in PoW, energy consumption scales linearly with the block reward value which is denominated in bitcoin thus scales with value of btc. Reward for mining is [ ( your hashrate / network hashrate) * block reward ].

so it's not usage that scales energy consumption, it's value of btc. Arguably though the two are intrinsically related (this should be obvious - if bitcoin somehow becomes the defacto global currency, a shitload of investment will pour in and bring its value much much higher)

in truth it's a moot point. even with lightning protocol, bitcoin as a protocol couldn't handle that much capacity. If a few hundred million people just wanted to publish a single transaction (putting money in a wallet and thereafter doing everything on lightning protocol), it would take literally years to process that many transactions.

Edit: just to be explicit, the reason energy consumption scales with block reward value is because it becomes very profitable to buy more mining equipment and mine more if the reward say doubles. It’s not an instant effect of course because there’s capital acquisition and operational capacity involved