Our energy story: Distilling with the sun, water cooling in a drought zone.

Our energy story: Distilling with the sun, water cooling in a drought zone.

Environmental sustainability and minimising impact is a key value of Envy Distilling. We work hard to lessen our footprint on the world, and these decisions impact our small batch approach and seasonally-driven processes.

Our distillery proudly runs off-grid. But not only that, we only use power captured from our solar panels, supported by batteries. As far as we know, that makes us unique in Australia, in not only being off-grid but also without emissions! It is somewhat challenging to do distilling this way - which is all about high energy needs: boiling and cooling!  All the water used for the products, the production process, and running the distillery door - is all rainwater captured on-site.  Our liquid wastes are treated in our worm-farm septic system, and our solid organic wastes (like used botanicals) are composted and/or dispersed back out to our vineyard and paddocks. 

Heating Power

Although our stills were originally designed to sit over an open flame, typically gas-driven, all our stills are electrically-run. The smaller stills use conventional kitchen hotplates, which is enough to provide the distillation heat at very small scale. Our spirits workhorse, Lady, is powered by a 4.5kW explosion-proof Italian electrical heating element, mounted into the back of the pot. Our larger wine still, Madam, is powered by two of these, capable of 9kW of heating.

Performing alcohol distillation over an open flame is frowned on in Australia, especially by our safety standards, and this would be a little difficult to do while staying safe and compliant. Importantly for us, using electricity allows us to keep our distillery powered only by the sun, during the many sunny days in Heathcote, and avoid creating any emissions from gas, wood, oil or other sources of off-grid energy, and also avoid loading the power grid with the energy intensive requirements of a distillery. We love our choices, and the sun has proven to be a very capable energy partner! However, this approach does mean we can only distill when the sun allows us to - and energy-hungry Madam is unable to run during the depths of winter, with its shorter days and weaker sunlight. As I write this blog, I've had to delay today's distillation on Madam due to a very overcast day.

We do use a battery system to provide supporting power during short times without sun - especially when we start distilling very early in the morning before the sun has yet to hit the right angle.  We often start the process using yesterday's power in the batteries from about 7am, which then get charged up when the panels are in peak output from about 10am.

The below graph shows our distillation load (amounting to 52kWh), the 17kW solar panels and the 26kWh batteries - and how they interact when Madam is performing a wine distillation.

Cooling Power

Heating and boiling the stills is only the first part. Distillers need to then remove all that heat to turn the vapours back into liquid form. All the energy put into the stills needs to come back out.

Our stills use old style "worm tubs" for cooling, following the Cognac and Armagnac traditions in France.  This is essentially a drum of water with the hot coil of copper pipe immersed in and through it, which turns our alcohol vapour back into liquid again. The worm tub has a cool-water inlet at the bottom, and a warm-water outlet at the top, flowing bottom-to-top.

 

For our small experimental still, a small 20L bucket of water is used, and for Little Miss we use a larger 80L drum of water. Pumped around with a pond pump, these water volumes are enough to take the heat of one distillation run without getting too warm.

Our larger stills are connected to a series of three IBC cubes, amounting to 3,000L of cooling water. The first IBC cube receives the warm water flowing out of each worm tub outlet, and is connected to the second IBC cube (bottom to top), which is then connected to the last IBC cube (bottom to top again) - from which the coolest water is then pumped into the worm tub inlet, completing the closed loop circuit. This setup separates the thermal layers of water, and keeps the last IBC cube as cool as possible. 3,000L is enough cooling water to run Madam several times a week, and more than enough for Lady.

We do all this because Heathcote is a dry, drought-prone climate. We don't have access to town water (or any such services!), and just can't afford to waste good water by pumping it away. We also want to reserve as much electrical power as we can for the stills, and so have avoided the need for powered water chillers or other coolers that would draw more of our precious energy. Our system works very well, even during hot days, and the worm tubs actually prefer to run a little warm in order to gently condense the vapours. We had some turbulent and undesirable results when we first commissioned the stills, by cooling too soon and too quickly!

In summary...

All this means that we not only enjoy reliable, cost-free power and cooling, but we're demonstrating something special for our industry, and others as well. Even an intensive process such as distilling in a rural drought-prone area can be done efficiently, environmentally, and produce great products. The constraints drive how we do business - as they always do. But for us, the results are worth it.


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