Quote:
Originally Posted by Shiraz
I see it completely differently Renato - these devices are not an alternative to the grid, but they do overcome the two major limitations of solar energy: 1. solar can now provide power at night. 2. the grid stability is no longer compromised by fluctuating generation. In fact, if enough storage could be made available, the utility companies could generate power much more efficiently since load peaks would also be smoothed out.
These things do not allow you to run your fridge for a day - your solar panels do that for half the day and the storage system only needs to do it for the other half. I could get about twice as much useful power out of my solar panels if I could store some (now I sell excess to the grid at nearly nothing - with storage I could actually use that power at night, rather than buy it back off the grid at 9x the feed in rate). That gives me an extra few bucks a day in the pocket (which would be a really good low risk return on investment), there could be a significant reduction in carbon pollution  and the utility company gets a better behaved grid and reduced costs of meeting peak loads - to me that's a win-win all round. Oh and I will also probably have some power for lights etc if the grid goes down.
Why would you think that getting a powerwall takes me back to the days of Edison? - I get to use all of my solar power for my own benefit and the grid is still there for the rest, only it could be a lot more efficient if these things were in wide use. |
Hi Ray,
What their site says is that one US$3000 unit will run your fridge for a day and enable you to do one load of washing. If you only had one unit, and you disconnected from your grid power - then on sunny days you wouldn't have much power to do stuff like run electric ovens, electric stoves, air conditioners, electric heater, electric hot water. On non-sunny days, you'd have to fire up a diesel generator.
Suppose that everyone bought one or more of these devices. Then the "savings" would disappear, because the electricity suppliers would have to raise their price of off-peak power, and charge for supplying the baseload.
Else they would go broke and close down the generators. At the moment they are effectively supplying the baseload for free.
At the moment, when the winds generators are feeding into the grid - usually at a peak power time of the day, the coal generators can't reduce their output because they can't turn off the generators. They just shed the power. There is no reduction in coal usage. Now add to this situation millions of these Powerwalls reducing demand at peak period on sunny days. And the power generators have to have capacity going for peak period on non-sunny and non- windy days - and there is a big problem. Yes, they can build gas-fired generators which are easier to turn off and on - but it costs a lot of money to build a gas fired generator to just sit there being run intermittently. It wouldn't be economic without it being paid for by a baseload charge on everybody.
In other words, the Powerwall is good for frugal individuals, but only for as long as everyone else doesn't do the same. But not everyone will join in because a third or so of the population are renters, who are unlikely to have their own solar panels and Powerwalls. Most likely they will be subsidizing the richer land owners, as they are doing now.
Regards,
Renato