Would a small home battery system (2kwh), without any solar, help with household energy bill crisis

markin

MWT said:

markin said:

How many people could do this before the grid dip becomes level/peak, The is around 10GW difference between the 2AM 25GW demand and 6pm day time low point demand, But the picture would be different anyway when the are 10m EV users charging up at 1AM

Still probably best to leave it to utility scale and V2G Deleted_User 'vehicle to grid'.

One big problem is that we are still having to use expensive gas/coal generation to supply even the lower demand overnight, so although we need less energy at that time of day it isn't necessarily cheaper energy right now.

Solar is obviously no help at night and the wind isn't strong enough often enough for wind generation to help all that much.

We have allowed our nuclear generation capability to fall too far below our needs and we are paying the price for that now.

V2G is still relatively expensive and uncommon as a car feature, and requires the car to actually be connected to the grid with sufficient energy to make it viable to consider taking it from the car, instead of charging the car which is generally why people have plugged it in ...

Yes spot on, I was looking at a random date and was blind to the fact it was all Gas! Only 1.3GW of Wind. lol

theoretica

Is this a technology that works best on the micro scale (lots of consumers having batteries) rather than on the macro scale (the suppliers having big batteries)?  I don't see why it would work better small and localised, with much duplication of battery chargers and inverters than fewer bigger ones.  So is this proposal a way of getting consumers to pay for the infrastructure, rather than the National Grid?

Sea_Shell

Maybe we all need to rig up a static bike* to a dynamo...we could get fit whilst powering the TV 😉

But then think how many calories we'd need to consume to provide us with the energy to power the bike...so we'd need to buy more pasta.

Cost benefit analysis anyone? 😉



*Other human powered machines are available

MWT

theoretica said:

Is this a technology that works best on the micro scale (lots of consumers having batteries) rather than on the macro scale (the suppliers having big batteries)?  I don't see why it would work better small and localised, with much duplication of battery chargers and inverters than fewer bigger ones.  So is this proposal a way of getting consumers to pay for the infrastructure, rather than the National Grid?

Small and local works to some extent when it is match to small and local generation, so it is used to boost the percentage of self-consumption.

In this case where the assumption is no solar just a battery, it is predicated on the availability of cheap over-night energy which currently does not exist, so it isn't really viable either at the micro or macro level right now, but in general, macro level developments probably make more sense as it can be stored nearer to the source of generation when there is over-production and distributed anywhere it is needed, rather than having it locked up in thousands of small storage points.

[Deleted User]

Worth remembering that it is not just the kWh size of a battery that matters but also the kW output. Even with a Powerwall 2, the battery alone cannot sustain an electric oven when it is heating, and a 3kW kettle.

QrizB

Sea_Shell said:

Cost benefit analysis anyone? 😉

A moderately fit but untrained adult human on a bicycle can achieve a sustained output of around 100 watts. There will be conversion losses so let's say we get 50 watts of electricity out of the cyclist.

Humans are pretty not particularly efficient at turning food into motion, around 25% per Wikipedia. 100 watts is about 90 calories per hour (it's not quite right but it's close enough for what we're doing here) so will need 360 calories of food energy.

Fuel will be mainly carbohydrate. Pasta is around 360 calories per 100g, so 100g of pasta will fuel your cyclist for four hours one hour, in which time you will generate 200 50 watt-hours. You'd need 400g 1600g for a full kilowatt-hour (and you'd be cycling for 20 hours, presumably taking it in turn).

Tesco budget spaghetti is 20p for 500g, so our kilowatt-hour will cost 16p 64p.

Also you'll save a fortune on heating because you'll all be hot and sweaty!

Edited after I checked my numbers and found I was wrong, sorry. Additions and alterations in italics.

Aussie_Tips

[Deleted User] said:

Worth remembering that it is not just the kWh size of a battery that matters but also the kW output. Even with a Powerwall 2, the battery alone cannot sustain an electric oven when it is heating, and a 3kW kettle.

Fully understand that, this is not a put going off grid, it's about redistribution of the off-peak capacity to supplement peak. Most home battery storage systems work in conjunction with the grid, so peak loads of over 2kw are topped up by the grid capacity. 

MWT

PGammage said:

[Deleted User] said:

Worth remembering that it is not just the kWh size of a battery that matters but also the kW output. Even with a Powerwall 2, the battery alone cannot sustain an electric oven when it is heating, and a 3kW kettle.

Fully understand that, this is not a put going off grid, it's about redistribution of the off-peak capacity to supplement peak.

First you need to have excess off-peak capacity, and right now, we don't.

As per the post earlier, we are currently burning gas to supply the overnight demand, hence the lack of low cost electricity at night.

PGammage said:

Most home battery storage systems work in conjunction with the grid, so peak loads of over 2kw are topped up by the grid capacity. 

 Most home battery systems limit themselves to below 0.5C to avoid over-stressing the pack and leading to a greatly reduced lifespan, so I'd suggest your 2kWh pack would be best limited to 1kW loads at most, but preferably lower, around 700Wh would be safer. 

Sea_Shell

QrizB said:

Sea_Shell said:

Cost benefit analysis anyone? 😉

A moderately fit but untrained adult human on a bicycle can achieve a sustained output of around 100 watts. There will be conversion losses so let's say we get 50 watts of electricity out of the cyclist.

Humans are pretty not particularly efficient at turning food into motion, around 25% per Wikipedia. 100 watts is about 90 calories per hour (it's not quite right but it's close enough for what we're doing here) so will need 360 calories of food energy.

Fuel will be mainly carbohydrate. Pasta is around 360 calories per 100g, so 100g of pasta will fuel your cyclist for four hours one hour, in which time you will generate 200 50 watt-hours. You'd need 400g 1600g for a full kilowatt-hour (and you'd be cycling for 20 hours, presumably taking it in turn).

Tesco budget spaghetti is 20p for 500g, so our kilowatt-hour will cost 16p 64p.

Also you'll save a fortune on heating because you'll all be hot and sweaty!

Edited after I checked my numbers and found I was wrong, sorry. Additions and alterations in italics.

And we have a winner!!

I always work on my runs = 100 Cal's per mile.   Treats are then calculated in "miles".    I work on a "one in, one out" policy!!! 😉😇

sabretoothtigger

MWT said:

PGammage said:

[Deleted User] said:

Worth remembering that it is not just the kWh size of a battery that matters but also the kW output. Even with a Powerwall 2, the battery alone cannot sustain an electric oven when it is heating, and a 3kW kettle.

Fully understand that, this is not a put going off grid, it's about redistribution of the off-peak capacity to supplement peak.

First you need to have excess off-peak capacity, and right now, we don't.

As per the post earlier, we are currently burning gas to supply the overnight demand, hence the lack of low cost electricity at night.

Is that true nationally, off peak demand exceeds any capacity ?   Is there a website that shows market rates that would useful