Which is greener; ASHP or EV?

shinytop

From a discussion on another forum for interest.  I've quoted it verbatim so don't shoot the messenger!  

This is the source of the Mitsubishi data.  Other heat pumps and EV manufacturers are available.

https://library.mitsubishielectric.co.uk/pdf/directory/heating/sales_literature/embodied_carbon_information/residential_?fbclid=IwAR1qe8oKn3sh0I62jO99LzHudpXn7RPg8oE7mJGTk6wu723ihoQt_owkIMI

"Mitsubishi have published their lifecycle carbon footprint data for all of their domestic models, it makes for interesting reading.

Quite a few people have the Ecodan 8.5kW model, so I’ll use that.

HEAT PUMP

- To build and dispose of, also assuming refrigerant leakage = 1.362 tonnes CO2

- In operation, over 15 years = 5.94 tonnes CO2.

- Total = 7.4 tonnes.

- Saving against a gas boiler over 15 years = 55 tonnes CO2

EV SUV

Now compare that with the great data Volvo give us when they compare their XC40 mid size SUV verses their battery version.

- C40 recharge build and dispose CO2 = 28 tonnes CO2

- In operation (using same electricity assumptions as heat pump) = 20 tonnes CO2

- Total = 48 tonnes CO2

- Saving over buying the petrol version = 17 tonnes CO2

Cost of heat pump = £10k to £20k saving 27 tonnes per £10k

Cost of C40 recharge = from £57,400 saving 0.3 tonnes per £10k

I have no idea what the residual cost of a 200,000km C40 will be, so I have had to ignore it. But as I’ve used the max cost of the heat pump, I think that it’s a fair comparison."

Meatballs

One positive for EVs is you can charge them almost exclusively off-peak (which is generally low CO2 intensity), whereas HP needs to run for most of the day and into peak times.

ispookie666

@shinytop many thanks for sharing this.  It is great to see a company publishing their lifecycle carbon foot print.  
How many miles can the car travel for the same KWh usage per year?  I would hazard a guess and say Under 4000miles

Reed_Richards

For heating we know the calorific value of different fuels so we can compare gas electricity and oil, taking into account the efficiency of the boiler.  It's much harder to compare cars.  You can compare different electric cars in terms of their miles per kWh but how do you compare that with an mpg figure for an ICE car?   

shinytop

ispookie666 said:

@shinytop many thanks for sharing this.  It is great to see a company publishing their lifecycle carbon foot print.  
How many miles can the car travel for the same KWh usage per year?  I would hazard a guess and say Under 4000miles

It is, but with most C02 emission estimates, it can be a bit smoke and mirrors. It is useful though as an order of magnitude comparison. And it sort of confirms what I thought in that there are a lot better C02-saving bangs for the buck than a £50k EV.  

JKenH

shinytop said:

ispookie666 said:

@shinytop many thanks for sharing this.  It is great to see a company publishing their lifecycle carbon foot print.  
How many miles can the car travel for the same KWh usage per year?  I would hazard a guess and say Under 4000miles

It is, but with most C02 emission estimates, it can be a bit smoke and mirrors. It is useful though as an order of magnitude comparison. And it sort of confirms what I thought in that there are a lot better C02-saving bangs for the buck than a £50k EV.  

Yes, but it is surprising just how many supposedly environmentally conscious people still stick with their gas central heating and buy a Tesla given the comparative CO2 savings. At the end of the day people vote with their pockets. The financial arguments for running a new EV vs ICE are overwhelmingly in favour of the EV particularly when tax advantages under company car/salary sacrifice schemes are taken into account but the argument for a heat pump is marginal if not negative financially.

It would make far more sense from an environmental point of view to buy a £30k EV and a £15k heat pump than a £45k Tesla or £55k BMWi4. 

2nd_time_buyer

It seems true carbon cost is very difficult to calculate. My approach is to ask "how do you spend 50k with the least environmental damage?".

If you need a car than a BEV is probably a good idea. A heat pump might be better but you still have another £40k to spend. Once you have solar panels and insulation, it is difficult to think of other things that are better than BEV, assuming you need one.

Even making ethical investments doesn't help too much, unless they tank. As you will still need to think of an environmentally friendly way to spend the money eventually.

Reed_Richards

JKenH said:

The financial arguments for running a new EV vs ICE are overwhelmingly in favour of the EV particularly when tax advantages under company car/salary sacrifice schemes are taken into account but the argument for a heat pump is marginal if not negative financially.

There was a show on Radio 4 last week all about comparative costs which showed how weak the financial case for running an EV is compared to the equivalent ICE model.  From what I recall, they calculated that you did not break even until you had driven over 50,000 miles.  

ABrass

Interesting, but flawed.

An EV also saves money compared to an ICE as well as reducing carbon. Heat pumps at best break even at the moment. If you're just looking at the up front cost rather than the running cost you're missing the majority of the costs for the heat pump and the majority of the savings for the EV.

arty688

When getting a EV I would say most people are not handing over £50k .My friend is getting an EV because he can offset 100% of the cost against his business . No idea on the numbers but I would guess most are company cars . So the choice isn't car or ASHP its EV or ICE car.

JKenH

The CO2 costs are heavily front end loaded for an EV - area under the curve again. People like me who are only doing around 6k miles a year in their EVs are going to take a long while to reach the 50k miles (or whatever figure it is) before we get a positive CO2 impact from buying a new EV compared to ICE. In my case 8 years on current mileage. Meanwhile those extra CO2 emissions used in the manufacture of my EV are up in the atmosphere warming us all up for an additional 8 years.