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ReNew 141: Store your solar

ReNew 141 editorial: measure it up – the benefits of monitoring

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I’M A big fan of energy monitoring. Most days we check the app from our electricity retailer to keep an eye on usage from the day before. Broken down into half hourly blocks, this proved particularly useful to see the (good) results as we switched out halogen lights for LEDs and got better at turning things like the computer and printer off when not in use (hibernation mode on PCs means you can easily pick up where you left off, and an ecoSwitch is great for quickly turning off printers or TVs). The app also keeps historical usage so you can compare winter to summer, or this winter to the last, useful for spotting a problem energy-user (a plug-in heater perhaps), before the costs start to add up.


Taking it a step further, you can even get near-real-time monitoring. Having just installed a solar system, I’m now a convert to its app which shows almost instantaneous solar energy production and electricity usage. Such real-time data makes it even easier to work out what’s chewing up energy—or as happened today, to tell whether your child has turned on the washing machine as promised while you’re out! Plus, the generation data helps you schedule appliances to run at a good time for solar self-consumption or to work out if your solar system is performing as expected.

In this age of Internet of Things and wi-fi connectedness, there are now so many more options for energy monitoring: some connected to a smart meter, some to a solar or battery system and others independent of these. Our guide helps you understand which type might work for your situation—definitely worth a look to help you reduce your bills and environmental impact. It’s just a pity the same tools aren’t available for gas monitoring.

Our other big topic this issue is energy storage—perhaps more of a barbecue-stopper than energy monitoring! It’s been heartening to see grid-scale battery developments in South Australia and Victoria, as a way to provide grid stability and assist with peak demand. There are solutions other than keeping ageing coal-fired power stations like Liddell open.

It’s great to see early adopters of home battery systems in our audience. Their ‘use cases’ will provide insights and help the market develop—similar to the role many ReNew readers played in the early solar days. It’s also good to see industry trials underway to measure the community benefits, plus government subsidies which a few of our case studies have been able to access. We’ve reviewed the market to provide pros, cons and the range of battery systems available. It’s a rapidly developing area, so we’ll keep providing updates and case studies to help guide your approach.

Plus: ‘home truths’ on how comfort and efficiency can go hand-in-hand, a heat pump hydronic system in action, using ratings tools during rather than after the building design process (there’s even a free tool available so you can DIY), second-life for EV batteries, DIY garden irrigation, a community aiming for net zero energy and much more. Enjoy!

Robyn Deed
ReNew Editor

ATA CEO’s Report

AS ReNew goes to print we are in the final stages of preparing for Sustainable House Day 2017. We are very excited to have 200 homes opening up across Australia, with 20,000 people expected to visit one or more of these homes on the day. The event provides a unique opportunity for people to come and learn how to make their homes more environmentally friendly, more comfortable and cheaper to run.

A diverse range of homes are opening their doors, including granny flats, student rental accommodation with battery storage, new contemporary 10 Star homes and homes where the owners have made gradual changes over a number of years. What they all have in common is that they’ve worked hard to improve the energy efficiency of their homes.

The average Australian home has an energy efficiency rating of just 1 to 2 Stars, making them cold in winter and warm in summer. Draughty and leaky, these homes use about 40% of their energy on heating and cooling. By walking into a well-insulated home you can instantly feel the difference in comfort.

We are also seeing new trends with an increasing number of homes that are all-electric and more homes incorporating battery storage or at least planning for future installation. They must have been keeping up-to-date by reading ReNew!

Sustainable House Day would not be possible without the generosity of the households opening their doors and over 200 volunteers who help out on the day. They are all part of ATA’s community of change, not only taking practical action for a sustainable future themselves but sharing their experiences and inspiring people in their community to do the same.
Donna Luckman

You can purchase ReNew 141 from the ATA webshop.


All-electric and hydronic

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There’s a lot to learn from this highly insulated and well-sealed renovation in Melbourne, not least how a heat pump is providing both hydronic heating and hot water. Cameron Munro explains the house’s modelling-led upgrades and the tweaks made along the way.

WHEN we bought our 1910 weatherboard home in inner suburban Melbourne, we were committed to making it as comfortable and energy efficient as we could. We’d partially renovated a previous home by installing double glazing and injecting foam into the wall cavity, but our new home presented the opportunity to do a far more extensive renovation.


Our approach was guided by the German Passivhaus movement (also known as Passive House in Australia), which requires extensive insulation and extreme attention to thermal bridging and airtightness. We really liked this approach as it’s guided by building physics and requires extensive modelling and verification.

Moreover, we weren’t comfortable with the usual practice of simply throwing energy into a building to keep it comfortable; whatever additional heat we needed, we wanted to ensure we could keep it within the building envelope for as long as possible.

First things first: going off gas
The previous owner used a conventional gas storage hot water system and gas heaters. Our strategy for heating and hot water was always going to be all-electric using an air-source heat pump and solar PV.

We liked the simplicity of minimising our grid connections and had concerns about the carbon footprint from gas production and use.

One of the first things we did was to have the local gas network utility remove the gas meter and cap the gas main in the street. This was surprisingly easy to do, and cost us nothing.

Read the full article here.


Knowledge is power – Energy monitoring guide

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Need help getting the upper hand on your electricity bills or checking that your solar system is working? You should consider an energy monitoring system, says James Martin from Solar Choice.

DO YOU have a clear picture of what’s drawing electricity in your home right now? If you’re like most Australians, you probably don’t.


Historically, this hasn’t been an issue because electricity bills weren’t a major concern for most households and, in any case, the number of devices was probably small. But these days electricity prices are high and there are likely to be more electricity-consuming devices plugged into the walls of any given home than the occupants can think of off the top of their heads.

Many Australians have turned to solar panels to help them fight rising prices. Rooftop solar is now affordable and commonplace — the Hills Hoist of the 21st century.

However, comparatively low solar feed-in tariffs in most places mean that solar homes have less incentive to send solar electricity into the grid and more incentive to use it directly. Despite this fact, many (if not most) solar system owners would be at a loss if you asked them how much energy their system produced yesterday, never mind the proportion that they managed to self-consume.

Solar systems have even failed without the homeowner realising until they received their next bill. So monitoring is important!

Types of energy monitoring and management systems
Thankfully, there’s a growing number of products on the market that shed light on household energy consumption and solar generation. These devices take a range of approaches and offer a range of functions, but can generally be classed as either monitoring systems or management systems.

As the name implies, a monitoring system enables the user to ‘see’ what’s happening with their electricity, usually via an app or web-based portal, whereas a management system lets them not only observe but also ‘reach in’ and control which devices switch on at what times.

In reality, the line between the two is becoming increasingly blurred as platforms that once offered only monitoring get upgraded to let them do more.

Monitoring and management systems can be lumped into roughly five categories based on how they are physically installed in the home.

Read the full article in ReNew 141.


Energy storage buyers guide

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With rapidly increasing demand, we survey the battery storage system market. We present the latest systems and the considerations to guide your approach.

WITH the steadily rising cost of grid electricity, many people are considering how to make the best use of the solar electricity they generate, to offset as much mains grid power as they can.


While there are a number of ways to do this, including shifting loads to the middle of the day or diverting excess energy to heavy loads such as an electric water heater, if those options are not possible or desirable, or you have other needs, such as a degree of backup during grid failures, then an energy storage system is an option.

There has been a move in recent years towards storage systems that contain the batteries and other components in a pre-configured ‘storage in a box’ module for connection to a PV array.

These sorts of pre-configured energy storage systems are the focus of this buyers guide. We do not cover individual batteries/cells in this guide, as they have their own buyers guide, the most recent in ReNew 131.

Pros and cons of ‘storage in a box’
There are several advantages to this sort of ‘storage in a box’ system.

Firstly, installation is usually quick as much of the wiring between components has been done.

Secondly, it often makes for a neater system as many components and their associated wiring are enclosed in a single cabinet.

There are some disadvantages too, including less flexible system sizing—most suppliers have a few standard battery bank sizes that they offer.

However, storage units may be modular so that multiple units can be used to make up the required capacity, and some are designed to have extra battery modules slotted into the case to increase capacity.

Read the full article online or in ReNew 141, covering:

  • Economics on the grid
  • The environmental equation
  • Community benefits of batteries
  • Types of system: AC batteries, Battery-only products & DC coupling, All-in-one units
  • Backup power
  • Which battery chemistry?
  • Battery smarts
  • Safety, Quality and Warranties
  • Sizing your system
  • Energy management
  • Retrofits
  • Maintenance and upgrades
  • Table of systems

For the abbreviated table of storage systems in PDF format, click here.
For the full updated Solar Quotes table of storage systems, click here.

1940s cottage with battery

Battery system case studies

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1940s cottage with battery

IN 2016 Liz and Charlie extended and renovated their 1940s cottage in Ainslie, a suburb of Canberra, applying passive solar design to the extension and retrofitting insulation and sealing to the existing home.


In early 2017, they also added 4.48 kW of solar, an LG Chem 10 kWh battery and Reposit software, costing around $20,000 as a package, after an ACT government subsidy.

“We chose to get a battery as we wanted to maximise self-sufficiency,” says Liz. They like that the battery allows them to use their generated electricity at night. They chose the LG Chem battery as it didn’t need to be undercover.

Their average usage is around 8 kWh to 9 kWh per day and currently, according to Reposit, they’re achieving 96% to 98% self-consumption, depending on the weather (and therefore their solar generation) and their electrical load for the day.

“Yesterday it was partly cloudy, and we generated 26.8 kWh, used 9.9 kWh ourselves, exported 17.2 kWh and imported just 0.3 kWh,” says Liz. “That’s pretty typical.”

The battery is generally fully charged by 11 am; on a sunny day it can be charged by 9.30 am, and occasionally not until the afternoon if it’s very grey.

The real-time monitoring available via Reposit is fascinating, says Liz. “It gives us useful feedback on our electricity usage patterns and, as a result, we make better choices about electricity consumption.”

For example, they noticed their hot water heat pump was coming on during the night when they’d prefer it to operate during the day from solar, so a timer to prevent that happening is on their to-do list.

Retiring sustainably

WHEN Julie May retired and bought a new home in Canberra, she decided to invest her savings in a sustainable lifestyle to reduce both her environmental footprint and her cost of living in retirement.

The house already had some good energy-efficient features including R3.5 ceiling insulation, R2 wall insulation, north-facing living areas with eaves to exclude sun in summer, high/low windows for cross-ventilation and a Daikin split system for heating and cooling.

Her changes began in July 2015 with the purchase of an Audi A3 e-tron plug-in hybrid electric vehicle, followed by installation of a 4.5 kW solar system (Nov 2015) and a 6.4  kWh Tesla Powerwall with Reposit for energy management (Aug 2016).

Julie also disconnected from gas in 2016, switching from instantaneous gas to electric-boosted solar hot water. Her gas bills previously comprised 80% fixed charge and only 20% for the gas itself, so going all-electric has meant a big saving.

She can now run her home and car mostly off solar and the stored energy in the battery, thus keeping imports low (1 to 2.5kWh/day, down from 10 to 23 kWh/day, counting electricity and gas).

Other notable achievements:

  • Julie has travelled 18,000 km in her Audi over the last two years and averaged just $155/year for petrol.
  • Reposit monitoring has meant she’s been able to better stagger appliance use so that grid energy is seldom required.
  • Julie has been paid Reposit premium GridCredits on several occasions for providing energy from the battery when there was high peak demand, e.g. she was paid $5.24 for four ‘grid credit events’ on 10 Feb 2017.
  • She also runs a cordless battery-powered mower as part of her all-electric home!

Eco additions

GREG and Maria built their passive solar house in Sydney in 1988, with a view to living as sustainably as possible. As technology has improved and become more affordable they have added more sustainable features.

A solar hot water system was the first addition in 1990, followed by 6000 L of rainwater storage in 2009, 2.8 kW of solar PV in 2010 and double glazing in May 2017.

Then, just six weeks ago, in late July 2017, they added a Tesla Powerwall 2 with 14 kWh of battery storage ($9300 installed).

Their motivations included to increase use of their solar and to ensure supply during blackouts, particularly to run tank pumps as they are in a bushfire zone.

The house’s energy consumption averages around 10 kWh per day, and the solar and battery were sized for this.

They expect they’ll use a little from the grid during the winter quarter, but they should be pretty well energy independent the rest of the year.

So far, the system has performed better than expected, with just a few days requiring grid draws of up to 2.5 kWh—usually when they’ve used their fan heater in the evening.

The battery charging and discharging is not timed—“it just works,” says Greg. “My experience is that there’s no need to manage it. So far, our limited experience is that if there’s a sunny day, the battery gets to 100% during the day with a small amount of grid export after that, and then the house runs off the battery all night.”

They can now run multiple appliances without drawing energy from the grid. Greg notes: “Being AC-coupled, the battery and solar add together, so we can supply a load of 7 kW quite easily, which was not possible before the battery.”


Read the energy storage guide and more case studies in ReNew 141.


Towards grid independence

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What happens when a home with very low electricity use adds a battery? Terry Teoh describes his home’s interesting results.

OUR house is an Edwardian three-bedroom brick home renovated in 2010 along sustainable design lines. With two occupants, our house achieves a very low average electricity consumption of 2.4 kWh/day, though note that gas is (currently) used for space heating, cooking and boosting of solar hot water.


We installed a 5 kW solar PV system in December 2016. With the array oriented east and west, the seasonal difference in energy production is accentuated compared to a north-facing array: our system produces on average 26 kWh/day in summer and 7 kWh/day in winter.

In April 2017, we added a 4 kWh Sonnen eco8 battery to our system to provide solar load shifting—storing solar energy produced during the day for use at night.

In the first two months of operation (to June 2017), our house has moved from 30% to 70% grid independence—i.e. 70% of our energy is now generated by our solar system.

Interestingly, that 70% is lower than we expected given a substantially oversized solar array and battery. It turns out that our standby energy usage is too low to be served by our inverter!

However, it’s still a good result and the battery has lifted solar self-consumption from 5% to 50% and paved the way for us to disconnect from the gas network and move to an all-electric, renewably powered household.

Our motivations for installing a battery system included a desire to maximise solar self-consumption and grid independence. The latter is not out of antipathy for energy companies or the grid. We want to stay connected to the grid.

The grid is good; it will just be used in a different way in the future to support a decentralised energy system where consumers will have more control over how they make, use, store and share energy.

Read the full article in ReNew 141.


Second life for EV batteries

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We’ve looked at recycling end-of-life batteries before, but what if they could be reused instead? A startup in Melbourne is making that happen for electric vehicle batteries.

In Australia, with just 4000 or so electric vehicles on the road, you’d be forgiven for thinking we can defer dealing with ‘end of life’ EV batteries for a good while yet. However, the global view is quite different.


Some two million EVs are on the road world-wide (up from around 400,000 in 2013) and, with warranted battery life ranging from five to eight years, a large number of batteries are approaching end of life. Whether that’s a problem or an opportunity depends on your perspective.

Getting value from a second-life battery
Relectrify, a Melbourne-based technology startup, is a company that sees the upside.

At the end of its usable life in an EV, says Relectrify’s Valentin Muenzel, a battery generally has around 2000 charge–discharge cycles left—or about half its life. It may not be suitable for continued use in a car, but there are other uses, in household systems, for example, where the lighter loads can mean it’s still got a useful future.

It’s not quite as simple as plugging a used EV battery in to your home energy system, of course.

One issue is that cells may have degraded differently across the battery pack. A standard battery management system (BMS) will prevent the entire battery from discharging below the fully discharged point of the weakest cell (a passive BMS) or take from those cells with more energy capacity to make up for those with less (an active BMS). The latter can improve the energy output, but the degree of improvement depends on the difference in capacity between the cells.

To maximise the energy output from the battery, the team of engineers at Relectrify has instead designed what they term a “BMS on steroids”.

This outputs full capacity for all cells that are functioning, rather than balancing the current between cells, in effect draining each cell completely to its safe end point voltage each cycle.
It’s a neat ‘plug and play’ system—a circuit board screwed atop the battery screw terminals (or welded if needed) that optimises at the cell level to use all the energy in the cell. It can work with lithium ion batteries as well as other types, including nickel-metal hydride—any that have a ‘contained’ battery chemistry, so not flow batteries, for example.

Firmware updates to the algorithm can be delivered via the cloud, so as they improve the technology, existing systems can benefit.

Read the full article in ReNew 141.

Beyond the Stars

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There’s much more to be gained from an energy rating tool than the number of Stars. Sid Thoo and Alex Raynes-Goldie demonstrate how an energy rating tool can help tweak the building’s orientation, materials, shading and more.

THE Nationwide House Energy Rating Scheme (NatHERS) ranks a home’s potential thermal performance (heating and cooling needs) based on its proposed design and construction. NatHERS is often used to demonstrate that projects meet the mandatory energy efficiency requirements of the National Construction Code.


In Australia, new residential projects are generally required to meet a minimum 6 Star NatHERS rating.

NatHERS is, however, more than just a certification tool. By estimating a home’s potential heating and cooling needs based on different design and construction options, NatHERS can be a useful tool in identifying the best design strategies for your unique project.

Good design can reduce the amount of energy needed to keep a home comfortable, often with little or no additional cost.

Many ReNew readers will know the fundamentals of designing a more energy-efficient home—NatHERS can help take this one step further, testing how to apply these principles to get the best value for money.

Using an example house design, we will look at some of the fundamentals of energy-efficient design and discuss how NatHERS can be used to inform the design process.

1. Climate
Understanding climate is the first crucial step in designing a more energy-efficient, eco-effective home. It’s for this reason that passive solar design is sometimes more accurately referred to as climate-responsive design.

In Australia, the National Construction Code identifies eight distinct climates around the country, ranging from hot-humid to alpine conditions (see

NatHERS breaks these down further into 69 climate zones, based on historical climate data which also takes into account solar radiation, wind speed/direction, temperature and humidity.

Because different climates warrant different design responses, a six Star house in Melbourne is very different from a six Star house in Darwin. Melbourne is a heating load dominated climate (i.e. more warmth is needed to achieve thermal comfort), whereas cooling is the main issue in Darwin.

Thus, it’s vitally important to prioritise the most appropriate design strategies for the particular climate.

This means the six Star scale is calibrated differently for each climate zone, depending on whether heating and/or cooling is required to achieve thermally comfortable conditions.

BASIX (a NSW-based rating tool) goes one step further and applies separate targets for heating and cooling, which can help to further fine-tune the thermal performance of a design.

Read the full article in ReNew 141.

Desert Rose render

A net zero energy home

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A net zero energy home for desert conditions is the mission of the next international Solar Decathlon, but the University of Wollongong’s entry could have applicability far beyond the competition.

The University of Wollongong’s entry in the next international Solar Decathlon is perhaps aptly named. It’s called the Desert Rose, after a plant that can cope with the tough conditions the team will encounter when they build and operate their sustainable house design in the host city, Dubai, in November next year.


With temperatures of 35+°C every day, less than 2 mm of rain for the month and desert sands that present problems for both greenery and solar panels alike, there are certainly challenges ahead.

Student-led sustainable innovation
What is the Solar Decathlon? Sometimes called the Energy Olympics, the decathlon was started in 2000 by the US Department of Energy to encourage innovation in sustainable, renewably-powered residential buildings.

The contest challenges university student teams to not only design, but also build and operate a home that produces more energy than it consumes—a net zero energy home.

The University of Wollongong (and Australia) first competed in 2013. Amazingly, that entry, the Illawarra Flame (, won with the “highest score ever recorded,” says a suitably proud Brendan Banfield, building services manager for the 2018 team.

It’s a crash course in construction for the student competitors. The houses they design get built, dismantled and rebuilt, perhaps many times over the course of the competition.

In 2013, the Illawarra Flame was built and dismantled twice before its journey in seven 40-foot containers to that year’s Chinese host city. It took 12 weeks to build the first time (in a warehouse in Wollongong), but then just five days to dismantle and ten to re-assemble on site in China.

It’s an undertaking that gives the student competitors—from diverse fields including engineering, architecture, health, arts, business and communications—incredible hands-on experience in design, construction and problem-solving.

In fact, a US Department of Energy survey (covering four solar decathlons from 2002 to 2009; see found some 76% of past competitors went on to jobs in the sustainable building and clean energy sector, compared to just 16% of non-competing fellow students (and 92% found the competition critical to their job-seeking).

Brendan says, “The technology used or invented is typically five years ahead of the market and 10 years ahead of the building code, giving competitors an ‘edge’ when seeking work or starting a business”—some 16% of those surveyed had started their own sustainability business as a result.

Read the full article in ReNew 141.

Read more about the Desert Rose team and their entry here.


Why test for air leakage?

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Energy efficiency consultancy SuHo explains the hows and whys of testing for air leakage in your home.

AN INTERESTING subject presently under discussion and development in the home construction industry is air leakage from buildings. You may have heard of terms like air permeability, air infiltration, air change rate and air flow rates. All of these terms relate to building air leakage testing, or ‘blower door’ testing.


What air leakage is and how it relates to home energy efficiency is commonly misunderstood. Air leakage is the unintentional introduction of outside air into a building and can account for up to 25% of winter heat loss. It occurs via uncontrolled openings such as gaps and cracks. Note that this differs from ventilation, which occurs via controllable openings such as doors and windows.

Testing for air leakage
‘Blower door’ testing is a method of testing how and where a building leaks.

It uses a high-powered fan mounted within an adjustable frame to control pressure levels within a building. The fan is mounted into an external door opening.

All controlled external openings (doors, windows etc) are closed for the test, while all mechanical ventilation outlets (such as exhaust fans) are left unsealed and internal doors are left open.

A blower door test is non-obtrusive and takes a couple of hours.

The rise in pressure elevates air flow through any uncontrolled leakage points such as gaps, cracks and poorly sealed door and window frames, as well as through non-baffled fans. These are photographed using a thermal camera, which differentiates surface temperature from cold (blue) to hot (red).

An added benefit is that the thermal imaging has the ability to identify such idiosyncrasies as missing or disturbed insulation batts, water ingress and electrical faults.

Losing just 5% of the total insulation area of a ceiling effectively halves its performance (based on ceiling insulation calculations from the National Construction Code Volume 2 Section Building Fabric Insulation; see also ReNew 140, p. 84).

The result is generally a building fabric audit report, provided to the homeowner and detailing all results, observations and recommendations, and quantifying potential savings.

Read the full article in ReNew 141.

thermal stratification

Home truths: notes from an energy assessor

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After conducting home energy assessments for several years, Richard Keech shares some of the all-too-common problems he sees.

Since mid 2015 I’ve worked doing building energy assessments in Victoria, mainly for homes and mainly on behalf of ecoMaster. In that time I’ve visited about 290 clients to inspect their premises. In this article I’ll try to convey insights about homes and energy based on my experiences. Some of this is specific to Victoria’s housing stock and temperate climate and some applies to all homes.


The assessment process itself
Winter thermal comfort is the biggest motivator in Victoria
I usually begin by asking clients what motivated their interested in an assessment. By far the most common response—probably three-quarters—is thermal comfort. Of that, most is winter thermal comfort. So whatever concerns people may have, it’s thermal discomfort that turns their interest into action. Given the current media discussion about energy costs, it’s interesting that cost is actually far behind thermal comfort in getting people engaged in the process.

People like to talk about their house
There’s an element of therapy about consulting on home efficiency that goes well beyond people simply receiving information about the state of their homes. It’s very much a two-way process. So patiently listening to people talk about how their home does or does not work seems to help people engage in the issue of home energy and comfort.

People don’t value professional advice highly enough
I’m very lucky to work for one of the few companies that consult on home energy efficiency. But even so, many people expect a lot for nothing, especially when it comes to draught proofing and general advice. Understanding a client’s home, sufficient to specify the many things typically needed to draught proof a home, is time-consuming.

The people who most need professional advice are the least likely to get it
A tiny fraction of households seek professional advice about their homes’ efficiency. And I expect that the homes we see are far from being the worst out there.

Tenants are missing out
Only a tiny fraction of our consultations apply to rented premises. Landlords and tenants both obviously lack the motivation to spend the money on a consultation because the cost and benefit incentives are misaligned. As a country we need ways to motivate landlords to improve their properties for the benefit of the tenants. This is worthy of a whole separate discussion; e.g. see and ‘Energy-efficient renters’ in ReNew 134.

Read the full article in ReNew 141.

curtain-making workshop

On the way towards zero net energy

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In November 2014, Uralla in NSW was awarded the opportunity to become Australia’s first Zero Net Energy Town. From the start—and one of the key reasons their submission was successful—this has been a story of community engagement and contribution, with whole-community benefit at its heart.

A blueprint for action
While other communities are moving towards 100% renewables in different ways, Sandra says that the “Z-NET Blueprint really gave us a focus and an overarching goal.” One of the first things the group did was to set a vision and mission for Z-NET Uralla, to guide decision-making around which activities to undertake.


As a relatively conservative population (“We’re not tree-huggers, we don’t talk about climate change or greenhouse gas emissions”), their focus is on renewable energy, energy efficiency and saving money on energy bills.

The group’s activities reflect this, and are centred around education and advising practical actions.

While the blueprint for Uralla (a shire of around 6000 people in 2200 households) is moving them towards 100% renewable energy for stationary use (i.e. not including transport) over a 10 to 15 year timeframe, Sandra notes that “at this stage, we are focused on energy efficiency and rooftop solar PV.”

She adds that the level of resources available (funding and volunteers’ time) has determined what the group has been able to achieve to date. But even with these constraints, they’ve achieved a lot over the past couple of years.

Energy efficiency first
The group received grants from both the Murray–Darling Basin Regional Economic Diversification Program and the NSW Office of Environment and Heritage, along with great support from the Uralla Shire Council. This enabled them to recruit a project officer to run free business and home energy-use reviews, with help from volunteers.

To date, 23 local businesses (including cafes, a brewery, orchard and dairy) have had an energy-use review, using thermal imaging and monitoring equipment donated by a Z-NET Uralla member. The equipment enabled businesses to get energy-use information specific to their business; for example, one café had eight meters installed on circuits for the coffee machine, fridges and ovens.

Read the full article in ReNew 141.

Orientation matters!

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With a low average energy use of under 5 kWh/day, Ewan Regazzo shares the lessons he and his family have learnt from building a new energy-efficient home on a budget.

OUT walking the dog one day in my local area—a relatively modern and well-established suburb in Maitland, near Newcastle in NSW—I stumbled across a small, secluded cul-de-sac that contained a huge (1117 m2) vacant block.


It appeared to be one of the few blocks remaining in the suburb and the faded and forlorn ‘for sale’ sign at the front, barely visible among the overgrowth, indicated it was still available.

Perhaps it wasn’t popular because of the site: the land was south-facing and fairly steep and narrow at the front, with a softer rise to the wider rear section. Further research showed it had a development application in with council for two narrow subdivisions, each with a small three-bedroom house, and I decided to invest with the idea of building two houses on the site, one for myself.

At that time I was living in a rental property which, although fairly modern, was a poor example of house design.

The rental house was unbearably hot in summer; aligned east/west, the lounge room was uninhabitable come afternoon.

In winter it would get down to 3 °C in the master bedroom and the gas heating in the open-plan living area provided little comfort for the financial outlay. In Maitland’s warm temperate climate, with hot summers and mild winters, passive solar design should work well, but it seemed this 15-year-old house had been built prior to the discovery of insulation and decent solar orientation!

Passive solar design was something I had been interested in for some time. I first came across ReNew way back in 1995, and had pored over copies of Owner Builder magazine, and had even investigated what I needed to do to be an owner-builder myself.

Full-time work meant owner-building wasn’t feasible, so I began investigating local builders to see what was available. I visited home display centres, walking through house after house and scrutinising plans for something that would work on my block. I ended up despondent: few designs considered site orientation and few builders were prepared to depart from a rigid formula that allowed for a quick, low-cost build at the cost of long-term efficient energy use.

Read the full article in ReNew 141.


Saltwater batteries in use

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When the old battery bank gave out, it was back to diesel for a time at this significant conservation site in the Mallee. But an innovative off-grid upgrade has changed that and led to a significant improvement over the old system, as Trust for Nature’s Chris Lindorff and Tiffany Inglis explain.

UP IN the Mallee, along the River Murray in far north-west Victoria, lies Neds Corner Station, a former sheep property now being restored as a significant natural habitat by the not-for-profit Trust for Nature.


With an extreme climate—temperatures soar close to 50 °C in summer and frosts occur in winter—and no grid connection, this 30,000 hectare (300 km2) property presents challenges not only for habitat restoration, but also for the off-grid energy system needed to support the on-site rangers and visitors.

Purchased by conservation organisation Trust for Nature in 2002, the site is now home to two rangers and up to 30 visitors at a time: researchers and students studying the flora and fauna; bird groups conducting site surveys; works crews working on neighbouring public land; volunteers assisting with site restoration tasks such as reducing rabbit numbers, replanting local species and installing fences to keep out foxes; and the occasional corporate days and camping trips.

The site includes a homestead, shearer’s huts (used as accommodation), kitchens and conference/workshop rooms, with associated energy needs for heating/cooling, lighting, water pumping, refrigeration and gas cooking.

Energy system, take 1
When the property was first bought by Trust for Nature, the site ran solely on a diesel generator. Then, in 2012, philanthropic donations enabled the installation of a solar power system with a lead-acid battery bank. The system was designed to cater for an average of 25 kWh/day energy use, with a 25 kVA diesel generator as backup.

Over the following years, however, more people came to Neds Corner and energy demand increased, which led to the generator running more often than not.

Frequent, heavy cycling of the flooded lead-acid battery bank meant it performed poorly and reduced its lifespan. Following the failure of multiple battery cells in 2016, the battery bank was disconnected and the diesel generator again became the sole source of electricity.

Read the full article in ReNew 141.


The Pears Report: Summertime, and the living ain’t easy

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With summer approaching, there’s a flurry of activity to ensure reliable energy generation under peak loads. We also need to look at the way our Star-rated buildings cope in the heat, says Alan Pears.

THOSE who have watched in bemusement the large numbers of new homes with black roofs and no eaves might be interested in some recent research. This has found that our 6 Star regulations are doing a good job of reducing winter heating energy use. But the way some designers use the rating tools may be making summer performance worse.


Basically, it’s possible in most locations to meet the 6 Star regulations with measures that improve winter performance. But this means homes can still let in summer sun and their improved insulation means they can behave like solar ovens, cooking their occupants. This can be relatively easily fixed by installing effective summer shading and also looking at orientation and areas of glazing.

Summer overheating is not benign. Analysis of outcomes during the very hot week preceding Melbourne’s 2009 Black Saturday fires showed that, just as extreme hot weather drives big peaks in cooling energy demand, it causes other peaks, too (see Twice as many people died from the heat in the days leading up to the fires as died in the fires. 374 people died, 62% more than in the same period the year before, many of them elderly.

Pressures on health services peaked. There was a 46% increase in ambulance callouts, with a 34-fold increase in heat-related conditions. Hospital emergency departments saw a 12% increase in demand, with an eight-fold increase in heat-related problems. There was almost a three-fold increase in patients dead on arrival.

RMIT research (a 2016 PhD by Niki Willand based on detailed analysis of a CSIRO field study), found the analysed 5 and 6 Star-rated homes were hotter than 4 Star ones on average, and had higher cooling energy use. This is due to the ‘solar oven’ effect. A 6 Star house can be designed to work well all year round, but winter performance dominates the rating rules.

None of the costs and human impacts of these statistics have been factored into national building code considerations. Indeed, it seems there will be no major changes to the regulations until at least 2022.

There is a glimmer of hope, though. The Victorian government’s new apartment planning guidelines include reasonably strong summer cooling energy limits (see as well as the annual energy limits. These will force designers of apartment buildings to rethink their approach. Let’s hope this spreads to all new homes.

The trend towards dark roofs is watched in bemusement by those concerned with summertime overheating of our houses. Image: iStock—mbolina

Energy pricing demands a response
When energy assets were being sold off, many politicians thought that people would blame the industry for any problems, not governments. Sorry guys. Everyone knows you write the rules and supposedly enforce them.

So governments are finally acting, after blackouts, skyrocketing prices and evidence that vulnerable households are worst affected. This is a crisis for neoclassical economics, which has driven energy (and other) reforms based on competition and ‘light-handed’ regulation.

The energy market is basically working the way it was designed to: high prices signal the need to invest in more supply capacity—and energy efficiency has never been on the agenda. Businesses exploit weak regulation and lack of enforcement to capture profit and shift costs onto others. The recent coal power station closures and high gas prices have really been the first test of the market’s design: it has failed.

Business and households both prefer stable, predictable, affordable energy costs and increasingly they simply can’t function without reliable electricity supply. Gas consumers have been lulled into complacency by extremely low prices for decades. They have been stunned by the effects of suddenly opening up gas markets to international prices, combined with exploitation of local shortages by gas suppliers.

There is now a flurry of activity. States are reinforcing supply and adding storage capacity. Rooftop solar and new large-scale renewable energy are both booming.

The Australian Renewable Energy Agency (ARENA) and Australian Energy Market Operator (AEMO) have bypassed the energy market to set up a long-overdue demand response mechanism. Consumers who agree to cut back power usage at critical times will be paid for their efforts. This was first called for by the 2002 Parer Review and energy policymakers have studiously avoided implementing it since then.

ARENA has been swamped by offers. It was looking for 170 megawatts (MW) of demand response. Bidders have offered 693 MW by December this year and 1938 MW by December 2018 (see Why am I not surprised?

So summer power supply now seems secure. Indeed, South Australia may need less emergency generation capacity than expected. We should be using this short-term breather to invest aggressively in energy efficiency, to lock-in lower demand and lower energy costs. No guarantees on that though, given past performance.

Billing reform
Federal and state governments finally seem to have realised that consumer electricity prices have three big components: wholesale energy price, delivery costs (mainly network infrastructure) and retail charges (including fixed charges). All must be addressed, but they require different strategies.

The Victorian government (see and the Australian Competition and Consumer Commission are running inquiries into retailer charges. There is evidence that consumers who fail to seek out discount deals or can’t meet criteria such as paying on time via direct debit are paying a lot more than ‘engaged’ customers. So vulnerable customers are paying higher prices; so much for social justice.

Prime Minister Turnbull has called energy retailers to Canberra to discuss this and retailers have agreed to some changes. These include attempts to better inform consumers when fixed-term contracts finish. Late payment of a bill will no longer mean a consumer loses access to discounts. What a breakthrough! I’m hopeful that the Victorian government will take stronger action.

Driving prices up
Electricity network operators have over-invested to maximise profit. They have been able to overrule the weak Australian Energy Regulator in the courts, adding billions to consumer costs.

The federal government plans to block the operators’ right to appeal (see Over time, that will help to bring network charges down. But it won’t be enough: asset values are way above likely market values in an emerging fair market and only asset write-downs will fix that. Policymakers and governments seem reluctant to unravel this welfare scheme for powerful incumbents.

Wholesale electricity prices have been driven up by a combination of factors, including Tony Abbott’s war on renewables (see my column in ReNew 139), closure of coal power stations, the gas price explosion and failure to drive energy efficiency and demand response. While gas prices seem likely to stay high, their impact on wholesale prices should be reduced by the responses outlined earlier.

But we do need to recognise that, in the past, wholesale electricity prices have been held unsustainably low by excess generation capacity. Regardless of the types of new generation built, it will be a challenge to achieve big price reductions for this cost component unless we manage to engineer oversupply by driving demand down and encouraging new renewables beyond both state and national targets.

Governments and policymakers still seem to be struggling to grasp that it is the total bill, not the unit price, that impacts on consumers’ hip pockets. Greater emphasis on energy efficiency, so we use less and pay less, and reducing outrageously high fixed charges would help.

Climate change is driving extreme temperatures. Very warm monthly daytime temperatures that occurred just over 2% of the time in 1951–1980 now occur over 11% of the time. Source: Bureau of Meteorology Australia,

Energy past, present and future
Sometimes it’s interesting to look back, to understand how things evolve. I was recently asked to look at historical energy use in Australia, which raised some interesting points.

Energy consumption (measured at the meter or fuel bowser) has more than quadrupled since 1961, while carbon emissions have increased by a factor of almost five. Energy-related emissions per person have more than doubled.

Oil has maintained a roughly 50% share, although more of it was used for non-transport purposes like heating in 1961, before the oil crisis and availability of cheap gas. Today around three-quarters is used for transport.

Home and business wood use has fallen from 18% to 2% of total energy, while direct coal use has crashed from 23% to just 3%. Gas has been the big winner, increasing from 2% to 20%!

Electricity’s share of energy has doubled from 10% to 20%, with renewables providing only 14% of electricity today compared with 19% in 1961. This reflects the shift towards a services economy that is more reliant on electricity, as well as the trend towards more electric technologies in homes.

It will be interesting to watch how things evolve, as we move towards a zero emission economy, gas prices increase, and efficiency and renewables transform electricity use and emissions. S

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

This article was first published in ReNew 141.


ATA member profile: Spreading the word on sustainability

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Long-time convenor of the ATA’s Perth branch, Travis Hargreaves tells Anna Cumming about his experiences in the retail solar sector and his real passion—educating people on sustainability and equipping them with the knowledge to continue the conversation.

ORIGINALLY from Melbourne, Travis Hargreaves took off around Australia on his motorbike when he was 20. “I went here, there and everywhere, then I ended up in Perth and met my partner, and the rest is history.” Travis has been in Perth ever since and is a stalwart of the sustainability movement there.


“I always had an interest in sustainability and the environment,” says Travis.

Ten years ago he decided to get proactive and do some study in renewable energy; the TAFE in Perth didn’t offer a dedicated course, so instead, Travis was one of just two students that year who undertook a Diploma in Electrotechnology, which covered renewable energy as one of its four subject areas.

At the same time, he started up his first solar business: “The market was small at the time. I provided solar system design, sales and installation services for three solar retailers,” he explains. In 2010 he set up a solar retailer that services Perth and southern WA with solar and battery storage system design and installation.

Travis has far more on his plate than simply running his business though. When the ATA’s Perth branch was set up, Travis got involved and was swiftly asked to become the convenor, a role he’s held since 2009.

Through the activities of the ATA branch, Travis has become a sought-after speaker on sustainability and it’s this educational role that inspires him the most.

“Consumers are wanting to get past the talking and have the information to take action,” he says. “I started talking about energy efficiency and the importance of making those changes before investing in solar. Then I developed presentations on the basics of solar panels and battery storage, then about three years ago I started promoting electric vehicles, and now vehicle-to-grid technology.”

“I like my audience to leave inspired but also frustrated and wanting to push for change; I try to give them the knowledge to continue the conversation. Rather than bombarding them with technical information, I provide them with arguments for why we should be heading down this path so they can have conversations with their neighbours and explain the benefits—to living costs, local job creation and, of course, the environment.”

Lobbying for renewables and the jobs that go with it at the Rally for Renewables in Perth in 2014.

Travis has been involved with several other environmental advocacy groups. He was the WA branch president of the Australian Solar Council in 2014 and 2015, and instrumental in the 2014 Rally for Renewables campaign in Perth which brought together a host of organisations to lobby for legislation favouring renewable energy.

He’s also proud of a successful joint campaign to protest and reverse the WA state government’s decision to remove the solar feed-in tariff in 2013.

While Tony Abbott was prime minister, local representatives from both the Australian Solar Council and Clean Energy Council met with Liberal senators in WA to discuss local renewable energy and the potential benefits to the community.

It was useful education for Travis. “I think we were successful to a certain extent, but I also became aware of how the politics around renewable energy worked. They understood, but were toeing the party line.”

Travis is quietly keen to keep on pushing for change. “I got involved with the ATA because of its independent voice and its mission to provide information to the community. That’s what I continue to do today—use my knowledge to educate and influence people and inspire them to take action.”

This member profile is published in Renew 141. Buy your copy here.


Product profile: Get the best from your fuel guzzler

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If you can’t afford an electric vehicle yet, you can still reduce the emissions from your fuel-burning vehicle to make the most of the fuel you use, while saving yourself some money in the process.


The GOFAR is a datalogger that plugs into the computer port on most newer cars and records fuel consumption, distance travelled, speed, acceleration and deceleration and a number of other parameters to let you know when you are driving most efficiently. The data is stored in the cloud (no ongoing fees) and you can access it using a phone app, which will tell you not only fuel consumption, but kilometres travelled and when (ideal if you have to log travel for work), when you need to check tyre pressure, when the next service is due and when you have to pay your rego.

But the cool thing about the GOFAR is the little dash-mounted LED display that tells you in real time when you are wasting fuel. When the LEDs are blue, you are driving well, but when they go red you are accelerating or braking too heavily. By watching the colours you can improve your driving and save considerable fuel and greenhouse emissions (and money!)

RRP: $99 for the datalogger dongle or $129 for dongle and display. A pack of three dongle/display sets is $297. For more information and to buy, contact GOFAR, ph: 0484 904 986,,

Read more product profiles in ReNew 141.


News: Innovative water battery

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Pumped hydroelectric storage to help maintain grid stability is not a new approach for the energy industry—indeed, it was first used in the USA in 1930. However, German wind turbine manufacturer Max Bögl Wind AG has introduced an innovative twist, which they showcased at the Energy Storage North America (ESNA) fair in San Diego in August. The ‘water battery’ combines renewable power generation with a modern pumped-storage power plant to be used in periods of high demand. The pumped-storage power plant is available in three performance classes (16, 24 or 32 MW) and can switch between production and storage within 30 seconds.


The first project to use the technology is being developed in Stuttgart, Germany. It comprises a windfarm of four turbines, each of which have tower bases with in-built water storage capacity of 70 MWh. These are connected to a hydroelectric power station with 16 MW installed capacity and a lower reservoir in the valley 200 m below.

Feature image: This windfarm in Stuttgart, Germany, is using wind turbines combined with pumped hydro for energy storage, with water stored at the base of the turbines! Image: courtesy Solar Consulting

Q&A: Enphase restriction?

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I am planning a rooftop PV system, using LG panels and Enphase microinverters. An experienced PV designer told me he thinks the use of Enphase microinverters will preclude the future addition of any battery other than one from Enphase.
I have never heard this before. Is there likely to be any validity in this opinion?
—Rod Sloggett



I think there is some validity in that opinion, but it’s overstated.

With microinverters installed on the panels, the cables coming from the roof carry electricity already converted from DC to 230 V AC current. To store this energy in a battery, it needs to be converted back to DC again. This is achieved with ‘AC coupling’, where the battery has its own inverter, connected to your home’s electrical switchboard. Many solar batteries are designed to work this way, but some are intended for ‘DC coupling’ instead. A microinverter solar system can’t use DC coupling, so your battery choices are more limited than if you selected a system with a central inverter.

With a microinverter solar system you should be able to add any AC-coupled battery (including the Enphase battery) and store excess solar for the evening. The battery has a sensor in the switchboard to detect when you’re exporting to the grid, and thus when to charge up.

Things get trickier in a grid blackout. The battery can power the house, if the system is designed and set up to do so. But since it has no communication with the microinverters, the battery may have trouble controlling the panels’ generation to prevent being over-charged. During a daytime blackout, your solar system will probably shut down immediately. If it does keep running, at some point the battery may force it to shut down by increasing your home’s electrical frequency. This process is not graceful and may cause some premature wear on the microinverters and/or affect their warranty. If you select an Enphase battery, this issue doesn’t arise because it’s not designed to operate in a blackout anyway.

Here’s an ATA article that gives more info on AC coupling, DC coupling etc:
—Andrew Reddaway