The sun and wind are very reliable sources of energy. They cannot be depleted. They are unarguable natural phenomenon inherent to the planet we live on.
A small solar power system (as little as $500) is enough to power a laptop computer, lights, and sometimes more. One very easy and permanent way to reduce your electrical bill would be investing in such a system and trying to use it instead of your grid power as much as possible.
Many other Earthships utilize power systems that would easily rival that of any building. They can be sized to meet just about any electrical demand, but their major plus is, when designed correctly, they are not subject to total and abrupt outages.