A Year with V2H

michaels

Not sure if folks on here will find this interesting but hopefully this tech will be coming to general availability rather than just trials sooner rather than later so here is a post I put on the V2X facebook group

Just completed 12 full months of V2H (started with V2H and TOU tariff mid September 22). First month we had 2 x leaf 24 (SOH 82-84%), thereafter we had 1 x leaf 24 (82%) and 1 x leaf 40 (90%). 24 used for 95% of journeys and 75% of miles

Tariff until Sep 23 was 5 hours at 4.5p per unit and the rest at 45p per unit. Thereafter 8p per unit / 36p per unit

Usage Data as follows:

Total consumption 17.1k kwh up from 11.4k kwh previous 12 m - why?

1) Using off peak electricity at 4.5p per kwh for night time heating and hot water (gas usage down from 26.6k kwh to 16.3k kwh)

2) Extra usage during turn down and save in day adjustment periods

3) Losses in V2H round trip

Monthly night rate consumption and average unit cost (note this is % of import, the analysis excludes own use of PV generation):

Nov 22 90% 8.4p

Dec 22 94% 6.9p

Jan 23 86% 10.2p*

Feb 23 86% 10.4p*

Mar 23 85% 10.7p*

Apr 23 90% 8.7p

May 23 95% 6.5p

Jun 23 93% 7.1p

Jul 23 95% 6.7p

Aug 23 92% 7.6p

Sep 23 93% 7.4p

Oct 23 92% 10.2p

*Extra day use during in day adjustment turn down and save events

Estimated 80% of day usage comes from residual grid draw (approx. 100w when no load plus bigger draw if usage goes over 5kw or v2h unit is slow to match changing load - on off induction hob is a big culprit). Remainder is from insufficient (car) battery storage.

michaels

New for winter 23

1) Gas tariff reduced from 10.3p per kwh to 7.6p per kwh and electricity off peak up from 4.5p per unit to 8p making it less clear whether to use electric hot water and space heating during off peak period

2) Second hand ASHP (if I can get it to work reliably) added to central heating circuit to be used during off peak electricity period and in peak subject to max battery storage. Gas boiler remains for other heating / hot water heating during the day.

Likely for future:

Switch to Leaf 62 to increase storage for ASHP (may well ditch gas altogether) and 7 hour off peak tariff (E7 or BG/EON) to increase max import (with Leaf 40 and 5 hours, max import is about 23kwh at rate starting at 4.5kw climbing to 5kw - not sure why this is not 6+ kw that the unit can support?)

Screwdriva

Very useful data - thanks for sharing!

michaels

Don't know if it exists but if anyone had a link to half hourly dataset of grid carbon intensity I could work out how the time shifting reduces the average carbon intensity of the electricity used.

70sbudgie

I don't know if this has the HH dataset that you're after, but it talks about an API?

https://www.carbonintensity.org.uk/

michaels

70sbudgie said:

I don't know if this has the HH dataset that you're after, but it talks about an API?

https://www.carbonintensity.org.uk/

Thanks - that has the data I need but annoyingly although it says you can download 30 days at a time it only seems to let me download 7 at a time.....