One of the reasons we are so happy at our new HQ, New Barns Farm, is that we work in an efficient, warm, near passive building.
Essentially we use less energy here, because the building is very well insulated. We have dramatically reduced our need for heat because the straw bale walls, insulated roof and floor are all doing their job. Our heat pump and MVHR (mechanical ventilation and heat recovery system) provide our warmth and cooling without fossil fuels. We have the most energy efficient lighting possible, again, reducing our energy demand.
But the best news? Our Solar Panels are really working. Here is the latest report from Justin Ford, who installed them back in October 2022 (with batteries following as they were available, in May 2023).
I have conducted a brief review of the performance of your PV system over the first 280 days since we started monitoring its performance in late April 2023. Total generation reported by the Solis monitoring portal is 11,575 kWh. This compares to an estimated annual output in our original proposal of 10,671 kWh. With only three quarters of the year gone the array output is already 8.5% above prediction, which is pleasing.
Since the SMA Sunny portal started collecting data on 4th May 2023, 191 kWh has been imported from grid, mainly between Oct and Jan, whilst 177 kWh has been exported to grid, between May and Sept. Over the same period 1439 kWh were charged into the battery at an average of 5.3 kWh daily, which is relatively high utilisation for a 7.68 kWh battery capacity.
Overall, based on this evidence the PV array and the ESS seem to be relatively well matched to the consumption in the new building with only small surpluses exported to and imported from the grid. Also there is little overlap between periods of importing and exporting, which indicates that the impact of additional battery capacity would be minimal.
So we are pretty self-sufficient, great. But why don't we, with our large roof, go for more panels and more batteries?
We import from the grid at 27.98p/kWh but when we export we are only paid 4.10p/kWh. Now I realise that we don't have the cost of operating the grid, but we pay a standing charge, a daily charge for that... Why such a large discrepancy!
Also, we have 3 supplies into the farm, and neighbours. Why couldn't we supply ourselves for say, 20p/kWh, or our neighbours?
We have been told by UK Power Networks that we can't.
I am thrilled that some community energy pioneers are finding ways around this, as we feel a distributed system, with local generation can help with the renewable transition and with energy independence.
Right now we are just proud of our HQ. Find out all about the build on another post.
Here is the Direct Comparison with our previous site, Tonge Mill:
In our last year at Tonge Mil we used 7767 kWh of energy. In our new building at New Barns Farm, which is three times the size, we used 6107 kWh in our first year. But! We also generated 4502 kWh, meaning that we cut our total electricity consumption from 7767 kWh to 1599 kWh… or by 79%. And do you know what else? Because the old site was on gas and the new site is on a heat pump we eliminated fossil fuels, and the kWh we were spending on gas now sits on our normal bill. In our last year at Tonge Mill we used 22360 kWh of gas….
That last year at Tonge Mill we used 7767 kWh in electricity plus 22360 kWh in gas, or 30127 kWh in total energy.
Now we are down to 1599 total… or a reduction of 94.7% in kWh demand. And we did this while trebling the size of the workshop!
