Battery Storage System for Solar/E7

Cardew

MFW_ASAP wrote: »

Possibly, though better than nothing. If enough people move to green tariffs or totally green suppliers then 'dirty' energy companies will see the loss of market share and do something about it.

Naturally, the first step should be to reduce energy waste, then look at how you use energy and perhaps modify behaviors (i.e. half full dishwashers/washing machines, thermostats on radiators).

It'd be interesting to note whether spending solar PV money instead on fitting modern zonal/per room central heating manifolds, energy efficient appliances, lighting circuits on timers, etc. would be cheaper and give a better return. Given that most solar energy is produced in summer, when most domestic customers use less energy and very little solar power is produced in winter, when domestic customers use the most energy....

You neglected to say 'and none at all at night'!

MFW_ASAP

Cardew wrote: »

You neglected to say 'and none at all at night'!

Yep. Whereas energy efficiency works 24hrs a day, 7 days a week, 365 days a year. It was good that the government changed the rules so that houses had to have at least a D rating to qualify for solar FITs at the higher rate, shame they chose a level that most households already meet.

If they had insisted on a B rating then they may not have had to start looking at reducing the FITs so quickly. We would have either seen a reduction in the number of households installing solar, or an increase in those households thermal envelope, making the FIT subsidy more than just a financial cash cow. It would actually do what it's there for - encouraging energy conservation, instead of people having the same or greater energy use, just with a different supplier (i.e. their roof).

Cardew

EricMears wrote: »

This is very odd ! I posted this as a reply to a new MSE member who said he was the owner of a website I'd quoted earlier ( http://www.homeenergystorageuk.co.uk/victron-hub-2-home-energy-storage/ ) but I saw later that it had been "Last edited by MSE ForumTeam3; Today at 4:43 AM.. Reason: Quoting deleted post " . The deleted post 'advised' me that a 4kWp solar installation in Derby would never exceed 12kWh/day hence I replied :-


Afraid there's an error in there somewhere.

PVGIS predicts (and 4 years local results confirm) that our 4kWp of panels (25mls N of Derby) should generate around 470kWh/month in May/June/July (and prob slightly more if our roof was steeper). That's an average of nearly 16kWh/day and of course individual 'good days' will be (indeed were) well over 20kWh/day.

But the person asking the question was actually asking if it might be possible to charge up batteries on E7 at this time of year then not buy any daytime electricity tomorrow. I'm sure that would require a huge battery !


Not only was that post deleted, but also its poster's only other contribution in which he introduced himself as the website owner has also vanished.

I think MSE insists that any poster connected to a firm needs their permission to contribute.


Whilst the posts, to which you refer were interesting and it is a pity they were deleted, they did have the potential to promote the firm, and could be seen as having MSE approval.

ed110220

MFW_ASAP wrote: »

Yep. Whereas energy efficiency works 24hrs a day, 7 days a week, 365 days a year. It was good that the government changed the rules so that houses had to have at least a D rating to qualify for solar FITs at the higher rate, shame they chose a level that most households already meet.

If they had insisted on a B rating then they may not have had to start looking at reducing the FITs so quickly. We would have either seen a reduction in the number of households installing solar, or an increase in those households thermal envelope, making the FIT subsidy more than just a financial cash cow. It would actually do what it's there for - encouraging energy conservation, instead of people having the same or greater energy use, just with a different supplier (i.e. their roof).

It should not be an either/or question - we need more low-carbon energy (not just solar!) AND better energy efficiency. This is a false dichotomy, which appears to be your stock in trade!

However, I don't think linking PV with EPC ratings was logical as PV can be a cost-effective way of improving the carbon emissions of hard-to-treat homes. Besides, a kWh of electricity is a kWh whether it comes from PV mounted on a well insulated house, a poorly insulated house, a shed, a ground framework etc.

Take my house type for example, a 1940s steel-framed semi, and my gas consumption of about 9000 kWh/year. I could spend £8-10 000 on external wall insulation and very optimistically cut my gas usage in half and save 833 kg CO2. Or I could spend £4-6000 on PV yielding about 4000 kWh/year, which given the DEFRA figure of 0.527 kg / kWh for grid electricity saves 2108 kg CO2.

(In reality I've gone for DIY insulation as part of the renovation, but I don't imagine that's a mass solution)

MFW_ASAP

ed110220 wrote: »

It should not be an either/or question - we need more low-carbon energy (not just solar!) AND better energy efficiency. This is a false dichotomy, which appears to be your stock in trade!

However, I don't think linking PV with EPC ratings was logical as PV can be a cost-effective way of improving the carbon emissions of hard-to-treat homes. Besides, a kWh of electricity is a kWh whether it comes from PV mounted on a well insulated house, a poorly insulated house, a shed, a ground framework etc.

Take my house type for example, a 1940s steel-framed semi, and my gas consumption of about 9000 kWh/year. I could spend £8-10 000 on external wall insulation and very optimistically cut my gas usage in half and save 833 kg CO2. Or I could spend £4-6000 on PV yielding about 4000 kWh/year, which given the DEFRA figure of 0.527 kg / kWh for grid electricity saves 2108 kg CO2.

(In reality I've gone for DIY insulation as part of the renovation, but I don't imagine that's a mass solution)

Thanks for making my point so succinctly. You benefit from solar by having more energy to waste.

Out of interest, if you hadn't had your solar installation subsidised by myself and other bill payers, would you have installed it?

I suspect your CO2 calculations would come second place to calculations around your personal finances. The payback from fitting external insulation would be far quicker and you'd instantly benefit from a warmer, more comfortable home. The payback from solar would take a lifetime without subsidies.

Interestingly, you'd make these improvements to your home (indeed you seem to already have) without expecting a handout from other people. I suspect you feel that as you're reaping the benefits, you should pay for it. Quite so, welcome to my world. I just don't understand why you can't extrapolate this logic to your solar panels....

ed110220

MFW_ASAP wrote: »

Thanks for making my point so succinctly. You benefit from solar by having more energy to waste.

Out of interest, if you hadn't had your solar installation subsidised by myself and other bill payers, would you have installed it?

I suspect your CO2 calculations would come second place to calculations around your personal finances. The payback from fitting external insulation would be far quicker and you'd instantly benefit from a warmer, more comfortable home. The payback from solar would take a lifetime without subsidies.

Interestingly, you'd make these improvements to your home (indeed you seem to already have) without expecting a handout from other people. I suspect you feel that as you're reaping the benefits, you should pay for it. Quite so, welcome to my world. I just don't understand why you can't extrapolate this logic to your solar panels....

So £8-10 000 giving a carbon saving of 833 kg/year is better than £4-6000 saving 2108 kg CO2?! Please explain how spending about twice as much to save less than half of the CO2 is the better option! I make the EWI £9.6-12 per kg CO2 saved per year and the PV £1.89 - £2.85. If you really think the former is better than the latter, your maths or logic need some serious work!

You would do better to focus on the facts rather than my motivations. As it turns out I don't have PV as my roof needs its asbestos covering replaced first. If you're really interested in what energy efficiency measures I've done you can see this page about how I opened my home as part of a local open day to promote greener homes: Bath Green Homes

MFW_ASAP

ed110220 wrote: »

If you're really interested in what energy efficiency measures I've done you can see this page about how I opened my home as part of a local open day to promote greener homes: Bath Green Homes

Interesting. With solid walls, why did you go for a non-breathable product? Did you do calculations to work out your dew point to help prevent interstitial condensation problems? Actually, perhaps you have left an air gap behind the insulation, combined with thru-wall air vents to provide ventilation to prevent damp?

ed110220

Solid walls wasn't actually my wording and isn't really accurate but it seems often any wall that is not suitable for cavity wall insulation is termed "solid wall".

The house is steel framed with a dry lining on on the inside and outer skin of concrete render on an expanded steel mesh lath downstairs and corrugated steel upstairs. The steel frame is in a ventilated cavity between the two. The original insulation was fibreglass in a brown paper casing nailed to the back of the dry lining.

I have removed the original dry lining and insulation, replaced it with Celotex type insulation and rebuilt the dry lining (this had other benefits too as the original was quite flimsy and only lined in 9mm unskimmed plasterboard downstairs and hardboard upstairs).

I went for that type of insulation as there is only a limited amount of space in the wall to fill but still leave a gap behind for ventilation, without making the walls thicker than they were before (creating problems with window reveals etc).

I used some calculators but found that whatever the wall build up is (including the one that was there for ~ 65 years!), they warn of a risk of interstitial condensation if the outermost layer is steel, which makes sense as it's such a good thermal conductor. Opening it up I didn't find much evidence of corrosion, so I think maintaining ventilation there is necessary to clear any condensation that does form. Using a non-breathable insulation should cut down on the amount of moisture that can get in there from inside the house.

Martyn1981

Customers of Scottish Power might be able to take part in a battery storage trial.

Noted on another forum, but I can't find any proper links to it, or the company running the trial BillSave Uk. It's a two year trial, and you get to keep the battery afterwards.

If you're interested, and an energy and FiT customer of Scottish Power, then it might be worth you contacting them to see if you are eligible.

Any feedback would be great, as I simply can't find anything more on this. Hope it's not a wild goose chase.

Mart.