Demand Tarrif Should be Charged Daily

[runbren]

Hi All,

I don't understand why we are being charged the Demand Charge rate for the worst day for the billing period across the entire period.

Doesn't it make more sense to apply that on a daily basis?

For example, if someone turns on the kettle, toaster and then a heater on one of the days of my billing period, I get charged as if I did that everyday.

My demand on the power grid was only applicable on that one day, so it makes sense to do this on a daily basis.

[Denmar]

I thought that too when I got the new smart meter installed and then got the email.

Surely it should be established on the average demand across the days of the billing period !

[runbren]

I agree with their strategy of charging for the max demand on the system for a small period such as 30min. It will create motivation for people to spread out their demand across the demand period.

I don't think it's fair to charge someone as if they had that max demand for the entire month if it was just for 1 night.

However, I had a call with AGL today and she explained you only get charged the demand charge on a per day basis. So the 1 night I use 8kWhs in 30 minutes, I only get charged the demand charge for that day. Unlike AGLs own explanation on https://www.agl.com.au/rates-contracts/electricity-tariffs?rmxt3r=vwt06z

Which states it's the max on 1 day times by the number of stuff in a billing period.

[_Mark_ · Accepted solution]

Hi @runbren, while I do get your argument for daily charges, I want to clear up what sounds like some misinformation. The webpage you linked is correct: Demand is calculated from the highest demand peak hit and applied to each day of the month. It is only recalculated if you hit a higher peak, and then that new peak would apply to every day. It's not calculated day by day as the call you had sounds like it was telling you, and i'm sorry if that led to any confusion!

Thanks,
Mark.

[runbren]

Thanks Mark.

I did explain to the AGL staff member several times how the AGL's website says it calculates the max and applies it to all days of the billing period and she kept insisting that different areas calculate it differently and mine is calculated on a daily basis. Thanks for clearing that up. 

I have yet to receive a bill with this new plan, so I'll see what that turns out to be.

1 other peice of information that i get conflicting answers to is how can AGL calculates the demand against a max kW for a 30 minute period? The unit of the demand charge is c/kW/day but AGL's explanation page is actually apply the demand to the max kWh for a 30 minute period. There is a massive difference between charging someone for the energy used in 30 minutes and the max instantaneous power consumed.

For example, I can use 8kW for 1 minute. That's 0.133kWh if I use no other energy in that 30 minuts, assuming this is the max for the billing period.

So is AGL charging:

8(kW)*2(hour)*0.25(c)*30(days) = $120 for the billing period as per the site

or

0.133(kWh)*0.25(c)*30(days) = $0.99 for the billing period

Obviously no one would only use 8kW for 1 minute and 0.133kWh would be the max 30 min energy consumption for the month but I'm just using it as an example to illastrate the difference.

[Giff]

Actually neither.

0.133(kWh for 30 minutes)* 2 (consumption for 1 hour)*0.25(c)*30(days) = $1.99 for the billing period.

The purpose of the demand charge is to encourage lower usage during peak times, but you are heavily penalised for the entire month if you digress just for just one 30 minute period.

[runbren]

Hi Giff,

Thanks for you reply.

That's interesting that you are multiplying the energy consumption of 0.133 by 2.

The reason the 8kW power measurement is multiplied by 2 is because it is power for 30 minutes i.e. kW x h = kWh (energy i.e Joules). Since 0.133kWh is already a measurement of energy you don't need to multply by 2 to convert to an hour consumption. Then it would be kWh x h = kW(h)^2 which is not a measurement of energy or power.

This is one of the reasons for my confusion with the demand charge having a unit of c/kW/day when even AGLs explanatory webiste uses the demand charge as if it's unit is c/kWh/day.

[Giff]

In order to get kW from the energy consumption, divide 0.113kWh by 0.5h (30 minutes). 

- the h’s cancel out and we just have kW

- dividing by 0.5 is the same as multiplying by 2. 

Cheers

     Giff

[runbren]

Hi Giff,

Thanks again. I see what you mean. I found the source of my confusion. AGLs explanation has this which contradicts. I thought the calculation was multiplying the kW by 2 but they're actually multiplying the kWh by 2, which makes way more sense.

AGL should really change that graph.

[schmidtronald24]

If agl. wants.to.keep.cusomers they need to rid themselves of high peek power AMD only charge what people use.

Agl. Has been warned of our separation if my power bill is to high.

They think once in always in.

No you don't double ones power bill over nightsa.power networks need a talking to also for the meter installed I won't pay for and didn't want

I am here and true 

Tassie and partner Ron orroroo