Wednesday, November 24, 2010

5974 cups of tea.

Just over a year ago we started a trial to see if we could harness the power of the sun to generate enough power to run our business.

The first step was to have a really good think about how we did things, what we needed power for, where we got our power from and how we could make this all as efficient as possible.

Our business doesn't really need much power, we need lights and to run some simple things, charge bike lights and laptop batteries and occasionally power some bigger things. But even we could be a lot more efficient about how we do things, instead of strip lamps (80 plus watts each) we could run LEDs (10 watts) and there were lots of other things we could do.

After we'd looked at making ourselves as efficient as possible we applied for a grant. Once we got the grant we started our installation, we changed everything over to 12v power (with inverters for occasional mains stuff but mainly with 12v variable charge adaptors for electrical equipment).

By November we were ready and we plonked our solar panels on top of our offices, and then we sat back and watched something amazing happen. We watched as the sun made enough energy for us to power our things. For us the opportunity to come off the grid was great, it gave us freedom to think about our business model and how it could operate elsewhere and also an opportunity to forecast our costs exactly.

Over the last year we've been diligently recording our figures:

It shows us that there was only 1 week in the entire year where we couldn't generate enough power from just the sun. Fortunately it was windy that month too so we could build some reserves with our wind turbine.

So what does this all really mean?

Well it's a bit of a mixed bag, we've calculated exactly how much power we generated from the sun. All in all about 10372 a/h at 12v, which means we could have outputted 124464 watts for 1 hour and the nitty gritty is we generated 448070kj, in real terms this means we could have made enough boiled water to make 5974 cups of tea OR that we made the same amount of energy that you'd get if you detonated 100kgs of TNT.... BUT really its not that much.

It's REALLY not that much, we could have bought the same amount of power for less than £15. But what we've learnt is to be masters of efficiency and the way to look at this is to say we've managed to make our business so efficient if we needed to buy our power it would only cost £15 per year, so we're making our drain on the earth resources much less. Even better is we're so efficient we can generate out own power for free (ish..)