Solar, Wind and Geothermal
About Solar Energy
Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaic convert light into electric current using the photoelectric effect.
Radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar energy technologies include solar heating, solar photovoltaics, solar thermal electricity and solar architecture, which can make considerable contributions to solving some of the most urgent problems the world now faces.
Canada’s energy resource-base and human talent have proven to be one of our greatest competitive advantages and sources of economic strength in the past. While many of our significant traditional and renewable energy resources are centralized (e.g. petrochemicals, natural gas, coal and geothermal energy in Western Canada and marine energy at our coasts), solar energy is both ubiquitous and abundant in each and every Canadian community and solar energy enjoys more public support than any other source of energy.
Solar energy is the cleanest, most abundant, renewable energy source available. And Canada has an excellent solar resource shining across the nation. Today’s technology allows us to capture this energy in several ways giving the public and commercial entities flexible ways to employ both the heat and light of the sun.
Active solar energy systems employ devices that convert the sun’s heat or light to another form of energy we use. Passive solar refers to special siting, design or building materials that take advantage of the sun’s position and availability to provide direct heating or lighting. Passive solar also considers the need for shading devices to protect buildings from excessive heat from the sun.
Solar Energy Technology
There are two common types of technology that harness solar energy in Canada today: Solar Photovoltaic or PV (converting light to electricity) and Solar Thermal (heating and cooling water and air).
Solar photovoltaic (PV)
Solar PV is used primarily for grid-connected electricity to operate residential appliances, commercial equipment, lighting and air conditioning for all types of buildings. Through stand-alone systems and the use of batteries, it is also well suited for remote regions where there is no electricity source. Solar PV panels can be ground mounted, installed on building rooftops or designed into building materials at the point of manufacturing.
The future will see everyday objects such as clothing, the rooftops of cars and even roads themselves turned into power-generating solar collectors.
The efficiency of solar PV increases in colder temperatures and is particularly well-suited for Canada’s climate. A number of technologies are available which offer different solar conversion efficiencies and pricing.
Solar PV modules can be grouped together as an array of series and parallel connected modules to provide any level of power requirements, from mere watts (W) to kilowatt (kW) and megawatt (MW) size.
The size of the solar array, battery bank, and AC inverter required for a typical solar PV application depends on a number of factors, such as the amount of electricity you use, the amount of sunlight at the site, the number of days without backup that you require, and the peak electricity demand at any given time. Sufficient battery storage can easily allow a solar PV system to operate fully independently of a utility or genset back-up.
On the technology side, it is easy to interconnect your PV system to your local utility company — there are no technical barriers. There may be regulations, however, that you will need to work through with your utility, in order for them to allow you to generate your own electricity. The Canadian Electrical Code makes provision for you to generate your own electricity and to feed any excess back into the utility’s power lines. Most solar PV equipment can be easily checked to ensure that it meets the provisions of the Code for safety purposes.
PV modules should be oriented between south-east and south-west (due south is best). Modules generally need an unobstructed view of the sun all the year. Systems can be sized to provide 100 percent of your electricity consumption at a cottage or campsite, or as a supplement to conventional utility electricity or genset electricity. A tracking system can orient the solar array to maximize its electricity production throughout the day and the year by tracking the movement of the sun, though this is typically not practical for most applications.
Solar Water Heating
Solar energy can heat water for at least four different applications:
- potable (drinking) and service use (washing) use in homes
- potable and service use in commercial, and institutional and industrial facilities
- radiant floor heating
- swimming pools (indoor or outdoor).
Almost all applications use collectors, which are aimed at the sun to collect as much radiation heat as possible. There are three basic types of collectors:
- seasonal collectors (these units are simple design and often circulate water through plastic pipes, they offer little protection from freezing)
- flat plate collectors (these units may circulate an anti-freeze fluid through insulated pipes, and release the collected heat through the use of a heat exchanger)
- evacuated tube collectors (these are highly insulated glass cylinders which maximize the absorption of heat and minimize the loss of heat from the system).
Generally speaking, the three types above offer increasing collection efficiency and increasing cost of installation.The number of collectors required for a site depends on a number of factors, such as the size of your load (ie: how much water do you need to heat), the efficiency of the unit, the amount of solar radiation at the site, the amount of storage available, etc.
Collectors should be aimed as south as possible, and installations require unobstructed access to the sun’s path in all four seasons. Systems can be designed to provide 100 percent of your water heating or to use the solar energy as a supplement to a conventional heating facility.
Geothermal heating and cooling systems can provide year round comfort, deliver excellent energy efficiency and reduce your heating and cooling costs by 60-70%. By converting to geothermal heating.
How it works
The fundamentals of a geoexchange system are quite simple. A ground heat exchanger uses the thermal energy stored in the earth as a source for heating and as a sink (depository) for cooling. The temperature of the earth starting at a depth of only a few metres below the surface remains constant at approximately 10 degrees Celsius throughout the year, even in the middle of winter with a thick covering of snow on the ground.
Specially designed high density polyethylene pipes are buried in the ground and filled with an ethanol antifreeze solution to create an efficient heat exchange fluid which is circulated through the pipes and delivered back to the heat pump, which is installed in the basement where the furnace would traditionally be located.
The collected energy is concentrated by the heat pump which then transfers this heating (or cooling) energy into the home by way of a forced air ventilation system.
In the summer months the process is reversed and heat is drawn out of the home and deposited back in the ground. In the cooling mode, the ground acts as a heat sink to absorb this excess thermal energy.
Geothermal energy originates from the heat retained within the Earth since the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface. Most high temperature geothermal heat is harvested in regions close to tectonic plate boundaries where volcanic activity rises close to the surface of the Earth. In these areas, ground and groundwater can be found with temperatures higher than the target temperature of the application. However, even cold ground contains heat, below 10′ or 3 Meters, the ground is consistently 12.8°C (55°F) in moderate climates, and it may be extracted with a heat pump.
Wind is powered by the sun. In fact, all renewable energy, and even energy in fossil fuels, ultimately comes from the sun. The sun heats our planet to different temperatures in different places and at different times. This unequal distribution of heat is what creates wind as warm air rises and cooler air descends to fill the void. Wind is the ongoing movement of this air.
As the sun warms the earth, it in turn, warms the air above it, making it less dense or lighter. As the light air rises, it creates a low pressure zone near the ground. Air from surrounding cooler areas rushes in to balance the pressure. These are called local winds. Temperature differences between the polar caps and equator, as well as the rotation of the earth, produce similar results on a global scale, called prevailing winds.
So how much wind do we have in Canada? We have more than we could ever use, and it’s free. Our vast landscape, our three windy coastlines, the plains and mountains all contribute to this endless resource. Canada has still only scratched the surface of its massive wind energy potential, which currently powers over 1 million Canadian homes. Tomorrow we hope to do even more. Countries like Denmark already get over 20% of their electricity from wind. If we did the same in Canada, we would have enough wind energy to power 17 million homes! As long as the wind continues to blow, there is a great future in wind energy.
How it works
Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface, and rotation of the earth. Wind flow patterns are modified by the earth’s terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when “harvested” by modern wind turbines, can be used to generate electricity.
Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current. Simply stated, a wind turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.
How it’s generated
The terms “wind energy” or “wind power” describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity to power homes, businesses, schools, and the like.
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