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What to expect from a solar panel

published, May 19, 2012 2:52am
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Solar has becoming really popular, and for a whole variety of reasons - including the spectacular price drops (look out coal burners...) that I'm not going to get into here.  Selecting solar is no longer the territory of the enthusiast, it's become a mainstream choice for many people amongst the plethoria of companies and related solar info out there.

I thought it might be helpful to provide some insight and real information about the performance you can expect from a good solar system, together with some other little known things that are an important consideration. This information comes from the eleventy million data points my SEGmeters recored for the 1kW system I had on the roof of my old house. So take all this and multiply the numbers for the size of your system - thought your mileage may vary ;)

Some details:

 

Now for some information

900 kWh is roughly how much energy would it generate in a year, against 7,970 kWh we would use. It was an all electric household, with three little boys and 2 adults all working from home! The following chart shows how this all adds up, interetingly the solar panels essentially powered our lighting!

If we look how this stacks up, in terms of our usage, generation and nett position (used for feed in tarrif billing) it's not a very big number! We never chose a feed in tariff, primarialy for this reason AND we would have paid 50% more for our energy AND we would have lost our electric off peak hot water AND we would have had to pay $350 for a new meter. Our old utility company meter was just left to spin backwards, which was a win.

As expected, output would vary over the year, with the summer giving the best outputs, and occasionally we would have a day that would end in a nett overall feed in!

Interestingly, as I had expected the best seasons for solar are in the Spring and Autumn, the reason being is that the panels are best aligned with the sun as it moves between winter and summer and that the number of hours the sun would shine on them was longer. In the summer, the sun would rise and set behind the panels! It was always peculiar to see them lit up from the underside, and in the winter - there are more cloudy and crappy days for the solar.

However, our usage was typically in stark contrast!

The important thing to take away, is that our solar panel system didn't really provide much to alleviate our energy position! What was more important is cutting our energy usage! We did a number of things to manage this better, hot water control, heating control, and air sealing. The next steps were to install LED lighting and better seal up the building and insulation. It's remarkable how many homes don't have basic insulation!

Get energy aware! Cut energy usage first, get efficient, work out how much energy is used - then size a system appropriately. Don't get into a situation where there is over generation, because who knows if the utility company is going to pay for it.

Then chose an installer who knows their stuff, chooses quality components not all panels, and especially invertors are equal...

There is a whole host of things, so if you have some questions, catch me on the twitters, or here on Smart Energy Groups!

Also, if you'd like to check out all this information online, or even download some data head over here!

Sam, @samotage

 

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