From soaring high energy bills to carbon neutrality

Tony Barry replaced his Porsche Cayenne GTS with a Lexus RZ450e, reducing significant fuel and service costs.

When former Aurecon managing director for Asia and past president of global engineering body FIDIC, Tony Barry, began looking at his soaring household energy consumption, he ended up on a journey that led him to reduced energy costs and being well on the way to becoming carbon neutral on electricity usage. Barry describes his journey here.

“After two years of high electricity bills, in 2020, during one of Melbourne’s Covid lockdowns, we began looking at our energy consumption which seemed very high compared with others we know. Being at home throughout the Covid lockdowns in Melbourne and retired, meant we were using more power ourselves in our own home.

“Our house was built in 2009 and received a 5 Star Green Star rating at the time. We had done many things that were thought at the time to be environmentally responsible and technologically advanced. We used Philips Dynalite to manage lighting and automate many other power consuming devices. We installed external louvres to shade large windows in the summer months. We used double glazed windows and doors throughout the house to support temperature control. We insulated all brick cavity walls. However, over the ensuing years, our consumption increased and cost of power and the carbon emissions from energy generation were high.

“We started by obtaining hour by hour consumption figures from our energy retailer and slowly identified areas where we could upgrade technology to reduce our demand. The first of these projects involved replacing nearly all light fittings with low voltage LEDs using drivers rather than transformers originally installed. We then upgraded some appliances to minimise energy consumption.

“While we were achieving substantial reduction in power demand, we began to see that we could do even more. So, we turned to installing solar panels on our roof and generating our own electricity. This meant removing the solar swimming pool heat matting from the roof.

“The question about how much we should install became an important consideration. We have the space on our roof to install 39 solar panels with nearly 16kW of generating capacity, which on a good summer day could generate over 110kWh, with an average of over 75kWh per day throughout the summer months. In the four coldest months of the year, the average generation would be about 30kWh. By contrast, our summer demand would be about 55 kWh per day and our winter demand about 70 kWh per day.

“We were influenced in this decision by the government rebate for installing rooftop solar and the feed-in tariff applied to surplus energy we generate and provide back to the grid. Importantly, providing surplus energy back into the grid to some extent offset the carbon emissions of largely coal based electricity generators, by which we were also motivated.

“We selected an Enphase system installed by Edge Solar. The team did a fantastic job explaining, installing and commissioning the system and then helping us to manage our usage to maximise our use of solar generation.

“What was also apparent was that we could further reduce our external supply by about 10kWh by installing solar batteries. While we would have liked to install more batteries, the storage capacity is constrained by the energy supplier’s infrastructure requirements. The batteries were installed nine months after the rooftop solar panels and have reduced our grid dependence.

“Once installed, by using the Enphase app supporting the solar system, we were able to manage the use of various appliances to best utilise the solar energy we were generating.

“We followed up by installing a heat pump to heat the swimming pool and then bought a fully electric car; a Lexus RZ450e to replace a Porsche Cayenne GTS, reducing significant fuel and service costs. I have enjoyed the driving experience with both cars enormously and they are two very different driving experiences.

“While not grid independent, we expect to substantially reduce our power bills and over a 12-month period be carbon neutral on our electricity usage.”