Cooking without gas
in Greener Homes on 4 November 2013
A zero carbon future means ditching gas for solar power
TOGETHER, Australia’s houses could produce more electricity than they use, according to think-tank Beyond Zero Emissions. And the transition need not take long.
The analysis, released last month in its Zero Carbon Australia Buildings Plan, shows that comprehensively retrofitting our buildings with insulation, double-glazing and efficient lighting and appliances could more than halve their energy use.
On our rooftops, we have space to accommodate enough solar panels so that our homes would collectively produce more energy than they consume, averaged over a year.
The report’s lead author, Trent Hawkins, says energy efficiency has a crucial role in reducing our greenhouse gas emissions.
“About one quarter of Australia’s emissions come from our buildings. We could carve that out really rapidly.
“The climate science says emissions need to peak internationally by 2016. Building efficiency is something we can roll out now that will give us big cuts,” he says.
The plan has been several years in the making. One of its key planks is to stopping using gas altogether.
“You can’t have zero emissions if you’re producing carbon dioxide, so that rules out fossil gas,” Mr Hawkins says. “The building industry should be looking at shifting to 100 per cent electricity, and then advancing the broader debate about renewable energy and decarbonising the grid.”
Mr Hawkins explains that while air conditioning is often demonised, Victorians actually consume eighty times more energy warming our homes than we do cooling them. The average across the whole country is ten to one.
“In Victoria we use a large amount of fossil gas. We’ve become dependent on it to be comfortable, and ignored the fact that our building envelopes are generally very poor,” he says.
Ducted gas heaters are common, but they’re particularly wasteful; they heat the whole house, not just a single room. Often, because of tears and rips in the tubes, they’re blowing hot air under the floor as well as inside.
The buildings plan advocates replacing all gas heating with efficient reverse cycle air conditioners. Mr Hawkins acknowledges that on certain summer days, air conditioners present a problem – we all turn them on at once, and electricity demand spikes – but he says we can solve that with smart management and incentives for homeowners.
The plan also proposes replacing all gas hot water systems with heat pump systems, which use similar technology to air conditioners. In our kitchens, gas burners can be replaced with induction cooktops, which are more efficient and responsive than traditional electric stoves.
These retrofits have a price tag, but it’s an investment, not simply a cost. Mr Hawkins says the worst-case scenario – “the most you’d have to spend” – is covered in the case study of an old, detached Melbourne house, with little insulation. The full overhaul, including double-glazing and replacing all major appliances, would cost about $36,000, plus another $10,000 for solar panels (unsubsidised).
Nevertheless, over thirty years, residents will come out well ahead (by up to $6000). “We would be sinking money into energy bills anyway, with no long term benefit,” he says. “We can spend that money to upgrade our buildings and we’ll be better off financially.
“One of the main benefits is that it gives households energy freedom. Today we’re all paying heaps of money on bills. Anyone can follow this plan, and it will give them permanent insurance against rising energy prices.”