What we did
We are on the mains grid in Melbourne. While we wanted to go with something more environmentally sustainable than brown coal, the payback times were very long and we didn't think we could justify it. Instead, we made sure we
purchased 100% Green Power from our retailer to ensure that what we did consume was produced from renewable sources (more accurately: the equivalent from renewable sources was pumped into the grid somewhere).
Once reasonable rebates for photo-voltaic systems became available, we went ahead and fitted a 1.5KW system. The most cost-effective approach at the time was to only fit a 1 KW system, but we were looking ahead to when better feedin tariffs
would become available. This has now happened in Victoria, and we are getting paid 0.66 $/KWh for energy we produce that is surplus to our needs, while paying only 0.22 $/KWh for energy that we pull in from the grid.
One annoying gotcha with our system that we didn't realise sufficiently at the time is that the inverter unit (which converts DC coming off the roof to AC for use by us) doesn't operate when the mains supply cuts out. This is a safety measure to
prevent the electricity coming off our roof potentially electrocuting linesmen who are working to repair a fault elsewhere in the neighbourhood, but it is still frustrating not to be able to use our own electricity during an outage. The only way
around this would be to fit a battery-system (rather than a grid-connected system) and that would have cost much more.
At the same time that we were looking to improve our drain on the grid (and particularly on coal-sourced electricity) we also undertook a gradual program to wind back our consumption. This involved replacing appliances as
they came due with the most energy efficient options available at the time. We considered replacing appliances before they failed, but felt on balance that we couldn't justify junking something that still worked perfectly well. It's a tricky
balancing act, and I'm not sure we always got it right.
We also did the obvious things like replacing our incandescent light globes with compact fluorescent ones, and leaving nothing in standby mode that didn't need to be. One particular challenge was the network backup server. If power cost nothing,
I would use an old PC running Linux, but this would consume 150-160 Watts. So instead, we use a low-power Synology, which only consumes 16 W when running.
We all use laptops (which draw a maximum of 65W each) so the number of computers in the house is less of an issue than it would be if we all used desktops.
We have currently got the electricity consumption for the entire house down to less than 8 KWh/day.
What we should have done
As (somewhat) early adopters of photo-voltaics we didn't get the best possible rebate, but we did start reducing our demands on the grid earlier so it balances out.
What we are doing now
Now that LED lights have got cheaper and provided a warmer light we have moved to use them throughout the house. We have also replaced our 12V halogen downlights with more efficient 240V LED downlights.