Discussion ... ASHP(Air/Air) with Solar pv ....

JKenH

The wife has been away helping with grandchildren Monday to Friday so I managed without any central heating and a 20/21C room temperature. Result was 11.1kwh used over 27.7 hours equals exactly 400 watts/hour. I was quite surprised at that but with less usage per day it spends a greater proportion of its time getting up to temperature and less time at a steady temp. Now the wife is back we have to have the oil C/H on for 1 hour in the morning on to dry towels etc. I also have had the kitchen ASHP at the other end of the house on for half an hour at breakfast and the occasional half hour at tea time. I only have one power meter so can’t monitor usage on both.

I can’t do it all on solar but at least I have the satisfaction this time of year of using all the solar I can generate with the ASHP, IBoost and cooking. I would love a battery but I could only use about 4kwh /day use of stored solar PV in summer and winter would be entirely from E7. I need to do the sums on TOU tariffs but how long will they stay cheap if BEVs take off?

Update 14 October: I ran the 3.5kw ASHP for heating continuously for 12.5 hrs today achieving/maintaining a temperature of 21/22C from a 19C start in a 38 sqm room.Outside temperature 6-12C. Used 3.4 kWh which works out an average of 272 watts/hour. This evening with the door closed consumption was 500 watts over 2h40m - 187 watts/hour average or about 3p an hour.
I also ran the kitchen ASHP for about 10 hours today and a few hours yesterday. I don’t have the facility to monitor power on both but despite two miserable days have avoided putting the CH on even though the wife is at home.
Update 15 September: I ran the 3.5 kw ASHP for 17.1 hours today to see if longer running would reduce the average consumption but it didn’t. Used 6.1 kw average 357w/hr. I was surprised at that as the outside temperature was similar to yesterday and although the door to the hall stayed open all day and evening that wouldn’t account for difference. The last 10 hours averaged 295w and the extra was all used in the first 7 hours.

mmmmikey

JKenH wrote: »

I need to do the sums on TOU tariffs but how long will they stay cheap if BEVs take off?

My planning assumption (and of course it's just speculation) is that over the 10-15 year lifetime TOU tariffs (E7 or "new") will average out at more or less the level they are now. My reasoning is:

1. In the short term, the continued roll out of SMETS2 smart meters will bring TOU tariffs into the mainstream, but there will be some attractive / loss leading offers to get people to switch. I'm guessing that if market forces don't drive this then Ofgem regulation will.

2. Even being optimisitc it will be a few years (maybe 3 to 5????) before EVs start to have a significant bearing on the market, but in this period they are more likely to bring down overnight prices than force them up as there is an effort to encourage the swicth to TOU tariffs.

3. As people gradually get used to the idea of using TOU tariffs and the number of EVs increases the differential between night and day tariffs will gradually reduce to the point where we're back to where we are in, say 7 to 10 years.

4. Only after that will demand have normalised to the point where the gap starts to close again.

Again, of course this is pure speculation on my part, but interested to hear alternative theories. One way or the other, I think that making the assumption that electricty prices will stay as they are (with the exception of normal inflationary increase) is almost certainly going to prove wrong. It might be difficualt to predict how pricing structures will change but I think it's almost a raging certainty that they will.

GreatApe

mmmmikey wrote: »

My planning assumption (and of course it's just speculation) is that over the 10-15 year lifetime TOU tariffs (E7 or "new") will average out at more or less the level they are now. My reasoning is:

1. In the short term, the continued roll out of SMETS2 smart meters will bring TOU tariffs into the mainstream, but there will be some attractive / loss leading offers to get people to switch. I'm guessing that if market forces don't drive this then Ofgem regulation will.

2. Even being optimisitc it will be a few years (maybe 3 to 5????) before EVs start to have a significant bearing on the market, but in this period they are more likely to bring down overnight prices than force them up as there is an effort to encourage the swicth to TOU tariffs.

3. As people gradually get used to the idea of using TOU tariffs and the number of EVs increases the differential between night and day tariffs will gradually reduce to the point where we're back to where we are in, say 7 to 10 years.

4. Only after that will demand have normalised to the point where the gap starts to close again.

Again, of course this is pure speculation on my part, but interested to hear alternative theories. One way or the other, I think that making the assumption that electricty prices will stay as they are (with the exception of normal inflationary increase) is almost certainly going to prove wrong. It might be difficualt to predict how pricing structures will change but I think it's almost a raging certainty that they will.

The UK nukes are going to close down the result is night time won't be as cheap as it has historically been especially for the warmer months.

The UK nuke closures will do far more than any deployment of BEVs over the next decade

The two links to Norway under construction or about to start will most likely pull 2.8GW from the UK for the lowest 6 or so hours and then provide the the highest demand 6 hours or so. With the other hours a mixture

So you lose 6GW of nuclear, and Norway pulls 2.8GW at night.
6GW less supply, 2.8GW more demand.
Expect the night time rate to not be as cheap as it otherwise would be

This story is repeated in Germany and Belgium

Cheap times will be when the wind blows hard and when it's sunny in Germany and they need to dump the power into nearby grids at close to £0

Nights will still be cheaper than days but kicking away 35% of night time supply that keeps going irrespective of price is going to have an impact

mmmmikey

GreatApe wrote: »

The UK nukes are going to close down

Fair point, hadn't really factored that in to my thinking. When are they expected to be decommissioned?

GreatApe

mmmmikey wrote: »

Fair point, hadn't really factored that in to my thinking. When are they expected to be decommissioned?

As things stand for the UK

4 reactors close in 2023 (less than 4 years away!)
4 in 2024
2 in 2028
4 in 2030

I would hope that they get extensions especially the 8 reactors closing in 4-5 years time
If the grid gets to less than 10% fossil then start closing the nukes makes no sense before then
Give the nukes a reasonable CFD if necessary

mmmmikey

GreatApe wrote: »

As things stand for the UK

4 reactors close in 2023 (less than 4 years away!)
4 in 2024
2 in 2028
4 in 2030

I would hope that they get extensions especially the 8 reactors closing in 4-5 years time
If the grid gets to less than 10% fossil then start closing the nukes makes no sense before then
Give the nukes a reasonable CFD if necessary

Thanks - this leads to some more questions, if I may....

Roughly what proportion of UK nuclear generation do the 8 reactors closing in 4-5 years time account for? You say you hope that they will get extensions. Putting aside the rights and wrongs of this, what do you think will actually happen? Is this likely to be a purely political decision or are there technical or legislative reasons that effect this (again, focusing on how you think the technical and regulatory framework in the UK actually is rather than how it should be)?

My questions stem from the fact that there is quite a big gap between EDF E7 pricing that I'm benefitting from and the pricing from other providers, which I have assumed to be because EDF have a greater proportion of nuclear power in the mix (which they generate a lot of themselves). Or am I over-analysing this? Interested to know, one way or the other....

GreatApe

mmmmikey wrote: »

Thanks - this leads to some more questions, if I may....

Roughly what proportion of UK nuclear generation do the 8 reactors closing in 4-5 years time account for? You say you hope that they will get extensions. Putting aside the rights and wrongs of this, what do you think will actually happen? Is this likely to be a purely political decision or are there technical or legislative reasons that effect this (again, focusing on how you think the technical and regulatory framework in the UK actually is rather than how it should be)?

My questions stem from the fact that there is quite a big gap between EDF E7 pricing that I'm benefitting from and the pricing from other providers, which I have assumed to be because EDF have a greater proportion of nuclear power in the mix (which they generate a lot of themselves). Or am I over-analysing this? Interested to know, one way or the other....

Those 8 reactors are about half of UK nuclear capacity
They can produce the same amount of energy as 10 million BEVs would consume

If they were all on and you are talking about a summer night they would be about 20% of total UK supply

Will they be extended? I don't know I think it's unlikely and very unlikely if they don't announce anything before end of 2020. Many of the UK nukes already had one significant life extension round under EDF who knows maybe they will extend again. From my understanding the UK government and regulatory body is not anti nukes. Labor government is anti nukes though so if they get into power perhaps they will block it

It's probably purely an economic decision but of course economics decision are impacted by political decisions
It can't help that we are building subsidised wind and PV which crashes the wholesale market so nuclear is worth less £££ as it sells into these subsidised depressed markets.

Personally if I were the government I'd give them a CFD to keep them going until the grid is less than 10% fossil fuels. This doesn't have to be long term it might be for just something like 6 or 8 years and then re-evaluate. Perhaps £50/MWh would do it.

Seems silly to be closing the nukes if they need just a small investment to keep them going
We still need to electrify transportation and heating so to knock out a HUGE quantity of UK nukes before the grid is <10% fossil seems silly

Personally I like the EDF tariff which is 8p off peak 16p other times
Off peak is 9PM to 7AM weekdays and ALL weekend
That means there are more off peak hours in the week than there are on peak hours
Good for EVs good for heat pumps good for electrically heated homes with tanks

mmmmikey

Thanks - will be interesting to see how this pans out.

Martyn1981

mmmmikey wrote: »

Thanks - this leads to some more questions, if I may....

Roughly what proportion of UK nuclear generation do the 8 reactors closing in 4-5 years time account for? You say you hope that they will get extensions. Putting aside the rights and wrongs of this, what do you think will actually happen? Is this likely to be a purely political decision or are there technical or legislative reasons that effect this (again, focusing on how you think the technical and regulatory framework in the UK actually is rather than how it should be)?

My questions stem from the fact that there is quite a big gap between EDF E7 pricing that I'm benefitting from and the pricing from other providers, which I have assumed to be because EDF have a greater proportion of nuclear power in the mix (which they generate a lot of themselves). Or am I over-analysing this? Interested to know, one way or the other....

A very important issue here is that extensions are not 'free'. They require huge additional investment each time, to ensure that the reactors are safe for the extended period. What we are seeing, all over the World, are generators not seeking extensions, or even shutting reactors early, simply because they are not economical.

Also, the longer these reactors are run, the harder the eventual clean up will be, incurring even more cost, and the UK fleet is already running at a lower level in order to provide for previous extensions.

But here's the best bit, nuclear is expensive, very expensive, despite over 60yrs of significant support in the UK. But RE is already far, far cheaper than nuclear, despite only ~10yrs of significant support in the UK, and what is the result, nuclear generation has been falling slowly and is around 20% now, whilst in just 10yrs, RE generation has risen from approx 5% to 35%, and there is a significant amount of 'cheap' off-shore wind already contracted, but not yet generating (commissioning dates 2022/23/24/25).

In short, we can do more, faster, and cheaper with RE.

Regarding night rates, since wind generation, especially off-shore, is a big night generator, and winter biased, then the impact on cheaper rates is pretty hard to predict.

mmmmikey

Thanks both, so putting this together it sounds like (whether you think this is good or not) you both think it's unlikely that the first 8 nuclear power stations will be kept open when the end of their planned life in 4 or 5 years time.


Assuming this nuclear energy is replaced with wind, then it would seem reasonable to expect that on windy nights energy will be cheaper than it is now, but on still nights it will be more expensive because we'll have to fire up some gas generators. So it seems quite possible things will average out at about the same, so my theory from a few posts back may well hold out, albeit for the wrong reasons.


All this might sound a bit obscure, but predicting future energy prices is critical to assessing the impact of any personal investment decisions in things like solar panels, batteries and heating systems.