On-grid domestic battery storage

Martyn1981 · 14 November 2017 at 11:56AM

EricMears wrote: »

However, after a better look at the relevant bit of the prog plus some strategic Googling I managed to find out that was actually a on vanadium redox flow system sold by Red T Energy. They have a website with lots of pretty pictures but manage to avoid giving any details of cost.

More news on RedT and storage systems.

1MWh flow machine to save business 50% on grid imports by time shifting solar

What is thought to be the largest operating containerised vanadium redox flow machine system in the UK has been connected to the to the grid by redT energy, with the 1MWh project expected to cut a Cornish business’ reliance on grid imports in half by time shifting excess solar generation.

The system from redT energy has been installed at The Olde House, a 600 acre working farm and holiday retreat situated in north Cornwall, which also has two small solar arrays with a combined capacity of 350kWp.

The project will shift the excess generation from these installations to use during evening peak times around the site, which is expected to save The Olde House up to 50% on grid imports during these periods.

It will also create revenue by tracking and dynamically responding to changes in grid frequency and providing grid services, while also aiming to participate in the Capacity Market.

RedT expects this type of project to achieve an internal rate of return (IRR) percentage in the mid-teens.

Martyn1981 · 16 November 2017 at 4:18PM

Centrica preparing to roll out solar-plus-storage in Cornwall

The goal of the project, as with the rest of Centrica’s activities in Cornwall, is to harness renewables and smart energy technologies to free up capacity on the local grid and provide flexibility to the distribution network operator or the national grid.

"With the residential [batteries] we'll be looking at the fleet of residential sites and how with aggregation we might access some of those national and potentially local services,” Orme said.

Martyn1981 · 6 December 2017 at 12:56PM

Forgot to post October's results, so here's a double dose. Also getting close to a year and some 12 month analysis.

[Doh! Nearly copied directly from e-mail, which got my IP banned last time, due to a 'quirk' in the MSE protection software - so just a reminder to one and all that this issue exists, and to copy/paste to notepad first. M.]

October -

Electricity imported - 188kWh (227kWh in Oct 2016)
Generated - 143kWh (149kWh in Oct 2016)
Battery discharge - 77kWh
ImmerSUN diversion - 8.7kWh (28.7kWh in Oct 2016)

So, similar amount of solar PV generation, a lower bill by about 50kWh with 77kWh out of the battery, so it's had an impact - also can see the ImmerSUN is taking a big hit now, it lost 20kWh vs this month last year...

Here are my November sums:

Electricity imported - 263kWh (256kWh in Nov 2016) - I've imported higher than that though in 2015 - 297kWh
Generated - 93kWh ( 85kWh in Nov 2016) - my highest ever November generation

Battery discharge - 42.9kWh
ImmerSUN diversion - 4.1kWh (19kWh in Nov 2016) - even worse than the 9kWh from Nov 2015!

So 11 and a bit months in, I've discharged 860kWh out of the battery, saving me approx £155 in imported electricity this year.

My electricity consumption to beginning of Dec is 1788kWh vs 2168kWh last year. So actually this year I've probably used more electricity than I did last year and still managed to reduce my bill because of the battery. Several reasons for this - both of us work from home more now, and the kids are definitely using the PS4 way more than we did last year!

Will I get to 1000kWh discharged for the year? No.
Have I reduced my electricity bill - yes.
Will I "break even" any time soon? - No.
Have I learned stuff - yes!

Martyn1981 · 15 December 2017 at 12:07PM

Article on Ireland testing ways to integrate storage, but I thought it was particularly interesting that they'll be trialing several batteries, to see how they perform over the next 2 years, so that'll all help to advise us better going forward.

Domestic batteries to link Irish homes together with variable renewables in new trial

The consortium behind the project - Electric Ireland, renewable supplier and technology provider Solo Energy, and network operator ESB Networks – will select both homes with and without existing solar PV to take part. The project aims to install batteries ranging from 7-11kWh in Q2 2018, with procurement already underway to batteries from different suppliers that could interact with both the grid and solar PV.

Matthew Kennedy, head of Strategy and Business at IERC, told Solar Power Portal: “We will probably select three of four batteries which we would test that are readily available, could work within our grid and the ones that are the most economically advantageous while providing the most output.

Dickymicky · 20 January 2018 at 2:16PM

Better off using a Solic 200 to heat your water from surplus PV.. they have a zero threshold, so even a few Watts will be used, all the other systems have at least 100W threshold before it gets diverted. Also costs less than £200 but you do need an immersion heater on a dedicated circuit.. they are really simple to fit but if not competent it won't cost a sparky much, less than an hour.

EricMears · 20 January 2018 at 2:40PM

Dickymicky wrote: »

. . . all the other systems have at least 100W threshold before it gets diverted . . .

Not quite true ! In particular, Immersun lets you choose your own threshold.

But there is a reason for having such a threshold : if you're diverting every single watt and the sun intensity changes slightly (perhaps a cloud pops in front of it) then you run a risk of starting to buy electricity for a brief period. having a threshold reduces that risk and the 'loss' of energy probably costs less than you might otherwise have had to pay for.

Martyn1981 · 25 January 2018 at 7:54PM

This may be years away, but if true and it can double the life of Li-ion batts, then that effectively halves the cost of storage ..... sort of.

Researchers double life of lithium-ion batteries by adding graphene girders

NigeWick · 26 January 2018 at 11:47AM

Martyn1981 wrote: »

This may be years away

I'm suspecting that the "next big thing" in batteries will come along before this lithium ion improvement is viable.

zeupater · 26 January 2018 at 1:03PM

NigeWick wrote: »

I'm suspecting that the "next big thing" in batteries will come along before this lithium ion improvement is viable.

Hi

Almost everything I've seen related to graphene seems to point more towards academic one-upmanship & an industry intent to tie down IP related issues more than commercialisation as that's where the future money is ... pretty standard really, the UK expends so much effort on the initial thinking but leaves the doing and creation of revenue streams (/commercialisation) to others ...

HTH
Z

pile-o-stone · 26 January 2018 at 2:55PM

Dickymicky wrote: »

Better off using a Solic 200 to heat your water from surplus PV.. they have a zero threshold, so even a few Watts will be used, all the other systems have at least 100W threshold before it gets diverted. Also costs less than £200 but you do need an immersion heater on a dedicated circuit.. they are really simple to fit but if not competent it won't cost a sparky much, less than an hour.

The downside for this is that a sender unit loosely clipped to the mains supply cable is not accurate to the watt, far from it. Your sender unit might be telling your Solic 200 that you have excess solar, when actually you haven't and you end up using mains power on your immersion heater. This can cost you a lot more in imported energy than you could ever save with 10 watts here and 100 watts there in lost solar diversion.

I discovered this issue when we had a smart meter fitted with an in-home display unit. The unit is 100% accurate because it's reporting what the electricity meter is doing. I checked it against what the solar diverter sender unit was reporting and there was over 250w difference. I changed the sender unit batteries and this reduced it to approx 60w difference.

Prior to changing the batteries, my solar diverter was turning on the immersion heater when it thought there was excess solar. There wasn't, it was using mains electricity.

Hopefully, one day we'll have soler diverters that can take their power readings directly from the smart meter rather than from sender units looped around an electrical cable. Until that day, I'm glad my diverter has a 200w threshold as it's unlikely to erroneously divert mains electricity to the immersion heater.

On-grid domestic battery storage

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