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Demand Meters

Your Commercial Electricity Meter

A commercial meter is different than a residential meter in that it measures energy usage and "demand", whereas a residential meter only measures energy usage.

Energy is the amount of electricity used and is measured in kilowatt-hours (kWh). Demand is the rate at which energy is delivered to an electrical load and is measured either in kilowatts (KW) or kilovolt-amperes (kVA). Your billing demand refers to the maximum amount of energy drawn through the meter at one time during your most recent billing cycle.

Commercial customers will notice both a demand charge and an energy charge on their bill. Demand charges depend on your rate class and time of the year which you require electricity.

What is Electrical Demand?

Electrical demand is the amount of electricity you require at a given point in time. The demand charge on a bill for a commercial service is the peak demand required to satisfy your electricity needs during your billing cycle. To understand how demand is measured let's follow this example: 
 
If 10 kW of electric heat, a 4.5 kW water heater, 3 kW of lighting and 15 kW of cooking load are all operating at the same time, the demand would be 32.5 kW (10 kW + 4.5 kW + 3 kW + 15 kW = 32.5 kW). The relationship of this demand to energy usage (kWh) is if the 32.5 kW of demand were in constant operation for ten hours, the amount of energy used would be: 32.5 kW x 10 hours = 325 kWh.

Kilowatt demand is a measure of the average rate at which kilowatt-hours are used during a certain time interval. The time interval our meters use is 15 minutes. The demand meter indicates the maximum, 15 minute, kilowatt demand during the applicable billing period.

At the end of the billing period, Newfoundland Power records both the kilowatt-hour and the maximum kW (or kVA) demand readings from the meter. The demand register is then reset so it can start to measure the maximum demand for the following month.

Why We Measure Demand

Instantaneously, any time of the day or night, electricity is there to power everything from your family's microwave to the high-speed presses that print your daily newspaper. Unfortunately, large amounts of electrical energy cannot be stored. It must be supplied to customers on demand, whenever their equipment calls for it and in whatever quantity they need.

We need to plan for the maximum electrical demand that could be expected during the year. In essence, we must reserve capacity for customers on our system and ensure our equipment is properly sized to meet the electricity needs of our customers. The cost associated with this reserve capacity varies between non-Winter and Winter (December to March) periods when energy requirements on the system are greater. This is why demand is charged at two different rates depending on the time of year.

By measuring demand, we are better able to ensure our equipment is adequately sized and customers are fairly charged for their capacity needs.

Tips for Controlling Electrical Demand

If you have thermostatically controlled appliances such as heaters, ovens and grills, turn on one appliance every 15 to 20 minutes instead of all at once. Thermostatically controlled appliances require more electricity when heating up than during ongoing operation. Staggering start-up times will reduce demand and save you money!

If you have flexibility in your work schedule, run high-demand equipment after regular business hours when your overall electricity usage is lower.

Indoor lighting can account for a significant amount of energy. If you have incandescent lighting, consider replacing them with high-efficient fluorescent lights or LEDs to lower energy usage and reduce demand.

For more commercial energy saving tips or to learn about our Business Efficiency Program, please visit takeCHARGE.

Reading Commercial Meters

Most meters used by Newfoundland Power have digital displays making them easier to read. A commercial meter will flash two different readings. The first reading is the total energy flowing through the meter (measured in kWh). We derive the amount of energy used in your current billing cycle by subtracting the read we obtained last month from the read we obtained this month.

The second display is for demand. This measures the maximum amount of electrical load you required at any given time during the billing month. Your meter is programmed to automatically reset the demand register every month. The maximum demand for that billing period is stored in the meter.