Storage - The Way Forward ?

[Worcester]

OK; so with slowly degressing PV FiT payments, though still the loophole (until everyone has smart meters ) of deemed export - and probably even then, the future is definitely looking towards options that will include storage so that you can use the generated power when you actually need it.

Additionally more and more products seem to be coming on to the market.

As yet we have no experience on installing 'on-grid' storage systems, has anyone else yet carried out an analysis of the capital and maintenance costs / returns / quality - or even got a list of all the offerings currently on the market place?

Perhaps here would be a good place to start - what experiences have you had, what equipment have you installed or had installed for you?

 

[amlu]

give it a couple of years...battery technology is picking up very fast.
heard of tesla motors, very popular with electric cars in US developing some off-grid storage.
in the meantime time to repurpose some immersion tank heaters and hook them up to the solar.

 

[Worcester]

Ok: So here's a starter for 10

Needap Power Router
Sunny Boy Smart Energy
Midnight Sun
Mage StorageTec
Antaris Solar eKiss BOX
Solax X-Hybrid
Moixa Technology Maslow
SMA Sunny Island?

What are your experience of these, typical price, components, usable storage power (kWh), duty cycles, cost of replacement parts, support etc..

What other units are on the market?

 

[whinmoor]

Growatt have brought one out - the SP2000 - available from Segen and Midsummer amongst others. I caught a glimpse of it at Ecobuild.

 

[SRE]

Going to the SMA training with Segen in a couple of weeks, will know more then but CCL are suggesting a minimum 10 year payback at which point the inverter & batteries need replaced. Segen quoting round £3750 for SMA. That's as much as I know at the minute.

Tesla are a bit behind - Nissan already has a unit that allows storage of pv in their Leaf that can be used in the house later but it's only available in Japan as yet and they haven't worked out how it's going to affect the battery guarantee that Nisan provides for the Leaf. When we were at Milbrook last year they were trying to see if there was a solution to this. I think it will be a while before they resolve the guaruntee issue and Tesla appear to already be having battery issues so I'm not sure they'll be any quicker.

 

[SolarCity]

Ok: So here's a starter for 10

Needap Power Router
Sunny Boy Smart Energy
Midnight Sun
Mage StorageTec
Antaris Solar eKiss BOX
Solax X-Hybrid
Moixa Technology Maslow
SMA Sunny Island?

What are your experience of these, typical price, components, usable storage power (kWh), duty cycles, cost of replacement parts, support etc..

What other units are on the market?

We're going to take a look at the Solax X-Hybrid at the end of the month. Figures still don't seem to add up but we're getting asked for this more and more.

 

[The Solar King]

Looked at the SMA unit. Even SMA now admit they got it wrong with this one. Battery pack is too small and cost is eye watering. They reckon it will boost self consumption to 50%.... Better fit a good quality proportional controller at this point in time and achieve the same or better.

Looked at the Growatt unit. Appears attractive at first sight, but still needed to be half the current price to be viable. Were some technical issues with it. As far as I could see, can only be attached with a single MPPT inverter.

Samsung/Panasonic offering looks interesting but again, not a viable proposition at this stage. The person selling it at both Solar Power UK and Ecobuild did not seem to fully appreciate the economics (or otherwise) of the thing.

There is a real and present danger of massive mis-seling of storage. Products are coming to market because of incentivisation in Germany. It should also be remembered that their unit cost of electricity is far higher than that in the UK. These two factors taken together can make storage worthwhile in that market.


It is possible that in the not too distant future we may even see limitation of export from PV even at a domestic level as the operators of the Grid find it increasingly difficult to balance the system due to injection it was not designed for. Unless they are forced to invest heavily in Smart Grids, this is almost inevitable. It is already being discussed. We could could even see additional charges levied against PV owners as happens in other markets.

These kind of factors could drive the market for storage.

Watch out over the issue of technical standards. These are being discussed and worked on. Those involved are endeavoring to produce a framework that does not restrict technical development but ensures compliance with current regulation. This could be a can of worms.

Storage can be on either the AC or DC side of the inverter. Both have advantages and disadvantages.

Storage is an exciting prospect but should be approached with caution and buckets of due diligence.

 

[Somecamel]

Glad I read this, looking forward to future updates

 

[Gavin A]

We've had a couple of nedap systems in since last summer using 6-800Ah 24V battery packs.

There've been a few teething problems, some of the settings were just plain wrong for the batteries, which took me a while to figure out.

Should be fitting an sma battery system shortly on a 24kW system, the issue with the SMA kit (the sunny islands) is that it's 48V, so it has to be really big system before it makes financial sense.

 

[SibertSolar]

Gordon - I won't repeat what others, and particularly Peter, have already said but if you have the time, take a look here as it might contain some useful info to base your judgements/decisions on. Personally, I'm looking closely at the Bosch offering at the moment....

For me, the key to you guys offering suitable/correct battery storage solutions to your customer-base, is understanding their existing load-profile first. I encourage customers to fit monitoring equipment for a few weeks, even before PV is installed, to ascertain the baseline load profile. Then can you put some numbers against what would be a suitable solution and the likely benefit to the end user, especially when considering battery storage integration.

Array orientation is also a consideration - moving away from a focus on ROI with due-south facing arrays, towards orientation favouring peak consumption matching is possibly something that might be a consideration for some clients, particularly in the domestic arena where the demand profile is often not in line with the yield profile.

 

[danesol]

Seen my post on the new units from Tesla ???

 

[Worcester]

OK, so Tesla are getting close

Powerwall | Tesla Home Battery

7 kWh $3,000 guaranteed 10 years = 7*365*10=25550 kWh vs buying leccy, 25550 * 15p = £3832.5;
so if dollars OK if translates $1 = £1 , not worth it ----YET , getting there, needs to be £2k to go mass market



Oops all sold out
Sold OUT! Tesla's Powerwall home battery - Manufacturing Talk Radio

"Homeowners will be able to get a Powerwall battery in 7 and 10 kilowatt-hour modules for $3,000 and $3,500 respectively. Tesla will also offer 100-kilowatt-hour modules for industrial applications at $25,000 each"

Really good article here: http://www.forbes.com/sites/christo...ery-hype-should-make-tesla-investors-nervous/

 

[TedM]

The batteries have a peak output of 2kW continuous so perhaps not ideal, and more than just the battery will be required to make a fully working system (unless you already have a Tesla EV sitting in the garage perhaps), pushing the price up even higher.

Nonetheless a good opener for Musk to get major media attention.

 

[sharpener]

Figures still don't seem to add up but we're getting asked for this more and more.

As a prospective purchaser I am struggling with the economics of storage systems, much as I would like to have one for reasons of self-sufficiency.

Suppose there are 300 days in the year when there is enough sun to fully charge the battery. At 16p per kWh of grid power my maximum possible saving will then be £48 per year per kWh of usable battery capacity. So a 2kWh Growatt will save £96/yr and a WattStor 3/3 will save £144/yr, hardly a great return for a capital investment of ~£3k in either case. In fact 16p/kWh will not even cover the cost of battery depreciation for most if not all battery technologies on the market.

Am I missing something here? How can the manufacturers justify claims of < 10 years payback?

Some other factors which make the economics even worse:

- Battery storage will cannibalise the savings already made with an immersion heater controller, as there will be days when there is only enough sun for one or the other but not both.
- Battery inverter needs (paradoxically) to be turned off at night since it is not worth sacrificing battery life to save off-peak electricity at only 7p/unit, I have not seen any system offering this.
- This also makes sizing the storage very difficult, if it is not to be too big in the summer it is likely to be too small to be much use in winter.

 

[bxman]

Would you not use the 7p off peak rate to charge the battery on the 150 or more days when generation was insufficient to bring them back to a safe level of charge .

I know prediction of production is not easy with English weather . But being grid connected means that there should be no need to draw in the battery when SOC is low and no point in using at all when off-peak is available .

It will need some careful monitoring and management . No non essential loads when conditions are unfavorable and no wasteful water heating that will not be used simply because the immersion heating controller finds there is surplus generation that would go back to the grid if not used .