At US $250K in today's dollars, say 5 years from now, the block reward will be BTC 6.25, i.e. over $1.5 million, every 10 minutes.

Assuming all miners together are willing to tolerate electricity costs of 50% of rewards, we will have:

Amount of reward = $1500k * 6 / hour = $9M/hour.

Electricity used = $4.5M/hour.

At a cost of $0.10/KWh, this translates to power draw of 45 MW. Neat!

$9M/hour, or $216M/day, or $79B/year is also the amount of net new demand (including miner retention willingness) required for price stability. Those are not bad numbers; the $79B/year maps to each human on the planet buying 10$ worth of extra bitcoin each year.