The race is on to develop the technology to harness hydrogen, widely seen as offering the most promising path to a carbon-free economy. And while it has taken more than 40 years to bring solar and wind power to cost parity with existing energy sources, those betting on hydrogen (everyone, it seems) hope to reduce this development work in a much shorter time. Envirotec reviews recent advancements.
On many levels, the predicted roadmap for hydrogen seems to involve a hopeful finger-crossing that many of the mistakes that have accompanied past technology deployments won’t happen this time around. Given the potential of hydrogen to offset carbon emissions, it would be a maddening development if those gains were to be jeopardized by leaks, for example, a topic that seems to have been on the agenda of many advisory groups these last months.
Leaks from production and distribution facilities provided one of the embarrassing stories in natural gas history, something that – it has become clear – is much more prevalent than has always been claimed. With hydrogen expected to use much of the same end-user pipeline, generation and combustion infrastructure, many experts have warned that special effort must be made to avoid something similar.
A study published in April by the UK Government BEIS explained that hydrogen is a more potent greenhouse gas than previously thought (about twice as much), although its warming effects are indirect and are attributed to its interaction with other gases in the atmosphere, which in turn leads to an increase in other GHGs, specifically methane and ozone.
Recognition of this warming potential has reinforced the sense of urgency to ensure that hydrogen infrastructure is designed from the outset to be secure against leaks. Speaking to Bloomberg in June, Ilissa Ocko of the Environmental Defense Fund emphasized the caveat as “not saying ‘no’ to hydrogen, but thinking about how we deploy it.”
Of course, when it comes to leaks, the most obvious concern is the ability of hydrogen to burn (as some might recall from high school science experiments and the audible “pop” that accompanied exploration on this question).
Fill the gap
Leak detection can be expected to be a crucial first line of defense, and recent weeks have seen funding announcements in the area of hydrogen gas detection systems.
In June, Robert Gordon University announced that it had received pump seed funding of £33,000 from the Scottish Government to research the manufacture of a “novel hydrogen gas leak detection sensor to support the safe expansion of clean hydrogen energy into everyday life”.
Safety is particularly important during transport and storage. As project leader, Professor James Njuguna of RGU explained: “Hydrogen can be a clean, dense source of energy but, when in a gaseous state, it can spread rapidly through the air without color, taste or odor.” Expanding its use will require very sensitive hydrogen detection.
The combustibility of hydrogen has made the use of fuel cells a preferred means of storage and delivery for many applications, such as hydrogen vehicles. And hydrogen in this case is either stored under pressure or at very low temperature. Fuel cells are a highly secure storage medium although expensive and always carrying the risk of catastrophic damage in the event of a malfunction.
One area of research is finding safer ways to store it. A study announced in May at the Johann Wolfgang Goethe University in Frankfurt demonstrates the possibility of using an enzyme derived from a bacterium (whose normal habitat is the deep ocean) to catalyze the conversion of hydrogen and oxygen into formic acid, a liquid that can be stored easily and safely.
In nature, the enzyme would continue to digest formic acid. The team used genetic engineering to alter the bacteria’s metabolism to prevent this further reaction.
In transportation, the most powerful use case for hydrogen fuel cells is in commercial trucking. In February, Aberdeen City Council unveiled the UK’s first hydrogen-powered refuse collection vehicle (RCV), a Mercedes-Benz Econic powered by a 45kW fuel cell.
The deployment was part of a project to determine how hydrogen trucks can reduce emissions from garbage vehicles, called the HECTOR (Hydrogen Waste Collection Vehicles in North West Europe) project, which includes seven European trials in total.
Hydrogen fuel cell vehicles and battery electric vehicles are similar in that they both power an electric motor. Both are said to be “tailpipe emission free”, in that they emit no carbon during transport, but there may be emissions involved, depending on how electric or hydrogen is generated first, and the method used to transport hydrogen to filling stations.
Refueling in less than 15 minutes is a widely claimed capability, as with HECTOR vehicles. This is also the case with the commercial trucks being tested with Volvo, which the group claims are capable of a range of 1,000 km.
Electra has announced a zero-emission refrigerated hydrogen fuel cell vehicle, the 19-tonne Electra eCargo, which would be the first of its kind to go into service in the UK, which will be tested by supermarket Sainsbury’s.
One of the main obstacles to the use of hydrogen vehicles is the scarcity of gas stations – at present there are only about 60 in the whole of the United States, for example, all located in California, and the number is expected to reach over 100 by mid-2009. -2023.
A relatively unexplored area has been the use of hydrogen in construction vehicles and equipment, but recent weeks have seen several announcements. Seemingly motivated by a desire to show leadership in decarbonization, while improving air quality around urban sites, a recent partnership between construction company Kier and AFC Energy, the supplier of fuel cell technology zero-emission hybrid fuel (HFC) engine, will see the start of testing in 2:22 hours. Kier plans to rent a Power Tower, which will be used to power the cabins on site.
Another trial will see the production and evaluation of a dual-fuel hydrogen stacking machine, apparently a world first. The trial will be conducted on a medium-sized pilling rig used in construction and involves collaboration between ULEMCo hydrogen vehicle company Cementation Skanska and building science center Building Research Establishment (BRE) .
Machines like these can use 100 liters of diesel per day of operation, resulting in emissions of 262 kg of CO2. ULEMCo’s Amanda Lyne says the trial is intended “to show that the dual-fuel conversion will save up to 50% CO2 in this duty cycle, while delivering emissions benefits such as reduction of NOx and particulates”.
Part of the impetus for the deployment of hydrogen came from the allure of being able to use elements of the existing natural gas transport and use infrastructure. In the UK, hydrogen blending into the gas grid is starting to loom over the horizon.
The government aims to have the UK gas pipeline network ready to supply 20% hydrogen to homes and businesses across the country from 2023, replacing a fifth of the natural gas currently used. And the viability of that schedule seemed confirmed by an ENA document released in January, Britain’s hydrogen blend delivery plan.
In the United States, a Californian utility, PG&E, announced in May its intention to test different mixtures of hydrogen and natural gas. However, this will apparently use a dedicated pipeline system, rather than the transmission network used for natural gas.
A company spokeswoman acknowledged concerns in some quarters about the possibility of leaks, as well as the need for “extensive research to understand the feasibility of injecting hydrogen into a pipeline system,” according to a statement. email message reported in Bloomberg. in June.
Generate a stir
Apparently, the first-ever hydrogen-powered gas turbine was announced in June by the University of Stavanger. The research was led by Professor Mohsen Assadi, who said his team had proven that hydrogen can be used in existing natural gas infrastructure without changing much of the original composition of the structures, although the efficiency to operate the turbine with hydrogen is somewhat less than with gas.
There is also strong pressure to identify greener ways to produce hydrogen. So-called “green” hydrogen will likely rely on electrolysis of water, fueled by nuclear or renewable sources, but this remains an expensive and inefficient process. Most of the hydrogen produced today comes from natural gas – about 95% of that produced in the United States, according to a report by the country’s Department of Energy earlier this year.
Light in the tunnel?
Several groups seem to be competing with each other to refine or improve the means by which electrolysis of water can be powered by solar energy. Two separate projects announced in recent months, by the University of Strathclyde and KAUST, relate to improving the properties of photocatalysts, allowing them to power electrolysis using visible light, a step forward from their reliance traditional ultraviolet light.
Despite the many challenges, the race to develop hydrogen appears to be accelerating – certainly if the volume of announcements is any indication.