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Christmas_Sweater

Winter comfort – not just a heater choice

There’s more to consider than just the choice of heater when aiming for winter comfort. Alan Pears searches for the ideal solution.

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For Australians living in cooler climates, use of heating to provide winter comfort consumes the biggest chunk of household energy. Winter comfort is also important for health and enjoyment. We typically invest thousands of dollars in heating technology, and effective heating is seen as an important factor in resale value.

In many other parts of Australia, winter is short and relatively mild, and many people just rug up and bear it. Indeed, I have felt colder in Queensland and Western Australia than in Melbourne because the houses and their heating equipment work so poorly!

Achieving winter comfort in a way that is affordable, effective and environmentally sound is tricky. Indeed, I find advising people on this topic to be difficult and frustrating: I still can’t
find the ‘ideal’ answer. This article is an attempt to at least frame the challenge and suggest some options, while flagging some of the mistakes to avoid.

How much heating?
Firstly, you need to think about how much heating is required for your situation. This can depend on many things, including climate, your house’s Star rating, draughts and microclimates.

Climate
It is important to get the building and heating right depending on climate: Melbourne is a heating-dominated climate (currently), but has periods of extreme heat. Brisbane is cooling-dominated, but can get chilly at times.

Thermal performance ratings
The better the thermal performance of a home, the less heating energy will be needed, along with potentially very different kinds of heating equipment. A 7 or 8 Star energy rating is needed before your home would be legal in many parts of the world. Figure 2 shows the improvement in building thermal efficiency for Melbourne as the Star rating improves.
It’s clear that Australia’s diverse standards of housing have widely varying heating requirements: what works for a 1 Star home will be very different from what’s needed for an 8 Star one.

Draughts
Sealing out draughts also improves comfort. Moving air has a windchill effect. Leaving doors open to unheated areas with fixed ventilation such as laundries and bathrooms increases draught problems. Even a pet door can be a draught problem if it doesn’t seal properly. The problems are increased where openings are on opposite sides of the house, or in ceilings of upper storeys: wind effects can suck far more air through the house.

Microclimates
Microclimates are also important, both inside and outside the house. A door exposed to strong winds will tend to leak air unless it has very effective seals and will allow blasts of cold wind in when it is opened. A protected area on the north-east of a home can provide a wonderful suntrap on winter mornings, also warming the rooms nearby. A balcony or courtyard on the south-west won’t get winter sun and can be cold and windy.
Inside the house, sitting areas tucked into a corner instead of in an air path between doorways can be more comfortable. Areas near single-glazed windows will be cold when there is no sun on them, although effective window coverings can help. A light blanket wrapped around a person can create a cosy microclimate. Indeed, you can now buy electrically heated throw rugs that can transform comfort.

Generating heat
The main options for producing heat in a home are gas (mains or LPG), electricity (resistance heating such as fan heaters and radiant panels, or reverse-cycle air conditioning), wood and solar energy.

Wood and Pellet heating
Wood heating creates some dilemmas. Its contribution to local air pollution is still a major concern, despite improvements in heater design over the past two decades. Poor user management and green wood seem to be a major part of the problem. Running wood heaters overnight on low output and overloading them with wood are particularly polluting behaviours. [We are planning an article on the best ways to use wood for heating in the next ReNew.]
Pellet heaters are beginning to appear in Australia (see our product review on page 82). These burn small pellets made from compressed wood waste (some can also burn grains), which are fed into the heater at accurately controlled rates to match the fuel requirements. The near continuous supply of dry fuel provides stable burning conditions, and much lower pollution levels have been demonstrated. However, pellets can be expensive and, as with normal wood, it is important that they are from a sustainable source.
One thing to note is that, when a building is thermally efficient, only a small capacity wood heater is needed.

Heating water (hydronic)
Hydronic heating systems use heated water, delivered through pipes, to warm a home either by running through pipes in a slab floor (or under a timber floor), or via wall panels or fan convectors, or a combination of these. The water is usually heated by a gas or wood-fired boiler, but electric heat pumps are increasingly being used.

Often hydronic heating systems operate at quite high temperatures of 80 to 90 °C. This increases pipe heat losses and can also undermine the efficiency of the boiler. In the UK, they found that the expected savings of condensing boilers (which recover the waste heat from water vapour in the flue gases by condensing it in a heat exchanger that pre-heats combustion air and/or return water) were not being achieved. This was because the return water temperature was higher than the condensation temperature, so the waste heat was not being recovered from the flue. Slowing the flow rate and/or lowering the operating temperature can solve this problem. Indeed, it makes energy sense to install a high-efficiency variable speed circulating pump and lower the water temperature in milder weather: this can improve boiler efficiency and reduce heat losses from pipes and tanks.

Read the full article in ReNew 127

ReNew 127 cover

Editorial ReNew 127

AFTER a summer which broke so many temperature and heatwave records, our theme of ‘keeping warm’ felt a bit out-of-kilter. Yet, of course, now is the time to be preparing for the cooler weather to come. Plus many of the approaches also have applicability to thermal comfort in warmer weather.

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With insulation key to thermal performance, our updated insulation buyers guide describes the different types of insulation available, their pros and cons, and addresses the important issue of installation— both in terms of safety and effectiveness. We also briefly touch on climate and insulation— just how much insulation is recommended in different climate zones?

Our case study of one home demonstrates tremendous (sometimes hidden) benefits from insulation, particularly after plugging the last thermal ‘hole’ via wall insulation.

Finding and sealing up gaps around windows, doors and in unexpected places, like behind the dishwasher, can also have a big impact. David Coote is on a mission to draught-proof his home—he explores the benefits of an audit to find the problems and, importantly, provide practical advice on how to fix them.

Our cool-climate build, featured on the cover, is a great example of a home excelling in thermal performance. The owners were influenced by the Passivhaus standard and, given the level of sealing achieved, they decided to use mechanical ventilation with heat recovery (MVHR, also known as heat recovery ventilation) to ensure a good flow of fresh air with minimal heat loss or gain. They talk briefly about their system; we also have Clare Parry from Passive House Australia describe such MVHR systems in more detail— what they are, when they’re needed and some of the options available.

Keeping warm does mean heating in many parts of Australia. Alan Pears considers this tricky topic, which, as he says, is not just about choosing a heater. He looks at what you might want from a heating system, evaluating how much heating you need and considers the pros and cons of various types of heat generation and delivery.

There’s more to this issue than keeping warm though. We delve into the ever-growing field of low-cost, low-power computing, with information on tablets, phablets and ‘nettops’—plus a Raspberry Pi-based DIY. Peter Reefman travels to China and reports on the development of the amazing and vital eco- cities (with 300 planned). Elizabeth Wheeler outlines a process that can help dispel the ‘too-hard’ feelings when sourcing green products during a build. Plus: we feature a DIY solar hydronic heater, a pellet heater product review, best practice for rainwater harvesting, the ATA’s water and cost saving report, all our regulars and more. We also have a new reader competition (p. 93) on energy saving—we look forward to your entries!

Robyn Deed
ReNew Editor


DID you know that the Alternative Technology Association (ATA), publisher of ReNew, conducts research into emerging sustainable technologies and practice? Our recent report, The Economics of Water Saving Technology in Victoria (featured this issue), is an example of our work.

With funding from the Consumer Utilities Advocacy Centre, we reviewed the economics of common water saving technology: efficient showerheads, toilets, dishwashers, washing machines, rainwater tanks, greywater systems and water recirculators.

We found that, as well as providing the environmental benefits of a smaller ecological footprint, water saving technology does save people money. This is believed to be the first comprehensive review of the economics of domestic water saving technology in Victoria. The ATA’s research work aims to empower consumers with the information they need for sustainable practice at home and in their communities. This includes investigating the economics, quality and environmental sustainability of green solutions.

Another recent ATA research project, developed with Energy for the People, is What Happens When We Un-Plug. This looks at the financial viability of stand-alone power (and will feature in the next ReNew). We are working on several other research projects, with results to be released in the next few months.

To download our reports, go to ata.org.au. You can help us continue our groundbreaking research into sustainable technology and practice—become an ATA member today!

Donna Luckman
CEO, ATA

Buy ReNew 127 at the ATA webshop.

127 cool-climate build

Cool-climate build

Designing a house to be as energy efficient as possible is one thing; actually achieving this can be another task altogether. Meg Warren and Fraser Rowe describe their building challenges and eventual rewards.

OUR quest to build a new sustainable home began about four years ago when we purchased vacant land in cool-climate Beechworth in north-east Victoria. We wanted a sizeable block, big enough for rainwater tanks and a small edible garden, but also walking distance from shops, cafes and work. But our most important criterion was solar access. We found just such a block with the added bonus of a well-grown oak to the west, offering summer shade. The real estate agent seemed not to notice these attributes: to them the block was just a problem to sell due to its odd shape and no services.

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Shifting from a rural property of 18 acres to an urban block of less than 1000 m2 brought a number of challenges. Our design was limited by council regulations, fences and boundaries, as well as a high, dense hedge on our neighbour’s property to the east.

Design phase

To help us achieve a truly energy-efficient design we engaged building designer Tracey Toohey whom we’d worked with on our previous owner-built rammed-earth house.

Tracey asked us to rate three areas to indicate our level of commitment to sustainability in the build. The first rated our desire for energy efficiency against overall cost. The second, and more difficult for us, assessed the compromise between sustainable materials and efficiency, and the third, between sustainable materials and cost. This interesting exercise helped us clarify our goals.

We worked intensively with Tracey for months, honing the design. Thought went into the glazing type and size to balance it with the floor area, together with the placement, type and amount of internal thermal mass, creation of airlocks, height of ceilings and all the other dimensions that impact on the energy rating. We also allowed for wider than usual walls to fit in more insulating layers beyond the standard 90 mm bulk insulation. Attention was given to the need for summer shading, rainwater harvesting and greywater recycling.

Read the full article in ReNew 127.

Sourcing green building products

Sourcing green products

There are ways to stop the ‘too-hard’ feelings when choosing green building materials. Elizabeth Wheeler describes the process she used when building her family’s home.

WHEN I talk with people about the process of building or renovating a house, what they speak about most is the stress of making hundreds of decisions. Even something relatively simple has ramifications for a whole lot of other decisions. A mere choice of hand basin, for example, affects taps, benchtops, cabinetry and plumbing.

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Especially for people trying to minimise their environmental impact, the number and complexity of decisions can sometimes feel completely overwhelming. Paradoxically, while there are more environmentally sensitive products available than ever before, the potential for greenwash means that consumers often lack confidence that a building product is as environmentally sensitive as the manufacturer claims.

Since our build, I have continued to be involved in the building industry, and people often ask me for advice. What I have noticed is that those who seem a bit ‘at sea’ are often unclear about the extent to which they want their home to represent their ecological and social justice values, how to obtain and understand information, and how to make decisions. In my experience, these are the people who often throw up their hands in despair and declare sustainable building ‘just too hard’.

The importance of process

Ultimately, I think people are more likely to feel confident about the building materials and products they choose when they are comfortable with the process they used to decide upon them. For this reason, I always encourage people to spend some time thinking about their values and priorities, and to work out how they will approach decision making. I also think it is helpful to keep one’s own choices as a consumer in perspective.

In terms of our process, while our house is notable for its lower-than-usual environmental impact, both aesthetics and affordability still played very significant roles in our decision making. We didn’t want to go further into debt than we could afford, and we felt that we would regret aesthetic compromises on a daily basis. We very much wanted a home we would love. However, we also wanted a house we could feel proud of.

Read the full article in ReNew 127.

Earthwool insulation

Insulation buyers guide

Is your home hot in summer and freezing in winter? It probably has little or no insulation. Lance Turner takes a look at how insulation can help fix these problems.

BY reducing heat flows into and out of your home, insulation can dramatically improve comfort levels during weather extremes.

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In winter, once the home has been heated to a comfortable level, it will stay that way with far less energy input than an uninsulated home would require.

The same applies in summer. A properly insulated home will take longer to heat up and if an air conditioner is used it will use less energy than one cooling an uninsulated house. Note though, that any windows with high solar heat gains need to be shaded, particularly west windows, as in hot weather, insulation can slow down the ability of the house to cool down if there are large heat gains from windows.

Heat transfer and insulation

There are three ways in which heat transfers to or from a house: conduction, radiation and convection.

Conduction means the transfer of heat through a substance, in this case the walls, floor and ceiling of the house. The type of insulation used to reduce conductive heat transfer is known as ‘bulk’ insulation.

This is the most common home insulation and may be in the form of fluffy ‘batts’ made of many materials, including polyester fibre, glass fibre and sheep’s wool. Bulk insulation may also be in the form of loose-fill material, such as treated cellulose fibre (usually made from recycled paper), which is simply pumped into the roof or wall cavities and sealed with a spray-on ‘cap’. All these materials are poor conductors of heat and so reduce the rate of heat flow, provided they are installed properly.

Radiation is a different form of heat transfer. All warm objects radiate heat in the form of infrared radiation. If this heat can be reflected back from where it has come from using reflective foil insulation, then heat loss or gain through radiation can be greatly reduced.

Reflective surfaces such as foil don’t just reflect, they also have low emissivity (the ability to emit radiation, or heat in this case), meaning heat that has entered the material from the non-reflective side is not emitted from the reflective side easily. This means that foils can work reducing heat flows in both directions, even if only one side of the material is reflective.

Convection heat transfer (heat transferred through the circulation of air) is often the undoing of many insulation jobs. Circulating air can pass between poorly installed insulation materials and thus transfer heat into or out of the house, vastly reducing the effectiveness of the insulation. Minimising convective heat transfer is discussed later in this article.

Read the full article in ReNew 127.

House at night

Case study: the benefits of insulation

Richard Keech found many hidden benefits from plugging the last thermal ‘hole’ in his house.

THIS article considers the many hidden benefits of insulation following the upgrade of my own home. The house is a renovated 200 m2 period timber dwelling in Melbourne and is home to a family of two adults and two children.

The value of completeness
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Heat flowing uncontrolled through the external surfaces of a home is like water leaking through holes in a bucket. With the leaky bucket, it probably makes sense to plug the worst hole first. However, until all holes are substantially plugged, it’s still a leaky bucket.

Likewise, with insulating a home, it usually makes sense to first address the biggest source of uncontrolled heat transfer—the ceiling. However, the full benefit from insulating won’t be realised until all external surfaces are improved.

The implications of this thinking are that it’s really important not to leave the task of insulation incomplete. Features such as floors and walls, if left badly insulated, can seriously compromise the overall thermal performance.

This is borne out by my own experience where plugging the last thermal ‘hole’— the walls in my case—made an enormous difference to the home’s apparent thermal comfort and air conditioning system performance.

The hidden benefits

Most people understand intuitively that insulating a home means that heating and cooling systems don’t have to work as hard to maintain a set temperature. This is the central and obvious point of insulation— better-insulated homes can maintain a given temperature more easily. However, there are a number of second-order benefits of insulation which I would argue make properly installed and complete insulation even more valuable and effective than is perhaps generally realised.

I think that people’s concept of thermal comfort is often based mainly on air temperature, but there are other factors. It might not be a surprise that mean radiant temperature, air velocity and humidity all contribute to thermal comfort. However, it might be a surprise just how important some of these other factors actually are.

Read the full article in ReNew 127.

Raspberry Pi and meter

Low-power, low-cost computing

If you need to be energy frugal, you can still have a real computer for real tasks that won’t cost the earth. Lance Turner shows you how.

OVER the years we have looked at many low-power computers in ReNew, and there are new models out on a regular basis. Many of these have considerable computing power for their size, but most cost in the realm of several hundred dollars and many are simply not available in Australia.

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The needs of computer users vary widely—some need higher processing power whereas others, who do everything in a web browser, need far less. The same applies to energy consumption. If you live with a small renewable energy system, your main priority may be to minimise energy consumption.

So just what options are there for really low-energy computing? Let’s take a look at the options, and then look a bit more closely at a low-cost option with surprising power.

Phones, tablets and phablets

Mobile phones, tablets and phablets (basically big-screen phones) are everywhere, and they may be all many people ever need to get connected. They have considerable processing power, are portable and are, by design, energy sippers. But they also have numerous drawbacks that make them unsuitable for many computer users.

Trying to type anything more than a few words on a tablet’s on-screen keyboard is a real pain, at least to anyone used to using a ‘real’ keyboard. Most tablets can take some basic peripherals, such as Bluetooth keyboards, or come with optional keyboard docks that also extend battery life. These can make a tablet more like a tiny PC and can push them into the realms of usability for users who may otherwise have overlooked them as an option.

Read the full article in ReNew 127.

Solar hydronic collector on roof

Low-cost solar heating

Solar hydronic systems don’t have to be complex and expensive. Chris Hooley describes his simple and low-cost solar hydronic heater.

WINTERS in Melbourne used to be predictable: four months of sog from May to September. However, whether due to climate change, El Niño or simple drought, the winter of 2010 had a particular impact on me in that I kept coming home in the late afternoon to a very cold house, lit by shafts of brilliant winter sunshine. “Wouldn’t it be good,” I thought to myself, “if I could catch some of that energy and keep the house warm?”

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I had a rough idea of what was available to make water hot using sunlight. Being a devoted handyman and incurable tinkerer, the seed of an idea took root and grew. My basic parameters were simple: I wanted a completely off-grid, stand-alone system that would ‘catch’ some energy in cooler months and put it to good use, without having to be plugged in or modified seasonally. Since the house already had gas central heating, the system would not need to meet all heating requirements but would rather take the edge off the cold on days when the sun happened to shine.

With this in mind I prowled eBay and mentally drew up plans until I could stand it no more and started buying parts. The key elements consisted of an evacuated-tube array piped to a fan-forced radiator. The collector heats the water and a pump transfers the hot water to the radiator in the house. A fan forces air through the radiator and into the room, heating it.

The system would be controlled by a thermo-switch and powered by a pair of 20 W PV panels. To avoid it freezing solid overnight or boiling away in summer and to eliminate the need for seasonal draining and refilling, I resolved to fill the whole system with car radiator coolant.

Read the full article in ReNew 127.

Induction cooktop

The Pears Report: Peak demand and ‘enoughness’

Why should we expect unlimited access to energy when we can take responsibility for how much energy we use, asks Alan Pears.

THE JANUARY 2014 extreme weather in southern Australia reignited debate over the role of air conditioners in driving peak demand. A few issues have emerged.

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A thoughtful study by Ric Brazzale of the REC Traders Association reframed debate about how useful PV is in managing peaks. Since electricity data from the Australian Energy Market Operator (AEMO) does not include PV output, because it happens on the consumer side of the meter, Ric recreated the real demand profile by adding estimated half hourly PV output to the AEMO demand profile. This showed actual peak demand occurred earlier in the day, when PV was producing much more electricity.

This challenges the simplistic approach usually taken, of just looking at PV output at the time of the AEMO peak. Ric also pointed out that PV helped to significantly reduce average prices on peak days below those before the Black Saturday fires. Of course, reducing peaks and peak prices undermines generator and network profits, which is seen as a bad thing by the incumbents and some policy makers.

As demand-response bidding, energy efficiency and energy storage progress, summer peaks will become less of a problem—and less profitable for the electricity industry. I can only wonder how much cheaper electricity costs would have been if the networks had invested in these solutions instead of more powerlines.

As the owner of a small high-efficiency air conditioner operating in a well-insulated and shaded room, my peak cooling load in the heatwave was around 300 watts during ‘cool down’ on arriving home, and around 125 watts at times of extreme heat. That’s much less than a plasma TV or six halogen lamps.

‘Enoughness’

All this brings me to an issue raised in the 2013 book Smart Utopia? by Yolande Strengers. She asks why the electricity industry is expected to provide unlimited power supply at all times.

This piqued my interest. In industry, I have found that the engineers who provide services such as steam and refrigeration often run grossly excess plant (and waste a lot of energy) in their quest to provide as much energy as users ask for, even if the request is unreasonably high. In the 1980s, I found the electricity industry shared this culture.

There is certainly a historical reason for this: without our modern energy options (which allow us to reduce and shift demand), many activities were critically dependent on reliable electricity supply. Indeed, many activities still are, but need not be.

The political price of supply shortages has traditionally been high, as daily life, health and business activity have been affected: heads of electricity agencies can lose their jobs, politicians can lose power. Engineers have a professional pride in providing what their clients ask for, and don’t like being blamed for shortfalls.

But modern energy solutions allow us to limit expectations of the traditional electricity supply system and, instead, place some responsibility on consumers. Such expectations would need to be phased in, with issues faced by tenants and financially stressed people recognised and transitional costs addressed. Incentives and support mechanisms, not just pricing, must be used. The alternative may be a mess, as those who are active, informed and have access to capital will look after themselves while others suffer.

This should be a core focus of energy reform policy.

Energy Issues Paper

In mid-December 2013, the government released an Energy Issues Paper and called for submissions by 7 February 2014. This process is a lead-in to release of a Green Paper in May and an Energy White Paper in September.

The Issues Paper seems to be focused on a list of short- to medium-term problems that the government thinks it needs to address. As far as it goes, this is useful, although the way issues are presented seems to disproportionately reflect the views of incumbent energy organisations and some policy makers.

Hopefully the Green Paper will take a broader view. Let’s face it, when the phrase ‘climate change’ does not appear in an energy policy document, our policy makers are struggling to be credible.

And I wish energy policy people would learn to differentiate between the price of energy and the cost of delivering energy-related services. Price matters much less if you are efficient and can avoid periods of high prices. The policy focus on price distorts energy policy towards measures that increase long-term total costs and social and environmental impacts.

Standing Council on Energy and Resources delays demand management bidding, yet again

A major criticism by the 2012 Senate Inquiry into the electricity industry, and by the Productivity Commission’s 2013 report into electricity networks, was the glacially slow progress on implementation of demand-side action. The Parer Review of 2002 and other studies have repeatedly highlighted the need to get the demand side of the market working. So it was very disappointing to see the ministers from states and commonwealth on the Standing Council on Energy and Resources decide at their December 2013 meeting to delay, yet again, rule changes to support implementation of a demand-response bidding scheme.

The only winners from this delay seem to be incumbent electricity generators and network owners. And some more demand management in the January heatwave would have been handy.

Sydney car trips

The bizarre outcomes of a car-based society were reinforced for me recently by some NSW transport statistics. Apparently 22% of all Sydney weekday car trips are to ‘serve passenger’. That is, they are unpaid chauffeuring trips, where the driver doesn’t actually want to go to the destination.

What is the cost of this planning failure in terms of time, inconvenience, congestion, parking issues, pollution, health and lack of independence? Surely it is time that local and state governments ensured our cities supported low car-dependency living? This would be much better for the young, old, parents, disabled, carers, poor and obese.

Emerging opportunities for energy storage

I wonder who will be first to actively promote an easy-to-add-on storage and smarts package for existing rooftop PV owners? This makes good business sense because hundreds of thousands of PV owning households are getting only 8 to 10 cents per kilowatt-hour for their exports, while paying 30 to 50 cents for energy in peak periods. These people are already committed to PV and frustrated with the efforts of the electricity industry and its policy makers to undermine their financial returns.

A second area for storage that I haven’t seen discussed is at the micro-level, building storage into appliances, or integrating (or plugging in) storage into local wiring within a building. This limits peak demand charges, offers potential savings on upgrading wiring and reduces wiring resistance losses in existing buildings.

Advances in supercapacitors may play a key role here. New Mazda cars use them instead of batteries for energy recovery and storage, and the CSIRO-developed UltraBattery uses supercapacitors to mediate between the battery and the load, to extend battery life and reduce losses. Research on graphene also seems likely to improve supercapacitor performance.

One example of this potential is in the installation of induction cooktops in existing homes. Most induction cooktops have ‘boost’ modes that can use over 3 kilowatts per pot, so manufacturers can claim they heat up quicker than gas. This potentially high peak demand can require upgrading of wiring back to the circuit breakers or even back to the street. But the amounts of energy required are not particularly large, so quite small amounts of storage would make a difference. For example, to boil two litres of water on an induction cooktop consumes less than a quarter of a kilowatt-hour.

A proviso is that the benefits must be balanced against the losses in the storage system.

When you look at the fine detail, the economics of appropriately designed distributed storage solutions could be much better than many expect.

Alan Pears has worked on sustainable energy issues since the late 1970s. He is one of Australia’s best recognised and most highly awarded commentators on sustainable energy and climate issues. He teaches part time at RMIT University and is co-director of Sustainable Solutions, a small consultancy.

Read more articles on energy efficiency in ReNew 127.

Swap_scooter

Product profile: Certified electric scooter

Weve seen a few electric scooters aimed at the daily commuter, and the latest in the pack is the Taiwanese-made SWAP SW2, available through Spruce Electric. The SW2 has been designed specifically for the Australian market and has passed testing to ensure compliance with all relevant Australian Design Rules.

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The scooter features a 3.6 kW brushless DC motor coupled to a continuously variable transmission, all powered by a removable 48 V, 45 Ah LiFePO4 or lithium ion battery. Maximum speed is limited to 50 km/h (as it is classed as a scooter), acceleration is quite good, reaching 30 km/h in 3 seconds, and the scooter can handle inclines of around 23 degrees. Brakes are hydraulic disk (front) and drum (rear).

Real-world range is said to be up to 70 km, depending on rider’s weight, riding style and road conditions, and the scooter can handle payloads of up to 150 kg. Scooter weight is 120 kg and it measures 1812 x 850 x 1050 mm.

RRP: $4490 inc GST. Available from Spruce Electric, 25 Vineys Lane, Dural NSW 2158, ph: (02) 8007 4787, sales@spruceelectric.com, www.spruceelectric.com

Q&A: Battery advice

I need to replace my 12 volt batteries. My power comes from a few solar cells and the load is relatively light and not every day—a studio with 60 watts of lights (currently old quartz halogen. which are easy to now replace with more efficient LEDs) and probably a 12 volt CD/radio. Would you recommend the Jaycar SLA deep-cycle battery SB1699—or indeed what else?

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Also, perhaps you may have ideas about inexpensive basic 12 volt CD or DVD players that could hook into existing speakers. I have been scrolling websites without much luck; portables seem to have their own lithium batteries which rather defeats my needs. Car stereos are too fancy, with Blu-ray etc.

Susie Edwards

Jaycar’s SB1699 might be a bit small for your use, but their next size up is 100 Ah, which is probably too large. There are a lot of battery suppliers that may have a larger range, such as www.batteriesdirect.com.au, www.batteriesplus.com.au and www.batteryworld.com.au (stores only, no online shop).

I have had a few problems with lead-acid batteries in the past being a tad flat when purchased (not good for lead-acids), although with a dozen or so cycles they usually come up okay.

But, given the falling price of lithium batteries and the fact that many are drop-in replacements for lead-acid nowadays, you might want to consider them. Examples are the 12 volt models at www.ev-power.com.au and www.evworks.com.au.

Re the CD player, you can reuse a computer CD/DVD drive (one with play and stop buttons on the front) for this sort of thing. There is an adaptor kit that lets you do this but you need electronics experience to build it; see Jaycar part number KC5459.

But if you want just simple play functions then you don’t need an adapter, just supply it with 12 V from the battery and 5 V via a small regulator, and connect the headphone output to the speakers. If they are powered speakers then you will get good volume; if not then you might need a small amplifier between the two, such as www.ebay.com/itm/140808997786 or Jaycar’s AA0487 or AA0473 (single channel only).

Of course, this is all very DIY and if that doesn’t appeal then a low-cost car stereo is probably going to be the best option.

Lance Turner

To read more questions and answers, buy ReNew 127.