SAP and EST - Assumptions

[finchy]

Hi,

Suprisingly we have customers calling wanting installations next year....however after looking on the EST the assumptions for exported and savings is 75%/25%. I was under the impression that 50/50 was agreed to use in SAP and EST plus our big six assume 50% exported (arbitary to install export meters). Has this changed ? obviously in my costing model only saving 25% reduces the returns.

I would like to say 100% savings plus 50% export due to not having a export meter, using 3.1p and 14.4p. Its close to the line but if a customer is home all day and the total generation is less than usage then this scenario will occur....

Whats the REAL and MCS guidance on this and has 50% export changed to 75%...?

Many thanks

 

[TedM]

Where on the EST site did you see that? Can you post a link please?

There is talk in DECCs consultation of changing the 50% value for deeming, but nothing else announced AFAIK.

 

[JulianC]

50% deeming applicable to export payments. Separately, EST began recommending using a figure of 25% of total generation for the amount of PV-derived electricity being used in the average household. They believed this was a more realistic figure to use in payback/income calculations.

 

[finchy]

TedM - if you click on assumptions pdf once you have used the EST calculator.

[TD="width: 50%"] Feed-in Tariff - generation rate
[/TD]
[TD="width: 50%"] 43.3 p/kWh until 11 Dec 2011 and 21.0p/kWh after 12 Dec 2011
[/TD]

[TD="width: 50%"] Feed-in Tariff - export rate
[/TD]
[TD="width: 50%"] 3.1 p/kWh until March 2012
[/TD]

[TD="width: 50%"] Electricty price (based on domestic use in 2011)
[/TD]
[TD="width: 50%"] 14.4p
[/TD]

[TD="colspan: 2"] Electricity home use fraction
25% (i.e. 75% of solar electricity is exported to the grid)

[/TD]

 

[finchy]

another point is being MCS we cant give any more emphasis to any other models other than SAP 2009 !! I have just done a sap calc and an equal EST the SAP figures give a higher return than EST. Because EST use 25% !!

 

[xanderfh]

Surely yopu should asses each custmomer as appropriate, if the customer is at home all day then they would potentially be using 100% of the generated electricity. If they want us to start doing epc's we are asses the house's energy rating we should also be looking at the consumers energy usage (time of day, etc)

 

[finchy]

And assume 50% exported tooo ?

 

[xanderfh]

of course, as long as the energy providers dont stipulate export meters fill your boots!!! We need all the angles at the moment to make solar as attractive as possible!!!

 

[GreggElectrical]

I really don't see how anyone can use 100% of the generation. Please explain how this is possible.

 

[xanderfh]

Example: a retired couple at home all day using appliances, etc using all power generated from their panels

 

[GreggElectrical]

So your saying they will always be drawing 4kw minimum? or at least using power equal to the generation at ALL TIMES.

 

[xanderfh]

Assumption of 4kw? A recent install of 2.5kw they had an energy monitor and they were using more or less all they generated (taking into account sap adjustments) obviously each install is different, as we carry out a full energy survey with each assessment we can ascertain their real saving

 

[GreggElectrical]

Please don't think I'm trying to be a clever git. We need to stick together more than ever.

I too have a client with a 2.0kw system installed who is getting close to using all their free electric. They are retired and watch all their meters very closely. They even boil the kettle when sun is out and put it in a thermos in case they want a brew when its cloudy. The kettle only goes on if they generate more than 1kw!!

I also know it is impossible to use 100% of the generated electric unless you have a load greater than you peak generation at all times. Customers can indeed make rather large savings, greater than most calcs. Just be careful estimating 100%.

Have you seen the inverters that link to batteries (small lithium type). They have the capability to Generate, export and charge. They only hold a small amount of power so far but if it can hold 2 Kwh of charge it would make a huge difference to customers bills. Imagine if they can go out on an average day (irradience wise) and come back and put a 13A load into use and it not cost a penny. Even if the PV is only making a few hundred watts.

This could be the next major step in small scale solar IMO.

 

[xanderfh]

Think that's a nedap inverter, incidentally i spoke NICEIC (I know they have a law of their own) the other day and they did say its possible to use 100%, but was advised to use 95% to be safe. We are also looking to Get some printing done for new tariff and asked a few questions to the Niceic and they advised not to yet as they believe more changes are coming (for the good)???

 

[GreggElectrical]

Yeah, that's the one. Spoke to couple of manufactures that say they will be releasing their version in 2012. Have ever had a price on the nedap inverter inc batteries?

Niceic are a joke. I bet the next man you speak to says somthing different. They also would run a mile if anyone ever tried to accuse you of mis-selling.

I hope some changes are coming, i would hold off your printing until.after 12/12.