Unexpected 25% Jump in School's KW Usage 4

[ELMPE1]

I have been invited to a meeting with a local school to discuss an unexpected 25% jump in the KW usage of their monthly High School building bills (last 2 months). The building (classrooms, gym, band hall) was built in 2002, and KW usage has been repeatable over the years, so the 25% jump is extraordinary. They say they have had an increasing amount of "brownouts" in recent months (...although in these rural settings a large number of brownouts from the utility is not at all unusual; this may or may not be connected to the current problem. However, some people at the school swear these brown-out occurrences are much higher.) I do not have many details at the present, but wanted to ask for help concerning this "brainstorming" meeting.

The electric delivery provider (Co-Op) has been involved and has said that they plan to change out the meter to make sure this is just not a metering problem. The electric delivery provider has not to date found any other problem.

I am assuming this initial meeting with the school will result in approval to bring in an electrical contractor to fully check out the electrical supply (after waiting to see if the meter replacement fixes the high KW billing problem).

Any ideas of possible causes to discuss or what would be recommended as a path forward different than the above would be greatly appreciated by me and the folks at the school.

 

[jghrist]

Thermal imaging of the roof might reveal damage that results in heat loss. Also have an HVAC contractor inspect the system.

 

[jraef]

Double check that it is truly an increase in the kWH use, as opposed to an increase in the bill. The issues may not necessarily be related. I have seen several times where voltage anomalies, such as your frequent "brown outs", can cause an anomaly on the demand meter so they get hit with a whopping Peak Demand penalty that increases the bill even though the overall kWH use stays the same. I have a consultant I work with on these sorts of things and he has provided documentation to PG&E, our largest PoCo in Northern Calif., to successfully reverse the penalties because he proved that the Demand spikes coincided with their voltage dip. Mind you he had recording meters installed to create that data base, but it's something worth investigating.

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[MikeHalloran]

Also check for correlatable changes in personnel.

I once discovered that a new night watchman had been, on his own initiative, adding cold water to our hot water heating system until the 'head' gage way up on the wall stopped rising. ... by which time the system relief valve had discharged an equivalent quantity of heated water down a drain.

The plant manager had noticed a step change in our energy cost that correlated with that watchman's arrival.





Mike Halloran
Pembroke Pines, FL, USA

 

[waross]

The most common failure modes of the old mechanical KWHr meters resulted in under-billing.
Not so the new electronic meters. I have seen electronic meters fail and over-meter. The utility acknowledged the error and credited the customer with the overbilled amount.
Note, an increase in ambient temperature from just below the A/C cut-in to just above the A/C cut-in temperature will often cause a dramatic rise in the consumed KWHrs.
If you have an electronic meter it may be programmed to record parameters periodically.
I have received from utility metering departments a file downloaded from an electronic meter. It listed:
Voltage per phase,
Current per phase,
Kilo-Watts,
Kilo-VARs,
Power factor.
The readings were at 15 minute intervals over a months time. It is worth an inquiry. If an electronic meter is in use it may be possible to obtain readings. If the meter is not programmed to save parameters you may be able to arrange for it to be programmed. You may have to purchase an internal battery for the meter. The battery is not needed for revenue metering but is needed for the internal clock for TOD metering and data storage.
Bottom line, check the weather records for the month in question to see if the weather has been unseasonably warm. I had to field this issue several times a year when working in Central America.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

I'd get good monitoring gear on the facility before the meter gets replaced and the usage magically drops.

I'd also want to know where the brown out was - PoCo side or customer side.

Otherwise The Meeting is going to be speculation about speculation.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[potteryshard]

A good internal audit to determine what loads they have and when they run is also useful. I've gone out to sites where the customer has sworn that 'nothing was running', but yet several breakers were too hot to touch.

I'm with jghirst however... As what is likely the single largest load, check into that HVAC. Depending on the size and type of the system, a relatively minor refrigerant loss, an air or water valve in the wrong position, an acess door left open, too-tight or mis-aligned belts, and so on can add up to large costs.

 

[magoo2]

What do you consider a brownout? I did some tests with a variac connected to a table lamp and, as I reduced the voltage from rated, I never saw anything brown.

 

[waross]

After rereading your original post, there may be another possibility;
Voltage regulation is frequently an issue in rural areas due to long circuits, voltage drop, and not enough load to justify the cost of voltage regulators.
Utilities from time to time address low voltage or "brown out" conditions by raising the voltage at the supply end. This often leads to high voltages to some customers during periods when the loads that are responsible for the low voltage conditions are off line.
Investigate whether the utility has recently raised the voltage on your distribution line.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Compositepro]

This was also an exceptionally hot summer in the southern U.S.