Solar 101

The Homeowner’s Guide to Going Solar

Adapted from Green Venture and Ruth Cooper’s solar webinar here (slides and video).

 

Canada has committed to achieving net-zero greenhouse gas emissions by 2050 (1). To avoid irreversible climate impacts, experts estimate that 75% of our energy must be from renewable energy or low carbon sources by 2050 (2). Since building emissions make up 18% of Canada’s carbon footprint, reducing our energy consumption in this sector is crucial to meeting climate deadlines (3). 

 

A net-zero building is one that generates as much energy as it uses. Luckily, transforming homes into net-zero buildings is more attainable than ever. By switching to solar, you are decoupling your home energy use from natural gas consumption – which is still a part of Ontario’s energy mix and releases greenhouse gasses with electricity use.  Hamilton is a prime candidate for solar power with a photovoltaic potential between 1100 and 1200 kWh/kWp (4).

The global environmental benefits of solar power are extensive. Solar energy can also improve air quality and reduce water use from energy production (5). An American study estimated the benefits from solar energy to be:

• ~10% reduction in GHG and air pollutants from 2015–2050.
• $56–$789 billion in climate benefits, discounted from the present value.
• $77–$298 billion in air quality and public health benefits.
• 4% and 9% reduction in water withdrawals and consumption respectively, including in many drought-prone states. (6)

On this page, we will cover the fundamentals of residential solar systems.

How does it work?

Solar systems work when sunlight contacts the semiconductor material of solar panels known as photovoltaic (PV) cells.. Light energy is converted into electricity when a current is generated by displacing electrons in the silicon material.

 

Components of solar systems

1. 

   Solar Panels on the EcoHouse roof

   Solar panels: The blue photovoltaic panels which, when put together, make up a solar array are an easily recognizable component of solar technology. 

2. Inverter: The inverter converts the electricity from direct current (DC) to usable alternating current (AC). This is necessary to match the type of electricity provided by the grid and operate most devices.
3. Racking system: The racking system is the metal structure that mounts and supports your solar array. It ensures the panels are fixed securely and positioned at the correct angle. mounting rack system and an optional battery pack for energy storage.
4. Battery (optional): Solar systems only generate electricity in specific environmental conditions like when the sun is shining. Residential battery storage systems can store unused energy during these times for later use instead of feeding it back to the grid. This affords homeowners energy independence, resilience against power outages and eases off reliance and strain on the grid.
5. Other
   1. Breakers: Prevent the electrical system from surges.
   2. Electric Meters: Monitors the amount of electricity passing to or from your home in connection with the grid. Utility companies use it to charge energy bills or reward credits for energy sold back to the grid.
   3. Wiring: A network of cables that transport the current of electrical energy.

 

Advantages of Going Solar

Energy Independence

When combined with batteries for energy storage, solar systems are not dependent on the grid and are resilient against power outages. Also, by generating your own electricity you are not subject to the unstable pricing schemes of utility companies whose rates are largely increasing. 

 

Environmental Benefits

Solar energy is a clean renewable source of energy that minimizes extraction of Earth’s quickly-depleting natural resources. It does not emit greenhouse gasses through its energy generation. Additionally, it reduces the demand on the electrical grid, which, when strained, burns natural gas to meet demands and, at worst, can lead to power failure.

 

Cost Savings

Save money on utilities by generating your own electricity! On average Ontarians save 43% on their electricity bill after installing solar panel systems (5).

 

Return on Investment

Solar systems can pay for themselves over time!  Savings from lower electricity bills and net metering offset the initial cost of installing solar technology. Net metering is used in Hamilton when the utility company issues credits to your energy bill corresponding to the amount of excess electricity that was generated by your solar system and has been donated back to the grid (6). By generating electricity for the grid, they provide you with a proportionate discount. Depending on the size and location of your residential solar system, it is estimated that in Southern Ontario, they pay for themselves in 9 to 11 years while having a lifespan of over 20 years (7).

 

Considerations

Cost

Despite the cost of this technology falling by over 80% since 2010, solar systems still have comparatively high upfront costs for installation (8). The total cost for all the components, installation and permits for a residential 5-10 kW system is 2.34 – 2.91 $/W (5).

 

Suitability

Although Hamilton is a great area for solar installation, each location must receive sufficient solar radiation in order for generation to be worthwhile. Panels that are south facing and unobstructed with easy access for cleaning are optimal. Obstructions and shading, such as trees or tall buildings, can inhibit your solar systems’ effectiveness.  For ground installations, consider the slope and type of terrain. For roof installations, consider the age of shingles and, the size, slope, direction and load bearing capability of the roof.

 

Standard vs operating conditions

Keep in mind that there may be differences between standard conditions advertised and operating conditions for your specific system. Standard test conditions (STC) assumes 25°C, 1000 W/m² solar irradiance and AM1.5 atmosphere thickness. In reality, weather, angle, aging and environmental conditions cause fluctuations in performance.

 

Lifespans and warranties

“On average, solar panels have a degradation rate of about 0.5 per cent per year which means that they will operate at 91 per cent of their original efficiency after 20 years, and about 82 per cent after 40 years” (7). The lifespan of inverters is typically 12-15 years and will need replacement after this period. Warranties typically guarantee a certain efficiency up to an age. For example, 90% at 10 years and 80% at 20 years.

 

Maintenance

Proper maintenance and care practices will extend the lifespan of your panels. Dust and grime can build up on the panels so periodic cleaning is important. Trimming of nearby branches and snow removal may be necessary.  Protect against wire damage caused by animal activity like chewing.

 

FAQ

What is a kW or kWh? What does this mean?

Kilowatt (kW) is a unit of power and kilowatt-hour (kWh) is a unit of energy. Power is the rate at which something uses energy. For example, an appliance that has a rating of 1 kW uses 1 kWh of energy in 1 hr, 2 kWh of energy in 2 hrs and so on.

 

What does it mean to be “part of the grid”?

Being part of the grid means that the excess power generated from your solar panels is fed back into the electricity grid rather than being used to individually power your home. Similarly, the system pulls electricity from the grid as needed.

 

What should I do before installing my residential solar system?

1. 1. Review your electricity bills. This will help you determine the size and number of solar panels needed. Add up your usage in kWh for the past 12 months and divide it by the number of sunlight hours in a year. Multiply this number the cost per watt to get a price estimate.
   2. Take steps to reduce your energy consumption before installing solar. By reducing your energy consumption, you can reduce the size of your system.
      1. Schedule a home energy audit with Green Venture! Green Venture offers home energy assessments with a registered energy advisor. Our advisor will come over, inspect your house and identify areas of inefficiency using building science. This is an excellent way to reduce your energy consumption without changing your habits.
   3. Apply for the Canada Greener Homes Loan. The federal government is providing an up to $40, 000 interest free loan payable over 10 years for energy upgrades such as solar installation. Take advantage of this unique financing option.

• Assess the age and condition of your roof. Repairing or replacing your roof ahead of solar installation saves time and money by preventing disassembly and reassembly to access the roof.

• Obtain at least 3 quotes from solar installers. To ensure you are being priced fairly and contracting a reliable organization, ask for detailed breakdowns of the work and cost to compare with other companies.

 

Sources

1. https://www.canada.ca/en/services/environment/weather/climatechange/climate-plan/net-zero-emissions-2050.html
2. https://www.toronto.ca/services-payments/water-environment/net-zero-homes-buildings/solar-to/about-solar/
3. https://natural-resources.canada.ca/transparency/reporting-and-accountability/plans-and-performance-reports/departmental-strategies/the-canada-green-buildings-strategy-transforming-canadas-buildings-sector-for-net-zer/26065
4. Photovoltaic potential and solar resource maps of Canada
5. https://iea-pvps.org/wp-content/uploads/2023/11/National-Survey-Report-of-PV-Power-Applications-in-Canada-2022.pdf
6. https://www.oeb.ca/consumer-information-and-protection/net-metering
7. https://www.toronto.ca/services-payments/water-environment/net-zero-homes-buildings/solar-to/considerations-for-solar-photovoltaic-pv-installations/
8. CanREA_Solar-Guide-2024-FINAL.pdf (renewablesassociation.ca)