Random Renewables Thread

Currently with Energia, Smart Meter, EV rate 2-6am, 9.43c & then 11.02c above 1000kWh (per 2 months) 40.16c day rate. 3.8kwp solar & 5kWh house battery. 2024 Kia EV9 & 2024 Tesla Model3 RWD out front. Gas rate at 10.13c also (central heating only not water)

Time for a change of supplier I figured, contract was up last month. Let's see what's out there.

Pulled my HDF file from esbnetworks and fired into energypal. It seems that the plan I am on is still the best for my needs. There are a couple of cheaper options but with a 2am to 5am window which is too short for our needs. Actually SSE Airtricity are doing a 6 hour window 11pm to 5am at 12.13c combined with a day rate of 33.76 AND a slightly higher export rate too.

It's a little more expensive but not much and that 6 hr window looks nice becuse i would occasionally have to charge a bit longer, up to 8 hours overnight if we had something on meaning about 30kWh being pulled at that 40.16c rate outside the EV window.

So I dropped my HDF file into Google Gemini for analysis and it proceeds to generate a few graphs for me and describe my usage to a tee. I then gave it the details of my current plan and the SSE option and asked for a comparison, to which it also replied that my current usage still favoured my current plan, although the pricing was pretty close.

So here's what energypal can't quite account for. I told Gemini - you're not taking into account that I will be shifting my heavy usage from that 4 hr window to the 6 hr window - you are basing your calculations on my past usage - not my future usage which i would obviously change - you can't calculate the airtricity number using any of the 5am to 6am usage, because I would not do that!

After making that adjustment, Airtricity came in slightly cheaper, especially taking into account the gas rate of 7.97c. So that, along with the 6 hr window had me sold and I made the switch.

2 days later I'm contacted by Energia retentions team, wondering why I changed and I explained. So they said they could not match the EV plan but could do the following, a 38% discount on rates locked in for 2 years -

26.12 - day
29.33 - peak
14.36 - night (11pm to 8am)

gas 6.98

On the face of it the higher night rate looks like it would be more expensive as I was hitting 1800kWh per billing cycle of EV units. After prompting Gemini again with these figures including rates, standing charges, HDF data and assuming a change of behviour depending on the EV window, the counter offer was actually coming in about 60 quid cheaper for the year (the gas rate having a large influence here), which surprised me.

It will definitely cost more over the summer given that I hardly pull anything from the grid when the sun is shining but over the year it works out that what might seem to be more expensive at first look actually isn't in the bigger picture.

The other thing I was able to ask Gemini was - can you tell from the HDF file how often I pull 7kw+ between midnight and 8am indicating that I have had to charge one of the EV's for 8 hours overnight, outside of the EV rate window of 2 to 6am

so we had 27 nights in 18 months of owning 2 EV's where we went outide the 4 hr window, anything from 1 to 4 hrs extra.

Another prompt: what would the hypothetical cost of that have been assuming the EV overusage price of 11.02c between 2 and 6am and a price of 40.16c outside of that compared to a price of 14.36 from 11pm to 8am

It would have cost €110 less if I was on the 14.36c night rate for those nights that I did extra charging. Sealed the deal for me so cancelled SSE and moved to this plan with Energia after double checking it was a better overall deal than my current one.

locked in for 2 years at those rates is decent i think, given the volatility at the moment 🤷‍♂️

Once a week Model3 charge and twice a week EV9 charge will be a bit more relaxed. up to now it was 5 or 6 nights a week, which was fine but part of the resaon we occasionally had to do an extra charge was just the conflicting needs of running 2 EV's and having an odd clash of needing a charge.

TLDR: - energypal gives a great overview but AI can read your HDF file and if you prompt it correctly can give you some very good insights.

Thanks mate - that's what I was looking for. (Strangely I couldn't find an actual reference to that on their website)

i don't know, in some ways your an ideal customer

• won't need to waste time explaining what an inverter/battery/kWh is
• You know they'll more than likely pay
• Probably don't need to run any cable anywhere
• Captive audience, don't need to be competitive price wise or in a hurry to make time for them.

Is there a thread for home batteries? I was wondering about the likely longevity of home batteries and in particular anyone's I experience of battery degradation. I have 2 Triple Power batteries myself.

Thanks for that. There seems to be very little information on the ground on home battery degradation data. A particular question I had is whether to reduce the battery charging setting back from 100% to 90%/80% now that we are going into brighter 🔆 months. Thinking more on it, on reasonably bright days the battery is likely to be cycled back up to 100% possibly more than once. Hence maybe leave well enough alone.

Many thanks for this detailed comment and information. As I've mentioned before a local supplier suggested not to run the battery at all during the summer months to perhaps "preserve " the battery- less cycles. This seemed off to me as my thinking is use it or lose it and as you say LFP batteries are robust. Reassuring to know from real experience that these batteries will likely last a long time.

To be honest, that's…..pretty odd advice that I wouldn't expect a supplier to make. Ultimately you buy a battery to use it to save money. The idea of "saving" the battery cycles would be akin to buying a car and then not using the car as the tyres will wear down. "Technically" true, but it goes against why you bought the thing to begin with.

The best way to look at it is, most batteries are good for 6000+ cycles. After those 6000 cycles or so, it's not that the battery will be discarded, but rather it will have a reduced capacity. Usually this is in the region of 75-80% as in your battery will still work, but you've lost 20+% of it's capacity. Now if you consider that you cycle the battery once a day, then 6000 cycles will be 16.4 years. So at the end of that ~16 years or so, your battery will still be working…. albeit reduced.

So as you correctly noted above, you want to be flogging that battery as much as you can. More you use it, the more you save with it!

Yes its called a Virtual Power Plant. Available in UK, Australia and expect plenty of other countries. Peaks are easy to deal with, inverter just doesn't generate power. In some places you get penalised for export during peak solar production as they have to much power!