Hydrogen safety: let’s purify the air

This blog is the first in a series exploring energy technology security considerations essential for a carbon neutral economy.

Many experts agree that ‘green’ hydrogen produced using renewable energy can play a key role in helping us achieve a greenhouse gas neutral economy by 2050, the level needed to avoid the worst effects of the climate crisis. The best use of green hydrogen may be in areas that are difficult to electrify, such as long-haul transportation, but some people are concerned that this may also create new safety risks, although hydrogen generally has properties that make it difficult to electrify. make it safer to handle than conventional fuels.

Hydrogen – mainly used in refineries and fertilizer production today – is currently produced through a dirty process that relies on fossil gas as a feedstock and emits a significant amount of carbon pollution. However, the process can be cleaned up to produce a “green” version using renewable energy and water.

Green hydrogen – produced in small quantities today – has the potential to replace fossil fuels in heavy emission vehicles like trucks, ships and airplanes, and in industrial processes like steel production and chemicals. This can help us achieve a 100% renewable energy electricity sector by allowing us to store energy for long periods of time. The gas industry is even pushing hydrogen as a clean substitute for fossil gas to heat spaces and water in buildings, even though that would be an expensive solution compared to transitioning our buildings to electricity. (See this blog.)

Security questions?

Some skeptics see hydrogen’s safety concerns as a potential factor breaking its more widespread use. While hydrogen has known safety hazards and we should continue to prioritize hydrogen safety measures, it also has properties that should make it safer to handle than conventional fuels like hydrogen. ‘gasoline and diesel when handled responsibly.

Hydrogen is the most abundant and simplest element in the universe. On earth, it exists mainly as an essential component of water (H₂O). Hydrogen gas (H₂) is made up of two hydrogen atoms stuck together, each containing just one proton and one electron. This simple chemical structure is what makes hydrogen gas flammable and relatively easy to ignite. This is also why hydrogen gas is non-toxic, odorless, tasteless and light.

Green hydrogen is safer than conventional fuels

To assess the safety of hydrogen, it must be compared to that of other conventional fuels like gasoline, propane, and diesel. Although no fuel is 100% safe, green hydrogen has been shown to be safer than conventional fuels in a multitude of aspects.

1. Hydrogen is not toxic, unlike conventional fuels. On the other hand, many conventional fuels are toxic or contain toxic substances, including strong carcinogens. In addition, when it comes to vehicles that run on hydrogen fuel cells, the hydrogen only produces water, while the combustion of conventional fuels in vehicles generates harmful air pollution. A hydrogen leak or spill will not contaminate the environment or threaten the health of humans or wildlife, but fossil fuels can pose significant threats to health and the environment in the event of a leak, spill. or combustion.
2. Hydrogen is 14 times lighter than air and 57 times lighter than gasoline vapor. This means that when released, the hydrogen will generally rise and disperse quickly, greatly reducing the risk of ignition at ground level. However, propane and gasoline vapor are heavier than air, which increases the likelihood of them remaining at ground level, which increases the risk of fires that damage people and buildings.
3. Hydrogen has lower radiant heat than conventional gasoline, which means that the air around a hydrogen flame is not as hot as around a gasoline flame. Therefore, the risk of secondary hydrogen fires is lower.
4. Hydrogen has a higher oxygen requirement for the explosion than fossil fuels. Hydrogen can be explosive with oxygen concentrations between 18 and 59% while gasoline can be explosive at oxygen concentrations between 1 and 3%. This means that gasoline presents a greater risk of explosion than hydrogen for any given environment containing oxygen.

Hydrogen safety standards have come a long way

While there has been a lot of recent hype around hydrogen, it is not a new technology. Industry has used hydrogen in rocket fuels, oil refineries, and fertilizer production for 40 years – longer than enough for scientists and engineers to develop and adopt robust safety protocols. Today, the Hydrogen Industry Codes Panel, the International Code Council and the National Fire Protection Association are working together to develop strict standards for hydrogen systems and fuel cells. Years of R&D and experience have made it possible to develop the appropriate technical controls and guidelines to mitigate the risks of high hydrogen flammability and low ignition energy (the energy required to ignite something).

For example, because hydrogen is colorless and odorless, sensors are essential for hydrogen refueling stations, equipment and facilities. Current technology enables remote detection of hydrogen to ensure robust detection of any hydrogen leak. Hydrogen storage tanks in fuel cell cars also go through rigorous testing standards, such as exposure to extreme temperatures and pressures, before they can be deployed. These are just a few examples of the standards and codes that have supported a safe hydrogen industry over the past four decades.

Importantly, however, hydrogen safety remains a key priority for R&D. At the federal level, the Department of Energy is funding hydrogen safety R&D projects within its office of hydrogen and fuel cell technologies, contributing to a future where hydrogen can continue to be be a safe fuel that can help decarbonise our future energy needs.

Hydrogen safety must remain a priority

While green hydrogen offers a solution for the most difficult to reduce sectors, we have little experience with its use in these applications. That is why hydrogen safety research is essential if it is to play a larger role in our economy.

Storing hydrogen in the tanks of fuel cell trucks and hydrogen airplanes – economically without sacrificing safety – presents a technical challenge. The fuel cell trucking and aviation industries will need to meet similar or better safety goals than fossil fuel trucks and aircraft, as transportation safety of any kind is extremely important. . New hydrogen refueling stations and hydrogen pipelines must be designed to mitigate any risk of hazardous leakage and combustion. Groups like the Center for Hydrogen Safety (CHS), a global non-profit organization dedicated to promoting hydrogen safety, are tackling these issues by providing resources to those responsible for designing or developing ” use various hydrogen systems and installations, as well as training in incident response. With more than 45 member organizations within CHS (Shell, Hyundai, Argonne National Laboratory, National Grid, to name a few), the industry puts safety first.

The verdict:

When handled responsibly, green hydrogen is less dangerous than the other flammable fuels we rely on today. Moving forward, industry and government institutions must build on existing robust safety protocols and continue to make safety a key priority for investment and refinement to ensure that hydrogen does. part of a clean and prosperous economy.