Toronto District School Board
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Action Solar Schools Calculating Solar Generation

Know Your Solar Power!

The TDSB has 358 buildings with solar panel installations, with a total of 38,357 kW of carbon neutral power generation! Over 1 year that works out to about 59,851,304 kWh of electricity, enough to power about 6,300 homes*!

* (Toronto Hydro estimates the average home uses 9,500 kWh per year)


Solar Energy - Key Terms

  • Kilowatt-hour (kWh): unit of energy equal to 1 kW of power sustained for 1 hour. More info
  • Carbon offset: a reduction of the carbon emissions normally produced by non-renewable sources. More info
  • Derate Factor: a factor used with all solar installations to account for electrical and efficiency losses in the entire system (e.g. dust and snow on panels, general climate, and panel age). More info
  • Marginal Emissions Factor (MEF): takes into account the average CO2 produced by all electrical generation, especially at peak times. More info


Calculate energy generated at a Solar School

The formula to calculate energy generation is:

size of system in kW x derate factor* of 0.75 x # of hours of sun/day x 365 = total kWh
Toronto gets about 5.7 hours of sun a day on average. The TDSB's total possible energy generation works out to:
38,357 x 0.75 x 5.7 x 365 = 59,851,304

Can you calculate how much your school's panels generate?
(Use the table on the Solar School page to find the kW rating for your panels.)

* (The derate factor of the system at your school may be slightly different.)


Calculate CO2 Reduction at a Solar School

The formula to calculate CO2 reduction is:

kWh generated x MEF* in g CO2e per kWh = total gCO2e
For all of the TDSB, that works out to:
59,851,304 x 134 = 8,020,074,719 gCO2e

When we divide by 1,000 to get kilograms, we get 8,020,075 kg CO2 reduced in one year!

In this case, we should divide by 1,000,000 to convert to tonnes, and get 8,020 tonnes CO2.

Calculate what your school's reduction in CO2 is from solar panels. Use both the energy generated and CO2 reduction from your school's panels to fill in the bubbles on your Solar Poster (see below).

* (In Ontario, we have a respectable MEF of 134 g CO2e per kWh. For comparison, in Massachusetts where coal is used, their MEF is 384 g CO2e per kWh.)


Promote your Solar Power and Climate Action in your Community

poster of a solar school with solar panel and stats Download an 11" x 17" Solar School poster for your school and promote your solar energy generation and carbon offset. For a 24" x 32" glossy poster contact, if your school doesn't have one.


Find out more about solar energy and greenhouse gas emissions: