The Sun. A great boiling ball of gas, nuclear fusion, massive, distant; it is the source of all energy on Earth. Sort of. But no, you say, there are many sources of energy which are not “solar”. What about hydroelectricity? The sun evaporates water, which forms clouds, which rain on uplands, which flow to lowlands, and pass over a turbine to generate power. Oil? The sun feeds photosynthesis (and pumps rain, again), to create plants, which are eaten by dinosaurs, which fall into mud pits, get buried by millennial layers of candy wrappers and banana peels, and decompose into oil. Carbon is simply stored solar energy. Wind? Temperature differences across continents and oceans, heated by the sun, generate air flow, as warm moves to cold. With the rare exception of nuclear, and the type of deep earth geothermal that feeds volcanoes and Iceland and a few unusual places on earth, all energy is from the sun. Then why is it not all sustainable?
Sustainability is all about rate. All energy sources are sustainable; it is our rate of consumption that is not, necessarily. Consumed a drop at a time, we could ostensibly consume oil at a rate slower than which it is replaced within the earth’s crust; a very, very slow process. The daily solar radiation which falls on this earth is free, infinite in the context of human existence, and at this time of year seemingly relentless. Does it not seem like a bit of a no-brainer to concentrate on capturing this daily abundance? Yet we continue to drill offshore in wildly unpredictable oceans, pump salt water into Saudi oil fields, and hydraulically fracture shale beds to extract less and less oil and natural gas. The recent British Petroleum atrocity in the Gulf is simply a concentrated example of the widespread risks associated with continuing to pursue fossil energy sources.
Photovoltaics (PV) are a 20 year old concept with a hot new reputation. Solar cells convert the sun’s radiation into electricity, harnessing between 12-18% of the potential. The map above indicates the amount of the Earth’s surface that would need to be covered with solar panels to generate all our current energy needs. Seem like it’s too easy? Put into real numbers, enough solar PV panels to supply the entire City of Toronto would cost about $400 billion dollars. Considering our entire “economic stimulus package” of the past two years totaled about $7 billion, that’s a bit of a stretch. Our provincial government, however, has made it financially possible for an individual to invest in PV through the Ontario Green Energy Act. This provides a guaranteed rate at which the electric utility will buy power from anyone generating electricity using PV panels, on a 20 year contract. Current math puts the payback on such a system at around 7 – 10 years, after which it would be a source of income. Many home and business owners are jumping on this opportunity, and we have two new solar panel manufacturers springing up in this region alone to supply the demand. Complications arise with mature trees creating shade, and rooftops which lack a good South orientation. And of course the best investment is in reducing the rate of consumption, not supplying more energy sources.
Solar hot water panels have been around for decades, and recent advances have made them even more efficient and user friendly. An average rooftop system will cost around $5-6000, and can easily supply the majority of your hot water needs, as well as part of your space heating needs. In Ontario, with our long winters, the majority our energy needs are for heat. It seems to make sense that this relatively low tech method of solar capture could be widely adopted if the price came down. As it stands, a typical solar hot water system has a payback of between 10-15 years. Recent examples have proven that a very efficient house could have up to 80% of its heating needs supplied by solar hot water. There are some complications, like what to do with all that heat in the summer time, and what to do for heat when the sun disappears for a week or more in January. But if we ignore our current government manipulated market imbalance, solar hot water is the simplest, most cost effective investment in sustainable solar energy we can make.
Wind power requires moving air, and lots of it. In urban areas, it is nearly impossible to capture enough consistent, strong wind to power even the smallest turbines. Are you living out in a field, on a shoreline, or at the top of a hill? Then wind power could be your best option. A quick online check of the Ontario Wind Resource Atlas will tell you whether it’s worth considering. And considering that you need to be about 30 metres above the ground (about 3 times the height of the average house) to catch enough wind, it’s all about the tower. If you have wind, and land, and friendly or preferably no neighbours, then there are some fantastic turbines out there that can provide sustainable energy for decades.
And lastly, let’s not forget the magic of photosynthesis, and the fantastic ability of plants to convert solar energy into food. Calories fuel us every day, and the two primary ingredients in these are water (delivered by the sun) and sunlight. Think about this when you eat, and strive to eat food which contains only these simple, free energy inputs.
Our resources are all we have, and the false energy abundance of the past century is due for a dramatic overhaul in coming years. We can talk about hybrid automobiles, ban pesticides, water our lawns on alternate days, fill our blue boxes, and cover our homes with recycled siding and bamboo floors, but ultimately the hard decisions remain, and they all converge on energy. We need to be using dramatically less, and we need to get serious about harnessing the abundance that falls on every square inch of earth every day.
A few resources to check out and learn more:
http://roofray.com/calculators – trace an aerial map of your home to find solar potential
http://www.crewzone.ca/ - Community Renewable Energy Waterloo – local info
http://www.solarcooking.org/plans/ - build your own solar oven. They really work!
http://www.merlynpower.ca/ - local solar electric and solar hot water providers
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