Let’s focus on large-scale geothermal. The fossil-fuel industry has developed sophisticated digging technology, which, ironically, can be used for the deep mining of underground heat. The most exciting developments in the U.S. are now happening in the West, where geothermal costs are plummeting. As they do, feasibility moves eastward. For example, a bill has been introduced in North Dakota to study costs of developing geothermal plants in defunct oil and gas wells.

Tapping underground energy has many advantages. It is continuous, not intermittent. It has a small surface footprint. When the geology is right, it can be developed near population centers, avoiding the need for long transmission lines.

Sadly, the U.S. seems to be ceding innovation in wind, solar and electric vehicles to other countries. Geothermal power could be a place for our country to make its own clean-energy mark on the world.

The writer is a member of Citizens’ Climate Lobby.

So the State Capitol is thinking of installing metal detectors to improve security? (“Calls made for Capitol security boost,” July 9.) I have my own story about that. In the summer of 1984, I was studying public administration and had an internship in Sen. David Durenberger’s office. (But I never saw him.) His office was in the Hart Senate Office Building in D.C., which had some type of metal detector. I think it used X-rays. For a Christmas present, my mother had given me a briefcase so I would look professional. One day I was wearing a suit and tie, carrying my Christmas briefcase and looking, and feeling, very professional. At the entrance, a security guard stopped me and said, “We will have to check your briefcase, sir.” He put the briefcase on a conveyor belt to be X-rayed. A photograph of the briefcase’s contents appeared on a TV screen. A look of horror appeared on his face. I saw real fear in his eyes. He yelled, “It looks like a gun.” Other security appeared. The X-ray picture showed something that looked remarkably like a gun. I was bewildered. All I had in my briefcase was books, papers and my lunch. After a closer look, someone said, “That’s a banana,” and walked away. I was allowed to enter the building.