“Solar water heating is a great opportunity for homeowners to go green and realize financial benefits now and for years to come,” says Nels Moxness, President of VELUX Canada.

As more homeowners are discovering , you don’t need a super hot climate and thousands of dollars to go solar. In many cases, all it takes to offset two-thirds of your hot water bill is a couple of panels resembling skylights, an 80 gallon water storage tank and a shade-free rooftop exposure. In an average home, harnessing the sun’s free energy for daily hot water needs can be a practical and affordable option. Water heating is the third largest energy expense in most households, after space and air conditioning, according to the U.S department of energy. The new solar heating system uses flat roof mounted solar collecting panels that actually look like sleek, skylights. The new system is so efficient that it can pay for itself in three to seven years.

“Hot water is the most efficient way to use solar, short of passive solar where you’re using sunlight to warm up tile or stone” says Monique Hanis of the solar Energy Industries Association Trade Group, which represents manufacturers and installers of solar products for electricity, water and other uses.

The cost of installed Solar Thermal systems will vary depending upon the volume of heated water required in a home. The water tanks come in 80 and 120 gallon sizes and usually require two or three rooftop solar collector panels per roof. Once installed, the systems can provide up to 75 percent of the demand for heating hot water in a home while replacing or adding on to an existing water heating system. More importantly, because the sun is free, you’re protected from future fuel shortages and price hikes.

How to find qualified installers? At minimum, seek licensed, insured contractors who warranty their work and have training certification from the manufacturers they represent. It can help to hire locally for future maintenance needs.

1. On the demand-side, by acting to reduce, and eventually reverse, the growth rate, using conservation and increasing efficiencies: e.g., better engines, higher efficiency lighting, better insulation, avoiding unnecessary waste; in short smarter, better and smaller. The McKinsey report on climate change5 indicates that over 40% of the consumption of major consumers like the United States could be met economically by smart conservation and efficiency alone.

2. On the supply-side, by tapping existing and new resources capable of meeting the demand remaining after conservation. Table 3 reports the current contribution of different
resources to the planet’s supply-side needs.

Finite supply-side resources: The lion’s share of the today’s primary energy comes from fossil fuels with the balance largely met by nuclear, hydroelectricity and biomass. Much of this supply chain is finite, and the world is rapidly moving into a phase where the balance between supply and demand will reach a tipping point. Oil is the first to approach its physical production peak and the inevitable supply-demand imbalance already causes chaotic market fluctuations with a strong underlying price strengthening.

Aside from oil, a look at the proven planetary reserves (Fig 1) of finite resources is quite revealing. Nuclear energy is often presented as the solution to oil depletion and global warming. Unfortunately, this “silver bullet” view may be too optimistic. Apart from the still unresolved issues of waste management and nuclear proliferation, and apart from the unaccounted need for large, if hidden, public subsidies (e.g., the Price-Anderson Act in the United States13, protection from terrorism, etc.) the supply of nuclear fuel may be just too small using current and planned nuclear generator technologies7. The current pressure on nuclear fuel price, paralleling that of oil, is an indication that supply-demand balance
is tightening.

It is helpful to distinguish between two types of solar energy applications: those which are designed to meet a particular end-use, and those which are universal in nature. The first group includes such applications as domestic hot water, passive or active heating of buildings, and utilisation of natural light. These applications are indeed ‘niche applications’ although their scope can be very large (e.g., the penetration of solar hot water systems in countries like Israel,
Spain Turkey and especially China1 is significant). However, the impact of these technologies is limited to meeting their specific end-use, contributing to the general perception that
solar is a useful but limited energy resource.

The second group includes technologies designed to generate electricity – i.e., a universal energy carrier that can be stored, transformed and reach virtually any enduse application requiring energy. This group includes photovoltaic (PV) power generation, concentrated solar power (CSP), and wind power generation2. This second group holds the key to a very large scale deployment potential that could, in theory, meet all the planet’s energy requirements
and beyond.

HU MANITY’S ENERGY REQUIREMENTS
At present the total primary energy consumption of the world is of the order of 480 exajoules3 per year, amounting to a constant power demand of 16 Terawatts4. This consumption is not distributed equally, with rich industrialised countries, such as the United States of America using almost 22% of the planet’s energy with only 5% of its population. Growing economic powers China and India are rapidly increasing their demand for energy with a combined consumption now exceeding that of the United States, suggesting that the current worldwide figure is headed for a strong growth. Table 1 reports energy consumption figures for major countries and groups of countries around the world.

Residential and commercial sectors (i.e., largely buildings) account for almost 30% of energy use in oecd countries. While the proportion is smaller in non-oecd countries, the commercial building sector’s energy demand growth surpasses all other sectors by far.