Friday, 1 March 2013

Solar panels - first full year verdict

Well, the electricity company finally sent us the last 6 months worth of bills, plus an adjustment for the 3 months before that (don't even ask...) so I can finally do a year on year comparison of electricity bills pre and post solar.  Which means it's time for a chart!!

I'm pretty happy with a 63% saving, particularly as we had to run the reverse-cycle most of winter for heating when the wood burning stove died. I think that if we'd had the alternate heating source our annual bill would have been more like $350.

The panels themselves generated $1,445 worth of electricity, but of course some of that has gone to paying availability charges and GST. This amount represents 15% of the cost of the panels, so if we repeat this kind of result each year they will have paid for themselves in about 6.5 years, as the feed-in tariff is guaranteed for 15 years. Of course there's also the incremental savings from the "free" energy we get when using the solar generated power during the day - probably between 5-10 kwh.

For those who like details we have a 3kw system, and we get a feed in tariff (gross) of 60c - so every kw we export earns us 60c. In an average day we would export 6-10kw. Since they were switched on 523 days ago our panels have generated 6247 kw of power, so that's an average of around 12kw per day. The best production has been 17, and the worst 1. In an average day we would export 6-10kw - less in winter and more in summer.

I have tried to adjust where possible our electricity usage so that we send as much as possible during the day, and then run dishwashers, washing machines when the panels aren't producing (early mornings and evenings). BUT, I still use the oven, and heaters during the day in the office, and of course I work from home so have lights and computer stuff on a lot of the day. So this result is really more about solar than behaviour change.

It was interesting (read: scary) to see that in the winter when we were running the reverse cycle and extra heaters our average daily off-peak use almost trebled compared to the same period last year. And not only that but I never felt as warm as I did with the fire going. Thank goodness we will have our new energy and emissions efficient wood burning stove in place in a month or so in time for this winter.


Anonymous said...

You have a very satisfactory system it seems and it's nice to read about your success. Here in my part of Canada (Manitoba right in the centre of the country) most of our electricity comes from hydro electric generation. We pay about 7 cents/KwH + some taxes. Unfortunately the electricity company/Provincial Government doesn't encourage us residents to install our own solar (or wind for that matter). The electricity company is what is called a Crown Corporation, ie it is a Government owned monopoly but allowed to operate independently. Any excess generated by solar and fed back to the grid only receives a credit of 7 cents/Kwh with no allowance for the taxes. In other words they credit us with LESS than they charge!!!

Margo said...

7c per kwh??!!!!!!! We pay around 30c!!!!!!!!!!!!!

But there is a similar situation here now in many states where the feed in tariff offered is only equal to or less than what it costs to buy in the power. We were lucky to get the premium tariff, and it was capped so limited "places"

poppykettle said...

I really enjoy reading about the after-life of installing solar and comparisons between usage, generation, costs and savings. Thanks for sharing :)

Margo said...

Thanks for stopping by poppykettle, glad you enjoyed the post

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