[c0-author: Mostafa Al Khonaizi]
Over the past several decades, public opinion and government policy directives have shifted significant resources away from carbon intensive sources, to cleaner and renewable alternatives. In addition to traditional wind and solar power generation, hydrogen could potentially play a significant role in a decarbonization strategy. Hydrogen is a green energy source if produced by electrolysis relying on renewable electricity (known as green hydrogen) or is coupled with carbon capture, usage and storage technology (known as blue hydrogen). However, in order for clean hydrogen to become a significant component of any decarbonization strategy, it must overcome a number of impediments to viability. Although moving in the right direction, clean hydrogen is currently uneconomic relative to grey hydrogen (hydrogen that is produced through means that emit significant amounts of carbon dioxide to the atmosphere). Storage is also an issue – gasoline has five times the energy density of compressed hydrogen, meaning significantly more hydrogen is required for the same amount of energy. Shipping, long-distance transportation and local distribution also present significant challenges. Nonetheless, while wind and solar are the mainstays of the renewable energy industry, the potential upside for hydrogen application in certain parts of the energy value chain is significant, and governments and private industry are coming together in organized ways to ensure its future.
This will be the first in a series of articles that takes a deep dive into the hydrogen ecosystem and value chain. This first article provides an overview of some of the legal, commercial and technical aspects of hydrogen as a clean energy source.
Traditional Industrial Uses of Hydrogen
Today, the petroleum refining industry has the highest demand for hydrogen, followed by the ammonia and fertilizer manufacturing industry. In the refining process, hydrogen is used to lower the sulfur content of fuel. Hydrogen is also used in producing several chemicals like ammonia, methanol, and other petrochemical products. Ammonia is mainly used in agriculture as a key ingredient in fertilizers, but it is also an ingredient in cleaning products, wastewater treatment, cold storage systems, plastics, pesticides, fabrics, and dyes. Other industries such as the steel and cement industries use hydrogen as a high-grade heat source. Given the quantities of hydrogen used in these industries, it is normally produced at scale by reforming natural gas in a steam methane reformer (i.e. grey hydrogen). Grey hydrogen currently emits between 9-20 kg of carbon dioxide for every kilogram of hydrogen, resulting in emissions of 830 million tons of carbon dioxide per year1 – more than Germany’s annual carbon emissions.
Transportation of Hydrogen
Hydrogen has a very low energy density (energy content per unit volume), lower than any other commonly used feedstock, so it needs to be compressed for economical transportation and storage for use in final applications. The gas compression process uses considerable energy, and like any pressurized gas, compressed hydrogen will have leakage, reducing the process’s total energy output. Some amount of hydrogen can also be injected into the existing natural gas grids up to a maximum of around 10% of the total amount of gas in the pipeline flow. However, most of the current natural gas pipeline infrastructure would be unsuitable to transport hydrogen in higher amounts, as hydrogen causes embrittlement of pipeline steel and welds, and thus would require upgrades to transport hydrogen. For industrial applications, hydrogen pipeline networks linking various industrial scale hydrogen production facilities with industrial end users exist in some industrial corridors, such as the Texas and Louisiana Gulf Coast.
Hydrogen liquefaction is a potential for long-haul transport; however, the temperature point of liquification of hydrogen (at -253℃) is much lower than natural gas (at -162℃), and thus consumes more energy. There is a potential application of using chemicals like ammonia as possible carriers of hydrogen. After ammonia is produced, it can be stored and transported in a liquid form, containing twice as much hydrogen as liquid hydrogen by volume.2 Compared to hydrogen, ammonia also has significantly higher liquification temperature, and therefore is easier to liquify than hydrogen, increasing the overall energy efficiency of the hydrogen lifecycle.
Hydrogen as a Fuel Source
The use of hydrogen in transportation, sometimes referred to as “hydrogen mobility” requires the use of fuel cells to produce electricity. Fuel cells are similar to combustion engines and generators in that they require a constant supply of fuel to operate. However, instead of burning the fuel to release the power as captured heat, fuel cells use hydrogen in an electrochemical reaction to release and capture ions to produce electricity. There are different types of technologies used to make the fuel cells, and manufacturers compete on the efficiency and costs of their fuel cells.3
Fuel cell electric vehicles (“FCEVs”) are made by several car manufacturers. However, due to the low number of FCEVs on the road and the qualities of hydrogen, placement of hydrogen refueling stations presents a financial and logistical challenge to the fuel cell industry, which affects the overall feasibility of using FCEVs.
Similar to natural gas, hydrogen can be used for power generation. Gas turbines powered by synthetic gas, which contains up to 95% hydrogen by volume, have been in use for more than a decade and are already commercially produced at scale. With modifications and adjustments to existing systems, switching to pure hydrogen combustion is a possibility.4
Hydrogen in Storing Energy
Hydrogen also has the potential to play a vital role in the renewable energy lifecycle by serving as a form of energy storage. Acting as a chemical energy store, hydrogen is an option for dealing with the intermittency and reliability of electricity generated through traditional renewable sources such as wind and solar. This is done through electrolyzers, where the electricity produced from the renewable source is converted into hydrogen. Electrolyzers utilize a reverse electrochemical reaction called electrolysis to generate hydrogen by running electricity through water. The created hydrogen can be used in any application as discussed above, and it can also be used to generate electricity again using a fuel cell. This “power-to-gas-to-power” route, however, suffers from a significant efficiency toll of around 45% of the initially generated electricity.5
While there are potential uses for hydrogen in an alternative, low-carbon energy portfolio, its success will require production reliant on lower carbon and energy efficient technology. The next article in this series will explore this prospect in greater detail, considering hydrogen production technology and restrictions in the current energy infrastructure.
*Mostafa Al Khonaizi is a law clerk in our New York office.
1 IEA, Hydrogen, https://www.iea.org/fuels-and-technologies/hydrogen (last visited Dec. 6, 2020).
2 Gencell, Ammonia Fuel, https://www.gencellenergy.com/gencell-technology/ammonia-fuel (last visited Dec. 6, 2020).
3 Two ways to increase efficiency for example, are the material used as a catalyst and whether the fuel cell system captures the heat it generates to mitigate energy loss.
4 GE Power, Hydrogen Fueled Gas Turbines, https://www.ge.com/power/gas/fuel-capability/hydrogen-fueled-gas-turbines (last visited Dec. 6, 2020).
5 Sonal Patel, How Much Will Hydrogen-Based Power Cost?, Power Magazine (Feb. 27, 2020), https://www.powermag.com/how-much-will-hydrogen-based-power-cost