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  • Writer's pictureMike Casey

A post for the energy geeks - the numbers behind a fully electric farm.

Updated: Oct 5, 2023

There has already been a huge amount of interest in our orchard and our upcoming episode on Country Calendar has already led to a heap of questions so I thought I would take the time to churn out a blog post about our energy consumption across the house and the farm now that we have electrified over 20 machines.

The TLDR is that we have increased our electricity consumption by nearly 900% compared to the previous owners of the property which is incredibly scary for the traditional suppliers of energy, but with modern technology we consumers can be smart. We actually took less power during peak periods compared to the previous owner so the argument can be made that no infrastructure upgrades (outside of the local transformer we had to pay for) were required in order to electrify everything.

There is a case that the smart consumer should now be considered part of the electric infrastructure and be rewarded financially for their contribution to the grid during peak times.

We have made all our data live on this amazing product called BlackCurrent which is an NZ-based startup helping with the data around the electrification of everything. Go have a look at our 30 day consumption and costs at and see how electric everything compares to our estimated diesel bill.

Our Household

When we bought our farm in 2019 it came with a lovely home that was built in 2008. Not the most efficient home but good enough. It's 290sqm and had diesel underfloor heating, gas hot water, and gas cooking and cost the original owners about $6000 a year in fossil fuels (the words of the previous farmer that I have no way of truly verifying).

We knew the paybacks on a Hot Water Heat Pump (HWHP) to do the underfloor heating and hot water would be immense so we fully electrified the house. Here is the breakdown of the consumption numbers for 2022.

When you include the family EV (around 35,000 kms per year) you can see we have increased our electricity consumption by nearly 400% which is far far greater than the 68% Transpower is estimating we need to increase generation by 2050!

The previous owners used 11MWh, we managed to reduce this down to 8.9MWh with more efficient lightbulbs, fridge and freezer. We added an aircon unit for our summer comfort and replaced petrol, diesel and gas with electric machines.

Our Farm

The farm had an almost infinite increase in electricity consumption because the previous owner ran sheep using almost 100% fossil fuels for energy (there were some lights in the shed but let's not count those).

As you can see, by far the biggest consumption of electricity on our farm is frost fighting. That is running the two 30kW frost-fighting fans and also a 36kW frost-fighting water pump for around 150 hours per year.

Now that we have a fully driver-optional electric tractor it will be interesting to see how much electricity we use when drive up productivity by doing more tasks and doubling or even tripling our tractor hours.

Overall Energy Costs

What is quite staggering is that with solar and batteries, and essentially becoming smart power consumers through generating our own energy, buying power from the grid when it is cheap and highly renewable and exporting it back when it is expensive (usually because Huntly is burning coal), is just how much money we can save across our household and farm.

Assuming diesel is $2.50 a litre and electricity from the grid is 30c per kWh (including all line charges, levies etc.) here is how the savings work.

By electrifying all 20 machines in our house and on our farm we more than halve our energy bill. By adding in solar (45kW, an arbitrary figure based on roof space) we reduce our electricity bill by a further 40% and then by arbitraging power through a spot price contract we reduce the total electricity bill including line charges by a further 60%.

With the right software improvements I could easily eliminate our energy bill entirely, and if we had a fair market where we were paid for our contribution to help avoid massive local infrastructure upgrades, fully electric small businesses and homes could even start to make revenue!

Something to aim for in the future!

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1 Comment

Billy Fung
Billy Fung
Nov 14, 2023

Awesome write up! How do you determine when to export back into the grid, and what kind of spot price contract are you on?

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