The whir of a wind turbine on a breezy day or the sight of a roofful of solar panels is a good feeling for any green home owner. There’s a certain harmony between living in a sustainably built home and drawing energy from renewable sources, which is why renewable energy systems are as popular as they are among green home owners. As technology rapidly advances in the world of renewable energy, prices are plummeting, making now a great time to invest in a renewable energy system. To lower costs further, it’s also possible to take advantage of government incentives and utility rebates, which are available across the country (see DSIRE for incentives in the U.S. and the NRCan Office of Energy Efficiency’s Financial Assistance page for incentive in Canada).
With near-daily technological innovations and with China cranking out solar panels at amazingly low prices (and the rest of the world struggling to compete!), solar photovoltaic (PV) systems have become an incredibly cost-effective renewable energy opportunity.
PV systems, commonly known as solar panels, directly convert the sun’s rays into useable energy to power anything from computers to fridges (as long as the system can crank out enough juice). They either feed that energy straight to the appliances or store the energy in a battery. Panels are generally placed on the roof, but can also be mounted on poles or walls (south-facing).
Though areas with high PV potential, such as sunny Alberta, Saskatchewan or the Okanagan Valley in BC, are ideal places for solar PV, with recent innovations a good payback can be had from just about anywhere.
Solar hot water
If you’ve ever left your hose sitting in the sun all day you’ll know how much the water left sitting inside it can heat up. That simple principle is the basic idea behind solar water heating. Some of the best value in renewable energy systems comes from solar hot water. It can produce 50 per cent or more of a home’s water heating costs.
Open-loop systems consist of roof-mounted collectors that absorb the sun’s rays and heat water that then gets used in the home. Closed-loop systems work the same way except the sun is used to heat up a heat-transfer fluid such as diluted antifreeze to absorb the heat that then gets transferred to the household water supply via heat exchanger. Closed-loop systems are great for cold climates where water freezes much of the year.
Heat naturally transfers from hot to cold places. Heat pumps work on this principle of transferring heat from the ambient environment using a pump. When a pump is placed outside it absorbs heat from the outside and delivers it into the building. They’re extremely efficient heaters as they can deliver three times as much energy in heat as they consume in electricity.
In the cold Canadian climate, however, typical heat pumps are not that effective because there’s too great a difference between the cold outdoors and warm indoors, but since underground temperature is more stable than air temperature, geothermal versions of heat pumps are a good solution for the Canadian winter. These underground pumps are either dug into the earth (drilled vertically down into the ground or laid horizontally in a trench) or placed in a body of water. They exchange heat with the earth or water via antifreeze solution that gets heated in the winter or cooled in the summer, then pumped up into the home.
Geothermal heat pumps are highly resource and economically efficient in cold climates since they can provide both heating and cooling. A 2007 study found that the average Canadian home when using geothermal averted 1.1 to 6.1 tons of CO2 emissions and saved approximately $1,000 per year (SOURCE: Ground Source Heat Pump Systems in Canada).
Humans have been harnessing wind energy for more than a millennium. This proven technology evolved from simple windmills, which were used to draw water or grind grain, to today’s advanced wind turbines. Turbines come in two basic types, horizontal and vertical axis, though by far the most common seen for home use is the horizontal axis.
Wind turbines need a good amount of wind to function cost-effectively. There are exceptions to this rule, since certain wind turbines are designed to operate well at low wind speeds. But even still, the more wind the better. The power generated by wind is proportional to the cube of wind speed. So, a doubling of wind speed from 10 to 20 mph results in eight times more power. In areas with a consistent, strong breeze, wind turbines are a great solution for home energy needs.
Just as hydroelectric power plants provide so much of our electricity, small-scale micro hydro can offer abundant energy to individual homeowners. Like wind turbines, these systems utilize a turbine to generate electricity, except it’s running water that’s creating the power, not wind.
Micro hydro will only work for homes that have a stream nearby. And the faster that water flows the more electricity produced.
Since so much of North America is covered with forests, wood is a plentiful resource that can also be a sustainable one when reforestation is practiced. The burning process only releases CO2 that was absorbed in the tree when it was growing. Forests always have deadfall or snags (standing dead) that are rotting away and releasing CO2 anyways, albeit at a much slower rate. By replacing dead trees, wood harvesting can become even more sustainable.
Wood-burning stoves can be used to heat up a single room whereas a boiler can be used to heat an entire home. For properties endowed with big forests, wood is a great option since it can be sourced locally and at no cost (aside from reforestation costs).
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image: Samuel Mann (Creative Commons BY)
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