# How to convert kWh to half hour time series?

I have an energy reading of 50 kWh. The duration of this reading is from 09:00 to 10:30 (or 1.5 hours).

If I want to make a 30-minute time series, how could I convert 50 kWh into 3 half-hourly intervals?

Is it 50 kWh / 1.5 hours? This would give 33.33 kWh/2 which seems wrong.

It seems like a simple concept but I am utterly confused so apologies for my ignorance.

• So you spent 50kWh in 1.5 hours, so in one hour you were spending (in average) 50/1.5 = 33.33kWh, so in half a hour it would be 33.33/2=16.66kWh. Commented Aug 17, 2022 at 20:46
• electronics.stackexchange.com/questions/361936/… seems very closely related. Commented Aug 18, 2022 at 5:24
• If you divide kWh by h you get kW... So what you calculated by dividing 50kWh/1.5h is getting the average power consumption of 33.3kW. You can now multiply that by 0.5h which gives you 16.7kWh per half hour slot. Never forget the units when calculating stuff. Commented Aug 18, 2022 at 6:26

The answer depends on what units you want: an energy consumption of 16.67 kWh in each 30-minute segment or an average power of 33.33 kW averaged over each 30-minute segment. Since you just have a chunk of energy consumption and some time over which it was consumed, you can't get more temporal granularity without additional information.

I have an energy reading of 50 kWh. The duration of this reading is from 09:00 to 10:30 (or 1.5 hours).

Is it '50 kWh / 1.5 hours?'

That's energy / time, which is power. 50/1.5 = 33.33 kW. That's the average power over your interval.

This would give 33.33 kWh/2 which seems wrong.

Yes, it is wrong. kWh/2 is not a unit. If that /2 is meant to scale the number, then it makes the number wrong.

If I want to make a 30-minute time series, how could I convert 50 kWh into 3 half-hourly intervals?

Do you want an energy time series, or a power time series? Energy would be easier, but power is only a scaling by time if you want that. Pay careful attention to whether the unit is kW (power) or kWh (energy).

Here you have to make an assumption. A common assumption is that the power constant over whole period, so the energy consumed in each of the three intervals is 16.67, 16.67 and 16.67 kWh. This is why an energy series is easier, you just have to make sure the three data points add to your original total energy of 50 kWh. But if you want the average power in each 30 minute interval, then divide each by 0.5 hours to get 33.33 kW. That's not only the power averaged over the 30 minute interval, but also the instantaneous power at any point during the interval. You would get this power consumption from 11 3 kW kettles.

If the power was not constant, then you might have different amounts of energy consumed in each interval. A series of consumption figures of 20, 10, 20 kWh, or even 0, 50, 0 kWh, would still give you a total consumption of 50 kWh.

It sounds like what you know is that you used 50 kWh of energy over a 1.5 hour time interval.

This is similar to observing a car in two different places 50 km apart after 1.5 hours. You can say that your average rate of energy consumption was 50 kWh / 1.5 hr = 33.3 kW.

Just as you could say that the car's average speed was 50 km / 1.5 hr = 33.3 km/hr.

But what if the driver sped at 50 km/hr for 30 minutes, then pulled over and napped for 30 minutes, then drove 50 km/hr for the final 30 minutes? With only the two observation points, you have no way to know how fast the car actually traveled at any particular moment.

So it is the same thing with the energy usage. In a sense, it is not possible to take data sampled at 1.5 hour intervals and somehow convert it to accurate data sampled at 0.5 hour intervals. Information has been permanently lost. You can only create the 30 minute data series by making the assumption that the power use was constant during the interval. That may be good enough depending on what your purpose is.

One more analogy. What you are trying to do is add detail to a blurry picture. Generally it can't be done after the picture has been taken. If it was not in focus when you took the picture, it never will be.

• Oh, yeah, the way to do it, if you just use the average consumption, is 33.3 kW * 0.5 h = 16.5 kWh used in every 0.5 hour interval. Commented Aug 18, 2022 at 6:06