Myth: Hydrogen Is A No-Regret Solution For Every Sector
The versatility of hydrogen as a decarbonization solution has created a lack of consensus and clarity on where it is really needed. Hydrogen is sometimes described as the “Swiss Army Knife” of decarbonization and plays a role in almost every sector, as it can be burned to generate electricity or heat, serving as a carbon-free input to produce “green” steel and fertilizer. , and powers everything from passenger cars to deep sea freighters.
Reality: Hydrogen Should Be Prioritized for ‘Difficult to Regulate’ Sectors
In theory, hydrogen could indeed be used to decarbonize almost every sector. But just because he can do it, doesn’t mean he can. As one of several tools in the decarbonisation toolbox, hydrogen should be preferred where energy efficiency and direct electrification are not feasible. In particular, hydrogen’s potential to quickly and cost-effectively decarbonize the hardest-to-reduce sectors makes it an essential part of the clean energy transition.
One of the factors limiting global decarbonization is the scarcity and cost of renewable electricity used to produce “green” hydrogen. The world already needs a cleaner electricity infrastructure, as energy consumption is expected to double in 2050 due to population and economic growth alone – and only 10 percent of electricity today comes from solar and wind. Add the electricity needed to make green hydrogen to decarbonize heavy industry and transportation, and energy consumption can triple. Against this background, it is important to prioritize the reduction of electricity consumption at the macro level and the most efficient use of renewable electricity. Thus, many of today’s micro-scale business cases for hydrogen for heating buildings, power generation, or fueling light trucks are better suited to investments in energy efficiency or direct electrification (see Appendix 1 below).
However, there are several applications where energy efficiency and direct electrification are costly, impractical, or simply impossible. Enter hydrogen. Considering its flexibility, technological maturity and relatively low cost, hydrogen is one of the key solutions to decarbonize hard-to-reduce sectors such as steelmaking and shipping.
The best tool for a difficult job
The specific applications where hydrogen shines may vary by geography, particularly as several developed economies are limited in land area and have limited capacity to generate renewable energy potential. But even before considering the limitations of the real economy, there are some unfortunate, high-priority applications of hydrogen that should be the main focus of policy and investment today: fertilizer production, petrochemicals and refining, steelmaking, maritime transport, and some markets, both iron and steel. road, as well as long-distance heavy cargo transportation by trucks. All of these sectors need hydrogen to decarbonize, are ready for a technology transition, and contribute significantly to global emissions. Over time, hydrogen may expand beyond these core applications.
Exhibit 1 shows the carbon reduction per kilowatt-hour (kWh) of zero-carbon electricity used directly in electrified end-uses or indirectly through hydrogen generation. This quantification confirms the guiding philosophy of priority hydrogen applications: use hydrogen where you can’t electrify. Using direct electricity whenever possible provides the greatest emissions reduction potential, given the low cycle efficiency of hydrogen use in these applications (building heating, power generation, and light trucking).
Note: Building heating compares a heat pump with a duty factor of 2.92 and a hydrogen furnace with 80 percent efficiency to burning natural gas. Power generation compares direct electrification and a 60 percent efficient hydrogen turbine to burning natural gas. Light Trucks compares a 50 percent tank-to-wheels efficient fuel cell electric vehicle and a 70 percent battery electric vehicle with a 30 percent gasoline internal combustion engine, including electricity for hydrogen compression. Hydrogen replaces coking coal for steel, steam-methane reforming hydrogen for fertilizer, and diesel for trucking. Ammonia replaces heavy fuel oil in a 39 percent efficient internal combustion engine for marine transportation. Source: Emissions intensity values from EIA
No regret applications today
Hydrogen is already widely used today – the problem is that most of it is emissions-intensive hydrogen from fossil fuels. Hydrogen production for fertilizer and oil refining currently accounts for ~2 percent of global emissions. The use of clean hydrogen is a necessary application to decarbonize the current use of carbon-intensive hydrogen, and the EU has committed to replacing all “grey” hydrogen from natural gas by 2030. with hydrogen feedstock resources, these sectors can act as locomotives in expanding the supply chain and reducing costs for clean hydrogen technology.
Given the scale of the sector’s emissions and the limited alternatives for decarbonisation, hydrogen is also a top priority for steelmaking. Steelmaking is responsible for ~8 percent of global emissions today, primarily through the use of coking coal to remove oxygen from iron ore to create pure iron, a chemical process called “reduction.” Replacing coking coal with hydrogen in this reduction process is the most promising and mature solution for the decarbonization of steelmaking.
Similarly, maritime transport—~2.5 percent of global emissions and growing—has few decarbonization options for deep-sea voyages beyond hydrogen-based feedstock. Electrification is possible for regional flights, but hydrogen or its derivatives (ie, ammonia or methanol) will be necessary for long-haul shipping, which accounts for the bulk of the sector’s emissions. Biofuels are an alternative to hydrogen-based fuel, but raw material resources are limited and are mainly prioritized for use in aviation rather than the maritime transport sector.
Heavy trucking, which accounts for ~4.5 percent of global emissions, will require hydrogen for the heaviest vehicles covering long-haul routes, given the limitations of battery energy density and long charging times combined with the distances required to travel. .
Longer term applications for hydrogen
Aviation has several decarbonization options, the feasibility of which varies by aircraft size and travel distance. For short routes, electrification is an option. For longer routes, biofuels, synfuels or hydrogen are emerging as the main solutions. However, there are technological, design and regulatory hurdles to overcome before hydrogen is ready for use in the sector; until then, zero-emission aviation is limited to the use of “drop fuels” that do not require modifications to the aircraft. To help accelerate the decarbonisation of aviation once aircraft-side technology is ready, hydrogen infrastructure must be built today to ensure future supply to airports by 2030.
As grids strive to become fully decarbonized, they will need clean, robust power to move from 80 percent to 100 percent carbon-free electricity. Hydrogen is one of many options to meet this need in the company’s solutions, including demand response, batteries, carbon capture and storage, and geothermal. While the jury is still out on the winning economic solution, hydrogen’s ease and flexibility—especially as a seasonal storage resource—provide key advantages. When these resources are needed to further decarbonize the power system varies from grid to grid, but generally renewable electricity today must be added directly to the grid instead of being used to convert hydrogen back into electricity.
Where direct electrification wins
Heating buildings and transporting passengers in light trucks are applications that are more suitable for direct electrification than hydrogen, as can be seen in Annex 1. Heat pumps are a commercially available, cheaper and more efficient solution for building decarbonisation in temperate and warm climates. climates. The efficiency and availability of battery electric vehicles for passenger transportation often make direct electrification the preferred solution. However, there may be cases where hydrogen may be a viable solution, such as where renewable resources are limited or where infrastructure is extremely difficult to replace with electricity.
In addition to direct use of hydrogen for building heating and electricity generation, some attention has also been paid to mixing natural gas with hydrogen. Blending hydrogen with natural gas does not require the upgrading of pipelines, turbines or boiler infrastructure, which is different in a pure hydrogen system. However, emissions reductions from blending hydrogen with natural gas are limited. Given the lower volumetric energy density of hydrogen compared to methane in natural gas, blending as much hydrogen as most pipelines can handle before degradation (~20 percent by volume) results in only a 7 percent reduction in emissions.
Hydrogen is key to meeting our climate goals, but in situations where energy efficiency and direct electrification are better options, implementing hydrogen will hinder our ability to quickly and cost-effectively decarbonize our energy system. In order to maximize the efficient system-wide use of valuable clean electricity, hydrogen should be used when these solutions are not possible. Fertilizer, oil refining and petrochemicals, steelmaking, and long-haul heavy-haul transportation are today’s most unfortunate applications of hydrogen, and may eventually be joined by aviation and long-term energy storage.
Tessa Weiss, Thomas Koch Blank
© 2021 Rocky Mountain Institute. Published with permission. Originally published on RMI Outlet.
Image courtesy of Siemens.
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