Convert KWH Metered Consumption to Peak KW Demand

[tigerbait]

Does anyone have any suggestions as to what multiplying factors are best to use in converting monthly KWH consumption to peak KW demand for residential customers?

Also, I am wondering what type if success have others experienced using this method when there is no other information available?

 

[CHDean]

With just consumption data I think it's pretty much impossible to extrapolate a peak demand. Peak demand is measured in windows of time. In a residential setting demand will swing with time of day and season due to heating/cooling loads or lack there of. Even in industrial
systems new peaks may not occur for long periods.

I assume that you are looking at a utility generated bill.
It may be possible to obtain that type of information from them depending on the complexity of the metering device they use. The other recourse would be to install a portable device temporarily to capture the information. If you're trying to split a bill between multiple users, beware of the slippery slope of generating power bills. State laws vary wildly, and it only takes one angry customer to start an inquisition.

 

[dpc]

I agree with CHDean, you can't determine peak kW from monthly kWh. You can only determine **average** kW.

You can ask the power company if they have any peak demand data from the meter. You might also take a look at the meter itself. On older meters, the demand register can be read from the front of the meter, although you have no way of knowing when it was last reset.

Residential customers are rarely billed for demand, so I doubt if the data is available.

 

[busbar]

For US regions, EPRI(.org) or EEI{.org} may have fairly detailed data, but expect to find a platinum price tag on such information for non-members. It is possible that some utilities, or state public-utility or energy commissions may have general information at a lower price. Some utilities may consider this information as proprietary in the leaner, deregulated setting.

Another potential source may be IEEE Transactions on Power Delivery, associated conference records or citations in related consensus standards.

 

[pablo02]

One of the reasons the peak demand is hard to interpolate from the energy use is that the peak is usually measure in 15 minute windows while the energy used over the month covers every increment of time -- as mentioned above, the residential usage is not normally metered for peak demand, I suspect because the demand won't justify the additional cost of the meter and it may not affect what the residential customer pays anyway --

they had a time-of-day pricing implemented for (as requested by the residential customer) in one of the NW states (Washington??) -- they were to get a slight break on their usage (cents/kwh) by shoving all their descretionay loads (washing dishes, washing clothes, drying clothes, etc) to the evening hours and as a result, I recall that many if not most of the residential users saw their bill actually go up -- after numerous complaints, and possibly pending lawsuits (I don't have the artical available), the program was dropped...

 

[jghrist]

If you can obtain a copy of REA Bulletin 45-2, Demand Tables, it includes a method of calculating kW from kWh data using the REA "A" and "B" factors that are included in many commercial distribution analysis packages. I don't know if it has ever been updated (it isn't on the RUS website), and my copy is from June 1963, using load data collected in 1954-1955 from systems around the USA.

There are a series of tables relating number of consumers to kW demand for different kWh/month/customer.