Gatsojon
Member
Yes you do. It’s a no brainier for me as I have no FIT contract in place. During the summer months it works very nicely but might need switching as the days shorten.
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I do not think the Tesla plan works for us.
We are a high electricity usage household, averaging around 14,000kWh per year of import (very little of which is as a result of needing to charge the Tesla M3). I don't yet have the Powerwall but even if I move to a time of use tariff, I think the higher peak rate charges would more than offset any benefit I can get from charging the Powerwall during the low night rate and depleting it during the high rate period. Doing a very unscientific calculation, I think a single Powerwall will not supply our house for enough hours to avoid the need to still import a substantial amount outside the low rate overnight period. A rate of 8p per kWh, at all times, with no daily standing charge seems attractive to me. I would be happy to be shown where my granted very superficial understanding is flawed. I am still waiting for DNO approval and then the actual Powerwall installation, so I am weighing all options at the moment. Thank you for any advice you can provide.I cannot see how this works for anyone with a PW and an EV to charge. Our grid export is virtually 0 even with the sun we had in May. If the PW is full, the car is been charged, if both are full than the water is been heated so reducing gas use.
You have to have a massive solar PV array to make the number work. Especially if you are a current 50% assumed export FIT.
I would be happy to be shown where my granted very superficial understanding is flawed.
A rate of 8p per kWh, at all times, with no daily standing charge seems attractive to me.
How are you managing that? Going off grid? If so, stop right there, thats a completely different conversation.
Octopus Tesla Tariff Page said:No standing charges. No exit fees.
Just renewable energy at the UK's best prices.
Yes we are in the same boat, we can charge the PW @ night in the winter and it does not last the day, then we move onto the 15p + standing daily charge, trying to fit both cars and a PW into a 4 hrs off-peak charge is tight we pull ~80+ amps if the hot tub kicks in we are very near to the 100Amp fuseWe are a high electricity usage household, averaging around 14,000kWh per year of import (very little of which is as a result of needing to charge the Tesla M3). I don't yet have the Powerwall but even if I move to a time of use tariff, I think the higher peak rate charges would more than offset any benefit I can get from charging the Powerwall during the low night rate and depleting it during the high rate period. Doing a very unscientific calculation, I think a single Powerwall will not supply our house for enough hours to avoid the need to still import a substantial amount outside the low rate overnight period. A rate of 8p per kWh, at all times, with no daily standing charge seems attractive to me. I would be happy to be shown where my granted very superficial understanding is flawed. I am still waiting for DNO approval and then the actual Powerwall installation, so I am weighing all options at the moment. Thank you for any advice you can provide.
Your Powerwall will have a life limited by number of charge cycles, or more simplistically, a limited total amount of energy it can store and discharge over its usable lifespan.
Last time that I looked, a Powerwall warranty was 37.8MWh when time shifting. Lets be generous and said that you got 70MWh over its lifespan. Back of a fag packet numbers, but lets say off peak you averaged charged 5p/kWh and that replaced electricity at 14p/kWh, a saving of 9p/kWh - call it 8p/kWh with losses. So the max saving of the Powerwall over its usable life will be 70000 * 8p = £5600. And thats probably being over generous. How much is your Powerwall costing?
You could achieve many benefits at a fraction of the cost with a smaller battery setup. DNO approval would be simpler if you had aggregate PV and storage < 7.2kW with max 3.6kW export - fasttrack G99. But there are compromises - you would be limited on peak power draw, but you are on powerwall anyway so 3 or 5kW is neither here nor there.
Seriously, the best way of saving on battery storage is to not buy and wait for prices to drop. I've already saved > £2k by putting my decision off 6 years and letting prices drop (oddly not with powerwall, they keep rising it seems). I've just jumped on board at around £3k. I might, with a following wind, break even.
How are you managing that? Going off grid? If so, stop right there, thats a completely different conversation.
I am not sure Agile is a 'No brainer',You guys all need to move to Agile. It is a no brainer. The only hours you have to cover with the PW are 16.00 - 19.00. Obviously you can still cover much of the night as well depending on your use. If you dont mind importing from thre grid you can use the cheap rates for 21 hours and export during the 16.00 - 19.00 time slot at increased rates using the Agile Outgoing tariff. The 8p Tesla rate is US really as they make money off you using a Agile type system and you totally lose control as they operate your app!
@VanillaAir_UK you are evidently knowledgeable about this stuff, but I find it difficult to understand your posts because I’m unfamiliar with some of the things you refer to.
I’m new to EVs and certainly no eco-warrior, but the shift has made me contemplate domestic renewables. My investigations suggest that they aren’t financially viable at this time. True?
What should I read to understand?
You get £1 per kWh?!I think I have done the math correctly, we receive ~£500 per year for generation on one array, we exported ~500kWh @ 8p we would receive ~£40; we charge the cars on the go tariff @ 5p. I do not think the Tesla plan works for us.
You get £1 per kWh?!
Thanks for the very detailed explanation!They would have got paid FiT on the generation plus export deemed to be 50% of generation.
So @Neil_dsb got their FiT payment based upon 5119kWh and export based upon 2559kWh export.
So say one got paid 15p FiT and 5p deemed export, that would equate to ~ £767 + £127 = ~ £894
However by giving up deemed export and going actual export @ 8p, the £127 drops to £46 because actual export was 580kWh.
So one would have to make up the lost £81 on savings through import (of 9526kWh) and standing charge reductions - to make it back, a 1p/kWh reduction would more than offset it on those figures, but it may need significantly more of a saving for someone with lesser import.
You guys all need to move to Agile. It is a no brainer.
I’m confused by this. Can you no longer have E7 with a smart meter?The final point is about if I want a smart meter installed, am still undecided, I like E7, its predictable, easy to plan around, and if I get a smart meter I loss the choice of been on E7. We all known how electricity companies can change their tariffs with little warning, what if I switch to Agile and Octopus whacks up prices?? I'll than be stuck not been able to move back to E7 and having to pay what ever the going rate is.