When we moved to our farm on the coast in Victoria Australia over 20 years ago our mains power was delivered by a single wire earth return (SWER) power line and we were the second to last house connected to it. This was just after the misguided privatisation of the power grid delivered this lifeline of civilised existence into the greedy hands of ‘competing’ power companies.
The previously state owned ‘Gold Plated’ system now had to turn a profit for investors so preventative maintenance services were cut.
We began to experience power outages, these were usually brief but occurred at least weekly. They would sometimes extend for hours and more than once for more than a day. With rainwater tanks and an electric pressure supply we couldn’t fill a kettle or flush a toilet.
The first response to this was to install a 5,000 litre tank on a hill 15 metres above the house with a 40 mm pipe to the house. We kept it full and only used it when we had to. One problem solved, but we were still sometimes reduced to kerosene lamps and candles after dark and couldn’t reliably run a freezer to store the food we produced.
So we decided to go off grid. It was a few years before we were fully independent of mains power.
Our system grew over time as finances permitted, technology improved and our experience and knowledge grew.
Now we have two three-bedroom houses 800 metres apart. One is 35 years old and only moderately energy efficient the other is eight years old and optimised for passive solar with excellent insulation, double glazing etc.
Both homes have wood-burning kitchen stoves with boilers for hot water in winter and for hydronic heating. They also have bottled gas stoves and solar hot water with instantaneous gas boost, which is almost never required because the heat exchanger on-stove boiler keeps the tank hot all winter. When the stove is not in use the solar hot water system with its heat exchanger does the job.
We grow all our own firewood. Providing around 100 kg of seasoned hardwood per house per week for the colder months is labour intensive and requires petrol powered chainsaws and a wood splitter.
Each house has its own completely separate power system, each with 30 solar panels of 300-440W capacity, MPPT solar controllers and a 1 kW wind turbine on a 19 metre mast of 80 mm diameter steel tube, stabilised by about 100m of 10mm steel cables and 3.6 cubic metres of concrete.
Running 24 hours a day the wind generators can sometimes equal the total daily solar input.
The power storage systems consist of a total of 60 German made lead acid gel 2V 600 amp hr batteries, shared between the houses (24 and 36). Each of these batteries weighs 48 kg and currently retails for $474 (AUD). They are rigged in series to provide 24 V power to a computer controlled DC linked inverter/charger. Each house also has an interconnected AC linked inverter/charger that sends 240 V AC power from part of the solar array directly to the house switchboard and also contributes DC charge to the battery bank.
In theory we have three to four days of zero input power supply if we were to flatten the batteries, but in practice we don’t let the batteries drop below 70% capacity in order to protect them and make them last as long as possible. So we are limited to about one day of stored capacity.
Both house systems are close to as optimised as we can get them and represent a total investment of around $160,000.
So how do they perform?
In summer perfectly. We don’t have to do much other than check in with the laptop once a week to monitor the system, and we often take the wind generators offline for extended periods.
In winter, when solar energy input per square metre drops to about 30% of peak summer level and then for only a few hours a day, the systems still work pretty well but require more monitoring involvement.
To some extent power usage can be matched to storage levels and fluctuating input from the wind generator. However, the total renewable input is just too patchy and unreliable so petrol or diesel powered generator backup is absolutely required.
It’s not just in winter, but in autumn especially and sometimes in springtime too. When cloudy skies and windless days persist we need to make recourse to our petrol generators, sometimes everyday for a week at a time to keep the batteries charged and provide peak load supply. The inverters are linked to auto-start the generators as required when the battery voltage drops below a set level or demand rises too high. They often come on in the evenings and have to be sited to minimise noise.
In the early days it was a case of dishwasher now, washing machine later, maybe tomorrow etc. and minimal use of electricity to heat things. Nowadays such restrictions on usage are limited to days when the generator starts to automatically kick in – we take that as a signal to check the system and ease off to save on fuel.
The generators have to be looked after and kept fuelled-up ready to go at all times. We have several of them, including a 70-year-old Lister JP 1/9 Startomatic – a 9 hp single cylinder water-cooled diesel running a 1,500 rpm 6.25 kVA generator that was retrieved from a sheep station in NSW. I recently substantially rebuilt it in my workshop with original spare parts. It is a magnificent 1.4 tonnes of the best of British engineering; it works perfectly and will soon be connected. The other repurposed diesel generator I’m working on is a solid old 1,500 rpm ST-6 designed for nonstop use in a commercial fishing boat. It will be driven by a 10hp air-cooled Yanmar L100N until I can find another auto-start Lister diesel for it. These will both soon take over from two two Honda 6kVA petrol gensets currently connected to the systems and will be about half the cost to run. Most years the annual generator run time is around 60-100 hours at each house but it’s as unpredictable as the weather.
After 20 years the first of our solar panels have started to fail and have been replaced. Rather than dump them into landfill because they can’t be recycled, I’m planning on using them to make north-facing sun traps for heat loving plants in our big vegetable garden.
Renewable energy systems should more honestly be called replaceable energy systems. None of the components can be expected to work for more than 25 years and often a much shorter time than that.
It is the journey as much as the destination. Producing our own power fits with our overall ethos of self reliance. We produce our own free range poultry and eggs and, in a good year, most of our fruit and vegetables. We breed Wiltshire sheep and buy in beef weaners, then we butcher, pack and freeze our own meat supply which we can supplement with hunting and offshore fishing.
Extrapolating from our renewable energy experience, anyone who thinks that a modern society can function with a power grid that runs on just solar and wind power without fossil fuel or nuclear backup that’s able to immediately provide up to 100% of power needs on cloudy, still days and dark, windless nights, is totally deluded!
And getting grid-scale lithium ion battery storage to provide the sort of supply time that we have on our farm would cost trillions of dollars, deplete the planet’s non-renewable resources to the point of imminent exhaustion and then it would have to be done all over again in 10 years.
It matters nought that you have massive renewable generation capacity if you can’t store power for extended periods.
So you can have all the wind and solar farms you want, but without fossil fuel or nuclear back up you’ll need to buy a good supply of warm blankets and candles if you don’t want to be spending a lot of time shivering in the dark.
The author was a part-time specialist medical practitioner until he refused to be injected with the experimental gene-based Covid vaccines just over two years ago and was sacked. Now he’s a fulltime peasant farmer who values his privacy and prefers to remain anonymous.