Solax Battery and 3 phase Inverter.

[Coops85]

Hi all, 

 

So as our planning conditions stipulate that our house has to be 'carbon neutral' we have planning for a fairly hefty amount of PV panels (11.7kW)! Not exactly what we want really but cant really escape it according to our as designed SAP calculation and architects advice.

So I have had Wagner Renewables design and quote us for this with battery storage added on.  They have suggested a Solax battery and a 3 phase compatible inverter to go with it. 

Does anyone have any comments on Solax batteries or inverters for that matter? Or do you suggest we try a different battery? 

What should I be looking for the battery to be able to do other than store energy for non-daylight hours?  Exporting power to grid?  Taking E7 electricity from grid?

 

Wagner and some companies we talked to at the H&R show are confident that there will be other export tariffs being introduced soon which will help us to recoup some of this cost.  They do say that the system has to be MCS installed to be able to reap any benefit from this though.  Do you reckon this is just salesperson talk?!?

 

Thanks in advance of any replies.

 

 

[richi]

9 minutes ago, Coops85 said:

Wagner and some companies we talked to at the H&R show are confident that there will be other export tariffs being introduced soon which will help us to recoup some of this cost.  They do say that the system has to be MCS installed to be able to reap any benefit from this though.

coughbullshitcough. Alternatively, “They would say that, wouldn’t they?”

[ProDave]

15 minutes ago, Coops85 said:

They do say that the system has to be MCS installed to be able to reap any benefit from this though.  Do you reckon this is just salesperson talk?!?

 

Thanks in advance of any replies.

 

 

I fear that may be the case.  Protecting the "schemes"

 

Unfortunately MCS seems to come with a big premium price attached.  I have just installed my own 4KW PV for £1500. Granted it was hard to get the kit that cheap but there are lots of people selling a 4KW kit for about £2000.  So why does an MCS install come in at 4K or more?  There is NOT £2K of install costs.

 

If you can, with batteries, self use most of it, the export payment may end up not worth it.  It is likely to only be about 5p per unit exported  which considering I have only exported 6.5 units so far means I would not bother even if it were available to me.

 

I am surprised you need as much as llKW to be energy neutral? do you need to address the insulation levels again:?  Others have managed energy positive houses with about 6Kw of PV.

[Jeremy Harris]

Sounds a bit awry to me, too.  We have 6.25 kWp of PV and our house is "carbon negative", even though it's all-electric, as we generate more electricity per year than we consume, and we don't have battery storage (yet).

[PeterW]

12 minutes ago, richi said:

coughbullshitcough. Alternatively, “They would say that, wouldn’t they?”

 

unfortunately most of these rebate or subsidy tariffs come with those sorts of ties. 

 

23 minutes ago, Coops85 said:

So as our planning conditions stipulate that our house has to be 'carbon neutral' 

 

@JSHarris managed that without a huge amount of solar and it was with good air tightness and uValues. Before you go down the renewables route, get the fabric values down and see what you need to achieve. 

[Coops85]

Thanks for all your comments. 

 

We are having an MBC 0.14 build with their insulated Slab.  I would have thought that would have been good enough.  I will re visit the SAP and challenge it again before committing to any PV supplier. 

 

Any thoughts on the battery and inverter? 

 

 

[Jeremy Harris]

I doubt that you'll find a battery system cost effective, TBH.  I'm fitting one, but I'd be the first to admit that the cost benefit is at best a bit marginal, but for us, the benefit of having a backup power supply during power cuts makes it worth fitting.

 

I'd get someone to look over your SAP calcs and check to see how much you need in terms of renewables to get to A100.  We're A107 with just 6.25 kWp, in an MBC house that's all electric, so getting to zero carbon (effectively A100) shouldn't be that difficult.

[Gone West]

17 hours ago, Coops85 said:

So as our planning conditions stipulate that our house has to be 'carbon neutral' we have planning for a fairly hefty amount of PV panels (11.7kW)! Not exactly what we want really but cant really escape it according to our as designed SAP calculation and architects advice.

We are A95 without any renewables so to reach A100 wouldn't need much in the way of PVs. Get your SAP calculations checked and if you really need 11.7kW of PVs then the fabric of the building/air tightness needs improving.

[jack]

Take a look at shower water waste heat recovery units. I believe they provide a good number of SAP points for the cost.

 

Also, I'm sure you know this, but you don't need battery storage to be carbon neutral across the year. You'll make way more than you can use in the summer months, and give back to the grid in winter. You just need to be a net contributor over the course of the year.

 

I'm sure the last thing you need budget-wise at this point in time is to be spending a pile of cash on a battery system.

 

You should, however, think about where you'd put batteries in the future, and include cabling or at least ducts for if and when you install them.

 

One other thing: if there is a new government scheme (and I think it's unlikely with this government), how can anyone be sure that existing owners will be asked to join it? It may well be limited to installations completed after any such scheme comes in.

 

[Coops85]

Trying to get my head around SAP calculations etc...

What is the difference between Carbon Neutral and Carbon Zero?  My Sap is currently giving a target Calculation as 114 A.  According to my architect the planning stipulation is carbon Zero. He seems to think that 100 A would be carbon neutral and what would have been an old code 5 house.  So carbon Zero is an old code 6... Is this correct?

 

I think tonights reading will be the local land setlement agreement where all the conditions of the house stem from!

 

 

 

 

[Jeremy Harris]

Carbon neutral = zero carbon, and may be an EPC of A100, but it's really making sure that the emissions part, the Environmental Impact Rating (EIR), gives a zero value for CO₂ emissions.  Taking our build as an example, we ended up with an EPC of A107, and and EIR of A107, with CO₂ emissions of -0.9 tonnes per year, so we're carbon negative, in effect.

[ADLIan]

I doubt the planning officers who come up with these conditions are aware of SAP, it’s outputs and SAP ratings. From past experience they only look as far as Appr Doc L1A and the CO2 emission rate (DER) - get this to zero or less and box ticked. Would be interesting to see the exact wording of the condition.

[scottishjohn]

Is this a common requirement with a new house  now ?

that far exceeds even scottish build regs  does it not?

 

Edited April 10, 2019 by scottishjohn

[ADLIan]

South of the border I come across similar planning conditions quite often - not many 'zero carbon' but lots of 10% (inset other values to suit!) better than TER under the Building Regs. Normally applied to developments above a certain size - 5 houses, 10 houses or total floor area on site. As ever major house builders/developers appeal this as it will make the scheme 'uneconomic' or otherwise not feasible and as if by magic the condition disappears.

[scottishjohn]

4 hours ago, ADLIan said:

South of the border I come across similar planning conditions quite often - not many 'zero carbon' but lots of 10% (inset other values to suit!) better than TER under the Building Regs. Normally applied to developments above a certain size - 5 houses, 10 houses or total floor area on site. As ever major house builders/developers appeal this as it will make the scheme 'uneconomic' or otherwise not feasible and as if by magic the condition disappears.

the old brown envelope always works  LOL.

 

[Coops85]

Thank you for your responses.  The planning legislation and frameworks that we are meant to comply to use to be demanding code 6 houses.  Then obviously the sustainable houses codes were abolished so the frameworks had to be modified to try and make a planning stipulation of a very high sustainable home where it suggests we need to offset both regulated and unregulated energy usage... which in essence is an old code 6.  However as there are no such terminologies or standards no in place for wide spread assessment of home sustainability it is going to be difficult for them to enforce anything.  In the framework it talks about carbon zero and carbon neutral.  Our own set planning conditions relating to 3 phase power and water usage both use the word carbon neutrality: -  

 

4. No development above slab level shall take place until the applicant has provided evidence of a formal application for, and written confirmation of,agreement to provide a new 3 phase electrical power supply onto the site, which shall be obtained from the local Distribution Network Operator (DNO). The 3 phase power supply to the site shall thereafter be maintained in perpetuity. (Reason: The provision of a 3-phase power supply is essential infrastructure to enable delivery of a photovoltaic renewable energy supply to the site, in order to achieve carbon neutrality of the dwellings hereby approved, as required by Policy H/5 of the adopted Local Plan 2018 and the Fen Drayton Former Land Settlement Association Estate SPD 2011).

5. No development above slab level shall take place until the applicant has provided evidence of measures to ensure the water calculations demonstrate a maximum of 80 litres per person per day to ensure the proposed dwellings achieve carbon neutrality. Development shall be carried out in accordance with the approved details. Development shall be carried out in accordance with the approved details and retained thereafter.
(Reason - The provision of water useage of a maxiumum of 80 litres per day is a requirement in order to achieve carbon neutrality of the dwellings hereby approved, as required by Policy SP/11 of the Local Development Framework, 2007 and the Fen Drayton Former Land Settlement Association Estate SPD 2011).

 

 

[ADLIan]

Lots of references to Code for Sustainable Homes and Zero Carbon Homes in the Fen Drayton doc. As these are both dead in the water I doubt these conditions are now enforceable. I believe JSH had a similar issue and had the condition removed.

[Jeremy Harris]

39 minutes ago, ADLIan said:

Lots of references to Code for Sustainable Homes and Zero Carbon Homes in the Fen Drayton doc. As these are both dead in the water I doubt these conditions are now enforceable. I believe JSH had a similar issue and had the condition removed.

 

Yes, I did, although we were only required to meet CfSH Level 5. As CfSh was scrapped between the time I put in our planning application and the time we started the build, I requested that the condition be removed, as there was now no underpinning legislation.  This turned out to be a formality, although the CfSH requirement remained a local planning policy for years afterwards, as the LA were really slow in getting it changed.

 

With regard to the condition requiring a 3 phase supply, I'd suggest that isn't technically sound at all.  A low energy home won't consume much power, and hence won't need a lot of renewable microgeneration in order to be zero carbon.  There's an underpinning requirement that all local policies have to be realistic, and that one is clearly pretty misguided and not supported by an adequate level of evidence.  I'm pretty sure it could be challenged pretty easily, as all it would take is to take the data from the SAP worksheet and use it to show that the "zero carbon" requirement can be met easily whilst staying well within the limit for a standard single phase domestic supply.  I manage to remain well within the single phase supply limit in a house that is all-electric, has a heat pump, 6.25 kWp of PV and two electric car charge points.

[Coops85]

54 minutes ago, JSHarris said:

With regard to the condition requiring a 3 phase supply, I'd suggest that isn't technically sound at all.  A low energy home won't consume much power, and hence won't need a lot of renewable microgeneration in order to be zero carbon.  There's an underpinning requirement that all local policies have to be realistic, and that one is clearly pretty misguided and not supported by an adequate level of evidence.  I'm pretty sure it could be challenged pretty easily, as all it would take is to take the data from the SAP worksheet and use it to show that the "zero carbon" requirement can be met easily whilst staying well within the limit for a standard single phase domestic supply.  I manage to remain well within the single phase supply limit in a house that is all-electric, has a heat pump, 6.25 kWp of PV and two electric car charge points.

 

How long does it usually take for a challenge to be accepted or declined by planning?  

 

So we will be an all-electric house too about 300Sqm, heat pump, MVHR, intend to put in an electric car point for future use and we put 8kw of PV on roof .  Would that all be within a single phase supply bearing in mind we have got 2 adults and 4 children using the house! Also treatment centre and rainwater harvest pump to use energy too! 

 

 

[Jeremy Harris]

13 hours ago, Coops85 said:

 

How long does it usually take for a challenge to be accepted or declined by planning?  

 

So we will be an all-electric house too about 300Sqm, heat pump, MVHR, intend to put in an electric car point for future use and we put 8kw of PV on roof .  Would that all be within a single phase supply bearing in mind we have got 2 adults and 4 children using the house! Also treatment centre and rainwater harvest pump to use energy too! 

 

 

 

Our planning officer accepted that the CfSH condition wasn't valid straight away, by an exchange of email, but you may need to mount a more vigorous challenge, given that your 3 phase condition seems to be worded more emphatically.  I'm not sure of the appeal procedure for unreasonable planning conditions, but would guess that @Temp may be able to help, as he knows far more about the detail of these things.

 

Your house is about twice the size of ours, but energy use doesn't scale linearly with house size.  Smaller houses tend to need more heating per m² of floor area than larger houses (the elephant versus mouse analogy), and hot water use scales with the number and age of occupants.  Cooking requirements tend to not vary very much with the number of occupants (running the cooker for an hour to cook a meal for two is much the same as running a cooker for an hour to cook a meal for six).  The PV requirement is export power related, not import power related, so unless the PV system is pretty big then the dominant factor will be the supply capability, and a "standard" 100 A single phase supply (which is what we have) can (in theory) deliver about 23 kVA (near enough kW for most intents and purposes).

 

We have a heat pump that's around 3 times larger than we need (it was available at the right price), so would probably meet your heating requirement OK, but a larger one would be needed to meet your hot water needs. 

 

At a very rough guess you might need a 12 kW heat pump, which would require around 4 kW from the supply, worst case (much of the time it would probably be using around 1.5 kW or so).  The treatment plant is trivial, around 50 W or so, so down in the noise.  The same goes for the pump for the rainwater harvesting (please check if rainwater harvesting makes sense - often it doesn't, and may be more trouble than it's worth, for toilet flushing, which is all you can really safely use it for).

 

The cooker and other house loads might need around another 4 kW to 5 kW or so, so heating, hot water and the normal house loads might add up to around 9 kW.

 

That leaves around 14 kW or so of "spare" capacity from a single phase supply.  That's enough to run two 7 kW car charge points.  7 kW is the maximum size standard domestic charge point, and all that's needed really, as a 7 kW charge point will charge my BMW i3 up from completely discharged to full in about 4.5 hours, and we have E7, so have 7 hours of overnight cheap rate charge time available.

 

The PV limit will be determined by whatever your DNO will allow as a maximum export.  I applied for an "unlimited" G59 (now G99) consent and was told that anything up to 10 kWp was acceptable, although in the end we could only fit 6.25 kWp on the available roof area.

 

I'd estimate that the house, plus a single electric car charge point, wouldn't even need the full capacity of a normal domestic single phase supply, and most probably the PV system wouldn't either (although this depends very much on the nature of your local distribution network).

 

 

[ProDave]

Really the only need for 3 phase is if the DNO refuse your request for 8KW of PV (or any upgrade costs they want to palm off onto you are more than the cost of a 3 phase supply)

[Temp]

As I recall you have 6 months from grant of permission to appeal against a planning condition. An alternative is to make a section 73 application to have a condition removed. The latter might be quicker. If you move fast you might have time to do both. 

 

Failing that you can make a whole new application that states you will only have a single phase supply (and makes the case for it).

[Coops85]

There are about 20 or more plots or new builds under the same scheme as us with exactly the same conditions so between us we will have a fairly hefty amount of PV panels between us... I reckon the DNO are protecting their supply/line with demanding that we all have 3 phase. Is this a plausible reason? 

 

Many of the houses already built with have benefited from getting up and running before fit ends.... so they will be exporting a huge amount of their generation. 

 

[Jeremy Harris]

8 minutes ago, Coops85 said:

There are about 20 or more plots or new builds under the same scheme as us with exactly the same conditions so between us we will have a fairly hefty amount of PV panels between us... I reckon the DNO are protecting their supply/line with demanding that we all have 3 phase. Is this a plausible reason? 

 

Many of the houses already built with have benefited from getting up and running before fit ends.... so they will be exporting a huge amount of their generation. 

 

 

That's not a valid reason from the DNO, as they are required to offer a connection if required, and they cannot dictate that a 3 phase supply has to be accepted.  They can charge for reasonable costs associated with reinforcing their distribution network, but those costs have to be shown to be due to the specific connection request, and have to be shared if there are several requests from the same area.

[ProDave]

I must admit I found SSE to become "hostile"  When I registered my G83/2 install  they initially thought it was 4KW not 3.68, and told me I had to apply for permission to connect it and sent the application form.  The tone of the wording seemed designed to put you off as there was talk of a charge to provide a quote and that charge would still be payable if you did not proceed with the quote.  I found it very intimidating.