#1 Feb. 8, 2014 12:14:00

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Solar Storage to take off?

A couple of similar articles about solar storage (i.e. batteries) filched another forum:


“PV storage in the UK is set to take off from next year according to new analysis that forecasts a global storage market of US$19 billion by 2017.
A report by IHS predicts that other countries, particularly the UK, will follow the lead now being shown by Germany in driving uptake of PV storage technology.
From the beginning of next month Germany is introducing a tariff for PV storage, which is expected to reduce the cost of a PV system with storage to 10% less than one without.
And as solar subsidies such as feed-in tariffs begin to dwindle, IHS expects other countries such as the UK to adopt similar measures to boost the deployment of storage technology.”


“Because domestic electricity rates now significantly exceed residential feed-in tariff rates, there is strong interest in increasing self-consumption in residential PV systems to maximize the financial return of the system,” said Sam Wilkinson, PV analyst at IHS.
“As a result, 8 megawatts (MW) of PV systems were already installed with storage in Germany in 2012, prior to the subsidy being released. The introduction of the widely anticipated subsidy will quickly accelerate uptake by making the lifetime cost of PV systems with storage cheaper compared to those without it.”
Although the rates are not confirmed yet, the proposed subsidy will reduce the average 20-year cost of a PV system with storage to 10 percent less than a system without it.
Previously, the high cost of batteries had more than offset the savings created by increased self-consumption, and PV systems without storage offered a more attractive return."

Also, an article about power to gas (P2G):

Mind you I'm not sure how I'd feel about a tank of explosive hydrogen, no matter how safely stored, in or near my house!


URN 215 North Yorkshire 3.96 kWp, S facing, 40 deg tilt, minor shading

Edited SteveRogers (Feb. 8, 2014 12:14:00)


#2 March 23, 2014 13:05:00

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Solar Storage to take off?


Thanks for sharing these links. I have invested in ITM Power which are leading the way in the UK on storage of surplus renewably generated electricity, especially in Germany with hydrogen to grid. The Isle of Wight Ecoisland project is of interest. Domestic storage always seems just over the horizon so I hope developments in Germany atre showing the way for us. So much will depend on economies of scale.


I notice our installations are on about the same latitude with broadly similar similar performance.


URN 709, 3.6kW, orientation 140 degrees, tilt 35degrees, marginal shading from chimney.

Edited Lyreslider (March 23, 2014 13:05:00)


#3 March 23, 2014 15:34:00

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Solar Storage to take off?

Thanks for the links Steve, it'll be interesting to see how accurate the prediction is.

On another topic, have you any idea how your iBoost is performing ?

Steve Webb

URN 6390, Southwell

Edited SunnySouthwell (March 23, 2014 15:34:00)


#4 Dec. 7, 2017 13:45:11

From: Surrey, on Gatwick flight path
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Solar Storage to take off?

I have been looking at battery storage and I think I have found a simple way to evaluate any of the systems on offer.

The important value is MWh delivered under warranty.

Forget the 5 years or 10 years life if your battery has a 10 year life listed (ie Powerwall 2) but you charge and discharge it by 5.3MWh a year then its life is only 7 years as the max kWh delivered for a Powerwall 2 is 37MWh. So, 7 years at 5.3MWh is 37.1MWh so your Powerwall 2 has reached the end of its warranty.

When considering system costs divide the cost of installation by the kWh delivered. So if a Powerwall 2 cost £8000 installed then divide by 37,000 = 21.6p per kWh delivered. So if you can charge your Powerwall for free from solar PV and you pay more than 21.6p a kWh for your power you could breakeven or be slightly better off.

However, if you are going to charge your Powerwall at night from Eco7 at 7p kWh then the cost of electricity has to be higher than 21.6+7 = 28.6p just to breakeven.

As a second example consider a Sonnen 8.8 system which has a 80MWh delivered warranty, but costs more at £9000. Dividing 9000/80,000 gives a value of only 11.25p per kWh delivered. Half the cost of a powewall 2 and would deliver your 5.3MWh every year for 15 years. Half the price and twice the life. This is an example I have no connection with Sonnen.

Don't be fooled by all the jargon and hype. Just divide the installed cost by the MWh delivered to get the true system cost. If it doesn’t show a profit over its true life, then walk away.

SolarEdge SE4000 inverter, 16 x Romag powerglaz 235W panels. South facing at 30 degree angle in Surrey just East of Gatwick and under the flight path.

ESS AC coupled system using a Victron Multiplus 24V/1600VA Inverter/Charger - 8.16kW Trojan 875 battery bank.


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