[Footprint] Sustainable Energy Basics

So you want to cut out fossil fuels altogether. You are worried about using natural resources that belong in part to future generations and you are worried about climate change from CO2 emissions from fossil fuel.

Well, it isn't simple. Where is your energy going to come from? We've already explored the good possibility that your energy is going to be more expensive and that therefore you will have to use a whole lot less.

You have two challenges:

1. Storing Energy.
2. Supplying Energy.

These two factors are massively interlinked. A tree, for example, is a store of energy, but when burnt it is a supply of energy which you may then wish to use immediately or convert to another form and maybe even store that for later use.

A great rule of thumb is that 'a sustainable system is a simple system'. Avoid converting your energy from one form into another too many times before you use it. Avoid storing it first in one form, then converting it and storing it a second time in another form. For example, if you have biomass (perhaps wood) then you don't have to convert it to gas, store it and then convert the gas to heat at a later time - unless you absolutely have to!

The cost of a system can often be subsidised by the fact that parts of your system were created with fossil fuels. Take photovoltaic (PV) cells (solar panels that produce electricity) for example. These are made in factories powered by fossil fuels. A great deal of energy is used to create such cells and it can take perhaps three years of use for the cell to have generated as much power from sunshine as it used in manufacture. So really, for the first three years you are running on (an expensive) form of fossil fuel! Not ideal if you don't want to be responsible for fossil fuel consumption!

But time for a bit of pragmatism - it is unlikely you will be able to use zero fossil fuels in the set up of your system. So we're just going to have to be careful and minimise our impact. To achieve this it is best to avoid manufactured systems, especially expensive ones! Electrical generation, storage and usage typically involves expensive manufactured systems - so perhaps we should think about minimising electricity usage - perhaps only using it for lighting and communications, not heating, cooking or transport. Perhaps we can use very small scale on-demand electrical generation and avoid battery storage (which adds massive costs). Unfortunately wind power (for example) isn't very 'on-demand'!

So what source of energy is also a good store of energy? Biomass. We don't need a system for converting it to a different energy form and then storing it. But that is yet another article - biomass energy systems.