Green hydrogen would provide a cleaner form of energy in many uses currently associated with pollution and would slow climate change, but experts say that the technology for economically producing it is still some years away. Eventually, though, as technology improves, green hydrogen may serve as an environmentally sound fuel for many years to come. Blue hydrogen, by contrast, is produced through a complex and energy-intensive process that mixes methane gas with water to create carbon dioxide and hydrogen. Unlike its cheaper and dirtier cousin, gray hydrogen (which also uses methane gas but emits the carbon dioxide byproduct directly into the air as pollution), blue hydrogen captures some of the carbon dioxide emissions and stores them underground. This underground storage process is called “carbon capture and storage” or “carbon capture and sequestration” (CCS). It’s what earns the process its “blue” name.
Can blue hydrogen save the planet? Blue hydrogen may not be the ready-for-prime-time fuel some have touted it to be. First, it’s relatively expensive to produce. A lot of energy must be expended to extract the methane fuel stock then to isolate, process, and stockpile usable hydrogen. A lot more energy is spent to capture the CO2 and store it underground. So much energy must be used in the process that some researchers say that the carbon footprint to create and burn blue hydrogen is significantly greater than using either oil or gas directly to heat your home or business.[1] Further, CCS technology is a problematic solution to taking the carbon out of, or “decarbonizing,” emissions. According to a current article in Scientific American:
[C]arbon dioxide doesn’t necessarily stay in the rocks and soil. It may migrate along cracks, faults and fissures before finding its way back to the atmosphere. Keeping pumped carbon in the ground—in other words, achieving net negative emissions—is much harder. Globally there are only [a] handful of places where this is done. None of them is commercially viable…. Meanwhile numerous CCS plants have failed. In 2016 the Massachusetts Institute of Technology closed its Carbon Capture and Sequestration Technologies program because the 43 projects it was involved with had all been canceled, put on hold or converted to other things.[2]
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Many experts believe that some end uses—long-haul heavy-duty trucking, high-temperature industrial processes like steelmaking, and long-duration energy storage of renewable energy—may not be readily electrified or decarbonized through other less polluting technology. So, blue hydrogen may offer a way to temporarily decarbonize such uses. But experts also recommend that the technology should be deployed only when it serves the most efficient pathway to a decarbonized economy, complementing proven and readily available alternatives.
There is also speculation that shale gas corporations are pushing blue hydrogen as a way to ensure a market for gas investments still in the ground. To protect against losing these investments, and to make the blue hydrogen industry attractive from a business perspective, sizeable subsidies of public dollars will no doubt be required. The argument can be made that these tax dollars would be better spent on lower-emission and no-emission renewable technologies.
Is blue hydrogen good for public health?
Setting aside serious technology and business uncertainties, the production of blue hydrogen raises the risk of public health impacts and the related healthcare costs in several critical ways.
First, blue hydrogen production requires the extraction of fossil fuels—typically shale gas—as feeder stock, demanding many more hydraulically fractured shale gas wells in areas already overburdened by this heavy industry. Increased well production means greater emissions of a variety of toxic chemicals, such as fine particulate matter (PM2.5), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), glycol, and radium into local communities. Studies have found that these emissions may raise the risk of asthma and other respiratory illnesses, heart disease and heart attacks, birth defects and pre-term deliveries, mental health issues, and cancer.