Hydrogen and “Renewable” Gas Aren’t Realistic Solutions for Decarbonizing Maine’s Buildings
Last month, the Maine legislature ended their session without formally enacting several pieces of environmental legislation, allowing the bills to die.
This included a bill that would have started a statewide conversation about the diminished role fossil fuels should play in Maine’s energy system as the state strives to meet its climate and clean energy commitments. The bill was set to require the state to conduct various studies and inquiries about fossil fuel use, particularly the use of methane gas (often called “natural gas”) in buildings.
From the time it was introduced in December, this gas study bill went through major changes before dying on Maine’s appropriations table (read on, I’ll explain that part in a bit). But since the bill’s introduction, gas utilities’ response to it included a consistent and disingenuous piece of messaging: what if we just made the gas “greener” and continued to burn it indefinitely?
Though the bill is now dead, the issue of how to transition Maine from methane gas to clean energy solutions in order to meet the state’s climate commitments is not going away. And the same line of messaging from the gas utility industry will likely pop up again, so it’s worth unpacking exactly what they’re talking about.
Gas is primarily composed of methane—a fossil fuel with extremely high global warming potential. Gas utilities often promote two main ideas for “greening” fossil gas: either blending it with biomethane (referred to by some as “renewable natural gas” or RNG), or blending it with hydrogen.
But gas utilities are only interested in these alternatives because they perpetuate investments in fossil fuel systems, not because they are optimal—or even viable—solutions for decarbonizing homes and businesses.
While these sources could potentially play a role in decarbonizing certain sectors, such as heavy industry, researchers and analysts have repeatedly found highly efficient electric heat pumps—which are already thriving in Maine—to be a cleaner, healthier, more cost-effective solution for decarbonizing space and water heating in buildings.
As Maine policymakers consider how to make the necessary move of revisiting this issue, it’s critical they consider the serious risks and pitfalls of biomethane and hydrogen. In assessing the next steps, they must prioritize the interests of the public, not the fossil fuel industry.
The bill: before and after
As mentioned above, this bill went through major changes before dying on the appropriations table. It was very close to being enacted as a modest gas study bill, but before that, it started off as a strong gas reform bill.
Included in that original bill was an ending of subsidies for expansions of gas distribution systems within the state—an important and significant step in stopping the growth of carbon dioxide and methane emissions from the state’s buildings sector.
That section of the bill was the most significant part of the proposal, but it was removed, along with some other pieces including a study of the public health impacts of indoor fossil fuel pollution. The later version that was set to be enacted would’ve established a just-transition commission, and required various studies and investigations of the future of gas to be conducted by the state government.
The bill was especially important for strengthening and formally requiring an inquiry—which the Maine Public Utilities Commission (PUC) has already indicated it will conduct—on gas use within the context of state climate goals and electrification policies. With the bill now dead, any such inquiry the PUC conducts could go many different ways. In addition to rigorously helping to meet state climate commitments, any investigation by the agency should also aid in protecting Mainers from paying excessive costs from further lock-in of fossil fuel infrastructure, which could impact low-income ratepayers in particular.
The bill was also set to require the Governor’s Energy Office to conduct a study of the role gas and gas infrastructure could play in the state’s decarbonized future. The study was going to consider various energy sources as possible solutions for meeting demand, including biomethane and hydrogen. But no matter what the industry says the next time around, these two sources are not good—or even realistic—solutions for decarbonizing the state’s homes and businesses. Let’s get into why that’s the case.
If you call it biomethane or RNG, it’s still methane
What is biomethane? Biomethane is a gas produced through anaerobic digestion of material from landfills, wastewater treatment plants, or animal manure lagoons. The resulting biogas is processed and purified to become biomethane, indistinguishable from the traditional fossil methane gas flowing through the pipeline network into homes and businesses.
Mainers use gas for a variety of applications including stoves, space heating, and water heating. Blending biomethane into the gas pipeline network does not address the public health harms of gas use in buildings. Research has shown this indoor air pollution from gas use in buildings consists of a slew of hazardous air pollutants, including the known carcinogen benzene. Children living in homes with gas stoves are as much as 42% more likely to develop asthma. An estimated 12.7% of childhood asthma cases nationally are attributable to gas stove pollution.
With climate impacts, the story is the same. Fossil fuel companies use wildly flawed carbon accounting methods to claim that biomethane is “carbon negative” to offset ongoing pollution from the gas system. That means biomethane is not a real solution for addressing climate pollution in a true net-zero framework—and could even make climate change worse. The fuel still emits carbon dioxide (CO2) when burned. If it were distributed via leaky infrastructure then it constantly would be released into the atmosphere as unburned methane, which has more than 80 times the global warming potential of CO2 over a 20-year timeframe.
Furthermore, gas companies found in their own industry-funded research that even under an implausibly optimistic scenario, available biomethane sources could only supply a third of Maine’s gas use. That means investing in biomethane would leave the traditional polluting gas system mostly unchanged and would fail to deliver real, durable progress.
Hydrogen, too, has limited potential and carries large risks
Despite what Maine’s gas utilities are claiming, hydrogen fails to deliver on climate, costs, and public health. The facts show that as a pathway for cleaning up homes and businesses, hydrogen is extremely unlikely to reduce the climate or health impacts of utilities’ operations.
First, like methane gas, when hydrogen is combusted it produces nitrogen oxides, or “NOx” emissions, which present severe harms to public health, including respiratory systems.
Second, hydrogen is much harsher on pipes than fossil gas, so a utility would only be able to get up to a 20% blend of hydrogen by volume before requiring prohibitively expensive replacements—and many systems are limited to much lower shares. Further, hydrogen’s energy content is much less than that of methane gas, so a 20% blend would yield only a roughly 6% reduction in carbon emissions at the point of use.
Hydrogen is also very prone to leaking. When it does leak it indirectly exacerbates climate change by increasing the amounts of other greenhouse gases in the atmosphere, threatening to undermine the overall climate benefits of even the most cleanly produced hydrogen.
For this hydrogen to have any potential climate benefit compared to the use of methane gas, it would need to be produced via renewably powered electrolysis. This would require using clean electricity to power machines called electrolyzers, which split water molecules into hydrogen and oxygen. And because this is an extremely energy-intensive process, that renewable electricity must be additional to what is already on the grid. Otherwise, the electrolyzers could nominally run on clean electricity, but fossil fuel-fired power plants would ramp up to replace the diverted existing clean electricity.
But critically, all that new renewable electricity needed to power electrolyzers to make hydrogen would go much further—more than four times further—if it went straight to powering highly efficient electric heat pumps to keep Mainers warm and alleviate all the harms that gas use brings.
Looking ahead: staving off distractions
Hydrogen and biomethane are purposeful distractions by the fossil fuel industry to keep the state’s buildings reliant on gas and keep the gas utilities’ shareholders happy. Maine policymakers should treat proposals for their use with skepticism, particularly when they are disingenuously pitched as strategies for reducing greenhouse gas emissions, public health harms, or costs.
Moving forward, Maine and other states will have to be bolder on policies that advance the transition away from fossil fuels if we are going to meet climate goals. Policymakers can ensure they’re taking the risks and pitfalls of biomethane and hydrogen into account when considering legislation aimed at decarbonizing buildings. The accounting of such risks must be informed by science, not by the preferences of gas utilities and their shareholders.
Originally published in Union of Concerned Scientists.
