2016, more than 20 fuel cell buses were in active service in the U.S. transporting over 17 million passengers. Fuel cell forklifts are also being widely adopted primarily for their zero-emissions performance and fast refueling compared to slower battery recharging for electric forklifts. Larger vehicles like delivery vans and drayage trucks have also been demonstrated.
The U.S. currently has about 30 hydrogen fueling stations, located primarily in California, with plans for 100. At least an additional 12 are planned for deployment in the Northeast with private funding. More work is needed to increase capacity and reliability and decrease cost and footprint.
Stationary power
Recognizing the vulnerabilities of grid dependency, organizations are looking at fuel cells as a reliable primary and backup power option. After Superstorm Sandy slammed the Caribbean and the East Coast, fuel cells provided emergency backup power to telecommunications towers operating for hundreds of hours in both the Bahamas and the Northeast United States. Fuel cells can offer significant cost advantages over battery-generator systems when shorter run-times of three days or less is sufficient.
The always-on nature of fuel cells provides reliability and can be used to fill in intermittency gaps. For example, stationary fuel cells can be co-located with resources such as wind turbines, solar panels, or batteries at discrete customer sites, like retail stores or corporate campuses.
Fuel cells are often implemented as part of a combined heat and power system, where the thermal energy from the fuel cell exhaust is recovered and used to heat or cool industrial facilities and commercial buildings.
Challenges
Currently, the cost of hydrogen production and delivery, as well as hydrogen use in certain applications, is prohibitive to wide-scale adoption. Significant research is necessary to lower the capital costs of electrolyzers and to enhance the readiness of earlier stage pathways, such as photoelectrochemical hydrogen production or solar thermochemical water-splitting. Game-changing advancements are also necessary to reduce the costs of hydrogen infrastructure (e.g. liquefiers, pipelines, or liquid carriers). Finally, technologies where use of hydrogen provides a performance advantage (e.g. diversification of feedstock or reduction in emissions) must be further developed.
DOE’s Fuel Cell Technologies Office (FCTO) has enabled 650 U.S. patents, 30 technologies commercialized by industry, and another 75 anticipated to be commercial in a few years. More work is needed to sustain the momentum and FCTO launched three consortia to accelerate materials discovery and development; Electrocatalysis Consortium (ElectroCat), Advanced Water Splitting Materials Consortium (HydroGEN), and Hydrogen Materials-Advanced Research Consortium (HyMARC)
In addition to ongoing analysis work, the DOE and its national laboratories have solicited feedback from stakeholders to identify key areas of interest and opportunity. Recent workshops held by the National Renewable Energy Laboratory captured input on key topics, including areas requiring R&D. Ultimately these efforts can pave the way to a low-cost, large scale hydrogen energy system to support energy, economic and environmental security for the nation. Most recently, DOE launched an H2@Scale Consortium, soliciting a call for Cooperative Research and Development Agreements between industry and DOE’s national labs, offering unique lab capabilities and expertise to enable the H2@Scale vision.
