Hydrogen blending: bad for your health, your wallet and our clean energy transition | Opinion

With rising temperatures and scorching heat waves shattering records in California, it’s clear we must rapidly decarbonize our energy system. As part of this transition, utilities in California have proposed blending hydrogen with natural gas in existing pipelines in proportions up to 20%. Indeed, the California Public Utilities Commission solicited hydrogen blending projects in December 2022, when it seemed to some like a reasonable idea. However, recent analyses and our own detailed report indicate that hydrogen blending is triply harmful: bad for health, bad for affordability and a poor choice for a clean energy transition.

Hydrogen is a gas that burns like natural gas, though hotter. It can be mixed with natural gas in small proportions, and burned jointly in gas stoves and furnaces. This mixing of hydrogen and natural gas in existing natural gas pipelines is called hydrogen blending.

However, hydrogen blending carries two crucial risks: indoor air pollution and gas leakage.

Indoor air pollution occurs when blended hydrogen is burnt, because flames from blended hydrogen are hotter than natural gas flames. Increased flame temperatures exacerbate the formation of nitrogen oxides, increasing the already significant air pollution in homes from gas stoves. This kind of pollution aggravates lung conditions and increases the risk of childhood asthma.

The hydrogen blending proposals from California’s largest utilities would spend millions in customer money on hydrogen experiments, including in homes, college campuses and commercial buildings across California. In Truckee, Southwest Gas is proposing a controversial hydrogen blending project that would serve a Highway Patrol building and commercial building.

In Orange Cove, a community in the state’s agricultural San Joaquin Valley already overburdened by air pollution, SoCalGas is proposing to blend up to 5% hydrogen into gas pipelines. The median household income in Orange Cove is roughly $34,000, far below the state average; 96% of its population is Hispanic. If SoCalGas is allowed to move forward with its project, these households would be at risk for potential health impacts.

Because indoor air pollution from gas stoves is already a major concern, entrenching natural gas with investments in hydrogen blending in already overburdened, lower-income communities like Orange Cove, is — to put it bluntly — unjust and wrong.

Blending hydrogen is also unlikely to deliver climate benefits: Hydrogen is less than 30% as energy-dense as natural gas per unit volume. Therefore, to deliver energy at a constant rate, the pressure in the pipeline must be increased, and natural gas reductions are lower than they may seem: Blending hydrogen at 5% by volume will mean only 1.6% less natural gas use in energy terms.

These higher pipeline pressures will also raise the risk of natural gas leaks. Hydrogen leaks at roughly four times the rate of natural gas, raising potential safety issues. And hydrogen, though not a direct greenhouse gas, aggravates warming indirectly via chemical reactions in the atmosphere. Consequently, the climate benefits of blending are minimal to nil, even if green hydrogen produced through renewable energy is used: blending 20% green hydrogen would only reduce emissions by at most 6%, even if added leaks are ignored.

Blending hydrogen will also increase gas bills for Californians. PG&E, SoCalGas, SDG&E and Southwest Gas all propose to increase gas rates to recoup their respective $94.2 million, $80.4 million, $9 million and $10.21 million proposed investments.

These trials would initially increase gas bills by amounts that appear small, but they only cover the costs of small pilot projects. Rate increases will be far higher if blending projects become widespread in the state.

Opportunity costs are also high. Our analysis found that the reduction in CO2 emissions would be five times greater if the same amount of renewable energy were used to electrify natural gas heating with efficient heat pumps. Put another way, hydrogen blending projects in California mean slower decarbonization and higher energy costs — and we can’t afford either.

There is simply no reasonable case for blending hydrogen. It is an incredibly inefficient, expensive way to decarbonize, and it would perpetuate health harms in ways that are environmentally unjust.

California leaders and regulators at the Public Utilities Commission should steadfastly reject utilities’ proposed hydrogen-blending pilot projects across the board.