Indeed … and not dissimilar to the practice of ‘gaming the denominator’ so prevalent in Corporate KPIs and Government stats. telling us all how brilliantly things are going by altering the value of the total (in this case daily energy burn i.e. denominator) against which the daily peak (i.e. numerator) is being compared. So in theory (if you have the capacity to store or are prepared to just pay) you could get free Sunday Saver energy by leaving your peak time burn unaltered and just increasing your off-peak burn enough to tweak the swing percentage. That’s essentially why of course EDF don’t really lose out because in the end we’re still buying their electricity, just at a different time because our totals won’t change that much (apart from seasonal heating if it’s electric like mine). So those with a big battery on wheels that they can charge at home like Harry are the clear winners here 🙂 … the rest of us are left topping out our existing ‘house’ batteries if we have them, or wondering what to switch on of a Sunday for the next 8 – 12 hours after we’ve done the obvious and run all the major appliances. Personally I found that without batteries I would be done running things like dishwasher, washing machine, vacuum cleaner, oven etc. well inside 8 hours on a Sunday. There was no real point aiming for 12-16 hours because I would run out of high load appliances to use by 4pm (apart from the electric radiator when required).

So you’re inflating your weekly off-peak usage total by topping off the big battery in the PHEV to make your end of week ‘swing’ from peak to off-peak look healthier thus earning some freebie hours on the following Sunday. Smart! 🙂
Plus I guess the recent energy price cap reduction effective until April coupled with the undoubted petrol price increase now coming down the line makes your petrol-electricity comparison look even better. Double smart!! 🙂 Nice one.

I think that a lot of people with proper house-battery installations and solar feeds to match (like Nick here) drop out of the Sunday Saver scheme once the sun starts to shine because they can generate enough for free anyway through the summer. I certainly wouldn’t buy batteries and/or portable power stations purely to take advantage of Sunday Saver simply because the number required to make any real difference would be both prohibitively expensive as well as logistically complex to accommodate and utilise effectively. The most likely year-round beneficiaries of the scheme would be EV owners I guess … but as you say who knows what changes to T&Cs and market regulations await that are likely to affect that particular dynamic? Personally I stick to Standard Variable Rate because my energy footprint these days is much reduced and I doubt that any fixed rate ‘deals’ in reality make that much difference to my personal situation. So I’ll just stick to SVR, charge my batteries on a Sunday for free for as long as it’s available and reserve the right to switch supplier whenever I like. I doubt any of the ‘offers’ we will be bombarded with next will see any suppliers suffering losses or price instability on the scale that occurred at the start of Putin’s latest expedition anyway. Happy hunting!:)

Ah yes, the cost of frugality 🙂 I recognise the problem. I’ve been a participant in the Sunday Saver scheme since it’s inception and have grown my little bespoke battery-solar system along the way and altered my energy usage patterns over time. For the last 12 months straight I have managed to achieve 16 free hours every Sunday and on average now use between 8am and midnight roughly 90kWh which equates to roughly £25 of free energy which is credited to my account, so about £100 per month. I then feed my battery power into my daily usage Monday-Friday by topping up a variety of power stations around the house for specific uses such as powering the microwave, the mini-oven, my laptop and the TV etc.
So does the Sunday Saver scheme actually save me money? … certainly it does if I just count the 90kWh hours of free battery storage Monday to Friday. That equates to something like 25-40% of my weekly total depending on the season and amount of heating required (I can of course only run simple appliances for free in this way … not electric heaters which must still come straight off the mains). But then of course if I take into account the capital cost of power stations, batteries and associated paraphernalia like extension cables & chargers etc. it’s more likely to be at least 5 years before I could honestly say I am actually making any money. In fact if I’m honest with 5 year warranty periods and expected lifespan of the new battery technology these days of 10 years plus I’m expecting at my age for the kit to last longer than me:)
So why bother? … in short security of supply. I’m in a fairly remote rural Devon setting where I expect in the near future to experience planned frequent rolling energy reductions/blackouts as the problems with the national energy grid evolve over time.
So I’m not doing it purely for financial gain … I predict that I will need to fall back on my battery storage system and supplement it when I can with whatever meagre solar generation is possible at this latitude.
I have to conclude therefore that, as James has testified to, using the full 12-16 hours on a Sunday is actually a challenge week in, week out if you don’t have the means to store it for use through Monday-Friday. Is it worth it? … that depends on your priority. It helps the longer term financing of my battery back-up system which gives me peace of mind and resilience if the worst happens. But would I recommend Sunday Saver as a handy money maker for those of us living less busy lives in retirement with more manageable energy footprints compared to the hectic days of family? Probably not to be honest. Plus of course as James alludes to the scheme itself is based on your peak time ‘shift’ not just overall daily reduction. So you still need to be able to show a counterbalancing off-peak weekday energy burn that will in turn show an inversely proportionate peak time reduction. Cutting your energy usage across the day on it’s own won’t cut it, you have to both burn less in peak time as well as correspondingly more in off-peak in order to make the calculation worthwhile otherwise you’re wasting your time. My bet would be that EDF do not lose any money operating Sunday Saver anyway.

I concur with Nick. I asked this same question quite a while back last year and posted a response from EDF Customer Services which confirmed that the ‘Fair Usage’ clause for The Sunday Saver scheme had indeed been dropped. I am regularly pushing my Sunday usage 8am to midnight past 90kWh now and am being refunded in full as expected.