Understanding the Variation in Electricity Rates in England

[jackson6612]

If my memory serves me right I recall once someone said something like that in England or the UK electricity rates varies during 24-hour period. It costs more during nighttime than during daytime. Is this true? What is the rationale behind this? Please let me know. Thanks.

 

[cobalt124]

I thought it cost less during nighttime to get more people to use it when demand was low.

 

[JaredJames]

It's cheaper at night than at day.

In my flat in London, the maximum charge was 20p/kwh during the day (this was the peak rate), and 5p/kwh in the night.

I had peak, off peak and night.

 

[brewnog]

Some tarrifs are cheaper during the night to encourage use of cheaper baseload power and discourage use of peak load. However, most nowadays are independent of time of usage.

 

[JaredJames]

However, most nowadays are independent of time of usage.

Really?

All of the EDF rates I've seen covering the UK are time dependent, and I believe EON are also.

You can look up their prices on line. Night time is significantly cheaper than day time.

 

[jackson6612]

Thank you, Cobalt, Jared.

I have a 1,500W generator. When I only lit one bulb it runs lightly and obviously consumes less fuel. When I connected something rated about 1,000W it gets grumpy and consumes a lot of fuel.

They charge you high so that the electricity usage doesn't exceed the maximum output of a power plant.

But at night when the demand is less, the power plant would use less fuel (in case of hydro-power plants fuel would be water). That would mean they can use that saved fuel during the period of high demand. But perhaps power plants are set to run at constant power output. Suppose the constant power output of a power plant is 100MW and if the demand is around 70MW, then that would mean 30MW is being wasted.

 

[brewnog]

Really?

All of the EDF rates I've seen covering the UK are time dependent, and I believe EON are also.

You can look up their prices on line. Night time is significantly cheaper than day time.

They may infer it from typical use, but to actually measure and bill according to time of use you need a different meter type installing (like you did with Economy 7 back in the day). Obviously EDF would have to install such a meter to use such a scheme, but most don't do this.

 

[JaredJames]

They may infer it from typical use, but to actually measure and bill according to time of use you need a different meter type installing (like you did with Economy 7 back in the day). Obviously EDF would have to install such a meter to use such a scheme, but most don't do this.

Certainly, they use averaging for single dial meters, but now most new digital meters have at least 2, if not 3 dials / readings for the various tariffs.

 

[JaredJames]

I have a 1,500W generator. When I only lit one bulb it runs lightly and obviously consumes less fuel. When I connected something rated about 1,000W it gets grumpy and consumes a lot of fuel.

Yes

They charge you high so that the electricity usage doesn't exceed the maximum output of a power plant.

No

But at night when the demand is less, the power plant would use less fuel (in case of hydro-power plants fuel would be water). That would mean they can use that saved fuel during the period of high demand. But perhaps power plants are set to run at constant power output. Suppose the constant power output of a power plant is 100MW and if the demand is around 70MW, then that would mean 30MW is being wasted.

Power plant output is varied according to predicted demand.

 

[NobodySpecial]

But perhaps power plants are set to run at constant power output. Suppose the constant power output of a power plant is 100MW and if the demand is around 70MW, then that would mean 30MW is being wasted.

Coal and nuclear stations are most efficient when run near their full capacity - this is called baseline load.
Gas stations can turn on and off much more quickly but their fuel is more expensive.
So the power companies would like you to use the same amount of power all the time so they offer you it more cheaply at night when businesses don't want it - you can use this to heat tanks of hot water of storage heaters that you use during the day.

It's difficult to cheaply store large amounts of power, the best way is to pump water back up into a reservoir and then let it flow out again during the day when you need electricity.

When there were only a couple of TV channels and 20Million households were watching the same saturday night show there was a huge power demand at the end when everyone went to make a cup of tea (most kettles in the UK are electric)

 

[jackson6612]

Thanks a lot, NBS. Your reply was really helpful.

It's difficult to cheaply store large amounts of power, the best way is to pump water back up into a reservoir and then let it flow out again during the day when you need electricity.

Couldn't a hydro-power plant adjust the output to the demand? Do hydro-plants actually implement this water pumping during the night?

Please guide me. Thanks.

 

[Phrak]

My electric bill is determined by Bistromathics the most powerful computational force known to parascience, thankfully explained by Douglas Adams. I am paying anywhere between two and twenty cents per kilowatt-hour, in humble terms. And probably both at the same time for the same Watt.

 

[xxChrisxx]

Couldn't a hydro-power plant adjust the output to the demand? Do hydro-plants actually implement this water pumping during the night?

Please guide me. Thanks.

Hydro plants pump the water up to a reservoir at night when electricity is cheap as a means of storing the energy to be used in the day.

 

[cragar]

Where do they pump it back up

 

[jackson6612]

I believe they pump it back to the reservoir. From less potential energy to the higher.

Best wishes
Jack

 

[Vanadium 50]

EDF? As in Électricité de France? In the UK?

 

[cragar]

I meant where , as in like us , uk , Because I am pretty sure they don't do that where i live .

 

[xxChrisxx]

EDF? As in Électricité de France? In the UK?

EDF is actually the biggest electricity generator in the UK. Quite a bit of energy is also imported from France. They took over a load of Southern power companies about 10 years ago.

 

[JaredJames]

I meant where , as in like us , uk , Because I am pretty sure they don't do that where i live .

Well in places that have enough rainfall to keep the resevoirs topped up they don't need to.

 

[brewnog]

http://en.wikipedia.org/wiki/Dinorwig_Power_Station

 

[AlephZero]

EDF? As in Électricité de France? In the UK?

When the UK electricity and gas industries were privatized in the 1980s, the functions of generation/extraction, distribution, and supply (i.e. sales) were separated into different companies. For electricity there is one nationwide UK distribution company (National Grid) which provides and maintains the wires and charges the generation and supply companies to use them.

There are many different generation and supply companies. For electricity most of the large companies do both but the two functions are (at least theoretically) separate entities. Some supply companies simply buy energy from the generators and sell it on to consumers, and probably make most of their profits from trading the energy futures markets. There are many different tariffs available as there are suppliers (I don't know the exact number, but it's probably of the order of 20 or 30).

Every consumer (i.e. electricity meter) in the UK has its own unique identifier (which is a 20 digit number, so the system is plenty of room for future expansion!) and every user can buy power from pretty much any supply company, at the cheapest tariff that matches their pattern of usage. When prices change, you just shop around for the best deal (though the best deals available usually lock you into one supplier for a period of time).

This setup allows market competition without the nonsense of needing multiple networks of pipes and wires - which would obviously be as dumb as insisting that every car manufacturer built their own road network.

EDF (French) and E-ON (German) are both big players in the UK supply and generation markets. There is a significant amount of electricity traded between England and Europe via undersea cables.

The same principles apply to the gas market. At present I'm probably using Norwegian gas, sold to me by a French company. Isn't global capitalism wonderful!

 

[jackson6612]

Thank you, Brewnog, Aleph.

I have learned some news things from your replies.