Public charging

[Mrklaw]

good point about 'local' vs 'individual' demand. Diversity doesn't really apply either. Although I'd say a possible caveat to that is the popularity of storage heaters and economy 7 may have built in more grid robustness than we might think?

 

[Jason71]

good point about 'local' vs 'individual' demand. Diversity doesn't really apply either. Although I'd say a possible caveat to that is the popularity of storage heaters and economy 7 may have built in more grid robustness than we might think?

Maybe, but my particular housing estate was built all gas in 1970 so the the local load calculations may have been based around that expectation.
If the estate was E7 then maybe it would have a bigger supply but if it was E7 then presumably it would still be E7 so any car chargers would be in addition to that

 

[AndrewGR]

Suggesting that everyone will be drawing 7kW simultaneously is unrealistic. The average car does about 20 miles a day which is about 5kWh of battery charge. So less than an hour of 7kW charging out of the 24 hours in the day. And most of the charging can be done in the early hours when domestic consumption is otherwise very low. I’d be much more concerned about the requirement for heat pumps. In cold weather they are likely to be operating continuously

 

[Mrklaw]

Suggesting that everyone will be drawing 7kW simultaneously is unrealistic. The average car does about 20 miles a day which is about 5kWh of battery charge. So less than an hour of 7kW charging out of the 24 hours in the day. And most of the charging can be done in the early hours when domestic consumption is otherwise very low. I’d be much more concerned about the requirement for heat pumps. In cold weather they are likely to be operating continuously

i know you’re supposed to run them continuoiusly but is that also overnight? I think you’d at least put a setback temperature so they wouldn’t run as much? Even when its freezing we’d turn the gas CH off overnight but then it warms up fast..

 

[Jason71]

i know you’re supposed to run them continuoiusly but is that also overnight? I think you’d at least put a setback temperature so they wouldn’t run as much? Even when its freezing we’d turn the gas CH off overnight but then it warms up fast..

I think the point he is making is that general consumption is much higher in the daytime so trying to run a load of heat pumps against that in the daytime would be a bigger deal than trying to run a load of car chargers overnight when the overall load is lower.

 

[Mrklaw]

More electric but less overall gas. Which is good but you need to have that capacity or build it

As they’re building out renewables I guess they can adjust how fast they ramp down gas and other power plants depending how electric demand ramps up? So at least we potentially have options

 

[WannabeOwner]

i know you’re supposed to run them continuoiusly but is that also overnight?

Bit of a moot point, but if the house was well insulated then 24/7 might well be the advised / best strategy ... of course if it was well insulated it wouldn't be drawing much power when it was on a heating cycle

I think the point he is making is that general consumption is much higher in the daytime so trying to run a load of heat pumps against that in the daytime would be a bigger deal than trying to run a load of car chargers overnight when the overall load is lower.

Is a heatpump, for an average sized house, going to need 7kW? (I have no idea on the answer).

 

[scdoubleu]

Is a heatpump, for an average sized house, going to need 7kW? (I have no idea on the answer).

Off topic, but I can somewhat answer that. Just had the final installation work done on air-air multi-split heating/cooling for our average sized 4-bed. Two outdoor units, feeding seven indoor wall-mounted units.

In heat mode, one outdoor unit is rated at max 1.4 kW AC power input and the other at 1.7 kW. So a hair over 3 kW total if working flat out. House is reasonably well insulated, so I doubt we'll see those figures very often.

Next on the list is disposing of the gas boiler and rads.

 

[Mrklaw]

Off topic, but I can somewhat answer that. Just had the final installation work done on air-air multi-split heating/cooling for our average sized 4-bed. Two outdoor units, feeding seven indoor wall-mounted units.

In heat mode, one outdoor unit is rated at max 1.4 kW AC power input and the other at 1.7 kW. So a hair over 3 kW total if working flat out. House is reasonably well insulated, so I doubt we'll see those figures very often.

Next on the list is disposing of the gas boiler and rads.

yep a lot of the time the 7kw is the output heat rating at max, so input will be more like 1-2kw max due to COP