Solar PV system

This Friday the solar PV system should be installed, and is something we have wanted to get done as soon as possible so that we can start producing our own energy (and making a return on the investment).

Having a solar PV system installed is a key feature of the project. As such the house was designed to to have the most optimal of for installing solar panels. For our location Shiga, Japan, the best angle of the roof is approximately 30 degrees. As can be seen, the front of the house which faces SSW (the closest we could get to due south) has a shallower and longer aspect than the steeper back roof.

house profile

After looking at many options we decided on getting CIS thin film panels. The reasons being that out of the different kinds of panels available:

    • they have the lowest embedded energy (up to 40% lower carbon footprint)
    • they don’t contain toxic substances such as lead or cadmium
    • they have good performance in both hot conditions and cloudy/shady conditions
    • they’re made in Japan (local)
    • they look good!
    • they’re cheap

The main disadvantages:

    • they are new and relatively unproven (although most commercial PV installations seem to be opting for them)
    • they’re less efficient so need more space, but if you have the space, a 5kw system is just that; 5kws, regardless of the efficiency.

The three main types of panels currently on the market:

    • Monocrystalline
    • Polycrystalline
    • Amorphous Silicon also called “Thin Film” of which CIS is included

Here are a few useful links: a comparison of the 3 types of panels and one showing in a little more detail, the benefits of CIS (thin film) panels


About ifd66

From UK and living in Japan. I am very interested in sustainable development and in general ecology and conservation issues and solutions. Finished building a low impact family house in Shiga, Japan in 2013 and am now focused on using permaculture to develop our plot of land into a more sustainable, productive, and attractive space. My hope is that this blog is useful to those interested in similar issues and way of life.
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