Does a single $4,000 power-wall do that? And if it is merely saving me the cost differential from electricity at noon and electricity at 6pm, is it going to pay itself off in less than 15 years?
Source: I build home battery backup systems for a living.
The types of people buying batteries today live in places where arbitrage is an option (california, hawaii), or where the grid is frequently or always down (puerto rico)... or rich people who want to be energy independent. They generally haven't made it to the general public yet, but cost is coming down every year and utilities/incentive programs are spreading.
Do you believe the batteries should be subsidized - Yes, I think that they should be subsidized now. I normally don't like government involvement in markets other than protecting against externalities, but in this case I believe that subsidies can expedite innovation in the area. Once the market exists and the technology moves far enough along, I think that we will be able to slowly remove the subsidies and battery systems will be cheap enough to warrant their place in the market without. Also I strongly believe that the faster we move away from fossil fuels, the less lives will be lost to climate change.
instead of the power going back into the grid - Not sure what you mean here. People sell back to the grid all the time. A battery backup system in sell mode is essentially another power plant. Great!
https://www.alibaba.com/product-detail/25kwh-48v-LiFePo4-bat...
Now this is Alibaba so we are talking about dubious quality still it's showing 2,000$ for 25kwh battery pack when buying 2 or more. 50kwh is 2 so that's 4,000$. That's for Lithium iron phosphate battery which should give ~2,000 cycles though they say 3,500.
PS: Grid scale you would want to install the batteries at the solar power plant so again no need for an extra inverter.
In a March 2018 report, BNEF put 2017 utility-scale battery costs at $209/kWh:
https://about.bnef.com/blog/tumbling-costs-wind-solar-batter...
And that report was already taking into account global supply chains. That's why I am skeptical about the low Alibaba price. If EPCs can get reliable battery packs at $78/kWh (sans inverter) just by ordering from China, I would expect utility scale battery installation rates to soon go from "brisk" to "breakneck."
They don't have a generator -- their property does not make one convenient, and they don't currently have medical needs that require constant power.
But when the power goes out in their neighborhood, just walk outside after a few minutes and listen to all the generators.
A lot of U.S. infrastructure is no longer really being adequately maintained. I expect quite a few battery packs will be sold to scenarios like theirs. As long as the power failures don't come to exceed the batteries' power delivery capabilities.
> run 2 loads through my washer and dryer (cause I have 3 kids)
Surely you don't run 2 loads through your washer and dryer _EVERY_ day, do you? Do your children change clothes every 2 hours? Do you change bedding and towels every day?
Point being, I can come up with incredibly inefficient and wasteful scenarios too and then say "well, it doesn't serve my needs either, see!"
Shifting energy usage patterns is just as much part of being green as is generating energy in a renewable way. Just because you can come up with a scenario that isn't 100% addressed by that, doesn't mean it's not worth doing in aggregate.
No, but I need to be able to _any_ day, and honestly for us doing 2 loads a day happens very often - it's not an edge case for us. If you're befuddled as to how that is possible, join the club.
As for shifting our day's schedule around electricity rates, good luck bringing that idea up with my wife.
> As for shifting our day's schedule around electricity rates, good luck bringing that idea up with my wife.
The electricity costs of washing and drying are significant, could easily be hundreds of dollars a year. If you could save half of that by generally running a programme overnight, lots of people would do it . Not everyone would be able to because of noise, with that number increased by technological developments in software and hardware specialized for that use-case, but a lot of people would. And you wouldn't do it for every wash, only when it was convenient. This already happens over here, I often run my dishwasher overnight when the tariffs are lower, it's good for the environment and saves me money, or when I need it sooner I run it straight away.
Then they should get newer appliances. Modern dishwashers are whisper-quiet, and modern front-loading washers are barely audible for most of the cycle. The energy savings on these newer appliances should more than pay for the initial costs pretty quickly.
No kidding. Our 2006 dishwasher wasn't too bad, but we just got a 2nd-hand 2016 Bosch and you can watch a movie while it's running.
I assure you, the vast, overwhelming majority of households can go a workweek without using washer/dryer.
We often had 2 loads of washing a day too; when you're night-time toilet training the kids it's a killer. Fortunately we're past that; now it's just loads of school and sports clothes, still not as much.
Many water heaters come with an integrated storage tank for hot water so they can actually be used as a form of energy storage. That leaves lights in your example and yes battery like powerwall will be more than enough to power modern energy efficient lighting and electronics overnight.
And no, our washing and drying can not be done on a weekend. We have 3 kids and if we waited for a weekend to do our laundry then that is the only thing we'd be doing all Saturday long.
With washing, if you have to do it every day you might want to start it right after the sunrise when you're likely to to leave for work. If your kids are old enough you can instruct them to take the washing out and put into a dryer as soon as they get home.
The point is you'll need to make some changes to your lifestyle and habits but these changes are not as severe and problematic as some people claim.
Aren't you looking for a way to store excess solar power generated during the day? Use it to cool your house! If your house is at 68 when the sun goes down and power generation stops, you may very well be fine without AC until the morning.
Use the power when its generated and you don't need as big of a battery to store it for later use.
But if you absolutely must use active cooling after sunset you might want to get something like Ice bear 20 ( https://www.ice-energy.com/technology/ - i'm not affiliated with them just an example) hopefully it should solve it once and for all.
There are many factors that influence how tolerable the heat is - low humidity and the presence of a breeze can make a huge difference on how tolerable 27C is.
I mean these temperatures don't strike me as particularly intolerable. I wonder if it's the case of keeping up with Joneses as in "my house is cooler than yours". There are some reports ( https://www.theatlantic.com/magazine/archive/2015/07/saudis-... ) that rich Arabs in Saudi Arabia are running air conditioners at temperatures that require sweaters — even when they go on vacation. Which is really amusing for these of us who come from colder climates.
In July and August it will often stay above 90F until midnight. There’s usually a few evenings in August where it will still be 100F at 2200.
The overnight lows in the upper 70s won’t be reached until dawn, and it will be back into the upper 80s before 10.
And the breeze is a hot wind, that feels like it makes it worse rather than helping.
Well, something like IceBear20 ( https://www.ice-energy.com/wp-content/uploads/2016/03/ICE-BE... ) seems to be the way to go. It can run for up to 4 hours off the stored ice so it should be able to cover you from sunset to midnight.
I believe that there used to be many fewer people (absolutely and relatively) living in the southern US. Then air conditioning was invented and people realized they could get away from the sometimes brutal winters in the north without having to be miserable in the summers.
For example, say you can store up 10 kWh of excess energy during the noon sun when it's worthless. If peak is from 5 to 9, you only need a 10 kWh pack that can discharge in 4 hours.
That's about the ballpark we are talking about though actual numbers will be different.