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ReNew 143 editorial: not just window shopping

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WHILE ReNew’s focus is normally in the energy arena, once a year we turn our attention to the building fabric, to consider sustainable materials/design and their energy implications. We’ve previously covered roofing and walls, and this time we give the lowdown on both floors and windows. Both of these really matter when it comes to energy efficiency.


Depending where you live, it seems that different sub-floor structures are in vogue. For example, in Queensland in descending order of prevalence are full concrete slabs, timber floors and waffle pods, whereas in the ACT it’s waffle pods that make up the majority of builds, according to 2016 analysis from CSIRO ( We look at all of these floor designs and consider their sustainability credentials, highlighting some excellent resources along the way.

Your final floor covering might be a concrete or timber finish (look for eco-products) or it might include colourful all-natural linoleum or beautiful bamboo. For all products, the eco-credentials will vary depending on source and the materials used. Our coverage aims to point you in the right direction and introduce you to materials you might not know about already.

Continuing our building materials theme, our buyers guide this issue is on windows. Windows consistently top the list of interest areas in our Sustainable House Day surveys. We’ve updated our guide to help you understand the choices from double glazing, to low-e coatings, to films or other treatments applied to existing windows. We’ve also tracked down nine case studies from readers who’ve upgraded their windows, from full replacement with high-performing windows through to secondary glazing of windows and DIY glass replacement.

As feed-in tariffs paid for solar generation exported to the grid have reduced over time, there’s been a lot of interest in what constitutes a fair rate. The ATA advocates for tariffs that reflect the many benefits of solar generation and has been pleased to see several state governments move in this ‘value-reflective’ direction. One big change on the horizon (in Victoria, at least) is a time-varying feed-in tariff, which rewards generation at the times of the day when the grid needs it most. We help explain the proposed tariff and estimate the benefits over a flat rate.

We also look at Paul Hawken’s Drawdown project, present an ‘almost off-grid’ experiment on the edge of Melbourne, cover how to prepare your home for an electric vehicle, plus much more. Who knows, with the current level of media coverage and new EV announcements, perhaps 2018 will (finally) be the year of the EV in Australia.

Until 6 July, we’re running our biennial reader survey. It’s your chance to let us know what you’d like to see more, or less, of in the magazine. It’s at We really use the feedback to guide our planning, so we’d love to hear from you

Robyn Deed
ReNew Editor

ATA CEO’s Report

AS WE change seasons, so does the inside temperature of our homes. For the majority of Australians living in energy-leaky 1 or 2 Star homes, it means going from being too hot in summer to too cold in winter, unless a substantial part of energy bills is spent on heating or cooling.

Helping to empower people to make their homes more comfortable to live in, cheaper to run and not cost the earth is what the ATA has been doing for 38 years. The great examples of what people have achieved in their own homes have filled the pages of many issues of ReNew and Sanctuary magazines.

As well as providing practical, independent advice, the ATA advocates for regulatory change to improve home performance. Currently in Australia all new homes and alterations/additions need to achieve a minimum 6 Star energy rating to comply with the National Construction Code. However, it is well-recognised that many homes are not performing at 6 Star once built. There is also an increasing body of evidence that the economically optimal level of new housing should be above the minimum 6 Stars.

According to a recent report from the Australian Sustainable Built Environment Council, 58% of Australia’s buildings in 2050 will be built after 2019, so improvements to the code and optimal performance are critical over the next few years.

The ATA is taking the lead and working with our partners in representing households and advocating for change to the code. We all deserve to live in comfortable, healthy homes that are resilient in a changing environment. You can support our work by making a tax-deductible donation to the ATA at


You can purchase ReNew 143 from the ATA webshop.


Window and film buyers guide

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Poorly performing windows can drag down the thermal performance of your home. Lance Turner looks at some solutions.

Reducing heat flows through windows and doors is critical for maintaining a comfortable temperature during weather extremes. Heat flowing through an unprotected single-pane window can be considerable, affecting the thermal performance of an otherwise well-insulated house. In fact, a single-pane plain glass window has almost no insulating ability—around R0.2.


The Australian Window Association (AWA) estimates up to 40% of a home’s heating energy can be lost through windows and up to 87% of its heat gained through them. Choosing high-performance windows, combined with sensible window placement, insulating blinds and other window improvement methods such as special films and coatings, can reduce energy costs and improve thermal comfort. Understanding how different windows interact with the design of your home can be key in window selection.

Heat transfer
There are three main ways heat transfers through windows: radiation, conduction and air infiltration.

Firstly, heat is lost by indirect radiation. Warm objects inside the room radiate heat at long wavelengths (between 5 and 40 micrometres). This energy cannot pass directly through plain glass as it is opaque to such long-wavelength radiation. However, some radiant energy is absorbed by the glass and this is conducted through the glass to the outside. In summer, the reverse occurs, with long-wavelength radiant heat (radiated by hot air and hot surfaces outside) passing indirectly through the glass into the room.

Still greater is the transmission of radiant short-wavelength solar energy—consisting of visible sunlight plus near-infrared radiation—which is largely transmitted directly through clear glass.

Secondly, heat is lost through conduction—direct transfer of heat from the warm side of the window to the cool side. In aluminium frames with no thermal break, heat is conducted up to six times more readily through the frame than the glass, as aluminium is such a good heat conductor.

In winter, conduction from inside to outside also drives a convection current on the inside of the window, accelerating the rate of heat loss. Warm indoor air cools when it comes in contact with cold glass and falls to the floor, drawing in more warm air from above. This heat loss method can remove a great deal of heat from a room.

A final method of heat transfer is air infiltration. This occurs when air leaks through the gaps between the inner frame (that holds the glass) and the outer frame (head, jambs and sill). Poorly sealed windows result in a high air infiltration rate and poor thermal efficiency due to the transfer of warm air. This is particularly an issue in areas that see higher winds.

How do you know which glazing system or treatment is the best solution for you? It’s a complex task for the average homeowner, so here we look at window performance measures and the types of glazing you can choose from.

Read the full buyers guide in ReNew 143.

Download the full buyers guide tables here.


The right floor for your build

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When building, you may put a lot of thought into the floor coverings, but what about the sub-floor structure? Both are important to ensure a sustainable result. Lance Turner surveys the options.

When building a home, often very little thought is given to the type of flooring and sub-floor structure used. Yet different sites need different materials, with some being far more appropriate for particular sites. The design of the rest of the house will also help determine the type of floor and sub-floor used.


Your architect will have good ideas about the best flooring system to use, based on their experience with the type of building system you are using and the site specifics. But it helps to have a good understanding of the flooring systems available, so that you can consider the pros and cons of different systems and materials, and ensure that your sustainability or other requirements are met.

So let’s take a look at the most common types of flooring systems (or, more accurately, sub-flooring systems), the materials most commonly used and the types of flooring materials they can support.

Flooring requirements

A floor/sub-floor system must obviously be able to bear the entire load on top of it, potentially including the house, contents and occupants (some floor structures, such as upper floors, will only need to support the contents/occupants).

The floor’s footing system must be suitable for the type of soil you have on your block. A soil report will be required which will tell you your soil type and how reactive it is. Reactive soils are soils with a high clay content which swell when wet and shrink as they dry. This expansion and contraction can cause structural cracking, sinking and other site issues. See for a quick rundown of soil types.

The level of insulation required for your home will also be a factor in the type of floor you select. If you are in a cold climate then you will need a highly insulated floor, so an insulated slab or a floor on stumps that can be insulated underneath will be required.

Of course, durability is also important: the floor must last the life of the home—for example, you don’t want to have to be restumping in 10 years due to degradation of the stumps or soil movement.

Thermal mass must also be considered if your house design makes use of it. A slab provides high levels of thermal mass, although heavyweight walls (on the room-side of the insulation) tend to provide better thermal mass both in winter and summer than do concrete ground slabs. Other floor types can have thermal mass added using a number of methods, from thick ceramic tiles or slate, to adding PCMs (phase change materials).

Read the full article in ReNew 143.

Download the summary tables here.

Renault Zoe at EV Expo

Understanding EV emissions

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Does it really make a difference to your emissions if you buy an EV but run it on fossil fuel generated electricity, compared to sticking with the petrol guzzler? Bryce Gaton re-examines this issue.

Does owning an EV make any difference to your personal transport emissions? In the light of recent statements about EV emissions from Liberal MP Craig Kelly, it seemed a good time to revisit my 2012 analysis of carbon emissions from electric vehicles (EVs) versus petrol vehicles.


In 2012, the result was positive for the only new EV available in Australia at that time—the Mitsubishi iMiEV—when stacked up against a comparable small car, the Toyota Corolla. The iMiEV had lower emissions when driven in all states in Australia on the ‘city cycle’ (modelling typical car use around the city). Only in Victoria on the ‘combined’ city/country cycle did the EV have slightly higher emissions—and that situation could be avoided if it was charged using solar and/or GreenPower.

Six years later, the grid has changed, and the EV and petrol car offerings have changed. So has the result changed too?

To investigate this, I will look at three scenarios for calculating your personal transport CO2 emissions:

  1. Buy an EV for city driving, but take no other CO2 reduction measures.
  2. Combine an EV with a solar array at home.
  3. Other methods for reduction of CO2 for EV electricity consumption.

Scenario 1:
Buy an EV for city driving, but take no other CO2 reduction measures

For this scenario, the answer will depend on where you live. Individual states and territories continue to use different mixes of brown or black coal, natural gas, hydro, wind and solar to generate electricity used in EV charging. These different generation methods produce different amounts of CO2 and other greenhouse pollutants (together referred to as CO2-e).

For petrol- or diesel-powered internal combustion engine (ICE) vehicles, the figures generally stated for CO2 emissions are not the full story. For ICE vehicles, CO2-e includes the CO2 from combustion, plus the direct greenhouse potential from CH4 (methane) and N2O (nitrous oxide) and the indirect emissions from extraction, refining and transport. Adding in these factors enables an ‘apples-for-apples’ comparison.

These factors for both electricity and petrol emissions are sourced from the National Greenhouse Accounts (NGA) Factors report published by the Department of the Environment and Energy and last updated in July 2017. The data on energy/fuel use is sourced from the Green Vehicle Guide (, see note 2).

Read the full article in ReNew 143.

Solar panels

Varying solar payments by time of day

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The ATA’s Keiran Price explains how minimum solar feed-in tariffs are set and helps demystify an intriguing new time-of-day feed-in tariff proposed for Victoria from July.

A FEED-IN tariff is a fairly straightforward concept—it’s the money paid to a household or business for solar electricity which they generate and export to the energy grid.


Feed-in tariffs were initially designed to ensure that a home or business that installed solar (or other renewable energy generation) achieved a competitive payback over the life of the system. Nowadays, the key purpose of the feed-in tariff is to ensure that homes and businesses are fairly compensated for the renewable electricity that they provide into the grid. But that competitive payback is still there!

Germany led the way

It can be argued that Germany is the home of the feed-in tariff. They introduced the world’s first feed-in tariff specifically targeted to subsidise renewables in 2000. Since then, feed-in tariffs for renewable energy generation have been introduced in over 40 countries, including Australia in 2008 (in South Australia and Queensland).

Early feed-in tariffs were designed to give certainty to renewable energy generators on the level of return that they would see on their investments. By having a fixed payment per kilowatt-hour, for a fixed period, it was easy to determine the payback time—how long it would take to earn enough money to pay for the initial investment and then start profiting—which made financing easier. The aim was to increase uptake and installation of renewable energy generation, with the multiple benefits that flow from that.

One such benefit is the reduction in greenhouse gas emissions that flows from increased renewable energy generation. This makes it easier for governments to meet targets for renewable energy. Another benefit comes from the increased demand for renewable energy technologies; this increases research and innovation in the industry, and leads to increased levels of production and cheaper products for consumers—as we’ve seen with the incredible price drops of solar technology.

As the cost of installing renewable energy generation like solar has decreased, the level of support from feed-in tariff schemes has also decreased. In Germany, Australia and other countries, the feed-in tariffs provided have decreased to the point that the initial tariffs look unbelievably generous!

In Germany in 2004, the feed-in tariffs guaranteed to new solar PV for a period of 20 years ranged from 45.7 to 57.4 c/kWh. By 2014 the rates had fallen to 8.9 to 12.9 c/kWh (still guaranteed for 20 years). However, at the same time the cost of installing solar PV has been decreasing by around 14% per year. Installing rooftop solar PV is now more than 75% cheaper in Germany than it was in 2006, with the cost of the solar panels themselves reducing even more.

The net effect is that the ‘levelised cost of power’ for solar PV has stayed roughly the same in Germany from 2000 to now. With low solar PV prices, new purchasers of solar are getting a similar payback time and percentage return on investment, even though the feed-in paid per kWh has dropped significantly.

Read the full article in ReNew 143.

Artists impression The Paddock 2 600px

Living Building Challenge in Castlemaine

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Central to the Living Building Challenge is design that takes account of much more than thermal performance, such as giving back to the local economy. Sasha Shtargot looks at one of the first projects taking this on in Australia.


When architect Geoff Crosby was approached in 2008 by Neil and Heather Barrett about their plans to develop an eco-housing estate, The Paddock, on their 1.4-hectare site in Castlemaine in central Victoria, he was keen to find a rigorous green design framework.

Geoff had been to a talk at Melbourne University about the Living Building Challenge (LBC) and was impressed enough to do some more research and eventually use it in his own work. The framework appealed because it was thorough in its approach to sustainability and it accorded with his own philosophy of tackling issues like water conservation, community and connection to nature firmly through a local lens: “My perspective is that good things come from the local context—you get much richer solutions that way.”

The LBC “ticked all the boxes” for both him and the green-focused site owners. The building standard, set up in the USA in 2006 by the International Living Future Institute, consists of seven performance areas, known as ‘petals’: place, water, energy, health and happiness, materials, equity and beauty. The aim of the LBC is to create excellence in green design; it visualises the ideal building as functioning as cleanly and efficiently as a flower with many petals.

The standard seeks to create healthy, regenerative and efficient spaces that give more than they take out of the environment, making a positive impact on people and nature. Geoff describes it as “the most rigorous and realistic approach to sustainable design he has found so far.” Sustainability academic (and keen supporter of the LBC, and this project) Dominique Hes notes: “There’s a reason it’s called a challenge!”

Read the full article in ReNew 143.

New extension

Material beauty

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Dion and Amy Zappacosta’s reno included some interesting material choices, including a raised timber floor rather than a concrete slab, recycled materials and eco-finishes. They describe how they went about it, and the results.

BACK in 2013, our family of four was looking for a new home in Wollongong, NSW. One of our main criteria was that it be on a flat block, as our previous home was a pole house on a very steep block—not great for family living! We were also looking for a house where the kitchen faced the backyard, and the yard itself had the potential to be kid-friendly and accommodate a decent vegie garden and fruit trees.


The house we found wasn’t ideal, but it had potential. A timber-framed weatherboard, around 80 years old, it was showing its age, but still retained some of the charm of its era.

There were lots of problems. It was suffering from some pretty average additions and modifications done in the 60s, including a filled-in section of the western verandah and an unattractive bathroom/laundry fibro extension. The layout and thermal performance of the house wasn’t great, as we found after living in it for 18 months. It was cold and draughty in winter, with only a sliver of winter sun landing on the kitchen bench. The high ceilings and steep pitched roof helped in the summer, but cross-ventilation was non-existent and most evenings were warm and clammy. The bedrooms and living room were a decent size, but the kitchen/dining space was very cramped. We knew we could work with it though.

The advantage of using an architect

From the outset we knew we wanted a bit more space and to improve the layout and remedy some of the dodgy alterations. We had no intention of demolishing the original part of the house, and were looking to improve the kitchen, dining, bathroom and laundry, as well as add some living space. We also wanted to do it in a way that improved the thermal performance of the house and not have to sit at the breakfast table shivering in a dressing gown and slippers!

We talked to architects and draftspeople with a brief of wanting to make sustainable modifications which incorporated passive solar design. The choice to go with Andy Marlow from Envirotecture was easy. We developed a good rapport with him from the first meeting; being aligned in our views on sustainability and the environment was a great reference point for discussing the designs and materials Andy had in mind.

The architectural fees through to start of construction can be daunting at first, but we decided the value of having an architect on board far outweighed this. Andy found ways to include what we wanted on a smaller construction footprint, which reduced our costs significantly. The comfort the finished house provides is also superior to what we could have specified ourselves. The specification schedule and scope of works documents vastly simplified the builder engagement process and the build itself.

Read the full article in ReNew 143.

Double-glazed windows waiting to be installed

Glazed and enthused: Window replacement case studies

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Replacing the entire window with a new double-glazed one was the answer to greater energy efficiency and thermal performance for these homeowners.

Switching to double glazing as part of a renovation
by Anna Cumming


Last year, we did a small renovation at the back of our 1920s Californian bungalow in Melbourne’s north, opening up the space across the back of the house and putting in a new kitchen. As part of the renovation, we installed glazed French doors opening onto our deck and new windows in the kitchen; we also took the opportunity to replace ugly aluminium-framed windows in our living room and a bedroom with efficient new windows.

We wanted timber frames for aesthetic reasons and to fit the character of the house. Sustainably harvested, ideally local timber was important to us, and I wanted the flyscreens to be timber-framed too as they are internal and thus quite visible.

For thermal efficiency, we upgraded to double glazing, but did not dig too deeply into the precise performance specifications of the various options as we are realistic about our old, leaky weatherboard house—basic double glazing would definitely be an improvement, but top-spec windows, low-e coatings and so on probably not worth the extra money!

Our first step was to decide on sizes and styles and put together a brief for our four new windows and one glazed door unit. Two of the windows were direct replacements for medium-sized existing ones, although we opted for casement openings to catch breezes instead of sliding openings.

In the new kitchen, we replaced a large west-facing window that had admitted far too much afternoon sun with a long, narrow fixed glazing ‘splashback’ window between the new benchtop and overhead cupboards; above the sink on the north wall we decided on a 1100 x 1800 mm window with a sliding opening.

In the centre of the north wall, we replaced the existing single back door with a pair of double-glazed doors we’d been lucky to acquire for $100 several years earlier from a neighbour’s builder—they had been made the wrong size for the job. As part of our windows order, we had a frame made to fit the doors, with an extra window pane on one side.

We sent the brief (see box in article) to seven window manufacturers, a list combining recommendations from friends, companies whose work features regularly in the homes profiled in Sanctuary magazine, and some joineries local to us in Preston that we found via internet search. Comparing the quotes was trickier than merely looking at the final figures (which ranged from $4100 to $8300), as despite responding to exactly the same brief, the detail of each company’s offering was different.

Read Anna’s full case study and two other window replacement stories in ReNew 143.

Fitting secondary glazing

Doubling up: Secondary glazing case studies

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We hear from a variety of householders about their window upgrades using secondary glazing and retrofitted films.

Film + DIY secondary glazing
by Jasper Lee


My wife Melissa and I purchased a three-storey 1980s double-brick townhouse in the inner eastern suburbs of Adelaide back in the middle of 2016. We were new to Adelaide, but quickly became aware of the climate extremes during summer and winter. As Melissa works at home, and we have a toddler at home as well, thermal comfort was important for us, and we wanted to achieve this in a sustainable manner. We had made some basic DIY draughtproofing upgrades at our last property, a rental, with the permission of our landlord, but really wanted to make major improvements now we owned our own home.

Prior to our purchase, the house had been rented out for several years and little had been done to improve its energy efficiency. We had a six-month overlap while we were still renting, so we had time to plan and execute our retrofit upgrades. We started with the low-hanging fruit first: draughtproofing doors, windows and skirting boards. We also took advantage of the support from REES, the SA government energy efficiency program, to upgrade all lighting from halogens to LEDs. We also discovered that the cathedral-style ceilings were missing any form of insulation, so improved this with blow-in Rockwool insulation.

The next things we tackled were the windows. We took a bit of a mixed approach, based on the window aspect and usage, and we staggered the upgrades over the time until we moved in. Our approach was also governed by cost. Replacing the windows or changing their sizes/position would have set us back in excess of $20,000, compared to the $2000 we spent on upgrading 14 window panes with window film and secondary glazing. We did replace a poorly functioning back door with an argon-filled uPVC double-glazed sliding door, because it needed to be replaced anyway; this cost $3300.

Read Jasper’s full case study and 3 other secondary glazing stories (on Magnetite, EcoGlaze and a DIY approach) in ReNew 143.


New glass is greener: Retrofit double glazing case studies

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Retaining perfectly functional window frames and replacing the glass with double-glazed units can save money, as these homeowners discovered.

Retrofit double glazing by Thermawood
by Carolyn Nguyen


The 1960s-era house we bought in 2014 had a compact footprint and good solar orientation. We recognised its potential and thought we could dramatically improve thermal comfort and reduce our power bills with the right kind of improvements. We started small: heavy curtains, pelmets and external awnings. In the ceiling, compacted loose-fill insulation was replaced with R4 polyester batts. Old air conditioners and gas ducted heating were replaced with energy-efficient split systems from Daikin.

Having installed new double glazing at a previous property, we knew of its benefits firsthand. It was initially at the bottom of our to-do list, however, because we felt the payback wasn’t worth it.

The first couple of winters made us reconsider our position. Our indoor toilet, with its louvred window, was effectively an outdoor room. In the bedrooms, warm air hit the glass panes and condensation would form.

Our old house had uPVC double-glazed windows from Ecostar. While they were low-maintenance, they required expensive specialty flyscreens and the uPVC aluminium look appeared at odds with the facade.

With the new house, we didn’t want to install windows that might polarise future owners, potentially resulting in the removal of said windows or the demolition of a perfectly functional building, so we knew we wanted wooden-framed windows. We also wanted to replace the louvres in the toilet with a fixed pane to minimise draughts, and replace the kitchen’s casement window with a bi-fold.

To replace all 10 windows (30 panes) with new high-performance double glazing and joinery, we got a quote of around $48,000 (in 2016), including an installation cost of $5000. Would that product match the house’s 60s aesthetic? We weren’t sure.

We decided to look at other options. One that appealed to us was from Thermawood. This approach reuses the existing window frames, so replacing nine windows with double glazing (28 panes)—the kitchen window was to be replaced entirely—would maintain an important original feature of our period home. Added benefits included saved resources and waste reduction. Plus, it would only cost $13,250. Unlike secondary acrylic glazing that is preferred by some retrofitters, Thermawood replaces the original panes with insulated glass units (IGU), which come with the option of being filled with a low conductivity gas (i.e. argon) and can be recycled at the end of their life.

Read Carolyn’s full case study and a DIY retrofit double glazing story in ReNew 143.

Charging station

Is your home EV ready?

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Electrical contractor, EV charging point installer and EV owner Bryce Gaton looks at what you need to know to assess the potential hidden installation costs and practical considerations in preparing your home for an EV.

AFFORDABLE electric vehicles (EVs) with a range of 300+ kilometres are about to hit the showrooms (see Table 1). If this is going to be your year to make the shift to electric transport, then now is the time to assess your home’s electrics and prepare for the installation of an EV charging point, commonly called an EVSE (electric vehicle supply equipment).


Here are four steps to help you prepare:

  1. Assess your home’s electrics for its capacity to deliver the fastest possible charging time.
  2. Choose your EVSE charging mode and current.
  3. Decide where to position the EVSE.
  4. Choose which EVSE to buy.

Assessing your home’s electrics

At one end of the spectrum, you might just need a 15 A socket outlet, with cost starting around $400 installed. At the other end, you might require a complete switchboard and supply upgrade, and full home rewiring. Costs for this can be $10,000 or more, and of course it will also entail time (possibly many months) to get the work done.

It boils down to what speed of charging you want/need and how much electrical energy your current household wiring can deliver.

First, let’s look at what the current and coming crop of EVs need if you intend to charge them as fast as you can at home. Table 2 lists the AC charging needs for all the EVs available now or coming soon to Australia.

From Table 2, we can work out what additional load (in amps) the EV will add to the household use. The next step is to assess the existing wiring, incoming supply and switchboard in your home to gauge if it is likely to be able to supply this load.

To assess your home’s electrical wiring and switchboard capacity to supply an EVSE, begin with the following checklist (of course, you will still need your installing electrician to check this via a full inspection before installation).

  1. Is your home less than 20 years old or has it been fully rewired in the last 20 years?
  2. Does your switchboard have at least one spare slot?
  3. Do you have three-phase power?

Read the full article in ReNew 143.

Solar panels towards east end of house because of afternoon shading issues_600px

Off-grid on the edge

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Jayne and Cathy Malcholm struggled with power reliability in their location on the edge of Melbourne, so in 2016 they installed battery backup as part of their long-term plan to go off-grid. They describe the system and results.

WE LIVE on the outer edge of Melbourne in a low-energy house which was designed with solar in mind. It has a north-facing roof pitched at 45 degrees to slightly favour winter solar collection. We are on the end of a SWER (single wire, earth return) power line, which over the years has proved to be very unreliable. It was this unreliability that drove us towards a solar + battery system; the power would go off a couple of times a week, resetting our clocks and dropping out the computer, not to mention the inconvenience of sitting in the dark.


We began our project in mid-2015 with some research on solar installers and chose a company that does both domestic and commercial installations. With Jayne having a technical background, she had a lot of questions before we signed on the bottom line. The negotiation took about three months. We kept refining the system speci

fication as we better understood what was being offered and what seemed appropriate for our needs.If you are thinking of going down the solar or battery storage route, our advice would be to pick a reliable company that is willing to spend the time answering all those difficult questions. It may cost you a little more, but our experience is that you get what you pay for, both in terms of product and installation quality.

System requirements
Our requirements were based on our long-term goal of being able to go off-grid; we are already off-grid for water. We decided to design for going off-grid while initially keeping our system on the grid to enable us to test whether it would meet our needs.

We wanted the system to be able to power the house for two days without significant solar input and to be able to start a water pump for fire-fighting purposes. As we were intending to install solar hot water collectors, we did not consider PV water heating at this stage.

Read the full article in ReNew 143.

Drawdown editor Paul Hawken

Drawdown: a plan to reverse global warming

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Paul Hawken’s Drawdown project brings together peer-reviewed science on the “top 100 solutions to climate change”, highlighting the benefits and costs of each. ATA member Tom Hunt met with him recently in Melbourne.

IN February, I was privileged to meet Paul Hawken in Melbourne while we were both touring Australia. I was merely on holidays while the US environmentalist, entrepreneur, journalist and author was presenting the Drawdown project to a large and enthusiastic audience at an event organised by Sustainability Victoria at RMIT.


Drawdown, the book, is Paul Hawken’s latest bestseller, but it is far more than a well-illustrated and readable tome. It represents the combined work of 70 scientists and researchers, and tells an inspiring story of the most important things we can do to combat climate change. It calculates just what we can achieve in terms of greenhouse gas emission reduction by applying the technologies and knowledge already at our disposal. The book is supported by the website, which also presents the data in a very accessible way, gives more information on the methodologies and updates the results as research continues.

Deciding what’s important
So what is the most important thing to focus on in the battle to combat climate change? Is it more important to replace coal with wind turbines, to put solar on every rooftop, to switch to electric vehicles or just to stop eating meat?

This is the type of question many people have posed, but few have properly explored. Back in 2001 Paul Hawken started asking the experts: “Do we know what we need to do in order to arrest and reverse global warming?” But the experts had no overall picture, only the knowledge within their own spheres of expertise.

Greenhouse gases are at an all-time high. In 2013 Paul was so concerned by talk of the unthinkable ‘game over’, he decided to pull together all the experts he could and work out, for us all, just where we stand on global warming with the options we have.

Read the full article in ReNew 143.


ATA member profile: A window on a life in building efficiency

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A physicist by training, Peter Lyons has spent two and a half decades involved with housing energy efficiency—in particular the role of windows, and windows ratings systems. He talks to Anna Cumming.

After finishing his PhD in cosmic ray astronomy at the University of Tasmania in the early 1980s, ATA member and Canberra branch convenor Peter Lyons made the move to the ANU to work in their very high speed wind tunnel project.


“Some of our work was in collaboration with NASA,” he recalls. “We helped design nose cones for unmanned spacecraft that went to Saturn and Jupiter!”

His involvement with the built environment began as part of the Solarch research group in UNSW’s School of Architecture in 1992. “Headed by Professor John Ballinger and CSIRO, we did the early work on housing energy efficiency that led to NatHERS and other energy rating software tools,” he says.

At the same time, the group got involved with an international collaborative development project on advanced glazing, helping coordinate work that was already going on in research institutions and private industry in ten countries. “That consolidated my interest in windows as an important part of the building envelope and a key factor in whether a building would be energy efficient or not.”

This led to a stint at the University of California at Berkeley where he worked on the connection between windows and thermal comfort.

“Everybody knows that windows in winter can make a space feel cold or hot, because of radiant temperature that is lower or higher than the desired air temperature. I worked on what was to be the beginning of a procedure for rating the thermal comfort impact of windows. Say you’re one to two metres from a window; will you be more or less comfortable than if the window wasn’t there?”

Later, he took up a position with the Australian Window Association as the first manager of the WERS energy rating scheme for residential windows, which was launched in pilot form in 1996.

These days, he runs his own consulting firm, offering design development advice on energy performance to the window and glass industries, full window system modelling, and building energy modelling. “Our clients are mostly designers and specifiers who need help with making decisions about windows, shading, and the combination,” he says.

Peter and his family have lived in a passive solar designed house since the 1980s, and he’s been a member of the Australian and New Zealand Solar Energy Society (now the Smart Energy Council) for years.

“A few years ago I became aware of the ATA—there is quite a crossover in membership between the two groups in Canberra—and I joined because I could see straight away that the ATA was extremely practical.”

He’s now been the ACT branch convenor since 2015. “Our branch is a big group with well-attended meetings, which I look forward to every month.”

Peter says he really enjoys the interaction with other ATA members locally and more broadly, noting that in many cases they are people he’s known professionally for years; further, he says that in Canberra, ATA branch activities often overlap with other professional bodies like the Australian Institute of Architects, allowing satisfying cross fertilisation of ideas.

Peter is fascinated by electric vehicles. “I have a hybrid car, but I realise it’s only a stepping stone. I really look forward to the articles on EVs in ReNew. Anything we all at the ATA can do to try to push the government to speed up adoption of EVs and the inevitable electrification of transport would be a great thing.”

“I really enjoy applying physics and good science to sustainability,” Peter concludes. “For me, the way I do that is through building energy performance, the building envelope—especially windows, which have always fascinated me. I guess I’ll do it until I retire. Even after that, I’ll be a keen ATA member!”

This member profile is published in Renew 143. Buy your copy here.

China 3 wheeler

Pears Report: Risky business?

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Transforming our energy system may prove far less risky than propping up traditional over-built electricity supply, suggests Alan Pears.

THIS summer has exposed yet another aspect of the fragility of our traditional electricity grid, with several failures in local distribution networks—the so-called ‘poles and wires’. As former ATA staffer Craig Memery has reminded us in a recent article (, the vast majority of power failures—97.2% on Craig’s figures—happen within local networks, with just 0.24% from insufficient generation.


Once again we face a choice between propping up traditional over-built electricity supply infrastructure or driving transformation. The first involves inefficient capital investment in power lines and equipment capacity used for just a few hours a year; the second involves innovation with  confusing options and other risks.

Energy efficiency, demand management, distributed storage, local renewables and new business models all have roles to play (as described in my columns in ReNew 140 and 141 and my article in The Conversation (

The risks seem very different depending on whether you look at the supply or the consumer side of the meter.

The supply side includes generation, wholesale markets, high-voltage long-distance transmission and local networks of poles and wires. The wholesale electricity market is fundamentally about supply and demand. When supply exceeds demand, prices fall and the consumer is king. When supply is tight, suppliers exploit the situation to maximise profit. Policymakers are frantically trying to develop better mechanisms to reward actions that ‘keep the lights on’, but this is a politically difficult area.

Networks are regulated regional monopolies, but regulation has failed to limit price increases, while network operators have failed to maintain reliable supply in extreme weather.

On the supply side of the meter, the situation is increasingly risky. Building a large power generator, transmission line or energy storage facility takes time and locks up a lot of capital for years: will there be a long-term revenue stream to repay the cost and provide profit? Will consumers continue to tolerate paying for poor decisions?

On the consumer side, if they were available, innovations such as better-insulated fridges that could keep food cold during a 10- or 20-hour power failure and use smart sensors and controls to maximise use of on-site rooftop solar generation—and in the process use $100 less electricity each year—could be attractive. An informed, rational business should be keen to buy behind-the-meter technology such as on-site renewable energy, energy storage and efficient, flexible equipment that could keep production going and income flowing for up to an hour during a power failure—and make money at other times by managing demand.

These products are emerging, allowing  more businesses and households to invest ‘behind the meter’ to take control of reliability and cost, and as a form of insurance.

Local action looks increasingly attractive when you consider the avoided cost of disruption to business, lifestyle or health, combined with increasingly attractive financial returns, lower climate impacts and the opportunity to ‘send a message’ to the energy industry and governments. A rapidly growing industry is happy to provide the technologies and services, although consumer protection issues need a lot more attention.

Snowy 2.0: silver bullet or white elephant?

The proposed Snowy 2.0 pumped hydro storage system provides an interesting example of the dilemmas facing energy investors. Pumped hydro uses cheap, excess electricity to pump water uphill, then produces electricity at other times as the water runs back downhill through a generator. The environmental credentials of pumped hydro depend on the source of its electricity input, design and environmental impacts on habitats.

To profit, it will rely on the gap between buying at cheap wholesale electricity prices and selling at high prices, after allowing for its large ‘round trip’ energy losses of over 30% (, as water flows through a 27 kilometre tunnel between the upper and lower reservoirs.

But the size and frequency of profitable price gaps depend on many factors. If too many energy storage facilities are built before it starts operating or demand response trims peak demand (when prices usually peak), the price gap will close. If improving energy efficiency drives demand down, it undermines the economics of all supply options by shifting the balance between supply and demand (see

Snowy 2.0 won’t be operating until well after the Liddell coal power station closes in 2022, so a lot of new storage and supply capacity and demand-side measures will need to be introduced before then. That will undermine the viability of Snowy 2.0. Given the rapid growth and declining prices of alternatives, Snowy 2.0 may require big subsidies. When price peaks are smaller, all generators operating at the time make less money because the most expensive generator running sets the price for all other generators.

So investors on the supply side of the meter face potentially significant and unpredictable financial risks. Projects that can negotiate long-term contracts and be built quickly have the best prospects. But investing in demand-side modular projects, especially at fringe-of-grid, and packaging high-value services with energy for consumers both look much less risky.

Future urban transport

China has over 150 million electric bikes, for good reason. Their experiment with car-based cities showed very quickly that cars simply take up too much space and conflict with more space-efficient solutions in urban areas. Cars injure or kill a lot of people. So Beijing now has many fenced-off road lanes for use by bikes and other low-speed, compact vehicles.

A lot of money is tied up in a car and the depreciation cost is high: in three years, the value of a new car can halve. According to the Australian Bureau of Statistics, an average household spent $195 per week on motor vehicle-related costs in 2015, of which only a quarter was fuel cost. Many spend far more. Annual fuel use contributes over five tonnes of carbon emissions per household.

The cost of new roads in urban areas is astronomical and the impact of disruption during construction and maintenance is high. The ‘avoidable cost’ of traffic congestion in Australia was estimated at $16.5 billion in 2015, and predicted to increase to around $30 billion by 2030 (see Parking space is expensive; it also forces everyone to travel further by taking up land that could be more productively used and limiting access to railway stations, workplaces and services.

There are much cheaper solutions with lower environmental impact.

Many Australian owners of e-bikes have enthusiastically described how their lives have been transformed. E-bikes deal with the hills, headwinds and sweating that discourage bike riding. They can carry substantial loads, including young children. And they can outpace peak hour car traffic.

But the common complaints from both e-bike users and observers are that they don’t work well with either pedestrians or cars because they accelerate rapidly and go too fast (see, for example, The cheap ones are not very durable and the good ones cost too much. And you can’t take them on most public transport, especially at peak times.

So what do we need? We need e-bikes that have sensors and smart speed controls. When they are near pedestrians, they would slow down and avoid them. They would warn riders of nearby cars or other dangers and slow acceleration to match traffic conditions.

Beyond that, we need new kinds of compact low-speed personal electric vehicles that can be carried on public transport. Already many people use electric skateboards. Some use fold-up scooters that could be motorised. My dream is a fold-up e-scooter with an integrated bag so it can become a wheelie bag on public transport.

Governments should be subsidising smart e-bikes and other low-speed personal vehicles, and accelerating roll-out of infrastructure to support them.

Australia’s recycling crisis

China’s decision to limit imports of low-quality recyclables has disrupted Australia’s pathetically inadequate waste management and recycling system. ‘Waste’ is a valuable resource, for many reasons including that minimising it will save energy and reduce greenhouse gas emissions. But we have failed to invest in the infrastructure and governance frameworks to capture its potential. Numerous studies over decades have shown us what we need to do and technologies are improving fast; for example, see

We need to invest in advanced sorting and reprocessing technologies and ‘close the loop’ by requiring manufacturers to include recovered materials in their products. And we should become world leaders in mining landfills.

Can our leaders lead us on this at last?

Alan Pears, AM, is one of Australia’s best-regarded sustainability experts. He is a Senior Industry Fellow at RMIT University, advises a number of industry and community organisations and works as a consultant. He writes a column in each issue of ReNew: you can buy an e-book of Alan’s columns from 1997 to 2016 at

Read more articles in ReNew 143.

News: Small battery uptick

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Recent figures from the Clean Energy Regulator, outlining the uptake in Australia of small-scale battery storage, reveal a 914% increase (693 to 7032 units) from 2014 to 2018. The figures represent voluntary disclosure of new system installations, and don’t account for those not disclosed nor those that may have been retrofitted, so the real figures are likely to be higher. And although battery system uptake only constitutes 2.5% of total PV systems installed in Australia last year, this is still just over double what was installed in 2016 (1.18%).


On the back of this sort of interest in storage batteries and sales growth, alongside nation-leading renewable energy policy and targets, and incentives promised by both major parties, German battery manufacturer Sonnen will be setting up a manufacturing plant in South Australia and moving its current Sydney headquarters to Adelaide. This will not only create around 400 jobs, but will also provide a cheaper battery storage option for the local market, using locally sourced components (apart from the cells, which are manufactured in Japan) and eliminating the significant cost currently tied up in shipping complete battery units from China or Germany. Sonnen hopes the SA plant will be established and producing its first batteries by the end of this year.,

2014 8 208 3 129 34 5 137 169 693
2015 3 133 1 186 21 6 163 24 537
2016 105 667 6 331 130 18 240 70 1567
2017 183 1742 16 773 445 90 686 204 4139
2018 7 38 0 26 12 0 9 4 96
Total 306 2788 26 1445 642 119 1235 471 7032

New solar PV systems with battery storage by year and state/territory as at 31/1/2018. Note that RET certificates can be created up to 12 months after installation, so 2017+ figures will rise.

Q&A: Understanding carbon trading

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When reading ReNew, I always turn first to the Pears Report, but sometimes I think Alan Pears is so familiar with his subject that he forgets others are not. The third-last paragraph of the latest report had me puzzled for some time and, while I think I understand it, it raises more questions and makes me aware that I do not understand how carbon is traded in Australia.


I thought that all forms of pricing carbon had gone and had been replaced by a scheme, dating back to Abbott, in which big polluters were paid in advance not to exceed a certain target; and that this system had come in for criticism on the grounds that it would be too expensive and in any case would leave us short of our obligations. This is probably wrong or outdated so I would like to know what we are doing at present. If it is still operating, are the government and big business exceeding their targets and purchasing carbon offsets in the global market? Why is this tolerated—is it not an extraordinary abrogation of responsibility in this area?

The suggestion to buy carbon offsets as presents is great but what is meant by “buy and surrender these offsets without emitting”? Surrender to whom and what would I use emissions for? Secondly, it seems improbable that even an army of “little people” would have the purchasing power of the big corporations or government. Also the available purchases vary significantly in price per tonne so would not the best strategy be to buy the cheapest first?
—Dick Varley


Yes, maybe I did assume a lot—I was short of space and it would take most of an issue of ReNew to explain it all properly.

Mandatory carbon pricing in Australia was shut down by the Abbott government. I was referring to the international scheme run by the UN under the Clean Development Mechanism (CDM), where developing countries can implement emission reduction measures and create carbon offsets if they meet the rules: for each tonne of emissions avoided under an activity that meets the CDM requirements, they create a certificate. These offset certificates can be sold to emitters in developed countries (and to governments to meet their Paris commitments), who can surrender them to the UN as an alternative to reducing their own emissions.

The website I referred to is fairly user-friendly and allows individuals to buy offsets from CDM projects and they are automatically surrendered through the website. Under the international carbon accounting mechanism, this is counted as additional abatement outside countries’ emission inventories. So if I buy a tonne of offsets through this website (and they are automatically surrendered) this means I have reduced my net emissions by a tonne of CO2 as measured by the official global accounting scheme. So I can offset my emissions from air travel or other activities that emit. I should probably have said ‘without net emissions’ rather than ‘without emitting’.

While the UN CDM scheme has plenty of critics (for good reason), the reality is that CDM offsets are ‘legal international currency’ so if I buy and surrender one, that is one less offset available for a big emitter to buy. I agree that we individuals can’t match the scale of big emitters, but my aim is to offset my emissions that I can’t avoid, and this is a way of doing it quite cheaply. And if people like me do buy CDM offsets in large enough quantities, it will push the price up a bit, which means developing countries will have a bit more money to fund emission-reduction activities, and the big emitters (and the Australian government) will have to pay a bit more for offsets, so they may be more interested in actually cutting their own emissions than just buying their way out of their obligations.

Given that all offsets that qualify under CDM are ‘equal’ (although it’s not quite as simple as that), buying the cheapest ones first does make sense—although some of the more expensive ones do have significant local social and environmental benefits that I don’t mind contributing to. So I buy a mix of cheap ones (under $1/tonne) and some more expensive ones—but even those are still under $10/tonne. Some of the more expensive ones also qualify as ‘Gold Standard’ which means they are verified by a group of environmental organisations and offer significant environmental/social benefits.

The scheme that replaced the carbon price in Australia is so-called Direct Action and the Emission Reduction Fund (ERF) is the mechanism. The ERF uses ‘reverse auctions’ so organisations that want to take actions that cut emissions (or store carbon) can bid and, if successful, are paid an average of about $13/tonne of emissions avoided or stored—effectively we taxpayers are paying this price per tonne of emissions avoided. This is just like a carbon tax, but we are paying, not the businesses that emit! Yes, there is a lot of debate about this scheme, and it is not very good for lots of reasons!

Some carbon offsets created under Australia’s ERF also qualify as ‘additional’ global emission reduction, but there are some complexities and I don’t think individuals can buy small quantities of ERF offsets, so I prefer to use the UN website.

Given that Australia’s emissions are not declining at anywhere near the rate needed to meet our 2030 Paris commitment (although we will meet our 2020 commitment), it seems increasingly likely that the Australian government will have to buy offsets to compensate for a proportion of our emissions, instead of cutting local emissions by enough to meet our commitment. I agree that, as a wealthy country that could cut its emissions at little cost, or even while saving money, we should be doing much more.

I wish I could point readers to a simple but thorough explanation of all this, but I don’t know of any decent source. The Voluntary Carbon Markets Association used to publish explanations, but it has not been active for some years—a group of us are hoping to reinvigorate it, so maybe then I can refer people to it.
—Alan Pears


Product profile: Flexible solar laminates

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Most roof-mounted solar panels are rigid, framed panels, but this has some disadvantages—they protrude from the roof, which increases wind loads, the mounting systems add considerably to the cost, and they may be aesthetically unappealing.


The Flex series of flexible solar laminates from MiaSolé (owned by solar giant Hanergy)are designed to stick directly to suitable roofing profiles (such as standing seam roof sheets), eliminating mounting systems and roof penetrations from screws. The modules are based on CIGS (copper indium gallium selenide) cells and have efficiencies as high as many crystalline silicon panels.

There are two models in the Flex range, each available in several power outputs. The FLEX-02N measures 2598 mm x 370 mm, with power outputs ranging from 110 W to 130 W, while the FLEX-02NL measures 5923 mm x 370 mm and can produce from 265 W to 305 W, depending on the version.

Thickness for both models is just 17 mm at the junction box, and the laminate itself is 2.5 mm thick with adhesive or just 1.5 mm without. The modules weigh under 3 kg per square metre and come with a five-year product and 10/25-year power output warranty.

RRP POA. For more information and to buy, contact Peter Park at MiaSolé, ph: +1 408 789 3369,, and see

Read more product profiles in ReNew 143.