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Glossary

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Glossary

Arizona Corporation Commission (ACC)

The Arizona Corporation Commission (ACC) is a state agency that regulates investor-owned electric and gas utilities in Arizona. The ACC also regulates water and wastewater utilities, telephone companies, transportation companies, and securities broker-dealers. The five Commissioners are elected by the voters of Arizona to serve four-year terms.

Arizona Public Service (APS)

APS is an electric utility company that covers part of the Phoenix, Arizona Metropolitan area and other parts of Arizona.

See our web pages on APS:

Buy Back Rate

This is the rate at which the utility company credits customers per kilowatt-hour (kWh) for sending electricity from their home solar panel system to the utility grid.

The utility installs a second meter at every home that goes solar in order to measure the amount of electricity sent to to the utility grid. Customers receive a credit on their utility bill each month for the amount of kilowatt-hours they sent to the grid that month.

Demand

Demand is the amount of electricity in kilowatts (kW) that the house is using simultaneously at any given time. The more appliances that are run together, the larger the demand is.

For example, the average air conditioner uses 4 kW of demand and the average clothes dryer uses 3.5 kW of demand. When the air conditioner and clothes dryer are run simultaneously in a home, the demand of the home will be 7.5 kW.

Demand Charge

This is a charge that electric utilities include in some of their rate plans. Typically, the utility measures the average demand of a home over a one hour or 30 minute period, and then charges the customer a multiplier of that demand.

For example, if a customer averages 8 kW of demand over the period measured, and the demand charge is $15 per kW, the customer will receive a $120 demand charge on their bill that month.

Demand Manager

A demand manager, also known as a load controller, is a device that is often installed with a home solar panel system. This device limits the total “demand” a house can use. Demand is the amount of electricity in kilowatts (kW) that the house is using at any given time. This is not to be confused with kilowatt-hours (kWh), which is the measure of how much electricity is used over time.

The more appliances that are run together, the larger the demand is. In the Phoenix, AZ area, the appliance that uses the most demand is the air conditioner. An air conditioner can use between 1 kW and 5 kW in demand, depending how big and efficient it is. Other appliances in the home use demand as well, but typically less than the air conditioner.

The demand manager has a demand limit setting, and the circuits of the large appliances in the home are hooked up to the device. Say, for example, the air conditioner uses just under 4 kW and the demand limit setting is at 4 kW.

If someone in the home turns on the electric dryer, the demand manager will cycle the air conditioner off. This is how the demand manager stops the home from going over a certain demand. The device does not stop people from using the large appliances, it just turns off other large appliances to keep the demand low.

Formula: Average Electricity Usage Per Month

To get your average usage, preferably add up your last 12 months usage and divide by 12.

Formula: Kilowatt (kW) to Kilowatt-Hour (kWh)

1 kWh equals one hour of electricity usage at a rate of 1 kW, and thus the 2 kW appliance would consume 2 kWh in one hour, or 1 kWh in half an hour. The equation is simply kW x time = kWh.

Production estimates for solar panel systems are typically done with the following calculations. For a 10 kW system, multiple the system size (10) by the derate factor of 0.8, then multiply by 5 hours of ideal sunlight per day, then multiply by 365 days per year. This is:

Yearly kWh Production: 10 kW x 0.8 derate x 5 hours x 365 days = 14,600 kWh production per year

To find out the size of a solar system from the amount of kWh needed or produced, do the reverse calculation:

Solar System Size: 14,600 kWh / 365 days / 5 hours / 0.8 derate = 10 kW

Formula: Kilowatt (kW) System Size to Amount of Panels

Multiply the kW system size by 1,000 and then divide by the wattage of panels being used. So for a 9.25 kW system using 370 watt panels, the formula would be:

9.25 kW * 1000 / 370 = 25 panels

Formula: Kilowatts (kW) to Watts

kW / 1000 = Watts

Formula: Watts to Kilowatt-Hour (kWh)

Formula for Calculating Watts Into Kilowatt-Hours: kWh = (watts × hrs) ÷ 1,000

Grid Fee (Service Charge)

A grid fee is the amount of money a utility company charges per month to be connected to their grid when you have a grid tied solar system.

Kilowatt-Hour (kWh)

A kilowatt-hour (kWh) is a unit of energy: one kilowatt of power for one hour. Kilowatt-hours are a common billing unit for electrical energy delivered to consumers by electric utilities. The kilowatt-hour is a composite unit of energy equal to one kilowatt (kW) sustained for (multiplied by) one hour.

Net Metering

A system in which solar panels or other renewable energy generators are connected to a public-utility power grid and surplus power is transferred onto the grid, allowing customers to offset the cost of power drawn from the utility.

Off-Peak Utility Hours

Off-Peak utility hours are times of day when electricity demand is lower. This is typically on the weekends and in the mornings during the weekdays. As a result, utilities charge less during Off-Peak hours. If you’re trying to save money on your electric bill, one of the best things you can do is use your large appliances, like your air conditioner and clothes dryer, only during Off-Peak hours.

Offset

Offset is the percentage of your home’s total electricity usage from the last year that will be produced by your solar system over a year’s time.

On-Peak Utility Hours

On-peak utility hours are the times of day when electricity demand is at its highest. In most cases, this means during the daytime when people are using lots of appliances and air conditioners. As a result, utilities charge more for electricity during on-peak hours in order to cover the increased demand.

If you’re trying to save money on your electric bill, one of the best things you can do is avoid using electricity during on-peak hours. This may mean turning off your air conditioner during the day or doing laundry at night.

Salt River Project (SRP)

Electric utilities typically charge different amounts depending on what season of the year it is. The utilities define the seasons by a period of months.

For example, APS defines Winter as November through April and Summer as May through October.

Seasonal Energy Rates

Electric utilities typically charge different amounts depending on what season of the year it is. The utilities define the seasons by a period of months.

For example, APS defines Winter as November through April and Summer as May through October.

Tier 1 Solar Panels

Tier 1 solar panels are the gold standard for residential solar installations in the USA. Tier 1 solar panels manufacturers are defined as those that:

  • Have been producing solar panels for 5 years or more
  • Are either publicly listed on a stock exchange or have a strong and stable balance sheet
  • Have fully-automated production and a high degree of vertical integration
  • Invest significantly in marketing their brand
  • Have a highly regarded reputation within the industry for quality and service

Time-of-Use Plan

This refers to a utility plan that charges different amounts per kilowatt-hour depending on the time of day and the day of the week. The typical segments are “On-Peak” and “Off-Peak”, but some utilities may have additional segments.

On-Peak times are typically when homeowners use the most amount of energy, in the afternoon on the weekdays. For example, the Arizona Public Service (APS) utility has On-Peak times on weekdays from 4PM to 7PM. APS Off-Peak times are on weekends and certain holidays.

Usage Charge

The cost of buying electricity from a utility company, typically measured in kilowatt-hours (kWh).

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What is Arizona Corporation Commission? What does ACC mean?

The Arizona Corporation Commission (ACC) is a state agency that regulates investor-owned electric and gas utilities in Arizona. The ACC also regulates water and wastewater utilities, telephone companies, transportation companies, and securities broker-dealers. The five Commissioners are elected by the voters of Arizona to serve four-year terms.

What is Arizona Public Service? What is APS?

APS is an electric utility company that covers part of the Phoenix, Arizona Metropolitan area and other parts of Arizona.

See our web pages on APS:
Arizona Public Service (APS)
APS Solar Programs
APS Rate Plans (Before Solar)
APS Solar Buy Back Rate
APS On-Peak Hours
APS Off-Peak Hours
APS Service Areas, Locations, and Substations
APS Solar Rebates

What is a Buy Back Rate (AKA Buyback Rate)?

This is the rate at which the utility company credits customers per kilowatt-hour (kWh) for sending electricity from their home solar panel system to the utility grid. The utility installs a second meter at every home that goes solar in order to measure the amount of electricity sent to to the utility grid. Customers receive a credit on their utility bill each month for the amount of kilowatt-hours they sent to the grid that month.

What is the APS Solar Buyback Rate?

From September 1, 2022 through August 31, 2023, the APS solar buyback rate is 8.465 cents per kWh.

What is the SRP Solar Buyback Rate?

As of November 2022, the SRP solar buyback rate is 2.81 cents per kWh.

What is electrical Demand?

Demand is the amount of electricity in kilowatts (kW) that the house is using simultaneously at any given time. The more appliances that are run together, the larger the demand is.

For example, the average air conditioner uses 4 kW of demand and the average clothes dryer uses 3.5 kW of demand. When the air conditioner and clothes dryer are run simultaneously in a home, the demand of the home will be 7.5 kW.

What is a Demand Charge?

This is a charge that electric utilities include in some of their rate plans. Typically, the utility measures the average demand of a home over a one hour or 30 minute period, and then charges the customer a multiplier of that demand.

For example, if a customer averages 8 kW of demand over the period measured, and the demand charge is $15 per kW, the customer will receive a $120 demand charge on their bill that month.

What is Demand Management? What is a Demand Manager? What is Load Controller?

A demand manager, also known as a load controller, is a device that is often installed with a home solar panel system. This device limits the total “demand” a house can use. Demand is the amount of electricity in kilowatts (kW) that the house is using at any given time. This is not to be confused with kilowatt-hours (kWh), which is the measure of how much electricity is used over time.

The more appliances that are run together, the larger the demand is. In the Phoenix, AZ area, the appliance that uses the most demand is the air conditioner. An air conditioner can use between 1 kW and 5 kW in demand, depending how big and efficient it is. Other appliances in the home use demand as well, but typically less than the air conditioner.

The demand manager has a demand limit setting, and the circuits of the large appliances in the home are hooked up to the device. Say, for example, the air conditioner uses just under 4 kW and the demand limit setting is at 4 kW. If someone in the home turns on the electric dryer, the demand manager will cycle the air conditioner off. This is how the demand manager stops the home from going over a certain demand. The device does not stop people from using the large appliances, it just turns off other large appliances to keep the demand low.

What is the formula for Average Electricity Usage per Month in a home?

To get your average usage, preferably add up your last 12 months usage and divide by 12.

How to convert kW to kWh (Kilowatts to Kilowatt-Hours)?

1 kWh equals one hour of electricity usage at a rate of 1 kW, and thus the 2 kW appliance would consume 2 kWh in one hour, or 1 kWh in half an hour. The equation is simply kW × time = kWh.

Production estimates for solar panel systems are typically done with the following calculations. For a 10 kW system, multiple the system size (10) by the derate factor of 0.8, then multiply by 5 hours of ideal sunlight per day, then multiply by 365 days per year. This is:

Yearly kWh Production: 10 kW × 0.8 Derate × 5 Hours × 365 Days = 14,600 kWh Production Per Year

How to convert kWh to kW (Kilowatt-Hours to Kilowatts)?

To find out the size of a solar system from the amount of kWh needed or produced, do the reverse calculation of kW to kWh above:

Solar System Size: 14,600 kWh ÷ 365 Days ÷ 5 Hours ÷ 0.8 Derate = 10 kW

How to convert kW to amount of solar panels?

Multiply the kW system size by 1,000 and then divide by the wattage of panels being used. So for a 9.25 kW system using 370 watt panels, the formula would be:

kW Solar System Size to Amount of Solar Panels: 9.25 kW × 1,000 ÷ 370 = 25 Panels

How to convert Watts to kW?

Watts to kW: kW × 1000 = Watts

How to convert kW to Watts?

kW to Watts: Watts ÷ 1,000 = kW

How to calculate kWh from Watts?

Formula for Calculating Watts Into Kilowatt-Hours: kWh = (Watts × Hours) ÷ 1,000

How to convert kWH to Watts?

Formula for Calculating kWH to Watts: Watts = (kWh ÷ Hours) × 1,000

What is a Grid Fee (Service Charge)?

A grid fee is the amount of money a utility company charges per month to be connected to their grid when you have a grid tied solar system.

What is kWh? What is a Kilowatt-Hour?

A kilowatt-hour (kWh) is a unit of energy: one kilowatt of power for one hour. Kilowatt-hours are a common billing unit for electrical energy delivered to consumers by electric utilities. The kilowatt-hour is a composite unit of energy equal to one kilowatt (kW) sustained for (multiplied by) one hour.

What is kW? What is a Kilowatt?

A kilowatt of electricity is the common measurement for electrical energy. All of the appliances and electronics in your home consume energy measured in kilowatts. A kilowatt is 1,000 watts. Kilowatts are used for measuring electricity because the amount of electricity that appliances consume. For example, an air conditioning unit uses about 4 kW. Stating 4 kW is easier when compared to stating 4,000 watts.

What is a Watt?

A watt is a unit of electricity that measures energy transfer. It was named after the engineer James Watt.

What is Net Metering?

Net metering is a system where excess electricity produced by a solar panel system is sent to the utility grid. The utility company credits the customer for every kWh sent to the grid. The customer only has to pay for the difference between the amount of electricity bought from the grid and the amount of electricity sent to the grid. If the customer sent more electricity to the grid than what was bought, the utility pays the customer per kWh based on the utility’s buyback rate.

What is Off Peak Hours?

Off-Peak utility hours are times of day when electricity demand is lower. This is typically on the weekends and in the mornings during the weekdays. As a result, utilities charge less during Off-Peak hours. If you’re trying to save money on your electric bill, one of the best things you can do is use your large appliances, like your air conditioner and clothes dryer, only during Off-Peak hours.

What is solar Offset? How much solar Offset do I need?

Offset is the percentage of your home’s total electricity usage from the last year that will be produced by your solar system over a year’s time.

In APS territory, you typically want 100% to 110% offset. In SRP territory you typically want 50% to 75% offset.

What are On Peak Hours?

On-peak utility hours are the times of day when electricity demand is at its highest. In most cases, this means during the daytime when people are using lots of appliances and air conditioners. As a result, utilities charge more for electricity during on-peak hours in order to cover the increased demand. If you’re trying to save money on your electric bill, one of the best things you can do is avoid using electricity during on-peak hours. This may mean turning off your air conditioner during the day or doing laundry at night.

What is Salt River Project? What is SRP?

Electric utilities typically charge different amounts depending on what season of the year it is. The utilities define the seasons by a period of months.
For example, APS defines Winter as November through April and Summer as May through October.

What are Seasonal Energy Rates?

Electric utilities typically charge different amounts depending on what season of the year it is. The utilities define the seasons by a period of months.
For example, APS defines Winter as November through April and Summer as May through October.