Hydrogen: Gray, Blue, and Green

December 7, 2020

Gray hydrogen is produced with a high energy, high carbon process.
Blue hydrogen is a high carbon process with sequestration.

Green hydrogen is produced with clean energy. That’s where we want to go.

Chris Tomlinson in Houston Chronicle:

Just one word: Hydrogen. There is a great future in hydrogen.

With apologies to Buck Henry and the screenwriters behind “The Graduate,” seems like energy industry insiders are adapting that classic quote for what they hope will be a promising future for fossil fuel veterans.

Last week, I wrote about hydrogen’s potential as a fuel and efforts underway to produce it without releasing greenhouse gases. By adapting existing petrochemical plants and creating new production techniques, Texas could remain a major energy producer even in a low-carbon economy.

Once we can produce so-called green hydrogen, the new energy source could solve the biggest challenge presented by wind and solar energy.

The most well-known application could be among the last to reach commercial scale. The hydrogen fuel cell, which generates electricity by combining hydrogen and oxygen to produce water, faces some significant hurdles.

NASA has famously used fuel cells to power spacecraft and satellites, and that existing technology led many to believe hydrogen would eventually replace gasoline and diesel as the world’s primary transportation fuel. General Motors introduced the fuel-cell powered Electrovan in 1966.

GM’s experiment revealed the problems automakers still face: Hydrogen and oxygen are difficult to store, the cell’s electrolyte is corrosive, the whole thing is heavy and manufacturing is expensive.

Nevertheless, Toyota started selling the Mirai in 2015 to specially-selected customers and Honda now offers the Clarity Fuel Cell and Hyundai has the Nexo. None of the models sell or lease for the cost it takes to build them, and California is the only state that has a hydrogen refueling network.

For most light-vehicle owners, electric vehicles make more sense. But for large, long-haul trucks, hydrogen fuel cells make more sense than batteries. They have a longer range, and established routes make it easier for fleet owners to install refueling stations.

Today, petrochemical plants combine hydrogen with nitrogen to make ammonia, which is then turned into fertilizer. But due to its flammability, liquid ammonia can also fuel modified internal combustion engines without releasing any carbon.

Because the world is already set up to produce and deliver liquid fuels, many innovators believe producing ammonia-powered vehicles will be easier than building a hydrogen refueling network. Like hydrogen, though, the industry has a long way to go to produce enough green ammonia to replace gasoline.

A more immediate, and frankly easier transition is using hydrogen to store wind and solar energy. As everyone knows, the wind doesn’t always blow and the sun doesn’t always shine. But when there is wind and sun, there is often excess generation.

Electricity generators want to use excess renewable power to make hydrogen and then store it in caverns. When the grid needs power, and there is not wind or solar, utilities can use hydrogen to fuel turbines to meet the power demand.

General Electric, one of the world’s largest gas-powered turbine manufacturers, has generated electricity from gases that range from 5 percent to 95 percent hydrogen for decades.

“As gas turbines are inherently fuel-flexible, they can be configured to operate on green hydrogen or similar fuels as a new unit, or be upgraded even after extended service on traditional fuels, i.e. natural gas,” GE says. “The scope of the required modifications to configure a gas turbine to operate on hydrogen depends on the initial configuration of the gas turbine.”

None of this will happen, though, until producers can bring down the price. Natural gas currently sells for under $3 for a million British Thermal Units. Hydrogen costs about $17.60, according to S&P Global Ratings, a financial data analysis firm.

“Ample availability of competitive renewable sources and simultaneous support for blue hydrogen (with CO2 capture and storage) are therefore prerequisites for hydrogen to take a more prominent position in the energy transition,” analyst Massimo Schiavo wrote. “A Hydrogen Council report suggests that hydrogen could account for 15 percent of global primary energy supply by 2050. Yet the huge cost of producing it is a potential stumbling block.”

3 Responses to “Hydrogen: Gray, Blue, and Green”

  1. doldrom Says:

    Hydrogen is a bit like fusion, a perennial promise.

    I know they had hydrogen buses in Vancouver (lots of cheap hydro) decades ago, never heard about it since.

    Ammonia is an attractive energy carrier, but also present yet to overcome challenges at both ends (production of ammonia and harnessing the energy).

  2. John Oneill Says:

    Cost of production is only one of hydrogen’s major flaws as an energy carrier. It can’t just be substituted for natural gas, either – it is not nearly as energy dense, and it embrittles seals and metals. This article gives detail on the numerous efficiency losses that a hydrogen economy would entail.

    Click to access hyd_economy_bossel_eliasson.pdf

  3. rhymeswithgoalie Says:

    I used to joke that it didn’t matter how safe EVs would become, Hollywood would still make them explode spectacularly in any end-of-chase collision.

    With Hydrogen vehicles, I wonder about the actual combustible nature of concentrated H after a collision damages its feeder valves.

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