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2.2 Renewable Generation
More than half of Canada’s electricity is generated through renewable sources.
Introduction
As we have learned, renewable electricity is generated by sources that can be used continuously without being depleted and are generally free of greenhouse gas emissions. Let’s learn more about the different sources of renewable electricity, and how they generate that electricity.
Hydroelectricity
Hydroelectricity involves harnessing the energy in flowing or falling water. Since various regions of Canada have abundant water—and geographic features that lend themselves well to highly efficient hydroelectric projects—this form of generation accounts for 60% of Canada’s electricity.
In some parts of the country “hydro” is commonly used in a generic sense to refer to electricity. This reflects the prevalence of hydroelectricity in the supply mix in those regions. Properly speaking, however, it refers only to electricity generated at a hydroelectric facility.
Hydro Generation and Storage
Hydroelectricity is the only renewable source of electricity that is well suited to generate baseload supply, meaning the minimum amount of electricity that we need to have consistently available. It is also dispatchable, meaning grid managers can decide when to use hydroelectricity and when to store potential generation for later use. There are two major kinds of hydroelectricity generation projects including dams and reservoirs and run-of-river projects.
Dams and Reservoirs
Most hydroelectricity is generated from projects that use a dam to create a reservoir. Water can be stored in the reservoir, allowing for ongoing generation even in drier seasons, and for generation to be scheduled for periods when other sources of electricity are less available.
Pumped storage projects are becoming more common and operate essentially the same as reservoir-based projects. The difference being that water is pumped to an elevated reservoir, at a time when surplus or lowcost electricity is available for later use.
Given the storage capacity of these two types of projects, hydroelectricity plays a very important role in balancing demand and supply on the electricity grid, and in ensuring that more generation from other renewable sources, like wind and solar, can be integrated into the grid while maintaining reliability.
Run-of-River
Another common form of hydroelectric projects is run-of-river, in which the energy in a river or stream is directly harnessed without use of a reservoir. While these projects lack storage capacity, they are lowimpact and add to the diversity of generation supply. They are also well suited to meeting generation needs in remote and off-grid areas.
Advantages
• Many existing and potential sites in Canada
• Well-established technology
• Long-lived projects, with low cost of operation
• Variable scales of projects
• Good storage capacity
• Well suited to backstop intermittent generation sources like wind
• Very low greenhouse gas emissions
Disadvantages
• Regulatory approval can be costly and time consuming
• Local opposition may arise to new development
• New projects typically require transmission line construction to connect to the grid
Wind Generation
Wind turbines capture the wind’s kinetic energy, or energy derived from motion. The wind turns the blades of turbine rotors, which are attached to a driveshaft. The driveshaft then spins a generator to create electricity.
Wind turbines come in different sizes and can be deployed in different configurations. In Canada, most wind turbines are utility-scale and feed power directly into the electricity grid. While all existing projects are on-shore, there are various proposals for off-shore wind developments, mainly on the Atlantic coast.
Wind speed
The amount of energy is determined by the speed of the wind. Although windmill blades can appear to move slowly at times, internal gearing—much like bicycle gears—allows for efficient electricity production. Wind turbines can generate electricity at wind speeds ranging upwards from as little as 10 km per hour, with a top safe operational wind speed of some 80 km per hour.
Low cost
Wind energy is now one of the lowest-cost options for new electricity generation in Canada, and there has been a sizable increase in the deployment of wind generation in the past decade.
Low environmental impact
The production of electricity from wind energy generates no greenhouse gas emissions, no air or water pollution, and no toxic or hazardous waste.
Wind is a renewable source of energy, and while it is intermittent, ongoing development of energy storage and other technological advances are improving our ability to incorporate it into electricity grids without negatively impacting reliability.
Advantages and Disadvantages of Wind Power
Advantages
• No fuel costs • No emissions or waste • Low-cost, commercially viable source of power
Disadvantages
• Intermittent energy source (requires the wind to be blowing) • Possible need for additional transmission infrastructure to connect dispersed wind farms • Environmental concerns regarding noise, interaction with birds and land use issues • Not well suited to provide baseload or always-available generation
In 2019, Canada had over 13,000 MW of installed wind capacity.
Solar Generation
The sun is our most abundant source of clean, renewable energy. Unlike other forms of generation, solar generation doesn’t require any spinning turbines or generators and is more akin to charging a battery. A solar panel contains photovoltaic cells, the crucial component of which is silicon. Silicon has conductive properties that enable it to absorb sunlight and convert it into electricity—initially direct current electricity—which is then turned into useable alternating current with built-in inverter technology.
Solar energy is deployed at wide-ranging scales. Single solar panels powering such things as road signs and parking meters have become a common sight. Many homes and commercial buildings have rooftop solar installations—generating electricity for their own use and potentially to sell back to the grid.
Most of Canada’s solar generation, however, comes from utility-scale solar farms, which generate large amounts of electricity which is then sold for use on provincial electricity grids.
Solar energy can also be harnessed in other ways besides the photovoltaic or PV methods described above. Solar thermal systems, for example, capture sunlight and use it directly to heat water for in-home or other use, without converting the solar energy into electricity.
Advantages and Disadvantages of Solar Power
Advantages
• No fuel costs
• No emissions or waste
• Silent, non-disruptive operation
• Suitable for use in remote areas not connected to the grid
• Scalable in size—from a rooftop to a large solar farm
Disadvantages
• Possible need for additional transmission infrastructure to connect dispersed projects
• Cost competitiveness remains a challenge
• Intermittent energy source, particularly in some regions
• Not well suited to provide baseload or always-available generation
• Solar farms can occupy large tracts of land
• Disposal of end-of-life solar panels presents a challenge
Landfill Gas and Biomass Generation
Landfill gas and biomass generation are both methods by which we can use existing facilities and processes to generate electricity as a by-product.
Landfill Gas Generation
Landfill gas generation effectively turns garbage into a source of electricity. A landfill gas generation plant drills wells in landfills to collect biogas, which can then be used as a fuel source. This gas—an important component of which is methane—is produced naturally as organic garbage decomposes. It is typically burned using on-site generating equipment to produce electricity.
Landfill gas generation facilities are, in some cases, developed by electricity utilities or their affiliates, potentially in partnership with a municipality; and in other cases, by private companies, who sometimes develop them as supplemental fuel sources at their own industrial facilities.
Capturing and combusting landfill gas prevents methane from escaping into the atmosphere. This is a significant environmental benefit since methane has more than 20 times the potency of carbon dioxide in terms of its global warming potential – and landfills account for one fifth of Canada’s methane emissions.
Advantages
• Captures methane that would otherwise be released to the atmosphere
• Provides a benefit from an otherwise non-productive garbage collection location
Disadvantages
• Quality of the methane may vary thus requiring treatment to make it useable
Biomass Generation
Biomass generation is the process of generating electricity by burning organic materials. This produces high-pressure steam that drives a turbine to make electricity. The most common biomass materials used to produce energy are plants, wood, and organic waste. Examples include low-value agricultural by-products such as straw, sawdust, and other wood waste, municipal garbage streams, and alcohol fuels.
Biomass is considered a renewable energy source because the energy within it comes from the sun and because the materials used can regrow in a relatively short time. Plants and trees take in carbon dioxide from the atmosphere and convert it into biomass as they grow, and this same carbon dioxide is released as they either decompose or are burned (meaning there is no net increase in carbon emissions over the plant’s full lifecycle).
Biomass use is important within the forest products industry, for example. Manufacturing facilities commonly use what would otherwise be waste sawdust and other residuals as a fuel to meet what can be significant proportions of their on-site electricity and heating requirements.
Advantages and Disadvantages of Biomass Power
Advantages
• Reliable, non-intermittent source of power
• Uses potential waste as fuel
• Creates revenue stream for biomass suppliers
Disadvantages
• High fuel and operating costs
• Requires extensive space and infrastructure
• Some adverse environmental impacts (e.g. ash and particulate releases)
Tidal Energy Generation
Tidal power is a form of hydroelectricity that converts the energy in the movement of tides into useable forms of power. Tidal power is generated when tides rotate submerged turbines; or when their energy is harnessed via a “barrage,” or a dam built across an inlet. Similar generation can be achieved by submerging turbines in flowing rivers.
Although not yet widely used, tidal energy has potential. Canada has been active in testing tidal generation technologies, particularly in Nova Scotia, where the Bay of Fundy offers exceptional tide heights.
An experimental tidal generation station—one of very few of its kind in the world—operated for an extended period of time in the Bay of Fundy. Today, the Fundy Ocean Research Centre for Energy operates as Canada’s leading test centre for tidal stream energy technology.
Advantages and Disadvantages of Tidal Power
Advantages
• Costs are expected to decline as technology develops
• Intermittent, but predictable source of green energy
Disadvantages
• Investment is needed to advance research and development
• High upfront capital costs
• Potentially intrusive to marine life and ecosystems
Geothermal Generation
Geothermal energy involves harnessing the internal heat of the Earth’s crust to produce electricity. Geothermal generation is most widely used in regions that are volcanically and tectonically active. Iceland and California are among various jurisdictions around that world that generate significant amounts of electricity using heat from geothermal sources.
Geothermal heat pumps or temperature exchange systems—which can be used to both heat and cool buildings—are relatively common in Canada today. Geothermal is not yet being used to generate electricity, but that may soon change.
In 2021, the federal government announced an investment in the Clarke Lake Geothermal Development project in northeastern British Columbia. This wholly owned and Indigenous-led project is expected to become one of the first commercially viable geothermal electricity production facilities in the country, and to generate between 7-15 MW of electricity.
Advantages and Disadvantages of Geothermal Power
Advantages
• Reliable, non-intermittent source of power
• Low operating costs
• No emissions or waste
Disadvantages
• High upfront capital costs
• Possible need for additional transmission infrastructure to connect dispersed projects
Knowledge Check
Solar generation: Uses the conductive properties of silicon to convert sunlight into electricity
Wind generation: Uses turbines to convert moving air into electricity
Hydroelectricity: Converts the kinetic energy of moving water into electricity
Landfill generation: Burns the biogas produced by garbage and converts it to electricity
Biomass generation: Burns plant matter to generate electricity
Tidal generation: Generates electricity using turbines submerged in the ocean
Geothermal generation: Generates electricity by drawing the internal heat energy from the Earth’s crust
