To speed up transaction at store check-out point Bitcoin will need payment service providers. People will also need BTC loan service, credit card, investment service... in short, when BTC economy exapands, it needs most part of today's financial institutions -- banks, incurance companies... Either that or BTC becomes a reserve currency only.
To the OP -- I think in China industrial electricity cost is about $0.13 and for residence it is $0.08 per kwh. Chinais a significant contributor to the total network hashrate due to ASIC miner and (I think) a large number of internet bars.
Could be. That's why the measure of electricity use is a better metric.