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Comment by transfire | Hacker News Reader

The cost is still too high, so the electric companies have little to worry about in the short run as long as they can find ways to improve their own margins. Of course lobbying for regulatory fees and reduced buy-back rates is one way to do that, but the utilities best be careful there. That could cause a blow back reaction.

In the long run though it is all downhill. Battery tech is getting better at around 8% per year. Solar efficiency isn't far behind. What cost $20,000 now to add solar or $40,000 to get off-grid completely, will cost half that in about 10 to 15 years. If the trend lines continue then in 20 to 30 years years its a done deal. No house will ever be built again without it's own power generation system.

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You can't get off the grid completely unless you are a) willing to suffer some downtime occasionally, b) way overbuild storage as compared to typical needs, or c) have your own backup fossil fuel generator.

Any way you cut it high availability costs money. If you expect the grid to handle backup for you then you should expect to pay them to do so. TANSTAAFL

On (b), in addition to total capacity (kWh) you also need to have the battery system designed for quite high transient discharge rates (kW). A typical American suburban house pulls well under 2 kW on average, but can have transient usage spikes in the range of 15-25 kW or so, depending on the house. It's doable, just requires an even more oversized/expensive system.

An alternative could be to avoid simultaneous usage of the major appliances (A/C, electric oven, vacuum, washer/dryer, tea kettle, etc.), of course. That would probably require a mixture of behavioral changes and changes to the A/C system. For example a house with multiple A/C units (window units or upstairs/downstairs) could have them wired so they don't kick on simultaneously.

I don't think (a) is true because (b) and/or (c) is exactly what people will eventually do --although in the case of (c) it will be hydrogen fuel cells.

It costs at least some $400/kWh for battery storage. That amounts to $12k dollars for each house for supplying average consumption; that's a huge cost already. If you want (a) to be false, I guess you need to multiply that by two at least. It just doesn't make sense to make each house do it individually, the grid is a wonderful technology that reduces this risks, smooths consumption and provides storage/generation economies of scale. It just doesn't make sense to abolish it entirely for all but the most isolated places.

I pay about $150/mth on electricity ($1800/yr), if your numbers are to be believed, then it would take about ~13.2 years to pay off a 24k battery pack, this doesn't include the cost of the panels which would probably be another 24K, so roughly a 26 years to pay off (Probably the working life of the panels) So basically at current prices the cost is on par with my utility. It's not amazing, but with the right gov't incentives and future advancements in battery and solar technology I don't see why we couldn't see renewables edge out the dominant players. Sucks for me though, just finished my B.eng in mechanical with specialization in thermal power generation.

I was just discussing this with someone who installed solar panels on their house about 8 months ago. I think your numbers are a little bit off.

We live in south western ohio and said person took their bill from $300-400/mo to $30/mo (at 13 cents per kWh) with $11k of solar panels. They have a payoff period of about 3 years not including the $4k rebate they got which reduces the payoff cost to a little under 2 years.

Keep in mind this is a place that doesn't get nearly as much sun as much more southern areas/Hawaii.

I do agree that batteries still have a payoff period that is too long to be economical. Here's rooting for Mr. Musk.

Here's a great recent article about the current and anticipated future prices of energy storage: http://rameznaam.com/2015/04/14/energy-storage-about-to-get-...

It's based mostly on a recent paper in nature that estimates "that EV batteries in 2014 cost between $310 and $400 per kwh", but anticipates "It’s now in the realm of possibility that we’ll see $100 / kwh lithium-ion batteries in electric vehicles by 2020, with some speculating that Tesla’s ‘gigafactory’ will push into sufficient scale to achieve that."

His numbers roughly agree with yours:

  So we’d estimate that at the following battery prices we’d 
  get the following effective LCOEs (Levelized Cost of Electricity):

  - $300 / kwh battery  :  33 cent / kwh electricity storage
  - $200 / kwh battery  :  22 cent / kwh electricity storage
  - $150 / kwh battery  :  17 cent / kwh electricity storage
  - $100 / kwh battery  :  11 cent / kwh electricity storage

  All of those battery costs, by the way, are functions of 
  what the ultimate buyer pays, including installation and maintenance.

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