Octopus Heat Pumps

MultiFuelBurner

rjmachin said:

Gerry1 said:

@Reed_Richards You reduce your demand.

https://www.engineeringnews.co.za/article/eskom-to-roll-out-load-limiting-to-more-gauteng-areas-following-fourways-pilot-2024-02-01

https://www.lbc.co.uk/news/risk-blackouts-uk-new-gas-power-plants-net-zero/

But how does / should it work practically?

I currently have:

• Electric cooker / hobs
• Tumble Dryer
• Dish washer
• Washing machine
• 7kW car charger

Would they really find it acceptable to cut off all power if the car charger and heat pump reached the limit?

I imagined (maybe incorrectly) that something would be needed to reduce the power being used by a device if it needs to.

For example, I have seen that the MyEnergy devices have the ability to place a limit and reduce the power used if needed.  (However, I do not have these devices and are too expensive to justify the cost - My heat pump cost would increase from £1,260 to around £2,500)

I guess I need to speak to my Octopus Heat Pump Install Coordinator and see what they say.

Definitely speak to Octopus and don't always believe what you see here as some people have a hidden agenda against smart meters and like to promote horror stories whenever possible and however implausible they just won't stop.

Octopus seem to be on the ball so hopefully it's something they have had to deal/advise upon on other installs.

Let us know how it goes 👍

Reed_Richards

The engineer who came to fit my 80 A mains fuse opened up the box and discovered I already has an 80 A mains fuse!  But he told me that these fuses are very slow-blow.  You have to exceed the rated current for some length of time in order to cause the fuse to blow.

Also, if you add up the current ratings of all the fuses/circuit breakers in your consumer unit you will probably find that this exceeds the current that your mains fuse can handle.  But you don't run every powered device in your house simultaneously so it's very unlikely to cause a problem; it's certainly not a problem that anyone worries about.  For example, how likely are you to be charging your car whilst simultaneously running your electric cooker and hobs?

I think this is going to turn out to be a storm in a teacup.  Do speak to your Octopus Heat Pump Install Coordinator and let them handle it. 

rjmachin

Thanks, I have emailed my Octopus Heat Pump Install Coordinator, with the details in the email (although I think they should have had a copy of it).

You are correct, I charge the car overnight at the cheaper rates, so the cooker/hobs will not be running then.   The only possible thing is the car charger and heat pump at the same time.

I will see what Octopus say.   Thanks

QrizB

rjmachin said:

Would they really find it acceptable to cut off all power if the car charger and heat pump reached the limit?

In other countries, if you've taken a tariff with a power limit, as I understand it you get a warning via your meter or IHD and then (if you don't reduce your drain) your power is disconnected for a period.

After that period you are automatically reconnected. Hopefully the power cut has spurred you to switch something off, otherwise the cycle repeats.

Reed_Richards

Can you get a discount for a power-limited tariff (in other countries)?

QrizB

Reed_Richards said:

Can you get a discount for a power-limited tariff (in other countries)?

Dolor would quote the French tariffs here, which do charge less for a lower power limit.

matt_drummer

I may be wrong but this is how I see it.

You will never be allowed to install something that will potentially draw too much power taking all other stuff into consideration.

It is not about the current owner and their operating practices, it is about what a potential new owner could do.

It was the same for my planning permission, even though me and my current neighbours had no issues, new owners and neighbours may do.

It's OK saying I will never charge my car with the heat pump running or I don't cook and charge my car at the same time, it doesn't matter.

The fact that you could, or more importantly, somebody else could, is enough to be a problem.

This is how it works in my experience.

Part of the heat pump survey is turning everything on at once to check the power consumption, cooker, kettle etc etc.

If you draw too much power you can't have a heat pump on a single phase.

Reed_Richards

I used to work in telecoms.  Turns out that if everyone tries to make a phone call at the same time then the telephone network didn't have enough capacity to cope, but providers relied on something called "statistical multiplexing" which basically means that it's so unlikely that very large numbers of people will all try to make phone calls at the same time that it's not worth worrying about.  The statistics of when people make telephone calls means the network didn't get overloaded.

I think this is a useful concept applied to domestic power consumption and your mains fuse.  That almost certainly doesn't have the capacity to cope with you running all your electrical devices and appliances at the same time but when are you ever actually going to do that?  All you need to do is ensure that you have sufficient capacity for likely scenarios.

MultiFuelBurner

Ah but the above does rely on the people in the house not being stupid (why do Darwin awards spring to mind)

100a is 24kwh constant load I believe.

For people here that know energy use and what to do and what not to do that's fine plenty of headroom for all the toys.

For less than savvy people you have to plan for "stupid" and that's what's happening.

rjmachin

My Octopus Heat Pump Install Coordinator had not received a copy of the email, so I sent her a copy yesterday and she is going to look in to it and will be in touch today or Monday at the latest.

I am preparing for the news that I will not be able to have a heat pump now and I get my deposit back, obviously it will be great if that is not the case however.

Unfortunately, if the DNO says no, even if I were to never reach the max by turning everything on at the same time, I guess I have no say in it.