conservation of energy
law of conservation of energy
first law of thermodynamics

"Energy conservation was the last thing they thought of 150 years ago."

Are you going to touch upon the issue of energy conservation?

Under the terms of the grant, he said, the money had to be spent for energy conservation.

"But we have to get the religion that energy conservation is even better."

Since the 1973 oil crisis, energy conservation has been an issue in Japan.

They have great potential for the future and could assist energy conservation.

The first video was about energy conservation and power storage.

He should instead work with business to improve energy conservation and supply.

For the second equality we have used the conservation of energy.

Suppose we had taken his advice about energy conservation 25 years ago.