Monday, 28 March 2022

Road to Net Zero - Chapter 1

Here's a thing: fermentation produces heat, and if we didn't dissipate that heat the beer would be rubbish, so we use electricity to run refrigeration plants that chill glycol and pump it around jackets on the fermentation vessels, taking the heat away. When the ambient temperature is low, such as in the winter (or at night) the chillers don't need to work so hard, and so draw little electricity, and, conversely, when the ambient temperature is high, such as when the sun shines, the chillers work harder, drawing more electricity. Happily for us this matches electricity production from solar panels - they produce more in the daytime, and in the summer, than they do at night time, and in the winter. In 2020, just as the world locked down, we installed 45 solar panels on the roof of the brewery, and we now have some data to analyse their contribution.

The above graph shows the last 7 days, starting with Tuesday 22nd. The red area is consumption, and you can see how we have a base level of around 2 kW during the night, rising up to over 10 kW on most days as the chillers work harder. The extra tall spikes on Mondays, Wednesdays and Fridays are from the cask washer.

The blue area is solar production and it's plain to see that it's well matched to consumption. Green denotes times when production exceeds consumption and the excess goes into the grid. In the last 7 days we've consumed 627 kW hours, producing 57% of that ourselves.

If we're paying 15 pence per kWh, we've saved £53.60 in a week. The total project cost was £15k, so you can see payback is going to be around 8 years at today's prices. 

We're currently doing some feasibility work on a solar roof for the warehouse - it's a chilled space, and so there should be a good match there, but it's also used to charge the fork lift truck, a motorised pallet truck and a delivery van, and, since these activities occur mainly at night, their consumption won't match solar production unless we invest in a battery system, or rethink our habits. Once we have some data on consumption I'll share it with you.


CM said...

Who did you use for the solar installation? I'd be interested in them having a look at our place.

Anonymous said...

Hi CM - sorry for the late reply but I'm not used to anyone engaging with blogger these days! I used a local firm called SGS.