Is hydrogen, the most abundant element on the planet and a clean-burning gas, the solution to the difficult dilemma of how to abandon carbon-dioxide producing fossil fuel? Hydrogen has been high up on the energy agenda before, fallen from favor, and now appears to be peaking again.
Ottawa has unveiled a “Hydrogen Strategy for Canada,” pledging C$1.5 billion to support low-carbon and zero emissions fuels. But Canada’s interest in hydrogen includes not just “green hydrogen,” produced by separating hydrogen from water by zero-emissions hydrolysis technologies such as photovoltaics, hydro, and nuclear, but “blue hydrogen,” made by steam reforming fired by natural gas. Canada is the world’s fourth largest oil producer.
At a recent zoom meeting arranged by the multinational law firm Dentons, former Obama energy secretary Ernie Moniz expressed optimism about hydrogen. Moniz said hydrogen, along with utility-scale storage, can be “the natural gas of the future. Technically, it is an energy carrier that serves multiple end uses, including heat, industrial feed stocks, high-temperature process heat.”
Utilities and industrial firms have been looking at hydrogen, with its zero production of carbon dioxide, as a favorable future fuel for decades. Back in the first decade of the 21st century, companies such as Ballard Power Systems and Plug Power were Wall Street darlings, promising widespread use of hydrogen-based fuel cells, converting H to power, to revolutionize transportation. But the hydrogen bubble deflated as costs overcame the promises.
Today, among the other touted uses of hydrogen, transportation remains a promise. Hydrogen can easily replace gasoline and kerosene in internal combustion engines, potentially taking the largest source of greenhouse gases off the market. Combined with electric vehicles with onboard fuel cells, that could be a major factor in a carbon-free (or dramatically carbon-reduced) world.
Raghu Kilambi, CEO of Power Tap Hydrogen Fueling Corp. makes a case for hydrogen fuel cells for long-haul transport, that is, truck engines. He says, “Battery electric vehicles are completely impractical for long-haul trucking” as trucks need to move long distances and refuel quickly to deliver their cargo.
Hydrogen fuel cells (making a big assumption about hydrogen delivery infrastructure), he argues, are the “more sensible, sustainable, and advanced form of energy which would have tremendous benefit if adopted by the trucking industry.”
Then there is electric power production, where hydrogen could be used to replace natural gas in both simple-cycle and combined-cycle generation. Siemens Energy, Duke Energy, and Clemson University recently announced a joint project to study using hydrogen, and hydrogen storage at a combined heat and power plant at Clemson’s South Carolina campus, beginning in March. The project has a $200,000 Department of Energy grant.
In an interview in mid-2019 with Power Magazine’s Sonal Patel, GE hydrogen guru Jeffrey Goldmeer notes that hopes of hydrogen as a fuel are not new. 19th century science fiction writer Jules Verne talked about hydrogen as a replacement for coal. He says hydrogen is essentially chemical energy storage (as is natural gas). He adds that utility owners of GE simple-cycle and combined-cycle gas turbines, long term investments, want to know if they will be able to transition to hydrogen as a turbine fuel. He said the answer is uncertain. “We don’t know what the future will bring, but we want to make sure that we are prepared to support our customers, and again, that’s part of the process we are going through.”
Amid the current hydrogen optimism, there are some serious cautions, both economic and technical. On the issue of economics, questions about the cost of electrolysis remain. The hopeful point to the declining cost of solar photovoltaics as favorable, as a recent article from the MIT Energy Initiative pointed out. Lower PV costs could make hydrogen by electrolysis competitive with natural gas reforming with carbon capture and sequestration.
But the costs of carbon capture and sequestration aren’t fully know, which renders the issue problematic.
But even if the costs of PV electrolysis come down, an unknown is the cost of hydrogen storage. Without cost-effective storage, hydrogen becomes another niche fuel. The MIT analysis found, “While geological storage proves to be the least expensive option and is key to lowering overall system costs, it is also limited in its geographical availability. The authors also considered the option of deploying battery storage as part of the system design, but found that across nearly all of the evaluated scenarios and locations, it was less economical than deploying hydrogen storage.”
Also on the economic side, hydrogen has a lower heating value than methane, according to GE’s Goldmeer, about 274.7 Btu/standard cubic foot, compared to natural gas in the range of 900-1,000 Btu/scf. That means a need to flow more hydrogen to the turbine, again impacting the costs of generating power.
How green is hydrogen? A recent CleanEnergyGroup analysis – “Hydrogen Hype in the Air” – argues that burning hydrogen is not a pollution-free proposition. While hydrogen combustion produces no carbon dioxide, it does produce oxides of nitrogen when burned alone, and not mixed with natural gas. “And that scientific fact is the untold story in this aggressive industry plan [for a hydrogen future], one that could turn green H2 into ghastly H2.”
GE’s Goldmeer said that the flip side of lower carbon emissions is that “hydrogen burns hotter than methane or other hydrocarbons, and since NOx is a function of flame temperatures, while you can get lower CO2 emissions, you actually get higher NOx emissions.
Also on the technical side, GE’s Goldmeer pointed to a safety issue. Because H is considerably more flammable than natural gas, “If you have a leak of hydrogen, it becomes more dangerous. Hydrogen flames are harder to see with the naked eye than a flame with a traditional hydrocarbon.” That means power plant operators “need to think about fundamental safety issues.”
What’s the verdict on hydrogen? Interesting and worth more study and analysis, but not a panacea.
–Kennedy Maize