The hydrogen energy economy for cars, trucks, ships, and power plants – where might we go get that hydrogen? We don’t mine it, even though there are small geological pockets of hydrogen.
We have to use other sources of energy to break hydrogen out of natural gas or water. In many situations those other sources aren’t best used directly. For example, excess solar energy often will need to be stored, in batteries or in fuels such as hydrogen.
There are huge challenges in storing hydrogen, cooling it or compressing it extremely or reacting it reversibly with chemicals. Let’s look only at the use of other energy sources to make the hydrogen. One of two big classes of sources is carbon-intensive nonrenewable energy– thermal or chemical reactions on natural gas, directly, or made in turn from coal. This is unattractive, especially for its greenhouse gas production, even if it may appeal politically.
The other class of sources is low- or no-carbon energy. One type is nuclear energy, almost low-carbon other than making the steel, concrete, etc. for the plant. The other type is renewable solar, wind, or geothermal energy. We can’t always use all their output, as noted earlier.
Making hydrogen from water is a way to store it. The process loses a fair amount of energy, and water is in short supply in most places. There are other energy choices than making hydrogen, We’ll see how it turns out.
Ref./nice summary: High Country News, July 2022
