Irony is dead.
There are some efficiencies of scale but not a factor of two.
The cost of residential (less than 10kw) is $5.47
Larger systems (more than 10kw) drop the price to $4.92
PV solar doesn't require either... it just works.
Where I live, the time of use differential is 14 cents. I could save $1.40 a day with this battery. $511 a year for an investment of $3500... good return.
Distributed solar generation is more efficient than central generations because you don't have distribution losses and don't have to have the high capacity power distribution network.
You don't have to have a string inverter. You can use microinverters such as Enphase.
Cost 250w panel=$200 plus 250w microinverter=$150 total $350. This is below the limit for requiring a building permit where I live ($500).
Just add them one at a time.
5 cents is low. Most time of use differentials are much higher. In my area, it is 14 cents. At that rate, it works out to $1.40 a day.
This is $511 a year return on a $3500 investment... pretty good return.
The battery is good for two things:
1. Backup power for power outages.
2. Time shifting energy use to take advantage of time of use metering. (You can charge the battery at night at cheap rates and use the power during the day when grid power is expensive.) This can also shift your solar production (9am to 3pm) to match time of use demands (1pm to 7pm).
It's not going to get you through a long, cold, dark winter but it can reduce your cost of power.
Everyone always complains that "the sun doesn't shine at night". Well, all power sources have time constraints... nuclear works best when it runs 100% all of the time... coal is also difficult to quickly ramp up and down to meet changes in power demands. That's why electricity is so cheap at night. This battery can quickly shift from storage to production to match demand and take advantage of the daily changes in power demand (and cost).
Your Guardian reference states 2.1% fall in 2014 and predicts 2.5% fall for 2015.
That looks like a reduction especially considering that their use has been rising rapidly for many years.
China has been burning less coal for the past few years, not more. They have figured out that their terrible air pollution in cities is caused by coal and they are investing heavily in solar and wind. They are shutting down old, inefficient coal plants (about 1000 of them, so far).
China is already doing it without anybody telling them.
They've figured out that killing their people with coal pollution is not a good thing so they are closing down old, inefficient coal burners and investing heavily in wind and solar. Coal use in China actually has been decreasing for the past few years.
The sun and wind are "infinite" resources for all practical purposes (5 billion years).
Lithium is very abundant. Not going to run out of it ever. Most lithium comes from brine pumped from the ground and evaporated in solar ponds. It doesn't get much easier (or cleaner) than that.
The Tesla has been judged the "best car ever" by Consumer Reports (not "best electric car" but "best car"). More range than most people ever need in a day and Superchargers for road trips. Eminently practical. Charge at home overnight or charge in 20 minutes on road trips.
Also, comfortable, smooth, quiet and better handling than most cars on the road due to low center of gravity and ideal weight distribution. Performance... 0-60 in 3.2 seconds... faster than anything except exotic sports cars.
Every Tesla owner loves their car and would never give it up... no one suffers with a Tesla.
In a few years you will have Teslas that anyone can afford.
Hopefully the rest of the auto companies will get out of their trenches and make cars as good (or better).
Carrying around a barrel of fossil fuel will some day seem odd.
Well, it you got creative about it, it could be garbage out from 6am to noon and packages in from noon to 6 pm... would probably require some cleaning or containment of the packages.
We have a complete reliable electricity network capable of recharging all of Tesla's cars right now and for the forseeable future. I generate all of my electricity needs including electric car with a smallish solar installation at home. I don't even need the grid. Electric cars are the future of road transportation and they are the reality of road transportation today... just buy and electric car and stop burning fossil fuel. You don't have any excuse to continue polluting the air.