The question of alternative power will continue to grow in importance. So too will the issue of sewage processing. The opportunities that lie here will, I believe, become fairly substantial over the next decade or so.
The use of solar and wind power is going to become very important at a home owners level. This will also see a return to older methods of heating and cooling, in order to reduce the power consumption of the home. These technologies are already being resusciated in the construction of large buildings, so why not smaller homes too?
An effort to reduce the need for power, and to generate a certain amount of own power, could see a significant drop in the need for power from external generators such as utility companies. Initially this will be driven by "green" people, but over time it is more likely going to become a cost issue.
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I believe a similar issue will arise around water and sewage. Many of us allow enormous amounts of rainwater to go to waste, and our toilet systems consume vast amounts of water. By installing a system to recycle sewage so that it creates water for the garden and also an inert compost, we can once again reduce the need for water.
These technologies are not new, but definitely underutilised. Now is the time to start building brand in these areas as these will be long term trends and not short term fads.