On-grid domestic battery storage

Martyn1981 · 30 March 2017 at 4:37PM

Solar-and-storage homes set for Swansea under historic investment deal for Wales

Thousands of new and existing homes are to be fitted with a range of low carbon technologies including integrated solar PV and battery storage systems as part of landmark funding agreement for the Swansea Bay area of Wales.

The Neath development will be used as a pathfinder vehicle to evaluate and test the design, implementation, installation and performance of the houses as power stations. The council is expecting to draw in excess of £517 million of funding for the total programme, generating an estimated 4,512 new jobs.

Martyn1981 · 3 April 2017 at 1:18PM

Article states that 50% of new PV installs in Germany now include storage. Unfortunately the video (interview) isn't working, but fingers crossed.

Also, "Dirk Uwe Sauer, Professor of storage system technologies at RWTH Aachen", prof of storage .... cool!

Storage is becoming more attractive in German power market

Martyn1981 · 3 April 2017 at 5:04PM

Info for March. All seems relevant and interesting, so I've cut and pasted it again:

March 2017
Imported 195kWh (249kWh March 2016)
Generated 205kWh (about average - best year was 238, worst was 108, but that was before I had the W-facing extra panels)
Battery discharge - 74kWh!!
ImmerSUN diversion - 9.9kWh (in March 2016 this was 35kWh - so again the ImmerSUN is getting pushed out of the system somewhat!)

So, it looks like we've noticeably reduced grid import with the Solar plus Battery, and the Battery has probably saved at least £11 this month in imported electricity avoided, quite a gain again over Feb. I wonder how much more it'll get in April!

You'll also be pleased to hear that on 3 days the battery discharged more than 4kWh - those were all on days where my generation was >10kWh which for my system counts as a very good day for March.

Definitely seems that the longer days, and of course higher sustained outputs, are both contributing (remember, the PowerVault can "only" charge at 800W max).

I'm definitely seeing battery support stretching later into the evenings now - so on those good days, the battery has been discharging until about 9pm - definitely peak shaving! Hopefully that trend will continue as we move towards those long summer evenings with late sunsets and my West-facing panels pushing out some late evening watts.

I guess if you've got more west-facing generation capacity (as you have), and if you've got a bigger battery than I have, you could peak-shave for much longer in the evenings. We'll see how it goes.

He talks about peak shaving for longer, but I assume (any thoughts?) that if the batt supplies a significant contribution till around 9pm, then from a national point of view it's done its job, as demand, price and carbon intensity will then start to drop.

I think these FFU's are educational, I've certainly learnt a lot from him. Ideally I suppose we need similar info from someone with a larger PV system, larger batt, and larger charge/discharge limits, but I'm sure that will come. Or perhaps there are folks out there blogging such stuff already - so much internet, so little time!

Martyn1981 · 6 April 2017 at 8:54PM

New episode of Fully Charged discussing the Redflow 10kWh flow battery and multiples thereof - 600kWh anyone?

Not cheap, about £10k I think in Australia, but also relatively new, and low production, so more time needed. The advantages though are that there is no loss of performance over time, and the battery is happy to be discharged 100%. Also the liquid is actually a fire retardant, so super safe.

Redflow ZCell batteries | Fully Charged

NigeWick · 7 April 2017 at 2:28PM

Martyn1981 wrote: »

New episode of Fully Charged discussing the Redflow 10kWh flow battery and multiples thereof - 600kWh anyone?

I watched it and thought it looked like a good idea. Then I thought what if I have a 60kWh battery electric car, why would I want the goo tank as well?

Martyn1981 · 13 April 2017 at 5:08PM

Possible confirmation that domestic storage is not yet viable in the UK.

Battery storage draws one complaint a week says consumer protection scheme

Not only do we need to see prices come down, but also some sort of standardisation, and industry regulation. But, in fairness, it's still early days.

Martyn1981 · 19 April 2017 at 4:41PM

E.on is now in the PV and storage business, though storage prices look high, and leccy savings seem a bit ambitious, but just to let folks know that interest in the market is clearly growing.

Energy giant E.on enters UK solar and storage market

Martyn1981 · 22 April 2017 at 12:24PM

Here is a compilation of battery use updates, which seems to show that April is a key crossover month, and might mean 6 months of major battery use per year.

With the excellent sun conditions we've had in the last few days, I've seen some really good numbers from my SolarPV, but also from the PowerVault.

5th April - 3.85kWh
6th April - 4.33kWh
7th April - 3.66kWh
8th April - 2.73kWh
9th April - 5.77kWh!

On those same 5 days, my generation was all above 12kWh, with 9th April being 14.21kWh, my best day of the year.

Looking at the data in more detail, the 8th April, we were all out of the house for most of the day and didn't come home until early evening, so there was comparatively little daytime use and no big ticket draws like dishwasher or electric oven. Consequently, the battery didn't have to actually do much - this meant it was able to discharge all the way through the night covering the fridge freezer into 9th April - which is why I think 9th April looks so high as it had a good 7 hours of that nighttime 90-180watt draw covered before sunrise, then the solar panels woke up, fully covered all daytime demand, fully re-charged the PowerVault and then was able to discharge again in the evening

In addition, the ImmerSUN has been taking at least 3kWh/day in the same period and has fully covered our hot water needs. There is now sufficient surplus power during the day to cover daily consumption, charge the battery, heat the HWT and actually still export a bit to the grid.

We were away on Sat and Sun [15th & 16th] so this is what the solar and battery can do without any big ticket home use items like the washing machine, dishwasher, tv and PS4 - 3.3kWh of battery discharge alongside the solar generation during the day basically covered the whole 24 hour period with effectively zero import.

It's definitely starting to feel like a more successful and useful installation now April has arrived - 67kWh from the battery up to the 19th, so I reckon 100kWh is achievable, and the ImmerSUN has been able to heat the hot water tank alone for most of those days with the export the PowerVault can't take. This seems to happen in the afternoons when the PowerVault charging rate falls away - I've noticed this pattern quite a lot now on the graphs, I'm guessing it's something to do with how the batteries cope with taking charge as they get towards full capacity and preserving the battery life?

Martyn1981 · 22 April 2017 at 12:27PM

Just some general battery news / official launches, but no prices.

Mercedes now selling into the UK, that should help create a market, competition etc etc.

Mercedes-Benz Ready To Sell Residential Storage Batteries In UK

and LG Chem launching in the US, which will hopefully create competition with Tesla, and stir up publicity, which again should help with markets, prices, progress etc.

LG Chem Officially Launches Home Batteries In North America

zeupater · 22 April 2017 at 1:12PM

Martyn1981 wrote: »

Just some general battery news / official launches, but no prices.

Mercedes now selling into the UK, that should help create a market, competition etc etc.

Mercedes-Benz Ready To Sell Residential Storage Batteries In UK

and LG Chem launching in the US, which will hopefully create competition with Tesla, and stir up publicity, which again should help with markets, prices, progress etc.

LG Chem Officially Launches Home Batteries In North America

Hi

Can't remember exactly where, but I came across a breakdown of prices for the Mercedes system at sometime within the last couple of weeks. It seems that the battery units are modular & stackable, requiring a floor-standing base or a wall bracket system - you also buy the plastic top with the Merc logo separately - at the time I was surprised how much these 'accessories' cost ... from memory the base was around £300 and the silver plastic logo cap well over £100, totally reinforcing the view that domestic storage is currently being considered as a generous cash-cow product sector for anyone entering the market ...

HTH
Z

On-grid domestic battery storage

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