Final 3 Kw Panels Commissioned.
On Monday Shane from Tansley Electrical arrived to install our final 3 kw of solar panels to bring both inverter arrays up to full capacity.
The project has grown since we first decided to go down the solar power path. Initially 7kw, we realised that although our mid spring, through summer and early autumn sunlight was pretty near all we needed to run our house the winter months were going to be a little short.. So we installed a 2nd array of 3 kw with it’s own inverter. And that worked just fine, until we realised that by installing an “air to water” heat pump we could seriously reduce our diesel fuel consumption for our diesel fired domestic and central heating boiler substituting> And with the ever increasing price of diesel oil that made pretty good sense. But it did impose a bigger demand on our electricity system.
Roof Space
Our second array of panels was only half the capacity of it’s inverter, but where to put the extra 8 panels??.
Quite a large area of our roof is flat. Butyl Rubber over heavy ply. I thought maybe I could install suitable footing for the panels without disturbing the waterproof integrity of the roof. An emphatic NO from our builder. So I had a look at our garage roof, and realised that by topping two trees which were shading the roof we had a clear view of the sun for all but late afternoon in mid summer.
And so we now have a total of 14 kw installed panels through two inverters. And as I type this each is producing 1.40 kw, with 2.56 kw going into the batteries. Up 25% on what we previously had.
We will still need to run our back up generator from time to time. Last week was very “Dark” and over the week we put 6 hours on the clock. Which sounds a lot of course. But since 1st August 2022 if averaged out our gen set running is just 6 minutes per 24 hours.
Is It All Worth the Expense and Effort
The short answer is a very firm yes. It did take time to adjust our thinking to the realities of solar power. For example we will generally not run our dishwasher in the evenings, although in summer we will still have lots of generation as late as 1900 hrs . Instead we’ll wait until our batteries are full, and then use the excess generation for things we can choose when to run. We do a lot more heat and eat. Choosing to cook enough for 2 days…. very little extra energy to cook 4 potatoes instead of 2. we are all electric cooking ….
Heat Pump.
Our heat pump takes around 2 kw to run, but produces 8kw of heat. From October through until the end of March our diesel fuel consumption for domestic hot water and central heating dropped to 25% of what we would have otherwise expected. And this with guests inhouse with their added demand. We do run the heat pump in winter, but only as is dictated by our power availability. We wont know how this will impact fuel usage until maybe the end of September.
Solar on Stewart Island
Its pleasing to see solar panels appearing on various roofs around the village, and a few days ago we had a visit from a couple about build an eHaus and were wondering how solar was working for us. The one thing we have learnt is that it’s not that easy sometimes to adapt an existing roof for solar installation. Layout and aspect are critical, and although ground mounting of an array would be quite simple a lot of properties just do not have the available or at least suitable aspect land to spare. Another thing we’ve learnt is that laying spare capacity cabling can save a heap of later grief if extending the system……. I couldn’t remember what I’d put in when I first installed the cabling from house to our electronics and battery shed. But I’d gone well overboard and we still have cables for another 12 kw if we needed it (and had a place to put the panels !!)
At 46deg 54 minutes south Sails Ashore is perhaps at the southern edge of full solar viability, and of course that works against solar in winter. But it’s fully overcast and quite a dull day at the moment, but we are still getting a bit over 10% of the maximum our panels can produce. And our projected return of around 12 to 13% on capital invested when diesel prices were around $1.50/litre now seem to be a little conservative. So we are best pleased. And there are some really great financing deals available
We have links to all our Solar Power Posts etc on our “Solar Power & Environment” page
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I arrived on Stewart Island in 1969 as Forest Ranger. Since then I've fished commercially both in Fiordland and around Stewart Island then skippered our charter yacht in the same waters, and also down into the Southern Ocean. More recently we now have "Sails Ashore" B&B, and I also guide our guests and others on Ulva Island, introducing them to the natural world of Stewart island