load factor

[Hameedulla-Ekhlas]

Greeting all,
A power plant runs at its 0.6 load factor. Does it mean at its 60% capacity out of 100%.

 

[ohmhead]

Well ill take a guess lets say the power output over time during a time period of load not it max output .

So i say no its not percent of total output .

 

[mivey]

It means that on average it runs at 60% of the plant peak (the plant capacity may equal the peak but is usually higher).

load factor = energy / peak power / time.

For example: 109500_kWh in a month, 250_kW peak for the month, 730 hours in a month. 109500/250/730 = 60% load factor.

Add:
For % utilization of capacity: utilization % = energy / peak capacity / time.

For example: 109500_kWh in a month, 250_kW peak for the month, 730 hours in a month 500 kW capacity. 109500/500/730 = 30% utilization

Add 2: The load factor is an indicator of load steadiness.

 

[Hameedulla-Ekhlas]

It means that on average it runs at 60% of the plant peak (the plant capacity may equal the peak but is usually higher).

load factor = energy / peak power / time.

For example: 109500_kWh in a month, 250_kW peak for the month, 730 hours in a month. 109500/250/730 = 60% load factor.

For % utilization of capacity: utilization % = energy / peak capacity / time.

For example: 109500_kWh in a month, 250_kW peak for the month, 730 hours in a month 500 kW capacity. 109500/500/730 = 30% utilization

thanks for good information.

 

[charlie b]

load factor = energy / peak power / time.

May I beg the favor of a reference source that confirms that equation? I submit that the NEC does not define the phrase, and I have not found a clear "industry standard" definition either.

Second question: What is "time" in your equation? That is,

1. Is it the amount of time the plant is in operation?
2. Is it the amount of time the plant is at the peak power value?
3. Is the total amount of time during which the energy value was measured (in other words, if the "energy" number was used during one month, then is the "time" number the total hours in a month)?

The closest thing I have found to a definition of "load factor" was "average divided by peak." That is the same as your equation, if the "time" number comes from my item 3 above.

 

[Hameedulla-Ekhlas]

May I beg the favor of a reference source that confirms that equation? I submit that the NEC does not define the phrase, and I have not found a clear "industry standard" definition either.

Second question: What is "time" in your equation? That is,

1. Is it the amount of time the plant is in operation?
2. Is it the amount of time the plant is at the peak power value?
3. Is the total amount of time during which the energy value was measured (in other words, if the "energy" number was used during one month, then is the "time" number the total hours in a month)?

The closest thing I have found to a definition of "load factor" was "average divided by peak." That is the same as your equation, if the "time" number comes from my item 3 above.

I will give you some information it may help you.

Load factor: It is defined as the ratio of average load to maximum demand. Load factors and demand factors are always less than unity. Load factors play an important part on the cost of generation per unit. The higher the load fctor the less will be the cost of generation per unit for the same maximum.

Load factor = Average load / Maximum demand

not Peak

The example which is given by mivey is not load factor. it is called capacity factor or plant factor.

Plant or capacity factor: it is defined as the ratio of actual energy produced in kilowatt hours(kWh) to the maimum poosible energy that could have been produced during the same period

Plant Capacity Factor = Energy / (C x t)

E: Energy produced (kWh) in a given period
C: Capacity of the plant in kW
t: total number of hours in the given period

Here "C" can be equal or higher as mivey has pointed than the load.


Note: According to load factor formula, it is Power ( MW or kW ) not energy (kWh or MWh)

Where you have seen this "load factor" was "average divided by peak."

 

[mivey]

May I beg the favor of a reference source that confirms that equation? I submit that the NEC does not define the phrase, and I have not found a clear "industry standard" definition either.

For now, I would have to be the source. It is a term used in the utility industry that I learned long ago. I have a decent library so I'll see if I can scare up a published source.

Second question: What is "time" in your equation? That is,

1. Is it the amount of time the plant is in operation?
2. Is it the amount of time the plant is at the peak power value?
3. Is the total amount of time during which the energy value was measured (in other words, if the "energy" number was used during one month, then is the "time" number the total hours in a month)?

The closest thing I have found to a definition of "load factor" was "average divided by peak." That is the same as your equation, if the "time" number comes from my item 3 above.

Door #3. It is the same as average divided by peak. The average value is not stored by the meter so we usually have to start with kWh, kW, and the time between readings.

The only time I could think of that someone might run across it on the retail side is in the rate. If the EC can help the customer improve their load factor, they may qualify for a high load factor rate. Load controls can also help manage the peak which, in turn, increases the load factor (reduces peak demand). Both can reduce the costs with certain type rates.

 

[mivey]

I will give you some information it may help you.

Load factor: It is defined as the ratio of average load to maximum demand. Load factors and demand factors are always less than unity. Load factors play an important part on the cost of generation per unit. The higher the load fctor the less will be the cost of generation per unit for the same maximum.

Load factor = Average load / Maximum demand

not Peak

If you are using the term load to mean power, then you are correct. Peak demand and maximum demand mean the same thing.

The denominator can also be peak billing demand. With that, it is possible to get ratios of more than unity. Using billing demand is not a true measure of the load by itself but includes the impact of the supply costs.

The example which is given by mivey is not load factor. it is called capacity factor or plant factor.

Plant or capacity factor: it is defined as the ratio of actual energy produced in kilowatt hours(kWh) to the maimum poosible energy that could have been produced during the same period

Plant Capacity Factor = Energy / (C x t)

E: Energy produced (kWh) in a given period
C: Capacity of the plant in kW
t: total number of hours in the given period

Here "C" can be equal or higher as mivey has pointed than the load.

You are talking about the % utilization that I added to my post. The first part of my post is indeed about load factor.

Note: According to load factor formula, it is Power ( MW or kW ) not energy (kWh or MWh)

Energy divided by time is power. You should know this.

 

[Hameedulla-Ekhlas]

load factor = energy / peak power / time.

.

In the above formula peak power you mean peak demand or peak capacity?

 

[mivey]

In the above formula peak power you mean peak demand or peak capacity?

peak demand

 

[Hameedulla-Ekhlas]

peak demand

Yes, then it is a load factor.

I thought it is a peak capacity that is why I refered the plant capacity factor.

 

[mivey]

May I beg the favor of a reference source that confirms that equation? I submit that the NEC does not define the phrase, and I have not found a clear "industry standard" definition either.

For now, I would have to be the source. It is a term used in the utility industry that I learned long ago. I have a decent library so I'll see if I can scare up a published source.

OK here are few. Let me know of you need more:

Electric Distribution Systems Engineering Manual-EBASCO/Electrical World, 1982, Vol 3, Ch11-E507 (pg 105):

...the load factor is the ratio of the average load over a designated period to the peak load occuring in that same period.

Demand Tables-REA Bulletin 45-2, June 1963, pg 7:

A demand of 254 kW for 500 consumers ... and 200 kWh/mo/consumer...
The actual load factor equals:
(Consumers x kWh/mo/consumer) / (kW x hours) = (500 x 200) / (254 x 730) = 54.0%

Standard Handbook for Electrical Engineers-13th Ed-McGraw-Hill, 1993, Sect 12-40, pg 12-17:

Generating unit capacity factor should not be confused with system load factor, which is the ratio of the average system load to the peak system load.
Annual load factor = total annual load_MWh / (annual peak load_MW * 8760_h)

Power Distribution Planning Reference Book-Marcel Dekker, 1997, pg 56:

Load factor is the ratio of the average to the peak demand. The average load is the total energy used during the entire period (e.g., a day, a year) divided by the number of demand intervals in that period (e.g., 24 hours, 8760 hours). The average is then divided by the maximum demand to obtain the load factor, as
LF = (kWh/hrs) / kW demand = kW average / kW demand = kWh / (kW demand x hrs)

 

[charlie b]

OK here are few. Let me know of you need more:

I found one more myself. I now remember having found this one before, but it was in a text book I keep at my office, not at home.

Load Factor: The ratio of the average load over a designated period of time to peak load occuring in that period.

Turan Gonen, "Electric Power Distribution System Engineering."

Thanks.