Electrical Energy Calculator - Ontario

This electrical energy calculator was created to support GreenLearning's Energy Revealed program.

Instructions

To use the calculator input the watts of the device you are investigating and the minutes a day in use. Once you click on 'Calculate Energy' the electricity used, greenhouse gases emissions (GHGs) produced and cost of electricity will be displayed.

Kilowatt Hours

Why is this important?
When you turn on any electrical device, it uses electricity and you are charged for the amount used. This amount varies greatly depending on the device and the length of time it is used. You need to know the unit of measure for electricity.

What’s a watt?
A watt (W) is the unit used to measure the flow of electricity.  Look at your device and find out the device use in watts. This hair dryer uses 1600W.  
A watt is a very small unit so kilowatt is used most often.
1 Kilowatt (kW)= 1000 watts
Convert from watts to kilowatts by dividing by 1000.

1600 W = 1600/1000 = 1.6 kW
The total amount of electricity used depends on how long the device is on. The unit for this is kilowatt hour (kWh).  
kilowatt hour = kW x hours

If the hair dryer is used for 4 minutes per day this amounts to:
4 minutes x 365 days
= 1460 minutes
= 1460 / 60 minutes per hour = 24.33 hours in a year.

In one year the hair dryer uses:
1.6 kW x 24.33 hours = 39 kWh

Greenhouse Gases

Why is this important?
The production of electricity produces by-products called greenhouse gases (GHGs).  These 7 gases cause changes in the upper atmosphere. Most climate scientists agree that the main cause of the current global warming trend is the over-production of GHGs.

GHG Emission Sources
Some sources of electricity production emit more GHGs than others.  Burning coal to generate electricity produces the highest GHGs and renewable energy sources produce almost no GHGs. In Ontario, electricity generates on average 0.077 kilograms of GHGs per kilowatt hour (.077 kg/kWh).
Save Energy, Save the Environment
Governments, businesses and citizens want to reduce GHGs emissions and the impacts of climate change.

Back to the hair dryer. It used 39 kWh in a year and in Ontario each kWh emits .077 kg GHG:
39 kWh x .077 kg/kWh = 3 kg GHG

Electricity Rates

Why is this important?
Electric bills can get very expensive. Everyone is trying to save money. Cost is a big motivating factor in energy conservation and efficiency.
In Ontario, electricity is priced depending on the time of day. This encourages people to adjust their activities in order to move thier electricity to off-peak and mid-peaks times. This also helps level the demand for electricity and reduce GHG emissions. During off-peak time the electricity is generated by hydroelectricity stations and nuclear generators that are always on and produce low GHG emissions. During on-peak high demand times, natural gas generators are turned on. The time-of-use rates change with the seasons as our electricity use changes. Summer peak is in the afternoon when it is hot and air conditioning use is high. The short winter days put the peaks in the morning and late afternoon.

Rates

Off-Peak:  $0.101/kWh
Mid-Peak:  $0.144/kWh
On-Peak:  $0.20.8/kWh

Time-of-Use for Winter Period (November 1 to April 30) 

Off-Peak:  7 pm - 7 pm Weekdays
all day Weekends and holidays
Mid-Peak:  11 am to 5 pm Weekdays
On-Peak:  7 am to 11 am Weekdays
5 pm to 7 pm Weekdays

Time-of-Use for Summer Period (May 1 to 30) 

Off-Peak: 
7 pm - 7 pm Weekdaysall day Weekends and holidays
Mid-Peak:  11 am to 5 pm Weekdays
On-Peak:  7 am to 11 am Weekdays5 pm to 7 pm Weekdays
To run the hair dryer for one year costs:
Off-peak 39 kWh x $ .101 = $3.94
Mid-peak 39 kWh x $ .144 = $5.61
On-peak 39 kWh x $ .208 = $8.11