Sun, wind, and water: these three natural elements can produce all the power you need with little or no impact on the environment.
Solar energy sustains life on earth for all plants, animals and people. The earth receives radiant energy from the sun in the form of electromagentic waves, which the sun continuously emits into space.
The earth is essentially a huge solar energy collector. This energy takes on various forms, from direct sunlight used through photosynthesis by plants to grow, to heated air that causes wind, to evaporation of the oceans that falls back as rain and becomes rivers.
This energy can be tapped indirectly as wind, biomass and hydroelectric power, and directly as solar energy (thermal and photovoltaic).
When building a house the incorporation of the sun into the design is a great way to save energy. Think about the sun and about your movements throughout your house. If you aren’t building a house now try an experiment: Think about the house or apartment where you live now with the sun in mind. If you are an early riser, is your bedroom window facing northeast?
If you are a late riser is it on the opposite side of the house? If the answer to either of those is “no” then — at least in part — your house is not designed well for you. If you like to sleep late and you have any window facing the early morning sun then you are battling nature. In the dead of winter as the first morning sunshine is beating down on your window you are keeping its rays at bay with thick curtains or blinds thus losing the heating benefits of those rays.
If you are building a house you should think about the way you move through your house during the day. Where are you going to be and where is the sun going to be?
If you are very careful in your design, a window with an awning that receives direct sun all day in winter will not in summer because the sun is higher in the sky. Simple trick. A grapevine trellis is another good option. Some other common sense ideas include species of trees on the property. Deciduous trees on the south side of the house will be lush and leafy in the summer helping to block that hot sun and bare in winter letting the rays warm things up.
Passive and active solar water heating is a growing trend. A solar hot water heating system is a relatively simple system whereby water is pumped through tiny tubes that run through black solar collectors on the roof of a building and then into a hot water storage tank in the building.
Traditional heaters are very inefficient ways of heating a house. While it might be 21oC at chest level, not only is it 30oC up on the ceiling where no one lives, but it is cold on the floor. If you heat the high mass areas of a house: the floor, the walls, then the air gets heated as opposed to vice versa.
If you open a door in a traditionally heated home the hot air rushes outside. The same thing happens where the floor is heated but you don’t really lose anything as the floor remains warm. It works well even in a badly insulated home but in a well-insulated home coupled with a good design, the energy savings can be substantial.
“Passive solar plus mass heating makes a huge difference,” says Magwood.
According to Blaize Monostory, an energy efficiency advisor, who designs and installs hot water heating systems the cost for a comparable house heated with hot water will be 30% less than hot air.
Mass heating systems are also quieter, there is an elimination of hot and cold areas, they don’t blow air (and the dust with it) around and if you’ve ever walked on a heated floor in winter you will know just how cozy they can be. And of course solar powered hot water heating can make a real environmental difference too.
Usually when people think about solar power they aren’t talking about having a deep, dark tiled window ledge or planting a tree in front of their bedroom window. Most people are thinking of photovoltaic (PV) cells. PV provides the simplest form of battery charging available. Power is created when sunlight is absorbed by solar panels and transformed into electricity. It is a common misconception that the heat of the sun is what creates power. In fact, it is the light of the sun reflecting through the solar panels that creates energy.
Solar energy is a renewable resource that is inexhaustible and readily available, unlike fossil fuels such as coal, oil and natural gas. It is a clean energy source that can be used pollutionfree and allows for local energy independence. The amount of power from the sun that reaches the earth at noon on a clear day is about 1,000 Watts per square meter.
This is equivalent to a 100 Watt light bulb completely focused on a surface the size of a large notebook. Capturing solar energy often requires purchasing expensive equipment. Yet because renewable energy resources are free, the cost to use them is similar to, and sometimes lower than, other energy sources such as fossil fuels. The environmental costs of renewable energy sources are much lower than conventional energy sources.
Commercial wind power generation is on the rise worldwide (and is being tested in South Africa) but small home models are also available and are becoming very popular. Remember the windmill? These newer models may look like science fiction, but given the right conditions, these sleek, modern turbines can be a great source of energy.
To use a wind turbine year-round, you will need constant winds year round. If the wind on your site is not consistent then you could create a hybrid system combining PV panels for electricity in the summer and wind turbines in winter.
While hydro is clean, it isn’t always green since many hydroelectric projects involve massive damming of rivers and destruction, or at least disruption, of eco-systems.
While requiring a lot of site specifics, micro-hydro is a great and green alternative energy solution if you’ve got the access to moving water. Flowing water can produce between 10 to 10,000 times more power than sun or wind for the same capital investment. It all depends on the amount of water, how far it drops and how close you are to it. Every microhydro system is unique because every water source is different.
If wind and solar are the “sexier” of the alternative energy sources, then biomass is the ugly sister. Biomass uses the energy content in all forms of organic matter including agricultural crops, forestry wood waste, and more creatively, the methane extracted from the decomposition of human and animal wastes, and municipal garbage.
Biomass also involves converting starches of crops like corn into ethanol. Ethanol is then mixed with gasoline and the burning of which, produces less carbon monoxide, sulphur dioxide and carbon dioxide, than regular gasoline. Not totally clean but a step in the right direction.