If you’ve been keeping up, you’ll know that Ardenham Energy have generously agreed to replace our original solar inverter, since the shaded panels were pulling down the performance of the whole array of 16. So in the pouring rain the scaffolding was put up again – amazingly in only about 3 hours.
Then the installers brought in the new magic boxes. They are micro-inverters made by enecsys. They’ve just been developed by the Cambridge-based firm and are being put into the first few houses in the UK on an experimental basis. The are mounted behind each individual solar panel and do their thing individually, so that the whole array will now work in parallel rather than in series. In time the idea is to build them into the panels themselves.
Being so new for the Ardenham Energy installers, they started by laying out all 16 and working out how the wiring should be done.
Then it was just a question of removing the panels, securing and wiring each micro-inverter and putting the panels back.
And while we had the scaffolding up, we installed a further four panels (using an old inverter), to take it up to the maximum of 20 allowed without a further licence of some kind.
Then the other magic box was put in place connected to our BT internet router.
This enecsys gateway reads the output of each micro-inverter wirelessly and then sends the readings to our dedicated web interface.
This was a really excellent bonus. The main display (which of course we can check from anywhere in the world) gives a real-time picture of the output of the array. In the first few hours of only patchy sunlight it recorded 2 kWh generated. And nice to see this expressed in all sorts of other ways – enough to power 22 light bulbs or 28 fridge freezers, or representing the same carbon savings as planting one tree or driving 5 miles. The money earned is wrong at the moment, but will actually have been close to £1 taking together the feed-in tariff and the money not paid to the electricity provider.
Then you can drill down and see the performance of each of the 16 panels. This is where the shading factor is so striking, with the output varying from 89 W for the best panel down to 9 for the worst, which was only lightly shaded. This was in weak sunlight, so it will be interesting to see how close the panels get to their stated output of 180 W.
Even more importantly we can now compare the performance of the new system to the previous one. Exciting day – and always a rush from being one of first kids on the block.