Towards sustainability: going solar 1


Towards sustainabilityFor the seventh part of this series – and after having tackled heating, electricity, water, transport, food and waste – I guess it is time for us to see how solar energies can benefit our lives.

I mention solar energies as there are three possibilities : passive solar applications, which are the most basic, solar thermal – which heats water – and finally solar photovoltaïc (PV), which generates electricity.

Even if most of us already use passive solar there are possibilities to increase our usage and go progressively to solar thermal and finish with solar PV

Passive solar :

This way of getting benefit from the sun and its energy supply does not require anything at all. In fact, putting windows or doors in a specific place when building a house can improve a great deal the heating or the cooling of any given house.

According to the Canadian Renewable Energy Network (CanREN), solar passive energy can benefit to people in three main ways. Here is a short overview for each of these ways.

  • Passive solar energy. This stresses its emphasis on the windows and their placement in a house. When the sun shines on windows, the reflection of heat is important. See for example a greenhouse that keeps the heat trapped inside.
  • Passive solar cooling, the potential is large in certain parts of the world. A good concept is to open windows at the bottom floor and let it go up in the building or habitation.
  • Passive solar daylighting. Most people prefer light from the sun than from electric light bulbs. Since the insulation of windows has never been that good before (double or triple glazing in modern houses), windows are more and more used in modern architecture, and this without much loss in heating.

Solar thermal heats water for hygiene or cooking needs. In fact, any activity requiring hot water can benefit from solar thermal. According to Jean-Marc Jancovici, the yield of this technology is three times better than for PV.

Placed on roofs – or walls in some cases – solar thermal installations can answer from 40 to 85 percent your water heating needs depending from where you live.

Not requiring complex electronic parts solar thermal is much cheaper than photovoltaïcs. As my fellow contributor Levent Bas noted on CleanTechies :

It is clear that installing the application is easy for households since the technology is less complicated and cheaper than PV. According to The Solar Guide, the payback period for an investment in a solar water heating system is 3 to 5 years, although it may vary a lot in different countries due to national standards and differences in manufacturing quality.

There are several types of solar thermal applications. From the monobloc solar heater to the passive open loop system there is surely one that will suit your needs. (cf. Wikipedia for more)

Solar photovoltaïc is a technology creating electricity with sun rays. Solar panels are generally made of silicon, the layer of silicon being between two layers of electrodes.

As for solar thermal, several technologies exist:  monocrystalline, polycrystalline, and thin-film. Each type have its advantages and drawbacks. Costs are also a differentiation factor.

For the time being –  and even if prices dropped dramatically recently – it is still expensive and few of us can benefit from the technology. Nonetheless it can represent a good investment if you are located in a very sunny area and if there are attractive financial incentives like feed-in tariffs.

Local authorities and companies will surely help you in determining whether such an investment is profitable. So if you have some money aside and are ready to invest in renewable energies, this is definitively an option to consider.


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