Making energy like the sun does might too cheap to meter or as uneconomical as a perpetual motion machine.

像太阳一样产生能量可能会太便宜以至于无法计费，或是像永动机一样太不合算。

youdao

It would be uneconomical to send a brand new tape.

送一个新磁带去不划算。

《柯林斯英汉双解大词典》

It soon proved uneconomical to stay open 24 hours a day.

每天24小时营业很快就证明是不经济的。

《牛津词典》

So fracking will continue for a while after it becomes uneconomical.

FORBES: What Would Happen To The Current Fracking Activity And Subsequent Booms Generated If Oil $/bbl Were To Drop?

But even then, getting a collect call from anywhere civilized was quaint (and ironically, uneconomical).

FORBES: Milton Friedman: An Open Book