DECC launch FIT review

[Gavin A]

well, I'm glad they've at least got the costs higher than we can achieve, and excluded the RPI uplift from their calcs or it'd have been even worse.

but 15.03p per kWh for offset savings is higher than I've come across from any customer, presumably this would be from bills that include the standing charge in the per kWh cost, but that's a small minority of bills. So I think they could be challenged on that assumption.

Also 47% offset seems very high to be an average, I'll see if I can dig out an average from the elios 4 you portal system we have - Andy (sibert) how many systems data have you got access to / could get access to do you think?

 

[TedM]

15.03p is worked out backwards from the £4210 savings. The predictions in the IA for future electricity prices are higher still.


sourced from: https://www.gov.uk/government/uploa...ECC-HMT_Supplementary_Appraisal_Guidance.xlsx
from Table 4.8 Central figures adjusted to a 2016 base.

The 47% is the balance of the figure of 53% claimed as actual export achieved from figures in the Parsons Brinckerhoff report from the survey they conducted. But DECC say:

7.8. There is uncertainty about the share of electricity that <10kW PV installations export. PB’s research gave an export fraction of 53% for all building mounted PV installations. However, it may be that domestic PV installations export more than 53%, given the electricity is generated in the day which is not when the majority of electricity is consumed. We are seeking further evidence on this through the consultation.

 

[TedM]

The PB report says:

2.2.3.1 A central case was estimated for export fractions across all capacity bands using the
average value of the data received and we have applied an export fraction that is
higher than the value in the previous assumptions at 53%, in comparison to the 50%
given in the 2012 report. This assumption was largely based on data from domestic
systems which had export fractions ranging from 33 – 80%.

The PB data comes from a survey response of 11 (yes, eleven) homeowners in the 0-10kW range.



The RECC data just relates to capex costs.

 

[Gavin A]

I'd really like to know how Parsons Brinkerhoff manage to keep winning the contracts to carry out those consultations - they've been consistently wrong on every consultation for the last 5 years.

 

[SolarCity]

The PB report says:



The PB data comes from a survey response of 11 (yes, eleven) homeowners in the 0-10kW range.

View attachment 29985

The RECC data just relates to capex costs.

Kudos to them for putting in so much effort.

 

[SibertSolar]

Gavin - I have visibility on about 30 or so E4U systems on my own profile, some of them on >10kWp installs though. As a rough guide, I've had a flick through all the applicable installations that I can, and averaged out the self-consumption data. It is a small sample but the average is approx 46%. Lowest is 15% and highest is 90%, it really does vary quite wildly depending on the nature of the install/premises.

 

[TedM]

Part of the nonsense in this is that the (sparse) data has been gathered from 0-10kWp systems and is then being applied to a 3kWp exemplar system to decide the tariff for the entire band.

It should be quite obvious that the export element in a domestic situation is going to be vastly different between 3kWp and 10kWp as well as other variances caused by the owner's circumstances.

But this variable has a huge effect on the calculation of the resulting tariff and consequential payback period. At 3kWp if self-consumption is halved then the tariff has to be trebled in order to obtain the same return. (DECC's stance on this is - well the only systems we want to encourage are these high self-consumption ones.)

The more solid evidence for export/self-consumption values that can be gathered and submitted in response to the consultation the better - at least where that export figure is above 53%. I guess very few people have this data though.

Also is there any evidence that can be put forward to show that the vast majority of domestic systems are no larger than 4kWp and that, therefore, anything in the 4-10kWp band should not be considered domestic and lumped in to the same band?

 

[SibertSolar]

Ted - all <16A/phase installations should be notified under G83, post installation, shouldn't they? Wouldn't Ofgem have this info, in terms of the number of registered installations installed under G83?

 

[SibertSolar]

Btw, I have tasked 4-Noks with assessing and advising the average self-consumption data for all Elios4You units installed in the UK on sub-10kWp installations. It may take some time to obtain the data but I will advise once I have it. This will only be a sample of installations, and only those where the Elios is reporting data to the portal, but it will be a larger sample than DECC have used!

 

[TedM]

Ted - all <16A/phase installations should be notified under G83, post installation, shouldn't they? Wouldn't Ofgem have this info, in terms of the number of registered installations installed under G83?

The G83 info sits with all the individual DNOs. I don't think it ever gets passed on to OFGEM.

All the stats for number of installs registered for FiTs is published by OFGEM in any case, so we know TIC and DNC for all those - but that doesn't help with export/self-consumption.

 

[Gavin A]

Hi Andy,

nice work, but a request - could that be split down more at all into different system size categories, also 3 phase and single phase?

I suspect there will be some bigger installs on high energy using houses that might swing the sample. Ideally we could do with data for each 0-2kWp, 2-4kWp, 4-6kWp, 6-8kWp, 8-10kWp so that we can assess not just the average but also the variability between the system sizes within that band.

er also, is there any way of them knowing which systems have a power reducer included?

I was just checking our systems and wondering why the self consumption seemed so high, and I just clicked that a lot would be the houses with power reducers.

I could set up a shared google docs spreadsheet to collate the data from different sources, though we'd need to be careful not to have doubled up with multiple inputs from the elios portal etc.

 

[SibertSolar]

I've asked them to focus only on the 1phase E4U Gavin, so that will be 0-10kWp installs. No way to tell from the portal end whether a site has a PR or not, unfortunately. No easy way to break down into groups of different size installs either as the size of the array is a metric that is programmed into the individual E4U, it's not translated to the portal I don't think. If I know 4-Noks, they will take some time to get this data back to me, but I have tried to pull a couple of favours and get some short-cuts taken where possible, will update in a day or two hopefully.

 

[Gavin A]

there could be another way around that Andy. Do 4 noks have records of how many non-standalone power reducers they've sold vs how many elios4you units?

 

[SibertSolar]

No....the PRs are standalone by default, switched into E4U mode via the internal software (boost button/power off_on cycle)

 

[Gavin A]

oh, I thought they did a version that came without the CT clamp?