We're almost there with PV Solar price/performance.

[Jester]

I was reading about...

http://www.rsc.org/chemistryworld/2014/0...grid-power

... this recently.

Indeed, the team's experiments with this novel storage system carried out at 450°C displayed a current density of 275mA/cm2, with a cycling efficiency of 98% on charging and 73% ‘round-trip’ energy efficiency.

I'm not sure how big a tank of liquid metal you would need to backup the local power grid... even so, having Ng backup during night time, windless or cloudy days would still make a significant change in emissions. Then toss in advances in Combined Cycle Natural Gas with CSS and we'd drastically curtail emissions even during backup operations. Prices per Kwh would increase by 46% for carbon sequestration and storage, but would be well offset by decreases in operating costs during sunny, and windy daylight operations. A big concern would be the capital and ongoing cost for redundant systems (which also had an energy investment which must be paid back by the system).

Any super-efficient battery storage is going to set sharp arbitrage-enforced limits on price variation between high and low output times. (That is to say, a good enough battery solves all our problems.) But I'll believe that when I see it - people keep coming up with good ideas, but I've yet to see anything cheap enough and big enough to be better than just having a gas power plant. Plus, we need to consider lifecycle emissions from building all that battery capacity.

But, long story short, I think we're doing much better than I worried we'd be at this point.

-Jester