What is environmentally sustainable is up for debate

Despite our political differences, Greens leader Senator Richard Di Natale and I have a lot in common.

In 1997 my wife and I left the big smoke to live in the bush. We purchased a block of land that we loved and built our house – a house that was ecologically sensitive and fitted well into the environment.

We had the choice of connecting to the grid or going offline, both choices cost about the same. But connecting to the grid would involve cutting a swathe through the trees on our property, and that was unacceptable, so we went solar.

We fought the council to install a composting toilet, and won that battle. They wanted us to install a particular brand of septic toilet that they considered ecologically desirable, but when we discovered that it used so much power that we would need 14 extra panels and considerably bigger batteries, we persevered. "It's our job to protect people like you from yourself" we were advised by a council officer. Now, of course, they encourage composting toilets. Ideas of what is clean and sustainable change over time, and there's always someone with your interests at heart to advise you.

Recently I was interested to learn from an online magazine One Step off the Grid (http://onestepoffthegrid.com.au) that Richard had followed much the same path some years later.

Reporter Emma Sutcliffe, when she visited the Di Natale property was greeted by the Senator riding a quad bike – and not wearing a helmet! "Despite plenty of sunshine," she writes, "their backup generator is humming, providing power to top up the state of charge [of their battery bank]."

"During winter we run the generator two or three times a week," Richard explained. He tells her that the batteries, now ten years old will probably need to be replaced next summer.

We both made the same mistake with our initial installation, which soon proved to be too small. Richard installed a 1.2kW system, mine was a bit less than 1kW. Improvements in technology over the years and generous government subsidies made it cheaper for Richard.

I installed a bank of lead-acid batteries that stored 720 amp hours, Richard's sealed gel batteries store 600 amp hours.

We have both upgraded our systems. The life of the BP solar panels I installed was expected to be 10 years – mine lasted a bit longer, but I replaced the whole lot with new panels totaling about 2kW, and guaranteed for twenty five years, which will outlast me. Richard upgraded to 2.5kW by adding to his existing BP panels.

With the new panels I upgraded my batteries to a bank of gel batteries that store 1300 amp hours.

We both have solar hot water boosted by a 'wetback' to our wood fire, which doesn't please those over-concerned with clean air policies. There are periods in spring and autumn when we don't need a fire and when the sun doesn't warm the water sufficiently, so we can also run the generator to ensure that we can have a warm shower.