ASHP vs Oil in 2022

[George]

Quote

Personal Energy Security:

ASHP: heat demand is at a time of year when personal generation not really viable so dependent on supply. Supply could be subject to interruption (blackouts, smart meter bugs). No flexibility on price.

Oil: bar it being stolen, when you have it you have it. Can stock up when price is low.

Winner: Oil

 

Oil won't work without electricity for the pumps etc so that's a draw in my book.

 

Also - electricity supply will always be a priority. At no point for the rest of humanity's future will we not be generating electricity somehow. Fuel oil, however, will hopefully get phased out in the new few decades! I could see a carbon tax being implemented at some point in the next 20 years, and at a minimum the green levies moving from electricity onto gas/oil. 

 

For a truly secure back up plan, have a biomass option (I kept my log burners in the house when I renovated). 

 

I don't understand the marginal vs the average rationale. 

 

Oil con - big ole ugly oil tank in the garden. An ASHP is a fraction of the size (although it does make a noise - not noisy - but a noise).

[Roger440]

Oil. Oil. Oil

 

Given the way things are going, especially with government, i think increased self sufficeny is where im going.

 

Sure, fit an ASHP as well, but when its too expensive or power is not available, oil is going to look good. Indeed, until the price cap was confirmed, things were in danger of oil being the cheapest form of heating!

 

The enviromental aspect is trumped by the requirement to have working heating when i want it. Not at the mercy of government whim/stupidity.

 

Of course, for the boiler to work you need power. A battery will cover that, as its unlikely you will have no power for days. Well, depending where you are. 

 

Or, like me, buy a diesel genset as back up. Wildy inefficient. Unless you have a battery, then you can charge that meaning you can run the genset at its peak efficiency. Following ofgems announcements of possible interupption to supply, one feels strangely smug.

 

The idea that there will continue to be super cheap electricity at night long term is one for the birds, so id certainly not base your decisions on that.

 

I think at the new place, its oil, supported with a bit of solar, and possibly, subject to what i can achieve a bit of hydro.

[Roger440]

1 hour ago, George said:

 

Oil won't work without electricity for the pumps etc so that's a draw in my book.

 

Also - electricity supply will always be a priority. At no point for the rest of humanity's future will we not be generating electricity somehow. Fuel oil, however, will hopefully get phased out in the new few decades! I could see a carbon tax being implemented at some point in the next 20 years, and at a minimum the green levies moving from electricity onto gas/oil. 

 

For a truly secure back up plan, have a biomass option (I kept my log burners in the house when I renovated). 

 

I don't understand the marginal vs the average rationale. 

 

Oil con - big ole ugly oil tank in the garden. An ASHP is a fraction of the size (although it does make a noise - not noisy - but a noise).

 

Electricity is a priority and will be available??? You sure.

 

Given an abject failure of succesive governments to do anything remotely intelligent, and demonstrably so, id say you are wrong. Its clearly not a priority. 

 

Oil phased out? Not in my lifetime it wont be. It will be something if it is phased out to force you to be reliant on an unreliable electricity supply! Though i suppose its possible.

 

ASHP, yes, noisy, Too noisy. But, as has been discussed is only a good option in a resonably efficent house. If you dont have one of those, not so much. There are limits to what can sensibly be achieved with existing properties.

[Onoff]

2 hours ago, billt said:

 

Sorry, but vegan merely means that you don't eat eggs and dairy products as well as not eating meat/fish. It is perfectly possible to prepare vegan food without buying ultra-processed rubbish. It predates the modern bandwagon by several decades. (Consults Wikipedia - in fact it dates back to 3300-1300 B.C.)

 

I fully appreciate your point. What I'm getting at as is very easy for the chemical industrial giants to jump on the bandwagon of veganism and basically produce ultra processed sh!t under the vegan banner, charge through the nose for it, get rid of lots of nasty, suspect ingredients to boot and pretend they're saving the planet. Advertising is geared to making you want it. The commodity is irrelevant as long as the masses keep paying for it. 

[George]

1 hour ago, Roger440 said:

 

Electricity is a priority and will be available??? You sure.

 

Given an abject failure of succesive governments to do anything remotely intelligent, and demonstrably so, id say you are wrong. Its clearly not a priority. 

 

Oil phased out? Not in my lifetime it wont be. It will be something if it is phased out to force you to be reliant on an unreliable electricity supply! Though i suppose its possible.

 

ASHP, yes, noisy, Too noisy. But, as has been discussed is only a good option in a resonably efficent house. If you dont have one of those, not so much. There are limits to what can sensibly be achieved with existing properties.

I live in a solid wall house built in the 1880s. The ashp costs less than I used to spend on oil (although its a thermally much improved house and the old oil system was incredibly inefficient so it's a moot point). Can't hear the ashp at all from inside and when outside when immediately adjacent to it as I said, it's a noise, but it isn't noisy. 

 

 

Edited October 6, 2022 by George

[MortarThePoint]

9 hours ago, Roger440 said:

The idea that there will continue to be super cheap electricity at night long term is one for the birds, so id certainly not base your decisions on that.

 

I agree, electric cars etc will create larger overnight demands.

 

10 hours ago, George said:

I don't understand the marginal vs the average rationale. 

 

This is a key point that is so often missed in the consideration of electric cars. If you're weighing up the choice of something that uses electricity Vs something that doesn't, you need to model it as additional demand on the grid. Some made up numbers to illustrate:

Scenario 1: 2.5GW of green electricity, 0.5GW  of dirty electricity, my oil heating.

Scenario 2: 2.5GW of green electricity, (0.5GW+3kW) of dirty electricity to include my ASHP.

The green electricity can't be dialed up to match the additional demand. Until we have excess green electricity capacity that is, which is a long way off. ASHPs and Electric cars will see us burning natural gas for years to come. Without them less gas would be burned, so their carbon footprint is that of the extra gas that is burnt, not the average electricity generation footprint.

[ReedRichards]

35 minutes ago, MortarThePoint said:

 

I agree, electric cars etc will create larger overnight demands..... Without them less gas would be burned, so their carbon footprint is that of the extra gas that is burnt, not the average electricity generation footprint.

 

I do not agree.  Some electricity generators cannot be turned off quickly so we tend to have surplus electricity overnight, hence Economy 7 tariffs.  Although electric cars may cause this to change, AFAIK they have not done so yet in which case you do not have to burn extra gas to charge them overnight.  

[MortarThePoint]

15 minutes ago, ReedRichards said:

I do not agree.  Some electricity generators cannot be turned off quickly so we tend to have surplus electricity overnight, hence Economy 7 tariffs.  Although electric cars may cause this to change, AFAIK they have not done so yet in which case you do not have to burn extra gas to charge them overnight.  

 

Two counters to that:

1. Are you sure no gas derived electricity is generated overnight?
2. If there is sufficient hydro storage, the electricity could be stored and used later, may not be enough capacity though

Additionally, if but not connected to E7, some people charge their cars outside E7 e.g. during their day at work.

[SteamyTea]

15 minutes ago, MortarThePoint said:

The green electricity can't be dialed up to match the additional demand.

As you say, not until we have true excess installed capacity.

It is because of this that we are also developing a new nuclear fleet.

Now whether that is the best thing to do, or as an alternative, just install a lot more RE and some large scale storage (which can be distributed) is a different debate.

Some made up numbers.

UK night usage:

Between 25 GW and 40 GW, so over a 6 hour window, 150 GWh and 240 GWh.

Now we know the price of both wind power and nuclear power, £40,000/GWh and £95,000/GWh respectively.

We also know the capital costs £1.25bn/GW installed capacity and ~£8.3bn/GW installed capacity respectively.

We also know the capacity factor, wind is around 40% and nuclear around 90%.

Once planning is consented, we know that wind can be deployed in about 18 month, and nuclear about 12 years.

Taking the most simple arithmetic model, how much wind capacity can we install for the same money as nuclear.

 

8.4 [£bn/GW_n] / 1.25 [£bn/GW_w] = 6.72 GW.

Multiply that by the capacity factor and you get 2.7 GW.

For comparison, taking capacity factor into account, you get 0.9 GW of nuclear for the same money.

You would also be generating, with wind, approximately, after 18 months, 3.5 TWh/year.

That will increase every 18 months, so:

3.5 TWh/year from Jan 2024

7 TWh/year from June 2025

10.5 TWh/year from Jan 2027

14 TWh/year from June 2029

17.5 TWh/year from Jan 2031

20 TWh/year from June 2033

23.5 TWh/year from Jan 2035

This is the point where the price of wind power equals nuclear power and nuclear is almost onstream.  So if we stopped investing in wind here, from every year onwards we would generate another 23.5 TWh/year.

 

Total wind generation to date would be 110 TWh/year.

Nuclear 0 TWh/year.

But we will give it a chance to catch up, by projecting into the future even more.

So nuclear will be generating 7.8 TWh/year, wind 23.5 TWh/year.

Really no need to project into the far future is there, nuclear is not going to catch up.

 

Yes we do need some nuclear (or other type of base load generation) so that wind power can be used for balancing, but the problem is at the moment (2022), we need new generation.

Luckily the people that put up the money are not investing in nuclear, or hydro, they are investing in wind (solar is a small fraction in the UK) and battery storage, because they know they get a return on their investment much quicker.

[George]

1 hour ago, MortarThePoint said:

 

I agree, electric cars etc will create larger overnight demands.

 

 

This is a key point that is so often missed in the consideration of electric cars. If you're weighing up the choice of something that uses electricity Vs something that doesn't, you need to model it as additional demand on the grid. Some made up numbers to illustrate:

Scenario 1: 2.5GW of green electricity, 0.5GW  of dirty electricity, my oil heating.

Scenario 2: 2.5GW of green electricity, (0.5GW+3kW) of dirty electricity to include my ASHP.

The green electricity can't be dialed up to match the additional demand. Until we have excess green electricity capacity that is, which is a long way off. ASHPs and Electric cars will see us burning natural gas for years to come. Without them less gas would be burned, so their carbon footprint is that of the extra gas that is burnt, not the average electricity generation footprint.

The counter argument for a heat pump is that it uses gas more efficiently than just burning it in a gas boiler. 

1kWh gas into a CCGT results in 0.6kWh electricity. At a SCOP of 3, you net 1.8kWh heat delivered. (Ignoring significant losses and assuming a 100% gas powered grid)

 

I have wondered whether gas powered heat pumps would be a better medium term solution. They exist as you can get gas powered fridges. 

 

I wholeheartedly agree electric cars are not good for the environment. But I think overall they are marginally better than petrol/diesel. Bicycles are the proper eco friendly choice. 

 

Edit - I've just remembered there is a government research paper from years ago that included gas powered heat pumps. Because the electricity grid has a significant (and always growing) non-carbon input they were worse on a carbon intensity measure than electric heat pumps. This was a carbon focused research rather than price. 

Edited October 7, 2022 by George

[SteamyTea]

8 minutes ago, MortarThePoint said:

Two counters to that:

1. Are you sure no gas derived electricity is generated overnight?

Here is what has happened so far this year, the missing 2% is due to imports, which I cannot account for.  Ignore my usage, which is 0.0000011% of grid capacity, and just read the green and red lines off from the secondary y-axis on the right.

[MortarThePoint]

8 minutes ago, George said:

1kWh gas into a CCGT results in 0.6kWh electricity. At a SCOP of 3, you net 1.8kWh heat delivered. (Ignoring significant losses and assuming a 100% gas powered grid)

That agrees reasonably well with my estimate:

    ASHP: When heating using an ASHP the marginal electricity* will be most likely generated from gas:  0.5kgCO2/kWh electricity / 300% = 167gCO2/kWh of heat

 

But if the marginally electricity is coal generated....

[SteamyTea]

Just because I like charts, here is the monthly breakdown.

 

 

 

 

 

 

 

 

[MortarThePoint]

11 minutes ago, SteamyTea said:

Here is what has happened so far this year, the missing 2% is due to imports, which I cannot account for.  Ignore my usage, which is 0.0000011% of grid capacity, and just read the green and red lines off from the secondary y-axis on the right.

 

Are the powers the power taken from the grid or the power consumed in the house, or do you not have batteries?

[George]

6 minutes ago, MortarThePoint said:

That agrees reasonably well with my estimate:

    ASHP: When heating using an ASHP the marginal electricity* will be most likely generated from gas:  0.5kgCO2/kWh electricity / 300% = 167gCO2/kWh of heat

 

But if the marginally electricity is coal generated....

It does except why use marginal rate? Electricity consumption has been falling for many years, and quite dramatically per capita. ASHPs and electric cars will likely reverse this trend but due to the cheapness of renewables, you'd expect this to be largely renewable sources to take up the increase. Or at least, not reduce their contribution from today.

[SteamyTea]

7 minutes ago, MortarThePoint said:

Are the powers the power taken from the grid or the power consumed in the house, or do you not have batteries?

All grid, I am on E7, which is why the larger loads are before 7AM.

You can see when I put a new timer on the DHW as I shifted it over an hour, so save on an hour's standing losses.

Edited October 7, 2022 by SteamyTea

[MortarThePoint]

2 minutes ago, George said:

It does except why use marginal rate? Electricity consumption has been falling for many years, and quite dramatically per capita. ASHPs and electric cars will likely reverse this trend but due to the cheapness of renewables, you'd expect this to be largely renewable sources to take up the increase. Or at least, not reduce their contribution from today.

 

I used gas generated for my comparison in the first post (just pointing out coal would be worse).

 

I need to consider marginal as I am deciding whether to add one extra system, not form a government guideline

[MortarThePoint]

Just now, SteamyTea said:

All grid, I am on E7, which is why the larger loads are before 7AM.

You can see when I put a new timer on the DHW as I shifted it over an hour so save on an hours standing losses.

Do you have a graph of indoor and outdoor air temperature vs hours of the day? I'd be interested by the dT/dt when it's cold outside.

[SteamyTea]

1 minute ago, MortarThePoint said:

Do you have a graph of indoor and outdoor air temperature vs hours of the day? I'd be interested by the dT/dt when it's cold outside.

Got this one, but not a correlation as I did not find it very useful.  Mainly because I am on E7 and the load is fixed, and my house temperature tends to stay the same.

[MortarThePoint]

1 minute ago, SteamyTea said:

Got this one, but not a correlation as I did not find it very useful.  Mainly because I am on E7 and the load is fixed, and my house temperature tends to stay the same.

Interesting. I think taken over such a long time the effects of solar gain mask the most interesting bit. Do you have that for just January 2022?

[SteamyTea]

1 minute ago, MortarThePoint said:

Interesting. I think taken over such a long time the effects of solar gain mask the most interesting bit. Do you have that for just January 2022?

Yes

[MortarThePoint]

15 minutes ago, SteamyTea said:

Yes

I'm surprised your indoor temperature is so constant during the day without the heating on. Do you have lots of glass and solar gain? It starts to drop at 9pm at a rate of around 1C in 5 hours.

[SteamyTea]

20 minutes ago, MortarThePoint said:

I'm surprised your indoor temperature is so constant during the day without the heating on. Do you have lots of glass and solar gain? It starts to drop at 9pm at a rate of around 1C in 5 hours.

Much of it is to do with my lifestyle.  I work evenings, so the house gets shut up at about 4PM, then I get home between 9 and 10PM.

Just realised, I leave the back, downstairs window (where the temperature logger is) open a bit at night, I am a smoker.

Here is a quick chart of mean house temperatures and solar power.

I would have to slice it a lot more to find out what is actually happening, but I like 23°C as a temperature (grew up in the tropics), so don't open the back, upstairs, windows till it goes over that.

But basically I have less than 3.5° swing between the coldest and hottest, and darkest and sunniest times.  Why all this nonsense about timber frame houses overheating is bollocks.

I probably have a greater percentage of glazing to wall area than most, but as it is small house, overall not much.

 

Quick chart.

Edited October 7, 2022 by SteamyTea

[Marvin]

16 hours ago, Onoff said:

"They" want "you" hooked into a commodity. Whether it be electricity or whatever. 

 

Hi @Onoff  head, nail, hit.  If only it wasn't everything! Sadly your dealing with human attitudes and the opportunity for some to take advantage of us which don't seem to have changed since Plato. It could be worse!!!

 

 

[Marvin]

3 hours ago, SteamyTea said:

Why all this nonsense about timber frame houses overheating is bollocks.

hi @SteamyTea

 

Yes for your home but not for this house!  

 

Just like an ASHP installation, the results are affected by the ASHP model, installation, insulation, presumably an MVHR, shadowing of solar, wind, rotation, airtightness, quantity and habits of occupants and finally if the occupants have actually been informed and understand the best way to run an ASHP.  

 

Hence the problem when trying to answer the questions people ask like:  "Is a ASHP cheaper to run?" or "Will an ASHP work on my house".

 

and to get back on subject, in my humble opinion, both ASHP and Oil have their challenges and the answer depends on many individual specific items.