Can someone explain to me why being able to build off the electrical grid is worth all this effort since you're still going to need running water, sewage, bins collecting, broadband and a number of other things?
I live in the Ohio Valley, near Pittsburgh, so we get some of the lowest amount of direct sunlight in the US. I'm not sure if solar is viable in my area yet.
Maybe I'm just spoiled by the German power grid. As far as I can remember I only a single blackout of 30 minutes in the last 15 years (some time around 2008).
But even then it's still good to be connected to the grid. It will serve as a backup line and if you produce more enery than you can consume, you might be able to sell something back to the grid.
This is increasingly how utilities are structured in Europe: You have connection charges, and usage charges, and they may be due to different companies (though are often billed together via the provider you pay usage charges to).
This has come as part of breaking up utility monopolies so that people can e.g. pick "their" electricity provider (of course in practice this just means the providers settle overall relative supply between each other).
Once the question is framed properly -- at least for a few million people in the US -- then the motivation for storage becomes much clearer. If you have a battery and an inverter then you hook that up and it feeds the house. And all your other power generation choices feed the battery. Solar, wind, hydro (if you live on/near a stream or river), small generator, etc.
If it costs $100k to get hooked up and then you're paying some fee for power every month it might make sense to buy the battery for $20k, buy a generator for $5k and spend $10k on a wind turbine and $10k on solar. That's $45k versus $100k which is a good chunk of change plus you can expect your prices to go down as solar panels and batteries and whatnot get cheaper, whereas fuel is only going to get more expensive.
Electricity, on the other hand, has no viable localized option today. It's also the only one of these that has a significant drop in efficiency due to the distribution itself and has a significant impact to the environment.
Local power storage means that grid can balance the load between peak and non-peak times. Also, local power storage means that wind/solar now has a solution for time where power output is reduced.
Having a battery that can power a home for a week is huge, if it's affordable. This could significantly reduce power generation costs.
This is usually less than the efficiency drop involved in a round trip through a battery. It's not as big a factor as you think.
This seems to me the big benefit here -- enough penetration of home backup batteries means public power generation doesn't have to be built up to provide massive peak surges. Further, trickle charging the backup batteries during the evenings/nighttime and allowing them to meet some needs during the day also means a higher net usage of generated power, so perhaps levels of generation could go down altogether.
There's also then the capitalistic angle -- if you want more peak power at your house, you can buy more batteries in lieu of (or in concert with) installing secondary power systems.
But reducing gross energy production due to higher net utilization would be a really cool thing, so long as the total cost to the macro system (considering full life of the battery vs. load taken off power plants) is a net positive.
One commonly suggested (and substantially cheaper) option is to just set things up so you don't have local battery storage and just redirect all excess power back to the utility company.
The problem with that has already been mentioned. You're giving power back to the utility company at a fraction of what you purchase electricity for.
But beyond that, as power requirements in appliances / computers / electronic gadgets continues to decrease, and efficiency and capacity of alternative energy solutions continues to increase, there will likely come a time (in the not-too-distant-future) when there will [at least in theory] no longer be a need for utility companies.
In fact, from varied sources online I've gotten the impression that many countries (besides US) have substantially reduced power requirements per household where even today it's feasible (for those with sufficient roof space) to move all of their power usage off grid, and rely strictly on power generated by solar.
That's not a problem, that's how the markets work. When electricity is abundant (i.e. sun is shining, wind is blowing), it's cheap; when it's in demand (in the evening, after the sun and wind stop but people want to cook and watch TV), it's expensive.
The problem with energy storage isn't just a home-problem, it's a network-wide issue. AFAIK, current batteries aren't really able to solve this issue, in the long-term (i.e. considering the lifetime and replacement of the battery).
Not if your region was forced to subscribe to a feed-in-tarriff subsidy scheme for solar. Around here, there was a time when solar generated power earned 10x the value of the same amount of energy purchased from the grid. That multiplier has fallen thankfully, but is still greater than one.
Right now, some locations have laws and/or regulation that force grid companies to buy solar-generated electricity from home owners at fixed rates. This makes a lot of sense right now as a measure to encourage the adoption of solar, as a way to get off fossil fuels. In the long term, it might become a less useful measure, and we might want to allow market mechanisms for time-of-day-based pricing. This is already happening on the big players' market, where you see drops of the spot price of electricity at noon on sunny days. Extending these market mechanisms to individual homes makes sense, as long as home owners are empowered by technology to make use of it.
A large battery is an important piece of such empowering technology (combined with being able to set a smart policy for when to run off the battery, when to run off the grid, and when to feed back into the grid).
The grid will become less reliable over time as utilization increases, and in many cases we have fundamental limitations that make broad-scale robustness difficult to implement.
So fake it out. If I have a reliable local power source, I can easily take short outages without user impact.
Here in Scotland it's the other way round. Orkney is detached from the grid and trying to get itself connected, so it can better balance local renewable generation with the rest of the UK (and thence ultimately the European grid as a whole). Maybe they'll go to municipal batteries but the cost is still not attractive.