Rooftop Solar Photovoltaic Installation

In 2014 the Town installed a 100 kW solar photovoltaic system on the roof of the public works garage.

The system is nominally rated at 100 kW though the capacity of the solar arrays totals 118 kW. The power is then converted from direct current that the solar panels generate to alternating current by 9 inverters. From there, it is piped to Hydro One through a meter that records the amount of electricity that is sold to Hydro One.

Hydro One pays the town 54.8¢ per kilowatt hour (kWh) that the town generates.

FIT Program

The system was built under the terms of Independent Electricity System Operator's (IESO) Feed-in Tariff Program.

"The fundamental objective of the FIT Program, in conjunction with the Green Energy and Green Economy Act, 2009 (Ontario) and Ontario’s Long Term Energy Plan, 2010, is to facilitate the increased development of renewable generating facilities of varying sizes, technologies and configurations via a standardized, open and fair process."

By encouraging the development of renewable energy in Ontario, the FIT Program is:

  • helping Ontario phase out coal-fired electricity generation - the largest climate change initiative in Canada;
  • boosting economic activity and the development of renewable energy technologies;
  • creating new green industries and jobs.

Why Mono?

By participating in the Feed-in Tariff Program Mono is honouring its Vision Statement:

"The Town of Mono will be a safe, sustainable municipality where the new Economy, our Environment, our Community and our Natural Heritage can flourish in harmony."

Mono Council made the decision to investigate the option of installing a solar array and to take advantage of the Feed-in Tariff program in 2012. Following a feasibility study, an application was made to Ontario Power Authority (OPA) in January 2013 which was subsequently accepted by OPA in August 2013.

Following a tender process, RESCo Energy Inc. of Mississauga, ON was selected as the contractor with construction beginning in August 2014.

Application to OPA January 2013
OPA approved FIT application August 2013
Council accepts RESCo as contractor 19 February 2014
County issued building permit 18 July 2014
OPA provides notice to proceed 24 July 2014
Construction begins August 2014
Hydro One connection 26 November 2014
System goes live 12 December 2014
   Note that in 2014 the Provincial government merged OPA into IESO.

The System

414 solar panels, each 285 watts, are mounted on the roof of the Public Works Garage. The panels covert sunlight into direct current electricity. This is sent to 9 power inverters that convert the electricity to alternating current. Once converted to AC, the electricity is fed to Hydro One, who sells it to Ontario Power Generation.

Major Components
Component Description Supplier
Solar panels SLA 285 M mono crystalline photovoltaic module Silfab Ontario
Power inverters IG Plus AFC1 11.4-1 UNI three power stage inverter Fronius Canada
Mounting System SCIROCCO® system low ballast flat-roof PV installation hb Solar Inc.
Balance of system & installation RESCo Energy
Click an image to enlarge

The cost & ROI

The entire project, including the cost for Hydro One to install a transformer to receive the generated electricity, was $391,431. This was entirely funded from the Town's reserves of over $5.5 million.

Revenue projections are based on the contract price of 54.8¢ per kWh that IESO pays the town. The more electricity that is generated, the more money the town makes. The caveat, of course, being that power generation is based on how much sunshine we receive. To determine that, we employed the RETScreen Software Suite.

RETScreen is a Clean Energy Management Software system for energy efficiency, renewable energy and cogeneration project feasibility analysis as well as ongoing energy performance analysis. In calculating an energy model, it takes into account historical daily solar radiation data (i.e. how much sunshine we get), photovoltaic panel and inverter efficiencies.

We then added a further factor to account for the panels being fully or partially covered in snow during winter months1.

Based on these calculations, the town estimates that we will generate a total of 132 MWh annually. At the contract price of 54.8¢ per kWh ($548 per MWh), that works out to $72,336 per year. Taking into account inflation, calculated at 3% per year, over its 20 year life the solar array is expected to generate $67,300 per year.

In addition to the initial capital investment of $426,587 we anticipate annual maintenance costs of $5,170. Therefore, our anticipated annual net revenue is $62,130. At that rate, it will take 7 years to re-pay the Town's capital investment.

% of days with snow cover 1
December 25
January 40
February 40
March 30
April 10
1 Calculations of power generated from December through April assume that the panels are covered by snow for the percent of the days shown in each month.

Additionally, the power inverters will need to be replaced at the mid-life point (10 years) at an estimated cost of $40,000. Total annual costs including maintenance and debt retirement (over the life of the system) are expected to be $26,500.

Taking into account the capital cost, annual maintenance and the mid-life costs, over the system's 20 year life, the town anticipates generating a net revenue of approximately $800,000.

Annual costs & debit repayment
Debt retirement2 426,587 / 20 years $21,330
Maintenance $5,170
Total Annual Costs $26,500
2 Capital came from reserves; it was not financed. Debt retirement payments are made to the Town.
Cumulative cashflow, after maintenance & debit retirement

Environmental Benefit

As shown above, the financial motive for investing in a rooftop solar system is significant. Equally important are the environmental benefits of employing renewable energy systems.

If the equivalent amount of electricity that this solar array will produce in one year had to be generated by burning coal, 128 tonnes of greenhouse gases (GHG) would be produced. If natural gas were used to generate the 138 MWh that this system will generate in a year, 69 tonnes of greenhouse gases would be pumped into the atmosphere.

It goes without saying that solar photovoltaic systems, which produce zero GHG, provide a substantial benefit to the environment.

GHG Emissions Equivalent
(138 MWh per year)
  Solar Coal Natural Gas
Greenhouse gases generated ( tCO2) 0 128 69
Gasoline consumed (litres)   55,000 30,000
Crude oil burned (barrels)   298 161
Forest absorbing carbon (acres)   29 16

Compared to generating electricity by burning natural gas, the Town's solar photovoltaic system will, over its 20 year life, save 1380 tonnes of carbon dioxide (tCO2) from being pumped into our atmosphere.