On-grid domestic battery storage

zeupater wrote: »

... Just checked the history on another laptop's browser and found the source mentioned above if anyone's interested ..... ( http://www.windandsun.co.uk/products/Batteries/Lithium-Ion-Batteries/Mercedes-Benz-Energy-Storage-Home#.WPtHkaLau02 ) ...

HTH
Z

Hello again, a thought struck me this morning, this batt has a round trip efficiency of 97% (presumably in DC use), so that's not so bad for those on the older FiT rates. Though it would mean installing a compatible inverter, but perhaps as and when an inverter fails in the future. More options better than less.

Anyways, just a thought.

Looks like the best 6 months will give good storage and Immersun use:

April numbers!

Electricity imported - 85kWh! (150kWh in April 2016)
Generated - 301kWh (exactly the same as April 2016)
Battery discharge - 102.88kWh
ImmerSUN diversion - 54kWh (51kWh in April 2016)

So with decent generation, I've been able to get 100kWh out of the battery and make a big dent in consumption, whilst also then still sending about as much as last year into the ImmerSUN for free hot water!

That's about £15 in avoided electricity in one month - something I hope to be able to see continue throughout the summer months. Nice to have broken the 100kWh/month figure

Large growth in PV and storage on the demand side predicted (kinda obvious I suppose)

Navigant: Distributed solar-plus-storage worth US$49 billion in less than 10 years

rugbyleaguesmate wrote: »

Martyn1981 wrote: »

Hiya Chopper, there are lots of battery systems, most much smaller than the PWII, and many modular so you cab add more later on.

For example there's the Enphase systems which are only 1.2kWh and about 350W charge/discharge.

So if the prices fall far enough for the smaller systems it might well be a good idea to buy then. I'm clearly quite passionate about batts and their future, but the time isn't right yet unless you generate and import a ton of leccy still, but we'll get there. Australia is leading the charge as they have great generation, but also very high import prices, so the industry is developing, but it's probably where PV was 5yrs ago, so patience is needed in the UK. Drat!

All the best.

OK Mart you can see that I am able to generate a lot of eleccy, but still appear to be consuming a lot also, say £30 a month, is this close to making a battery viable for me yet?

Hiya. My thoughts.

First off, my opinion, but I think prices will probably fall faster than savings will be earned for the next few years. So you are almost certainly going to be better off waiting. Also as costs fall, and hopefully life cycles or warranted cycles rise, then the cost of storing a kWh of leccy will also fall, which will improve your savings/returns.

Next. My way of calculating my savings and battery size, and it's crucial to point out that this is for me, as I genuinely don't know the best way to calculate this, nor exactly how it will vary from PV'er to PV'er. So here's the link to our previous discussion:

Martyn1981 wrote: »

Hiya. To start

So I think you need to do some number crunching, and I'm happy to help, in fact it should be interesting seeing the numbers from a different angle (higher import/export). Hopefully others will comment and assist so we start to get an idea how to do this.

So, are you able to make a reasonable guess at each months import and export broken down to a daily amount, to see how much of a batt's capacity you need and so we can see what can be displaced? I think a 4 way breakdown might be enough (Winter Dec-Feb, Summer June-Aug, Spring/Autumn Mch-May & Sep-Nov).

Can you supply import price, and I assume you get the 5p export rate, which might become a factor in the future. Savings will be import - cost of storage, or later on, import - (cost of storage + export rate).