Storage Heaters - Would charging them from a Solar System make sense?

johntheexpat

The best return on your money is almost certainly more insulation.  And that is also quite probably the greenest solution too.  Its all very well everyone generating relatively small amounts of PV derived electricity when the demand is not particularly high.  Its better all round if people take measures to reduce consumption when demand is at a peak.

Peak demand in France is usually in December, Friday evenings around 18.00, during a really cold snap.  One which is normally associated with freezing air coming in from the east.  So, no sunlight, no wind power.  Which means that 110GW of electricity must be generated in order to keep the lights on.  So there must be 110GW of generating capacity. A lot of this won't be used at any other time, or at best the power stations will be running at a less that 100% capacity which has an associated drop in efficiency.  So the electricity must be more expensive to pay for the maintenance of the "stand-by" capacity and/or the less efficient running of the power stations normally.

So, the truly "green" route isn't PV solar electricity, but taking steps to reduce consumption (and insulation allows you to do this without drop in comfort levels).  And saves you money.  And there is no risk of Governments deciding to unilaterally change the rules over PV, because they cost too much, etc etc.

Just my opinion, rant over.

Solarphil

Dont disagree that insulation is a great route to lower costs/use but its really only the best approach when your building from new or your construction of your building allows it. If you speak to any of the guys running things like green deal (UK's programme designed to increase home energy efficiency) they will tell you that a great number of the UK building stock is hard to treat and so costs quite a lot to apply insulation to. e.g. single skin brick properties of the back to back type where its almost impossible to insulate them without major disruption or massive cost.

Another oft missed point is that doing things like applying External Wall Insulation to older hard to treat properties could have profound effects on the look and feel of the UK's cities as swathes of properties become cement rendered rather than brick. Of course you can apply brick facades to EWI but a lot of those properties are council owned and they simply don't have enough money to do that sort of finish.

Fully agree that solar / wind need backup capacity on the grid but the future is not one of emitting CO2 burning up millions of years of stored fossil fuels (for a number of reasons). The future will be a combination solar, wind, gas, nuclear, waste to energy and storage and most importantly demand reduction.

Cant say I'm a massive fan of nuclear but it will have an important part to play in providing the baseload contribution, solar and wind in conjunction with storage will then be able to top up during the day peaks with the peak demand being filled by peaking gas plants. Storage will help to flatten out the peakiness of renewables, the other main area I see is distributed CHP (combined heat and power - gas generators that supply heat from the cooling jacket) these work really well for things like care homes where hot water demand is high.

In short the market will be a lot more complex than it is now but will use technologies that suit the situation and be much more distributed, large central power plants are a thing of the past (other than nuclear / waste to energy).

Oh and on PV cost you are behind the times While You Were Getting Worked Up Over Oil Prices, This Just Happened to Solar - Bloomberg Solar has beaten gas and coal in recent power auctions in the US, whilst this is in high sun areas e.g. Nevada this was also against gas at some of the cheapest prices in the world, this will spread to the rest of the world as PV prices continue to decline. In Italy and Spain solar plants are being built right now that don't have any subsidies and sell power into the open market competing against traditional generation.

Traditional generation can only get more expensive as they are mature technologies, with increasing emissions regulation costs and increasing fuel costs they will become more expensive. Solar on the other hand is dropping in cost by 20% for every doubling of installed base, its decreased by 70% in the last 3 years alone. With no fuel cost solars costs are fixed at build stage so the levelled cost of power production is very predictable and increasingly more cost effective over the long term than traditional power.

Rant over ;-)

irenealice2015

To hopefully answer the original question .... We had a solar pv system fitted plus ImmerSun unit to feed into a thermal store two years ago and have found it works well, the input is extremely variable and winter input is understandably low but in Spring and Autumn there were a lot of cold but sunny days, giving a good input and we have a cold living room so are just installing a solar fed night storage heater (the ImmerSun is capable of feeding two channels) to take off the chill during these periods. It is a 1.7kw with input and output controls and is being fitted with an isolator switch so that it can be turned off during heat waves. I will add my findings to this thread to hopefully help anyone else wishing to try it out. It is not a cheap option but we did find a large percentage was being output to the grid during both seasons and we were having to heat the room by conventional means, which I object to.

irenealice2015

Storage heater is now fitted and working. Immersun putting in very small amount - today 1.5kw in total, into a 1.7kw heater. Surprisingly the heater is warm and definitely took the chill off the room, which was the hope.
I should just point out that I am not using it to heat the thermal store as I fitted a separate solar thermal panel which is heating the water fully.
So, it does work. Hope that helps

blankscreen

thanks for this, i was courious as if viable it is an independent means of heating a conservatory and so a direct saving, not really turning it into a sauna but simply to keep the worst of the chill off.

perhaps an idea for keen gardiners with a polly tunnel?

irenealice2015

The nightstore leaks out a small amount of heat all the time (even though. Set on minimum) so I think it would make the conservatory or polytunnel overhot in summer, not giving out enough heat in winter - we just wanted to use all the excess power and this seemed a good experiment - it does the trick in our lounge and definitely takes the chill off this time of year. However, I suspect too much heat will leak in summer and it will be isolated till autumn. Even on just a 0.7kw total charge, which trickled in over a few hours, it worked.  It would not be cost effective to have an electrician fit a new heater and Immersun unit. Incidentally, I thoroughly recommend the Immersun for water heating useage, we have the older model, which will run two outputs.

broadie

I am interested to know how your storage heater had performed since 2015 - as I am about to buy a 1.7kw storage heater plus diverter - we have a 4kw solar pv system in the south of england - should I get an auto or manual heater ??