The key to getting the best from it is to go all-in with your home automation so that you can ensure you're not pulling from grid at the expensive times (particularly the 4pm - 7pm stretch). To be frank, that has a far bigger effect than whether it's sunny or cloudy. The other big one is, if you have an EV, making best use of the times of negative pricing.
As you can probably guess I’ve not been persuing TOU tariffs but just following the topic with interest. Your comments above are very useful and I can see that automated controls, EV and solar, storage transforms the home energy usage. But my thoughts are that it comes at a significant cost and personal time commitment.
At the moment we have a reasonable kw rate of 19p. (That’s compared to a previous variable rate of around 26p) it’s not a high tech solution but it is hassle free and has substantially lowered our annual energy bill.
The key to getting the best from it is to go all-in with your home automation so that you can ensure you're not pulling from grid at the expensive times (particularly the 4pm - 7pm stretch). To be frank, that has a far bigger effect than whether it's sunny or cloudy. The other big one is, if you have an EV, making best use of the times of negative pricing.
As you can probably guess I’ve not been persuing TOU tariffs but just following the topic with interest. Your comments above are very useful and I can see that automated controls, EV and solar, storage transforms the home energy usage. But my thoughts are that it comes at a significant cost and personal time commitment.
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Glad you're finding the information useful; I try to keep it "warts and all" since that helps people judge within their own context. With that in mind, it's still worth unpicking further the thoughts you've mentioned.
There are certainly significant costs involved in the installation of solar PV and the investment in an EV. However, the costs I've run up to date on home automation are £34.50 for an RS485 to Ethernet converter (the way I decided to link up via Modbus with my inverter) and £26.99 for a new hard drive. Everything else has been free (Home Assistant free download installed onto a free PC (being thrown away by my company) with the new hard drive fitted).
The personal time commitment that was necessary (and I'm separating that from my periodic bits of tinkering which are purely for fun or learning) was not huge - let's call it a day or so - since the automation I achieved means the system does what I need it to without my need to get involved. That said, IT is my business so I'm well aware what I've put in place was a lot easier for me than for some. The point I was making in my last post, though, is that this level of automation is necessary to really benefit from the half-hourly pricing of Agile otherwise you need to be hunched over a PC monitoring your home's consumption all the time.
The existence of systems like Homely and Havenwise do allow for some automation to be provided to a homeowner in a far more plug and play manner, thereby sidestepping the need for the homeowner to know what they're doing. However, they currently have a blind spot with regard to solar PV, home batteries and EVs and can only optimise based on heat pump, weather and tariff. As a result, the market is currently a trade-off; either you have a plug and play system that can optimise performance but ignores some important parameters or you put in place a system that can take all parameters into account and optimise your whole home but requires a learning curve.
As a result, I'd say the personal time commitment isn't that great but the commitment to gain greater understanding is more significant.
At the moment we have a reasonable kw rate of 19p. (That’s compared to a previous variable rate of around 26p) it’s not a high tech solution but it is hassle free and has substantially lowered our annual energy bill.
That, of course, is the only end goal that really matters. All I would say is that the price per kWh imported from the grid is not as relevant as the number of those units actually imported and consumed. For me and my situation, the solution I've put in has both reduced the unit price and the number of units consumed so the net yearly bill has plummeted. From what you say, you've achieved something similar. Whether or not you see opportunities in the future to do more of the same remains to be seen, but each time your starting point will be an already improved situation.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
As a result, I'd say the personal time commitment isn't that great but the commitment to gain greater understanding is more significant.
That would be my biggest commitment -time to gain greater understanding. That has definitely been the case when we installed our Ecodan. That knowledge gained has been priceless.
For me and my situation, the solution I've put in has both reduced the unit price and the number of units consumed so the net yearly bill has plummeted. From what you say, you've achieved something similar. Whether or not you see opportunities in the future to do more of the same remains to be seen, but each time your starting point will be an already improved situation.
I’m hoping not to spend so much time learning, which came with the heat pump. As I’d rather be out windsurfing on a sunny day…😎… but I will definitely be keen to adopt a solar PV and storage some time in the near future, since we have already got planning permission for the panels.
Watching Gary Does Solar’s latest YouTube video on the future of export tariffs got me thinking about how I would adapt if Octopus were to drop the export rates. I did a bit of data downloading from Octopus poetal and some Excel modelling, and I find that moving to Agile Outgoing might not be that bad after all.
Having a decent sized west-facing array definitely helps — so far this year, we have exported 40 percent during the 4 pm to 7 pm peak period. This is without force discharging the battery in any way, just exporting the excess solar production. The only change I would make is to avoid charging the battery or running the domestic hot water on our heat pump overnight using the cheap Octopus Go rates. I would let the solar top up the battery and heat the water from morning to mid-afternoon using excess solar instead.
Like Gary says in his analysis, if Octopus were to make Agile Outgoing a bit more appealing by increasing the export rates slightly, it would work even better for my setup and I would not see any drop in export revenue.
I am interested to hear from others here — have you run any similar simulations, and what did you find?
To be honest, just being able to download our half-hourly data in a CSV format is good enough reason for me to stay with Octopus! I cannot imagine doing anything even remotely useful with the data we used to get from our previous supplier.
Watching Gary Does Solar’s latest YouTube video on the future of export tariffs got me thinking about how I would adapt if Octopus were to drop the export rates. I did a bit of data downloading from Octopus poetal and some Excel modelling, and I find that moving to Agile Outgoing might not be that bad after all.
Having a decent sized west-facing array definitely helps — so far this year, we have exported 40 percent during the 4 pm to 7 pm peak period. This is without force discharging the battery in any way, just exporting the excess solar production. The only change I would make is to avoid charging the battery or running the domestic hot water on our heat pump overnight using the cheap Octopus Go rates. I would let the solar top up the battery and heat the water from morning to mid-afternoon using excess solar instead.
Like Gary says in his analysis, if Octopus were to make Agile Outgoing a bit more appealing by increasing the export rates slightly, it would work even better for my setup and I would not see any drop in export revenue.
I am interested to hear from others here — have you run any similar simulations, and what did you find?
To be honest, just being able to download our half-hourly data in a CSV format is good enough reason for me to stay with Octopus! I cannot imagine doing anything even remotely useful with the data we used to get from our previous supplier.
@chandykris I watched that video with interest too.
For us, with a south facing array. I think such a change would be more detrimental. Unlike Agile for import, where we can move our consumption to cheaper/greener time slots, we are unable to move our generation to optimise Agile Outgoing (rotating ground mounted array, anyone?). However, we may consider adding a few panels on a west facing garage roof if evening solar becomes more lucrative.
We have just doubled our south facing array to 7.2kWp and added a Tesla PW3 battery. We've just signed up for Intelligent Octopus Flux which is a 'net metering' tariff having the same price for import and export (22.3p day, 29.8p peak). Those rates are approximately 150% and 200% of the standard 15p SEG export rates so are highly cash generative for large net exporters during summer (and need to be to help pay back the cost of the battery!) Previously we were using ToU tariffs such as Agile or Cosy to try to get our import price as low as possible and using the grid as our 'storage battery' at 15p SEG.
If payments for export reduce substantially or disappear, then self consumption becomes more relevant and battery storage even more important such that one can be self sufficient for half of the year and supplement their consumption for the other half.
Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.
I also saw this video by Gary Does Solar… and his predictions on export tariffs and the risk of them dropping, not just here but across Europe.
My attention was also drawn to the possible introduction of aggregators - possibly our energy suppliers? who may take control of the rewards offered to home owners for home energy generation. Gary’s own words describe some scepticism-
“Will those aggregators fairly distribute those rewards back to home owners who are enabling this (solar generation)”
It’s easy to anticipate that as the solar generation increases to provide a reliable capacity the rewards may become less generous. it may be I am overreacting because I’m not invested in PV solar as yet but I would welcome a clearer picture of the future benefits.
@old_scientist With a 7.2 kWp south facing array, you should be generating enough during winter months as well. I am definitely jealous as our winter generation hardly makes a dent in our usage!! I wouldn't mind adding a small south facing array to our set-up when we get an outdoor kitchen/bar installed, hopefully sometime next year. As that wouldn't require scaffolding, I could go for micro inverters and help with the winter usage. Looks like being on Intelligent Octopus Flux sounds like the best in your scenario. Highly unlikely that Octopus would drop IOF rates too much given that they control the battery, and that benefits them enormously during peak 4 to 7 pm daily.
@sunandair Another point to consider is whether those virtual aggregators would be regulated by Ofgem. From what I hear from some family and friends in Australia is that such VPPs might not always distribute the benefits back to customers, like you have pointed out.
Having tweaked my Excel models a bit, I see that I could move to Flux too. Stop charging the batteries and run the heat pump using the grid from April onwards to September. Instead let excess solar do that work, and still come off better than being on Go and Outgoing Fixed. As Octopus have already dropped Flux export rates, hopefully they don't drop it further. So, that could be another option too. All thanks to the west facing array.
@old_scientist With a 7.2 kWp south facing array, you should be generating enough during winter months as well. I am definitely jealous as our winter generation hardly makes a dent in our usage!! I wouldn't mind adding a small south facing array to our set-up when we get an outdoor kitchen/bar installed, hopefully sometime next year. As that wouldn't require scaffolding, I could go for micro inverters and help with the winter usage. Looks like being on Intelligent Octopus Flux sounds like the best in your scenario. Highly unlikely that Octopus would drop IOF rates too much given that they control the battery, and that benefits them enormously during peak 4 to 7 pm daily.
@chandykris in winter modelling predicts generation of 200-230kWh for Dec/Jan, and our usage is 700-900kWh, so maybe a quarter of our usage at best. Contrast in summer where we can generate upto 4 times our daily usage. Without decent export rates, the case for battery becomes far more compelling.
Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.
I also saw this video by Gary Does Solar… and his predictions on export tariffs and the risk of them dropping, not just here but across Europe.
My attention was also drawn to the possible introduction of aggregators - possibly our energy suppliers? who may take control of the rewards offered to home owners for home energy generation. Gary’s own words describe some scepticism-
“Will those aggregators fairly distribute those rewards back to home owners who are enabling this (solar generation)”
It’s easy to anticipate that as the solar generation increases to provide a reliable capacity the rewards may become less generous. it may be I am overreacting because I’m not invested in PV solar as yet but I would welcome a clearer picture of the future benefits.
@sunandair therein lies the issue - no one can say with any certainty what energy markets will look like in 12 months time, let alone over the payback period of any investment. For now, solar is relatively cheap to install with good payback. If you have or are planning to get other electrified technology such as EV/ASHP then that can only help the economics should SEG rates for export fall.
Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.
@old_scientist Cosy has been providing us with all our grid needs at the lowest rate as a total of 8 hours per day and battery storage provides sufficient charging potential even in the depth of December - February ASHP demand. I have been ‘keeping an eye’ on Agile rates over the last year and seem to find that there are few hours in many of the days where the HH’s are priced at or below <13 pence per kWh (current Cosy price). Most days where I have checked, Agile rates are well above this rate and I really cannot see how it can be a cheaper option these days? Ample solar energy production does not appear to have pulled the price down so I assume that the rate is most influenced by Wind Turbine energy production and that the winds are ‘resting’ a lot of the time at present. Has any reader found that Agile has been the cheaper option over the last year please? Regards, Toodles.
@old_scientist Cosy has been providing us with all our grid needs at the lowest rate as a total of 8 hours per day and battery storage provides sufficient charging potential even in the depth of December - February ASHP demand. I have been ‘keeping an eye’ on Agile rates over the last year and seem to find that there are few hours in many of the days where the HH’s are priced at or below <13 pence per kWh (current Cosy price). Most days where I have checked, Agile rates are well above this rate and I really cannot see how it can be a cheaper option these days? Ample solar energy production does not appear to have pulled the price down so I assume that the rate is most influenced by Wind Turbine energy production and that the winds are ‘resting’ a lot of the time at present. Has any reader found that Agile has been the cheaper option over the last year please? Regards, Toodles.
@toodles I agree. I was on Agile from the beginning of April but switched back to Cosy a while back as the pricing on Agile was not great, as you say. I still monitor the prices daily, and Cosy is definitely the best bet at the moment to lock in those 13p cheap rates if you don't have an EV and don't fancy IOF. The good thing is you are able to switch instantly so can be agile in jumping back and forth between Cosy and Agile as rates dictate, plus you get to see the Agile rates a day ahead so you know what you are switching on to or away from.
I'm going to give IOF a go until October I think, before switching to Cosy for the winter as our battery is nowhere near big enough to run the heating in the winter months. October and April look like the switch over points for us, with the exact dates determined by what the weather looks like and when the heating goes on/off. It was the first full day on IOF today, and Octopus are currently draining the battery during peak rate. We are currently participating in a VPP consisting of 1080 properties and supplying 6MW of electricity to the grid. Given the current price of electricity is £93.85/MWh, Octopus are paying us well at 29.8p per KWh, roughly 3 times the spot rate so they must be making a bit on the other bits.
Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.
@old_scientist Cosy is a really good tariff for heat pump owners. The ability to run hot water during the 1 pm.to 4 pm period when the outdoor temperature is likely to be higher, even in winter, really helps. We had a smaller 6.5 kWh battery last winter, so having three periods to top up the battery was helpful too, but was concerned about excessive cycling. It was doing about two cycles a day. We doubled the battery storage in May, so we should cycle less, maybe 1.5 cycles a day As my Mrs and I work from home most days, the option of running heavy loads such as the dishwasher, washing machine and dehumidifier during the 1 pm window also helps. We are a low mileage home, so having to pay slightly more for EV charging should not impact much.
Overall, despite my forecast that Go will be slightly financially advantageous than Cosy in our scenario, I might be tempted to switch to Cosy again towards mid October. If we had a compatible charger or a car, then definitely Intelligent Octopus Go would be a better option in the winter, given slightly lower rates and the extra one hour during the cheap rate window.
