American Scientist

To the Editors:

I found Lee S. Langston’s article “Generating a Greener Future” (Technologue, March–April 2021) very informative and interesting, but I stumbled over the idea of using the electrolysis of water to generate hydrogen for use in power plants.

The use of green sources of energy to hydrolyze the water would still result in a waste of energy because it takes a greater number of kilowatt hours to release the hydrogen from water than the number of kilowatt hours that would be obtained from burning the hydrogen as fuel in a gas turbine–driven generator. It doesn’t matter what generated the electricity, green or not; it is a net loss from the available power in the grid.

The nearest source, of which I am aware, of free hydrogen is the planet Jupiter, and a hydrogen pipeline to Jupiter seems unrealistic.

Paul White
Portsmouth, RI

Dr. Langston responds:

You are correct that taking useful electrical power to electrolyze water in order to produce hydrogen—which in turn would produce more electrical power—would result in a fairly great loss of available energy. However, the key words in my explanation (on page 82) are “created from a surplus of renewable energy.“ One problem with wind- and solar-generated electricity is what to do with those electrons when there is no market for them, because there is no economical means of storing them.

For instance, Denmark has on occasion resorted to paying neighboring countries to take surpluses of its extensive wind power electricity rather than shut down whole arrays of wind turbines. Germany has had a similar problem with surplus solar power generated in its southern states.

Wheeling electrical power from one electrical grid to another certainly leads to electrical losses. And some grids don’t talk to one another. That problem was made evident last year in Texas when millions of people lost power following an ice storm, and neighboring states could not supply energy to Texas’s isolated grids.

To the Editors:

I read Lee S. Langston’s article “Generating a Greener Future” with great interest. I am the president of a New York City co-op building, which we are trying to harden against some of the consequences of climate change, and I wonder whether we could use the type of equipment described in the article on a smaller scale.

Is it possible to take advantage of the combined Brayton cycle and Rankine cycle turbines at a scale of several hundred kilowatts? I don’t know whether the equipment described can scale down and still be highly efficient, or even work.

John Waldes
New York, NY

Dr. Langston responds:

You can indeed take advantage of the two heat cycles at a much smaller scale. Smaller gas turbine companies in your power range include Solar Turbines and Capstone Turbines.