In ‘Renewable energy’ Category

csr-bradford-solar

Finding value in sharing

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Can we find value for both customers and the network in sharing locally generated energy and thus accelerate a transition to 100% renewables? Bruce Thompson and Paul Murfitt discuss the potential in microgrids, virtual power plants and more.

The transformation of the electricity network is certainly now upon us. Years of environmental advocacy, rapid technology advances and shifts in consumer demand are driving an unprecedented shake up of our century-old supply network. With this change come opportunities (and some risks) to harness the value of renewable energy across the grid as we drive towards zero emissions.

READ MORE »

Traditionally, Australia’s electricity networks were largely built and controlled by state governments, and operated as central power supply systems managed with two policy imperatives in mind: security of supply and cost-effectiveness. The much-heralded disruption is turning this system upside down, bringing technical and financial challenges along with opportunities.

The big shift to date has been ‘behind the meter’, where there is a clear case for householders and businesses to invest in solar PV to avoid the cost of conventional energy supply. Yet establishing value ‘in front of the meter’—sharing your locally generated energy across the grid—has so far been fraught.

With the tapering off of feed-in-tariffs, owners of solar have been frustrated they don’t receive a fair price for their homegrown generation. On the other side of the fence, network operators have been aggrieved by the need to manage the technical impacts of solar PV and wind while their business model ‘death spirals’ from lower consumption.

Beyond the angst, new models such as microgrids and virtual power plants are starting to demonstrate that sharing solar PV generation and battery storage across the grid can leverage the opportunities and help manage the risks inherent in Australia’s changing electricity sector. For customers, potential benefits include access to wholesale pricing and retail tariffs. For networks, there can be lower costs from local control and load management, particularly if the models can reduce peak demand and avoid the need for network infrastructure augmentation.

Of course, the value of sharing locally generated energy across the grid is dependent on the time of day, the time of year and the location. The key challenge for ‘in front of the meter’ solutions is not only to understand the technology, but also to apply the fundamental principles of supply and demand to determine where the greatest value can be realised.

Bruce Thompson recently joined GreenSync as the Community Development Director following 12 years at Moreland Energy Foundation Ltd (MEFL) as major projects director. He is also the outgoing chair of the Coalition for Community Energy (C4CE). Paul Murfitt was recently appointed director of energy efficiency for the Victorian Government and is the outgoing CEO of MEFL.

Read the full article in ReNew 137.

mooroolbark

Neighbourly sharing: mini-grid in Mooroolbark, community battery in WA

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Neighbours in the Melbourne suburb of Mooroolbark are set to share their energy generation via a mini-grid in an Australian-first trial run by AusNet Services. Eva Matthews finds out what’s involved.

IN AN Australian first, network provider AusNet Services is currently rolling out a solar + storage mini-grid trial in Mooroolbark, in Melbourne’s east.

READ MORE »

Of the 16 homes on the chosen street, 14 will each have between 3 and 4.5 kW of solar panels and a 10 kWh battery storage system installed, with a cloud-based monitoring and management platform to optimise power flows across the mini-grid and to provide demand management support to the network.

The two-year trial was announced in April and was made possible with funding from the Demand Management Innovation Allowance. Participants don’t pay for the equipment and, at the end of the trial, get to keep their panels and inverter (but the control system and battery storage go back to AusNet Services).

As at end August, all houses have solar panels, inverter and battery storage installed, enabling data gathering on energy generation and usage patterns. The control system should be in by end October, which is when testing can begin in earnest. Testing will include deciding when to charge and discharge the batteries, and at what rate, based on current and forecast customer usage and PV generation as well as the network requirements. A single objective (e.g. minimising the overall peak demand on the mini-grid) can be implemented in a number of ways, so they will be developing and testing different approaches. The stabilising device and switching equipment that enable the mini-grid to be islanded (isolated from the rest of the network) will be installed towards the end of this year.

The group of houses will operate as a mini-grid from a control and electrical point of view, but the metering and billing arrangements are unchanged. To enable financial offsetting of one participant’s generation against another’s usage would require different meters to be installed—with a parent meter for the mini-grid and sub-meters for each house—so instead they will be modelling the potential financial effects.

Two households were unable to participate in the trial; however, this will provide fortuitous real-world data for where there is less than 100% opt-in—testing how the mini-grid can serve the energy needs of these houses without having their energy contribution in the mix. AusNet Services’ Distributed Energy and Innovation Manager Justin Harding explains, “Those houses will simply appear as extra loads in the mini-grid. For example, if we are trying to reduce the net demand of the mini-grid to zero at the connection point to the main grid, all houses would need to export a small amount of energy to offset the non-participants’ load.”

Simone and Joel Beatty make up one of the households participating in the trial. When they purchased their home five years ago, Simone says they noticed that a lot of the new houses being built were having solar installed, and it was something they were interested in, but hadn’t been able to afford. So when AusNet Services came knocking on their door with news of the trial, Simone says they were “definitely excited.” As well as looking forward to seeing how it all works, and the impact on their electricity bills, Simone says they have also benefitted from the information provided by AusNet Services—how they can log in to a web portal to monitor their electricity usage and ways in which they can be more energy efficient. She says they have “definitely already altered some behaviours.” And not only has there been an educational side effect of having the technology installed, it has given the neighbourhood something in common to talk about and get excited about. Simone says “everyone seems very positive about it” and adds that friends and family are jealous!

This trial follows a three-year battery storage trial by AusNet Services that tested how residential batteries can reduce customer’s maximum demand for electricity and support the network. Justin Harding says that there will likely be an “evolution of trials” into the future. This Mooroolbark trial has a strong customer learning and technical focus; the next step could be a larger project with more of a commercial focus, looking at how best to structure finances and customer agreements.

Tech used in Mooroolbark mini-grid:

  • 3 kW of panels (JA Solar) per house, except where customers had existing PV systems
  • 10 kWh lithium ion battery storage (LG Chem) per house
  • 5 kW battery inverter (Selectronic
    SP Pro) per house
  • Peak Response Unit (GreenSync) per house—a communications device for optimising power flows, includes 3G modem that talks to the main control system and battery inverter
  • cloud-based control platform (GreenSync’s MicroEM)—runs forecasting/optimisation calculations to enable locally generated/stored energy to be shared between homes, based on the needs of individual houses and the needs of the mini-grid
  • a separate 3-phase inverter and Toshiba battery system from Power Technology to keep the mini-grid stable when in islanded mode
  • switching cabinet with circuit breaker and protection relay to transition the mini-grid to/from the main grid, supplied by EIV.

Aims/benefits of the trial:

  • test how mini-grids can support the network, e.g. to better manage peak demands, reduce risk of system overload, defer capital expenditure
  • optimise value of the assets both for customers and the network, e.g. getting full value from battery storage when customers are grouped and there is one overriding control system versus single households exporting/importing energy to/from the grid
  • better understand household generation and usage patterns to help determine payment structures and tariffs, and test how energy self-sufficient a community can be
  • test potential for an uninterruptible power supply, i.e. where homes can be islanded, either individually or as a microgrid, and stored energy used if the grid goes down
  • investigate the performance of new methods to identify and mitigate electrical faults in a 100% inverter-based supply environment.

Best of both? Community battery trial in WA

A CUTTING-EDGE residential battery trial underway in the new Perth suburb of Alkimos allows residents to generate solar electricity and benefit from access to a ‘virtual storage’ battery system.

Led by local energy provider Synergy, in collaboration with Lendlease and LandCorp, the project involves a utility-scale grid-connected 0.5 MVA/1.1 MWh battery energy storage system located on-site in two shipping containers.

It has a number of aims: to reduce energy bills for participating households and improve network efficiencies by ultimately reducing connection costs. However, the most interesting and important aspect of the trial is Synergy’s ‘time of use’ billing product called the Peak Demand Saver plan.

The plan works by offering a three-part tariff for network energy, with different energy charges for peak daily (4 pm to 8 pm), off-peak day (midnight to 4 pm) and off-peak evening (8 pm to midnight). The time-of-use energy tariffs are designed to encourage households to minimise consumption and maximise returns on their solar PV investment—but without the need to invest in their own battery storage.

This new-style product means Alkimos residents pay a fee each month to have access to the community-scale battery storage. Those who store solar credits during the day draw on them first during the peak daily period, and then for the evening off-peak without incurring any additional costs, in much the same way they would their own battery.  During the day households use their own solar energy.

“It’s everybody’s battery to use. Customers pay $11 per month to use it, and then we calculate their usage over a 60-day billing period,” said Synergy.

“Anything they put into the batteries is theirs to draw on at peak times at no additional charge. And whatever they have left in the battery after the 60-day billing cycle is purchased from them at a 7 cents per kWh [feed-in tariff] rate. Because it is ‘virtual’ storage you can pretend it is your own battery, it’s just your neighbours are pretending it’s their battery too.”

So far, 65 residents have opted to participate in the trial since it began in April 2016 with the aim that 100 households will take part over the four-year trial period. Before residents join the trial, Synergy analyses their historical consumption to ensure the tariff suits their usage patterns.

“However, we’ve already had customers who want to participate even though they are not necessarily going to be better off, because they want to be part of the first shared battery trial in Australia,” said Synergy.

The trial will cost around $6.7 million and is backed with a $3.3 million Australian Renewable Energy Agency grant, and when launching the trial ARENA CEO Ivor Frischknecht said community-scale battery storage held great promise. “A new [housing] development like this might actually need less of a connection, or a smaller connection [to the electricity network]. That means lower costs for those people that are buying new lots and less investment into poles, wires and transformers,” he said.

For more info: www.synergy.net.au/Global/Alkimos-Peak-Demand-Saver-plan

Read more on microgrids in ReNew 137.

ev-update-bolt

Electric vehicles: the market in Australia and overseas

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Bryce Gaton reports on the evolution of government support and global carmakers’ production plans, which together are driving uptake of electric vehicles.

This year has seen a plane fuelled only by the sun travel around the world, a plethora of home electric storage systems come on the market, Australian households with solar PV systems pass the 1.5 million mark and a Tesla Model S travel from Sydney to Broome. Given 2016 is just past halfway through, what else is to come? Is 2016 to become the year that the hoped-for seismic shift in sustainable transport, energy sourcing and use truly begins?

READ MORE »

The power to change things is more in our hands than ever before and I will offer examples from around the world that hopefully we can look back on in 20 to 30 years time to say, “We really did start the sustainable transition then!”

Electric cars around the world

Right now, pure EVs with a 300+km range—the ‘Bolt’—are rolling off the Chevrolet production line to arrive in US showrooms in the last quarter of this year.

Similarly, Mercedes, Volvo, Renault, Nissan, BMW, Kia and many other Chinese makers already offer pure EVs in their lineups, and most of these have announced plans to match the 300+km range of the Bolt and Tesla Model 3. Mercedes is releasing plug-in hybrids (PHEVs) and even Jaguar is rumoured to be well down the track in developing an electric sedan and SUV to match the belatedly perceived threat to their core market from Tesla’s Models S and X.

And VW, as part of its mea culpa for the dieselgate emissions scandal, has recently announced plans to heavily move into electric vehicle design and production.

Overall, the trend towards less polluting vehicles continues, with global uptake of EVs and PHEVs climbing at an increasing rate, growing from 45,000 EVs sold in 2011 to more than 300,000 in 2014 (see Figure 1). EVs represent more than 1% of total new car sales in the Netherlands, Norway, Sweden and the USA (closer to 20% for Norway). And in China, 2014 saw 230 million e-bikes, 83,000 electric cars and 36,500 e-buses hit the road.

Read the full article in ReNew 137.

carnegie

Still a clever country

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Energy efficiency consultant Geoff Andrews admires Australian innovation, but, as has often been noted, finds the next step—commercialisation—is lacking. Collaboration, governments and risk-taking could all improve that, he suggests.

I view innovation as change for good, so change which improves sustainability clearly qualifies. Most readers of ReNew would agree that we have to improve the sustainability of our society, so we must innovate. But, how do we do that, and what lessons can we draw from Australia’s sustainability innovation performance to date?

READ MORE »

There is no question that Australia has provided the world with more than its share of innovations, including in sustainability. In renewable energy alone, Australia has led the world in PV efficiency for decades, pioneered many improvements in solar water heaters, and is now developing wave energy. We’ve been first or early implementers of two flow battery technologies (vanadium redox by Maria Skyllas-Kazaco at UNSW in 1980 and zinc bromine by RedFlow). Scottish-born James Harrison built one of the first working refrigerators for making ice in Geelong in 1851 (before that, ice was imported from Canada),and we invented wave-piercing catamarans and the Pritchard steam car. We even had manned (unpowered) flight by heavier-thanair craft a decade before the Wright brothers with Lawrence Hargrave’s box-kite biplane.

Of course, Australian innovations are prevalent in many other sustainability areas including medicine, construction, agriculture and fisheries, but space is limited here. What we could have done a lot better is commercialising those innovations in Australia. Imagine if Australia led the world in the manufacture of solar panels, refrigerators, air conditioners, wi-fi devices and evacuated tube heat exchangers, the way we do with wave-piercing catamarans and bionic ears.

Improving commercialisation would provide funds to improve our budget bottomline and allow us to do even more innovation and more commercialisation. To achieve this, I think we need to do several things.

Read the full article in ReNew 136.

White Cliffs 150px

From engineer to activist: a renewables industry is born

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

ATA member Trevor Berrill has been involved in the renewables industry in Australia since it began, as an engineer, academic, trainer and ‘alternative technologist’. He gives a personal take on the slow emergence of an industry.

My own interest in alternative technology sprang from disillusionment with the engineering education I’d received at QUT in the early 1970s. It was a time for challenging the establishment, but engineering seemed all about fostering the status quo. I worked as assistant to the maintenance engineer in a coal-fired power station near Ipswich, and also down Mt Isa Mines. I saw and smelled the pollution, and I wasn’t impressed.

READ MORE »

I entered an essay competition on energy futures run by Engineers Australia. My essay outlined a decentralised power system run from renewable energy. I came second in the competition. The winning essay promoted the status quo, more fossil fuels.

There had to be a cleaner, greener way. With Friends of the Earth, I was involved in activism, campaigning hard against nuclear power. But I thought we shouldn’t just be against something; we had to present an alternative energy future.

Then I was given a copy of Radical Technology, edited by Godfrey Boyle and Peter Harper. Therein lay the foundation of a future I could believe in—renewable energy, energy-efficient buildings, organic food production and sharing resources in self-sufficient, ecologically sustainable communities.

Defining alt tech
It was one of those editors, UK scientist Peter Harper, who coined the term alternative technology, to refer to “technologies that are more environmentally friendly than the functionally equivalent technologies dominant in current practice.” Peter went on to be a leading researcher and educator at the Centre for Alternative Technology in Wales, a centre that’s been showcasing sustainability since 1973.

Birth of an alternative technologist—and an industry
I went on to become a technical officer at the University of Queensland in the mid-1970s, and there I worked for leading academics in renewables research, Dr Steve Szokolay, a solar architect, and Neville Jones, a wind energy researcher. We tested solar collectors and built low-speed wind tunnels, an artificial solar sky and controlled environment rooms. In my spare time, I became an ‘alternative technologist’ at home, building solar water heaters, pedal-powered contraptions and small wind generators—perhaps in common with many ATA (ReNew’s publisher) members!
Then I got invited by Adrian Hogg, owner of Alternatives to work part-time designing and installing small PV systems throughout south-east Queensland. Adrian was a founding member of ATRAA, (the Appropriate Technnology Retailer’s Association of Australia) along with Stephen Ingrouille and Tony Stevenson (Going Solar in Melbourne), Brian England (Self-sufficiency Supplies, Kempsey) and Sandy Pulsford (Solaris Technology, Adelaide).

Read the full article in ReNew 136.

raygen

Solar sells: Australian PV research and innovation

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

From PERCs to heliostats to improving PV quality, Andrew Blakers from the Australian National University describes high-impact innovations that found their way through Australian-led, government-supported research.

Through consistent government grants for innovation over the past 40 years, Australia has punched far above its weight in renewable energy innovation, particularly when it comes to photovoltaics (PV). The potential benefits for the Australian economy are substantial. PV now constitutes about a quarter of new electrical generation capacity installed worldwide each year; wind comprises another quarter; and coal, oil, gas, nuclear, hydro and all other renewables combined constitute the other half. In Australia, PV and wind comprise practically all new generation capacity.

READ MORE »

Support for research and innovation lies at the heart of accelerated growth of the renewable energy industry. It supports later-stage commercialisation directly through technology development. Additionally, university research groups underpin undergraduate and postgraduate education and training of engineers and scientists.

High-impact Australian innovations
What are some of the ways Australia has contributed to solar research, and what are some of the commercial successes? Here are eight examples of high-impact innovations that emerged from Australian-led R&D.

1. PERC SOLAR CELLS
The PERC silicon solar cell is an Australian invention which is now used in about half of new solar cell production lines worldwide. It’s set to soon dominate the worldwide solar industry, according to the International Technology Roadmap for Photovoltaics. So far this is the most successful renewable energy technology to emerge from Australia.

2. PHOTO-LUMINESCENCE
BT Imaging’s advanced photo-luminescence characterisation systems for research and industry emerged from the University of NSW. They enable researchers and industrial engineers to visually assess silicon quality in great detail and to modify processes to maximise quality.

Read the full article in ReNew 136.

Renew_performance_kings

Less noise, no fumes – testing cordless leaf blowers

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

ReNew reader Colin Dedman puts the latest generation of lithium-ion cordless leaf blowers to the test and is blown away by how far they’ve come, though price and run time can be an issue.

Why would you buy a cordless leaf blower? Why would you buy a leaf blower at all? For the most sustainable living, shouldn’t we rake up all our leaves and debris by hand, and clean out our gutters by crawling around on the roof?

READ MORE »

For those of us with rainwater tanks, cleaning the gutters frequently is a necessity rather than a luxury, to ensure that precious rainwater ends up in the tanks rather than spilling out of a blocked gutter. For many years I cleaned up the leaves by hand, while cursing the weekly scream of my neighbour’s two-stroke leaf blower. Then my aging back convinced me that if you can’t beat them, join them, so I purchased my own screaming $88 petrol blower, that does clean the gutters and patio well. But I hate using it on account of the noise, fumes, hard starting and mixing/storing of two-stroke fuel. There must be a better way.

Corded electric leaf blowers are quieter, always start first time and can potentially use renewable electricity, but the inconvenience of a long extension cord rules them out for me. What about the electric cordless blowers then—are they just ‘toys’ as many people think?

Here I blow away the myths, by subjecting a variety of cordless blowers to a series of standard tests so you can judge which blower, if any, is suitable for your needs. I’ve included two mid-range petrol blowers and a corded blower in the tests for comparison.

Measuring blower performance
Some manufacturers would have us believe that the all-important parameter is the air flow rate in cubic metres per hour, while others boast of their impressive discharge velocity in kilometres per hour or metres per second. In reality, both are important.

The most useful single parameter to measure a blower’s effectiveness is the blowing power in watts (W), being the power of the moving airstream, as this relates directly to the ability to shift stubborn debris and move a lot of leaves and debris in a short time. The blowing power is less than the input power, due to inefficiencies in the motor and fan.

Manufacturer published values of air flow and velocity have not been included, because they are sometimes incomplete or inconsistent. In one case the specifications printed on the box were different to in the user manual—both can’t be right! Other issues include quoting the peak rather than average velocity at the discharge nozzle, and quoting the higher flow rate without the nozzle attached. Therefore, to enable meaningful comparison of competing blowers, I’ve measured the air flow rate, velocity and blowing power according to ANSI Standard B175.2, using calibrated equipment, and tabulated this for all the blowers tested, providing a resource for comparison of blower performance.

To read the extended version of this article in its entirety, click here to download it in PDF format.

iStock_000020246728_Large

Solar panel buyers guide 2016

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

We’ve contacted photovoltaics manufacturers for details on warranties, cell types, size and price to help you decide which solar panels are best for you.

Large-scale manufacturing of solar photovoltaic (PV) panels has led to significant price reductions in recent years, to the point where they have become a common sight in the Australia urban landscape. From powering domestic dwellings to providing power for camping or even hot water, PV panels are everywhere.

READ MORE »

Or almost everywhere. While there are well over a million homes in Australia sporting solar arrays of various sizes, there are still many homes without solar.

This article aims to provide up-to-date guidance for those people looking at purchasing a solar installation, whether that’s a new system or an upgrade. It includes types of solar panels and factors to consider when buying them. The guide focuses on PV panels only. For information on other components that may be used in a solar installation (e.g. inverters), system sizing and economic returns, see ‘More info’ at the end of the article.

Types of solar panels: monocrystalline, polycrystalline and thin film
Solar panels are made from many solar cells connected together, with each solar cell producing DC (direct current) electricity when sunlight hits it. There are three common types of solar cells: monocrystalline, polycrystalline and thin film.

Both monocrystalline and polycrystalline cells are made from slices, or wafers, cut from blocks of silicon. Monocrystalline cells start life as a single large crystal known as a boule, which is ‘grown’ in a slow and energy-intensive process. Polycrystalline cells are cut from blocks of cast silicon rather than single large crystals.

Thin-film technology uses a different technique that involves the deposition of layers of different semiconducting and conducting materials directly onto metal, glass or even plastic. The most common thin-film panels use amorphous (non-crystalline)silicon and are found everywhere from watches and calculators right through to large grid-connected PV arrays.

Other types of thin-film materials include CIGS (copper indium gallium di-selenide) and CdTe (cadmium telluride). These tend to have higher efficiencies than amorphous silicon cells, with CIGS cells rivalling crystalline cells for efficiency. However, the materials used in some of these alternatives are more toxic than silicon—cadmium, particularly, is a quite toxic metal.

Read the full article in ReNew 134

Click here to download the full buyers guide tables in PDF format.

Chris's off-grid wind and solar system powers his home and electric vehicle.

Off-grid wind and solar

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

It’s a windy place near Canberra, and Chris Kelman is taking good advantage of that! He describes the evolution of his impressive off-grid wind and solar system — and the avid meter-watching that goes with it.

In a quest to demonstrate the possibility of living a fossil-fuel-free life, I have now made a couple of attempts at setting up my house to run on ‘home-grown’ energy.

READ MORE »

My first project, back in 1987, used home-made solar hot water panels, a ‘massive’ 90 watts of PV plus a 1 kW Dunlite wind generator (pictured on the cover of Soft Technology 32–33, October 1989; Soft Technology was the original name of ReNew). At this stage, renewable energy technology was in its infancy and everything was DIY, including building an 18 m tripod tower for the turbine (overcoming a fear of heights was a personal fringe benefit). On this basic system I did manage to run lights, computer, TV and stereo, but there were thin times, of course.

These days, home energy systems are more like Lego — you just plug and play. So with a move back to the bush near Canberra a few years ago, I decided to do it all again, but this time with sufficient capacity to run a standard 230 V AC all-electric house, workshop, water pumps—and an electric vehicle.
The house I purchased had been set up pretty well as a passive-solar home, though it was connected to the grid at the time. It has a north-facing aspect, good insulation and a lot of (double-glazed) windows allowing winter sun to maintain a cosy slate floor. The result is a very stable environment for most of the year.

Energy production—phase 1
In phase one of my new project,in 2012, I installed 3 kW of PV with a Sunny Island off-grid inverter and 40 kWh of VRLA (valve-regulated lead-acid) batteries. Initially, hedging my bets, I configured it as a grid-connected system, with the grid acting as a backup ‘generator’ when required.

After a few months I realised that I rarely needed to use the grid and, as I owned a small antiquated petrol generator from my previous project, I decided it was time to cut the umbilical cord. This turned out to be a rather amusing process. My local energy provider didn’t seem to have an appropriate form for ‘removal of service’ and was bemused about why I would ask them to take the meters away. It was all a bit much for them. Even after the process was completed, I would still occasionally discover lost-looking meter readers around the back of the house!

The weather in this region is well known for its reliable solar insolation, apart from some lean months in mid-winter. Fortunately we are well supplied with wind power as well, as indicated by the Capital wind farm only a few kilometres away.

To confirm the wind resource, I set up a Davis weather station on a 12 m mast at my proposed turbine site and undertook a six-month wind survey. The results from this were compared with historical records from the area and a good correlation was found. This was enough evidence to convince me that wind power backup, particularly to cover the lean winter months, was the best option for my system.

Read the full article about Chris’s impressive off-grid setup in ReNew 134.

”The future is bright fellow women of renewable energy.” Miwa Tominaga delivering a rousing speech at the
2015 All Energy Conference. Photo courtesy of the Clean Energy Council.

The double-glazed ceiling: Women in renewables

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

When asked why it is important to have a gender balanced cabinet, Canada’s Prime Minister replied, “Because it’s 2015.” Sarah Coles looks around in 2015, wonders why Australian women are under-represented in the renewables sector and speaks with leaders in the field about ways to address the imbalance.

LAST month the Clean Energy Council (CEC), the peak body for renewables in Australia, held a Women in Renewables lunch as part of the All-Energy Conference in Melbourne. The lunch was organised by Alicia Webb, Policy Manager at the CEC. Roughly 20,000 people work in the renewables sector in Australia. Men outnumber women in all fields: solar, wind engineering, energy efficiency, hydro, bioenergy, energy storage, geothermal and marine. At the 2015 Australian Clean Energy Summit hosted by the CEC there were 93 speakers, 11 of whom were women.

READ MORE »

Women are generally under-represented across science, technology, engineering and mathematics (STEM) fields. According to the Australian Bureau of Statistics, of the 2.7 million people with higher level STEM qualifications in 2010–11, men accounted for around 81%.

There are myriad reasons for the low numbers of women in renewables. Gender disparity starts early with cultural stereotypes and lack of encouragement from teachers. Around 25% of girls are not doing any maths subjects in their last years at high school. When I was in year ten and acing science, my biology teacher said to my mother, “Sarah is good now but her grades will suffer when she starts noticing boys.” Returning home my mother (holder of a science degree) delivered a succinct verdict, ”Mr P. can get stuffed.” But discrimination like this is still common.

Some people think a change in governance is needed; that if there are more women in leadership roles this will have a trickle-down effect. As of 2014, women made up 21% of the Rio Tinto board and 22% of Qantas. Stats like these are often bandied about as examples of progress but to my mind if you take a big piece of pie and cut it in half you end up with two equal portions, not one piddley 22% sized piece and one 78% chunk. I decided to speak with some women at the top of their game to find out what should be done to even up the portions.

Miwa Tominaga

Miwa Tominaga knows what it is like to face gender discrimination at work. Miwa’s first full-time job was as the only female electronics technician at a radio transmitter site. She moved to Victoria to pursue a career in the sector, first working as a CAD drafter for electrical building services and then landing a job in renewables doing technical support at a company that manufactures electronic solar charge controllers. While she was working she studied renewable energy through an online course. When she provided phone support, hearing a woman, people would often ask to be put through to someone technical.

Later, installing solar panels at Going Solar, a woman said to Miwa, “Don’t take this the wrong way, but you do know what you are doing, don’t you?” The answer is a resounding yes. Miwa won 2014 CEC’s awards for ‘best install under 15kW’ and ‘best stand-alone system’. She currently works at a solar inverter manufacturer doing sales and tech support: “because it’s a worldwide company there are lots of opportunities.”

When I ask Miwa about discrimination she says, “A lot of women have experienced renewables being a male-dominated industry.” Miwa gave a speech about it at the CEC lunch. “I think it makes a huge difference if you’re working with men that see you as an equal not as an assistant. There have definitely been times when I have been judged for being a woman, especially by customers.” But she says that most of the time people are very supportive or indifferent towards her gender. “They say, ‘Oh wow, you’re gonna get on the roof by yourself!’”

Miwa thinks a top-down approach is a game changer. Danish legislation requires companies to work actively towards gender equality. It is one of the countries that has legislated for quotas around female board representation. Norway passed a law in 2005 requiring companies to appoint boards that include at least 40% women. Malaysia passed a law requiring female board representation of at least 30% by 2016. Miwa thinks Australia needs quotas too. “Start from the top at the board level. I do some volunteering for Beyond Zero Emissions (BZE) and I know that they make sure the board is about 50% women, 50% men. It makes a difference when they start at the top. It sets an example and really gives women opportunity.”

Emma Lucia

Emma Lucia felt empowered by encouraging teachers at school, and went on to study Mechanical Engineering and Arts at Monash University. Emma says she became interested in renewables when she was at university and studied abroad. “When I was finishing university everyone went into either automotive, mining, or oil and gas. My first job was actually supposed to be as a mining consulting engineer! I remember sitting in an environmental engineering class, which I did as an elective in my final year of university and thinking, ‘Is this [mining] what I really want to do with my life?’ I wanted to have a positive influence on the environment not a negative one.” The mining consultant role fell through and Emma worked as a building services engineer doing environmentally sustainable designs. “Through that I knew energy is where I wanted to be. I wanted to be in renewable energy. I could see that that would be a game changer.”

Early on in her career she felt constrained by the attitudes in the male-dominated engineering field. “In one company the more interesting work was often offered to my male colleague ahead of me,” says Emma. She found support, though, from other colleagues, who refused to see her sidelined. But it was difficult having to fight such battles, and in the end she decided a sideways transition was needed. “I now work in a more people- oriented role, but still using my skills, and in a renewable energy company. It’s been a good move,” says Emma.

She believes that having support mechanisms within organisations is a crucial step in overcoming discrimination. Emma says that “sometimes women may be a little bit more self doubting” so support from the organisation can help. “Also you need to trust yourself and trust in your abilities and really back yourself.” She adds, “Find a mentor or trusted advisor or someone you can bounce ideas off of who can help you cut through when you have problems in your career.” Emma thinks a key to gender diversity is to network with like-minded women and to get more women on boards, “I’m on the board of the Australian Institute of Energy and I actively look to increase the diversity of our committee members and speakers. I feel very strongly that change doesn’t happen in isolation.”

Katrina Swalwell

Dr Katrina Swalwell is a senior wind engineer and former Secretary of the Australasian Wind Engineering Society. After school, Katrina was all set to go into science at university but happened to do work experience at CSIRO with an engineer who said, “Why don’t you go and become an engineer and get paid more for doing the same job?” She completed a Science and Mechanical Engineering degree followed by six months study in Denmark looking at wind turbines. At university, about 20% of the undergraduates in engineering were women. “The vast majority of my fellow students were really supportive, nice guys. I had one case where a guy complained openly that I got better marks than him because I was a female. My friends and I just laughed because I did preparations for the pracs and he never did, so we thought that might have a bit more to do with it.”

Katrina says that, while she has always been supported in her career, most of her female friends who went through in engineering are no longer working in technical roles: ”The opportunities aren’t necessarily there. There are more opportunities in management or other things. They’ve gone into a whole variety of roles, a lot of them technically related, like one is a patent lawyer and one does electricity market modelling; she would call herself a modeller rather than an engineer now.” It isn’t all doom and gloom: “I think renewables is a great industry in that it is relatively new so there isn’t that entrenched resistance to females in the roles.”

Katrina says flexibility is key to attracting more women to male-dominated roles. For example, in Denmark there is state-supplied childcare. “The company that I work for is German. They’ve got laws now where there is six months paternity leave just for the father, so it has really prompted guys to take some time out.” Taking time off becomes more accepted for everybody as a result.

Katrina says girls need to be informed about their options, “If I hadn’t had that mentor when I was in year 12, I probably wouldn’t have been an engineer.” Like Miwa and Emma, Katrina sees boards as an important catalyst for change. “I’ve been involved in the women on boards group. They encourage women to consider taking board roles. They provide a service for companies that are looking to increase their gender diversity.”

Mentoring, support for diversity, workplace policies that support flexible working hours, baseline measurements and representation targets are some of the ideas for tackling the under-representation of women in renewables. At last year’s All-Energy Conference there were only three women speakers out of a total of 30. We still have a long way to go but change is afoot. The Clean Energy Council has introduced a policy of no all-male panels at the 2016 conference.

The renewables industry in Australia is working hard to accelerate the advancement of women but it needs to get gender equality targets enshrined in law. We need to address gender pay gaps, prioritise the issue and create accountability. We often hear politicians speaking about renewables targets but the time is ripe for them to address the issue of gender targets across this booming sector because, as Emma puts it, “Renewables are going to play a significant role in Australia’s growth so encouraging diversity in renewables will ensure better outcomes for the future of our country.”

Lego v Barbie

Miwa: “I was definitely a Lego kid. I ended up playing with a lot of my brother’s cars and stuff. I think my Mum stopped buying me Barbies because I didn’t play with them!”

Emma: “I did have a Lego kit and another one of my favourite toys was my Barbie Ferrari car.”

Katrina: “I had a Lego technical kit, the one with motors, so I could play with that. I was encouraged to explore whatever I wanted to do but I think my mother was still very surprised when I chose to do engineering

Image: ”The future is bright fellow women of renewable energy.” Miwa Tominaga delivering a rousing speech at the
2015 All Energy Conference. Photo courtesy of the Clean Energy Council.

 

Solar_Reserve_project

The future of energy: Large-scale solar worldwide

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Not just good for the planet, large-scale solar is now often the cheapest option. Lance Turner looks at some of the impressive projects powering up right now.

As the world’s governments slowly wake up to the reality of climate change and the need to shift energy generation away from fossil fuels to renewables, the corporate world is just getting on and doing it.

READ MORE »

Large-scale wind farms have become common, but large-scale solar farms are less so. However, this seems to be changing, with multi-megawatt and even gigawatt-scale solar generation plants being developed at a considerable pace.

Cheaper than the fossils
The main driver behind this seems to be that solar has actually become one of the cheapest forms of energy generation. In many cases, solar plants are proving to be cheaper than gas, nuclear and even coal-fired power plants, especially when the complete life cycle and environmental factors are taken into account. Indeed, recent tenders in both Chile and India for energy generation have been won by solar because it was the cheapest option. The Chilean auction was open to all technologies, yet solar won the majority of the generation contracts, with other renewables taking the rest. Not a single megawatt of generation capacity went to fossil fuel projects. Further, the auction produced the lowest ever price for unsubsidised solar at just US 6.5 c/kWh!

The huge US renewable energy development company SunEdison won the entire 500 MW of solar capacity on auction in the Indian state of Andhra Pradesh with a record low unsubsidised tariff for India of 4.63 rupee/kWh (US 7.1 c/kWh)—lower than new coal generation, particularly when using imported coal.

It’s not just in the developing world that solar is beating fossil fuels. In October, an auction in Austin, Texas, resulted in 300 MW of large-scale solar PV being contracted at less than US 4 c/kWh. Even before tax credits, the price is still under US 6 c/kWh—beating gas and new coal plants.

While many of these contracts involved photovoltaics, other forms of solar generation such as concentrated solar thermal systems also fared well, gaining some contracts and producing prices under US 10 c/kWh.

Read the full article in ReNew 134.

Renewable Energy Superpower

Book review: Renewable Energy Superpower

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Author: Beyond Zero Emissions
Published by Beyond Zero Emissions
RRP $30.00

READ MORE »

Australia has been a laggard when it comes to emissions reductions, but with the rest of the world coming to the understanding that the future lies away from fossil fuels, we are set to see some far-reaching changes in not only the energy industry, but the traditional big exports such as coal and natural gas.

Over the next few decades, most countries will shift their energy generation towards renewables. Renewable Energy Superpower looks at what the post-fossil fuel world will be like, where those opportunities lie and how the changing economics of energy generation will affect us all.

The gist of this entire shift is summed up in the Executive Summary: “Every day that passes with uncoordinated development of the energy system adds cost and undermines Australia’s future renewable energy advantage.” We need to move now or risk being left behind the rest of the world and becoming an economic and energy backwater.

Renewable Energy Superpower lays out a plan for making this transition, including National Energy Market reform, cessation of investment in the gas network, promoting adoption of electric vehicles and increasing the efficiency of the nation’s appliances. If you want to get a grasp on what the world’s energy markets and systems will look like in the next decade or two, this report is a good place to start.

Review by Lance Turner
This book is available for order at
bze.org.au

For more book reviews, buy ReNew 134.

Earthship Ironbank

Off-grid meets reuse

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

It’s taken a few years, but Australia’s first permitted earthship is almost ready to set sail in its new life as B&B accomodation, and as a living laboratory. Read all about it here.

Read more articles on reuse and recycling in ReNew 133.

Three options of hot water plumbing: gas-boosted solar, full gas and solar only.

Farming Renewably: Reaping the benefits

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

One person/farm can make a difference: David Hamilton describes how his farm’s sustainable conversion cut carbon, benefited the landscape and turned a profit.

READ MORE »

I’ve read many inspiring articles in ReNew from individuals trying to live more sustainably and lessen their impact on the planet. This article takes a slightly different approach–a rural perspective–to demonstrate that it can be commercially viable to run a farming enterprise using systems that are truly renewable, whether that’s for water, electricity, housing, food, livestock, pasture or wildlife.

Our journey to sustainable farming began in 1993, when my wife Roberta and I purchased a 60-acre property in the south-west of WA with the twin objectives of restoring the degraded land and becoming as self-reliant as possible. The land included pasture that was totally lifeless and neglected, along with a dam, two winter streams, old gravel pits and two areas of magnificent remnant native forest. We wanted to be independent for water, electricity and as much of our food as was practical. Withe fewer bills to pay, we could work fewer hours off the farm–which was very appealing.

As a registered nurse with no farming experience, I was on a vertical learnign curve. Luckily, Roberta has a dairy farming background and, with her accounting experience, is a wizard at making a dollar go a long way.

When we began, we were both working full-time. We spent the first two years establishing a gravity-fed water supply, preparing the hosue and shed sites, and fencing the property, including to protect remnant bush from planned livestock. We also planted over a thousand native trees and shrubs, plus a few ‘feral’ trees for their air conditioning and fire-retardant properties.

Read the full article in ReNew 132.

 

Bosch_hybrid

Going hybrid: Adding batteries to grid-connected solar

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Going off-grid may not be for everyone; a better route may be to ‘go hybrid’, by adding batteries to grid-connected solar. Andrew Reddaway explores the options.

The solar battery industry is on the verge of disruptive change. Traditionally, large batteries were only seen in houses at off-grid locations such as Moora Moora (see box on the solar hybrid training course held there, which I attended earlier this year and which provided input to this article).

READ MORE »

For off-grid systems, reliability is crucial; failure prompts an emergency call to the solar installer, so such systems have been designed conservatively using proven lead-acid batteries.

Meanwhile, in towns and cities, grid-connected solar systems have gone mainstream. As feed-in tariffs for solar export have dropped far below the rates paid for grid electricity, householders are looking for ways to cut bills by making better use of their excess solar generation. One answer is to add batteries to create a hybrid system: a grid-connected solar system with batteries either for backup or load-shifting.

This article gives an overview of current hybrid technology and the options available for adding batteries to an existing grid-connected solar system.

Different batteries for hybrid
A hybrid solar system is tough on batteries. Unlike an off-grid system that may store enough energy to last multiple days, a hybrid system’s entire usable capacity will be charged and discharged daily. This requires a battery that can handle fast discharge rates at high levels of efficiency. Lithium batteries fit the bill, and have already become dominant in consumer electronics, power tools and electric cars. Compared to lead-acid, they are also smaller, lighter, don’t require monthly maintenance and don’t emit hydrogen gas. The only things holding them back in the solar market are unfamiliarity and price.

The recently announced lithium Powerwall battery from Tesla is priced well below previous products and has a 10-year warranty. Traditional lead-acid batteries cannot compete with this new benchmark, so it’s expected that systems will start to move away from them. Hybrid systems are now expected to become viable on pure economics in a few years or less. Early adopters are already installing lithium hybrid systems, as are some who value maintaining power during a blackout.

Read the full article in ReNew 132.

SAMSUNG DIGITAL CAMERA

A micro-hydro buyers guide

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

A micro-hydro turbine can be one of the cheapest sources of reliable electricity—if you have the right site. Lance Turner looks at what’s available.

Solar panels are the energy generators of choice for most domestic renewable energy systems, but there are other forms of renewable energy generation that can provide supplementary or even primary power generation if you have the right site.

READ MORE »

One possibility is a micro-hydro system: the production of energy from water, with domestic-scale systems sized up to 100 kW. If you have a rural property with a suitable water source, then micro-hydro may be a good option, particularly if a high tree canopy precludes the use of solar panels or wind turbines.

The kinetic energy stored in flowing water can be considerable. You just need to look at the deep pools often found below large waterfalls or how the rocks in a creek are worn smooth by the flow of water. To get an idea of the forces involved, try aiming the jet from an ordinary garden hose at your hand. You will feel the force of the water striking your hand and being deflected. This is basically how many hydro turbines work.

Run-of-river versus dammed
Hydro systems fall into two broad designs—run-of-river and dammed systems.

Run-of-river systems simply take water from a high point of the river or creek, pass it through the hydro turbine and return it to the river or creek at a lower point. Only a portion of the water in the water source is diverted through the system.

In a dammed system, the water source is dammed, producing a water reservoir. The height of the water behind the dam produces the required head for the hydro turbine (the head is the term commonly used to describe the vertical height of the water column that is producing the pressure to run the turbine).

Most domestic systems are run-of-river types, as these produce the least environmental impact and are the cheapest to install. They are also the type your council and/or water authority is most likely to approve. After all, damming a water source can cause considerable environmental disruption and should be avoided.

Some run-of-river systems do use a small dam, known as pondage, to ensure an adequate flow into the intake pipe. The amount of pondage can be small or may be increased to provide more reliable energy output from the turbine during times of lower water flows in the water source. It is possible to use pondage that is separated from the water source completely, to prevent any negative effects on the water source.

Read the full article in ReNew 132.

Montessori-solar1_small

Revolving donations fund 35kW of community solar

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

A people-powered movement is helping to fast track Australia’s renewable energy revolution. 

READ MORE »

A recent solar PV installation at Camden Park, SA brings the total amount installed by CORENA’s Quick Win community solar projects so far to 35kW. Another 8kW has been added by recipient organisations in conjunction with these projects, giving an overall result of 43kW installed. Two of the projects have also included replacing lights with LED alternatives.

CORENA (Citizens Own Renewable Energy Network Australia Incorporated) provides interest-free loans to pay for solar installations and energy efficiency measures. The loans are repaid over about five years out of the resultant savings on power bills, meaning that non-profit organisations can reduce their carbon emissions without diverting funds from their core purpose. As the projects ‘pay for themselves’, the original donations are then used over and over again in new projects.

CORENA has now funded Quick Win projects for four non-profit organisations in three states: Tulgeen Disability Services in Bega (NSW), Gawler Community House (SA), Beechworth Montessori School (Vic), and Camden Community Centre (SA). The next project in line, in Nannup (WA), is already half-funded, and a community centre in Ravenshoe (Qld) is queued as Project 6.

“After just four projects the growth potential of our revolving funding model is looking quite exciting,” said CORENA spokesperson Margaret Hender. “The four projects completed so far have cost a total of $63,460. Climate-concerned citizens donated most of that, but $10,438 of it came from loan repayments from completed projects.

“The first project was funded entirely from donations, but already $5,000 of that loan has been paid back into the revolving pool of funds,” said Ms Hender. “As the number of completed projects increases, an increasing proportion of the cost of new projects is covered by loan repayments. Eventually the revolving loan repayments will cover 90%, or even 100%, of the cost of new projects.

“I could talk to politicians until I’m blue in the face in the hope of getting better renewable energy policies, and never know if I’ve had any effect,” said Ms Hender. “But if I put $100, or $10 a week, for example, into solar panels on a roof somewhere, within a matter of weeks my money will be reducing carbon emissions and keep on doing so forever as it is used again and again in future projects.”

For more information visit www.corenafund.org.au

 

 

SONY DSC

A battery buyers guide

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

The battery bank in a stand-alone or backup power system can make or break the system. Lance Turner examines what to look for in a battery bank and how to get the right battery for your needs.

An extract of the article is below, or read the full article in ReNew 131.

READ MORE »

You can also download the full table of manufacturers, suppliers and their batteries.

Article extract:

As more people look to go off-grid due to the ever-increasing cost of electricity bills and the unreliability of the grid in some areas, the market for energy storage systems is set to expand massively in the next few years. That’s not to say there aren’t options available already—there are plenty, for both off-grid and on-grid use.

There are two main approaches to energy storage: you can buy the required number of individual batteries or cells and have them installed and connected together on-site, or you can buy an integrated ‘storage system in a box’, containing batteries, safety equipment such as fuses and disconnects, and possibly a charge controller or other equipment.

As we looked at integrated storage systems in ReNew 128, this guide looks mainly at the first of these options: buying batteries or cells for assembly into a large battery bank. We also don’t cover batteries for electric vehicles (EVs); see our All About EVs article on p. 38, for a discussion of batteries for EVs.

Battery selection is critical

Arguably the most important part of any renewable energy system involving energy storage is the battery bank. All other parts of a system can be upgraded or added to quite easily, but if you select too small a battery or one not suited to your needs then your system performance, and the battery’s usable life, will suffer. Unfortunately, the battery is the component most likely to be specified incorrectly, either due to a lack of understanding of how batteries perform, or budgetary constraints—the battery bank is now the most expensive single component in the average stand-alone power system (SAPS).

Battery requirements

Batteries are designed for specific applications. In this article, we look at batteries suitable for use in renewable energy systems, either off-grid, in stand-alone power systems (SAPS), or on-grid, in a grid-connected system with storage for either load shifting or backup power.

Over time, and with changes in technology, the requirements for domestic energy storage systems have changed quite considerably. Once common, 12 volt DC systems are now mainly found in caravan and camping situations, though small SAPS systems may still run at this voltage.

Current homes instead usually run AC-based systems. They have 24 or 48 volt (or even 120 volt) DC power systems with inverters to convert the power to 240 volts AC, and use efficient AC appliances.

Such systems need large capacity battery storage to cope with the high surges required to start the motors in appliances such as water pumps and vacuum cleaners, and ensure long battery life through shallow discharge of the batteries. Generally speaking, the deeper a battery is regularly discharged, the shorter its lifespan will be.

Useful characteristics for batteries in renewable energy systems are:

  • long life under a continual charge/discharge regime
  • ability to withstand numerous deep discharges over the life of the battery (e.g. in winter when it may need to be discharged more deeply)
  • low maintenance requirements
  • high charging efficiency; some energy will be lost when the batteries are charged, but the lower this is, the better
    ability to perform over a wide temperature range.
  • low self-discharge; all batteries slowly discharge themselves over time, but the lower this is, the better.

Common renewable energy system battery types

The most common chemistry used in household energy storage systems is still the lead-acid battery. These have been around for more than a century and work well provided that the appropriate size and type are selected, and they are used and maintained appropriately.

As demand for more advanced energy storage grows, there has been much focus recently on lithium-based batteries. For household energy systems this generally means lithium iron phosphate (often called LiFePO4 or even just LFP) chemistry, which has seen considerable advancements in the last few years, with a steady decrease in cost as the scale of manufacturing has increased.

Nickel-cadmium batteries were used for a period in stand-alone power systems. However, their high cost and relatively high toxicity means they have all but disappeared. A related but much safer chemistry is the nickel-iron battery.

Other battery types found in commercial systems, though generally not used in domestic-scale systems, include flow batteries, sodium-sulphur batteries and even flywheel batteries.

Lead-acid batteries
Lead-acid batteries consist of lead and lead-sulphate plates suspended in a sulphuric acid electrolyte. They are a reliable and well-understood chemistry that is relatively forgiving to mild overcharging, although over-discharging can impact lifespan considerably.

In years past, the most common type of lead-acid batteries in household power systems were flooded cell types. At the time, these offered the longest life and best value for money over their lifetime.

However, in more recent times there has been a trend towards prioritising lower maintenance requirements, resulting in an increasing number of systems being installed with sealed lead-acid battery banks. With these, you no longer need to check cell electrolyte levels, and the corrosion by acid that occurs with flooded cells is virtually eliminated.

Sealed lead-acid batteries come in two main designs—AGM (absorbent glass mat) and gel cell. Gel cells have their electrolyte as a gel to prevent spillage and stratification (where the acid density of the electrolyte varies from the bottom to the top of the cells), while AGM batteries have liquid electrolyte, like flooded-cell batteries, but it is absorbed into fibreglass separators between the cells to provide the same benefits as the gel type. Either type can usually be mounted in either an upright or sideways orientation.

Lithium batteries
While lead-acid chemistry is still the mainstay of the renewable energy storage industry, this is steadily changing, with other battery chemistries such as lithium potentially offering considerable advantages over lead-acid batteries.

Lithium iron phosphate (LiFePO4) batteries have higher storage densities (more energy can be stored in a battery of a given volume), greater power densities (smaller batteries can produce greater instantaneous power outputs), much better charging efficiency and longer lifespans than any lead-acid formats.

They can be more expensive to purchase initially, but this is rapidly changing as the push for lower cost batteries for electric vehicles as well as domestic energy storage systems has spurred on many manufacturers to reduce prices and increase availability.

In addition, due to the longer life and higher efficiency of lithium cells, and the fact that their capacity is not affected by discharge rate like lead-acid cells, enabling lower capacity banks to be used compared to lead-acid, lithium batteries are already a cost-effective option when total cost of ownership is considered. While lithium batteries are still a relatively small segment of the domestic energy storage market, this is set to change in the next few years.

Lithium batteries must have an effective battery management system (BMS). This enables each cell in the battery bank to be individually monitored when charging and discharging. Overcharged cells and cells discharged below the minimum voltage point can fail, so a good BMS is a must.

Buy ReNew 131 to read the full article which includes:

  • other battery technologies
  • battery specifications (capacity, battery formats, voltage, battery charging efficiency, battery life)
  • sizing the battery bank for a stand-alone system
  • maintenance
  • battery sustainability
  • safety and a home for your batteries
  • battery bank do’s and don’ts
  • secondhand batteries.

 

This trough collector sits on the Charlestown Square Shopping Centre in Newcastle, NSW, as part of a solar cooling system installed in 2010.

The state of solar cooling

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

It’s the holy grail of cooling—using the sun to power your cooling system. Mike Dennis from ANU takes us on a tour of where the solar cooling market is now and where it’s headed.

READ MORE »

Most Australian homes are now equipped with some kind of air conditioner, but their rise in popularity over the last decade has put substantial pressure on the electricity transmission and distribution network—and the required investment in ‘poles and wires’ has been blamed for recent spikes in retail electricity bills.

Some electricity retailers charge a premium for grid electricity drawn during afternoon periods when air conditioning may be in use, but offer a paltry sum in return for photovoltaic power supplied to the grid during the same period. One NSW retailer charges over 50c/kWh between 2 pm and 8 pm on weekdays while offering only 6c/kWh in return for net photovoltaic energy exported to the grid.

Water heating and air conditioning are usually the two main energy sinks in a residence. To some extent, water heating may be time-shifted to avoid exposure to peak tariffs, but air conditioning load offers less flexibility. What can be done about this?

The first consideration, of course, should be to try to reduce or eliminate the need for active air conditioning. A well-designed building with appropriate shading, insulation and thermal mass is a good start. Secondly, householders should explore opportunities for passive air conditioning using prevailing breezes and carefully designed cross and stack ventilation.

As a last resort, a householder may decide to install an electric air conditioning system. These devices are intoxicatingly effective in providing comfort with convenience and immediacy. The shopfloor price may not be as confronting as the first electricity bill, however!

So, how can householders sidestep peak electricity charges and be comfortable in their homes at the same time?

Active air conditioning options that minimise environmental impact 

PV-POWER 

The obvious option is to install a photovoltaic (PV) system to drive a regular air conditioner. Several companies offer packages to do this directly, or it can simply mean installing a larger PV system to run the whole house (‘Solar cooling options available now‘ also in this issue).

However, electrical supply will be required late in the afternoon and into the evening to offer proper service during summer cooling and winter heating periods.

It is worth noting that peak summer cooling loads often occur late in the afternoon, while peak solar is at noon. In winter, peak heating loads are in the evening.

Hence, backup will be required in the form of either a grid connection or a local electricity storage device. Both of these options come at a price. It is likely that future electricity storage prices will make this option viable. No doubt someone will produce a simple Sunulator-type calculator to size the PV collector and battery bank for such purposes. [Ed note: Adding batteries is planned for the next phase of Sunulator development!]

Read the full article in ReNew 130.

This trough collector sits on the Charlestown Square Shopping Centre in Newcastle, NSW, as part of a solar cooling system installed in 2010.

Solar cooling options available to households now

Share : Share on FacebookShare on Google+Pin on PinterestTweet about this on Twitter

Solar cooling is possible at home writes Lance Turner.

READ MORE »

Solar cooling is perfectly achievable for homes and businesses using off-the-shelf technology. The simplest system, and the lowest cost to install, uses high-efficiency heat pumps (reverse-cycle air conditioners), which can have EERs (energy efficiency ratios) of up to 5.7 for the smaller models, combined with a grid-interactive solar power system. By running the heat pumps during the day, when the solar system is producing the most electricity, the heat pumps are, effectively, completely solar powered.

There are other cooling system types that can also be run directly from solar-generated electricity, with evaporative cooling systems being the most common. However, most common evaporative coolers use a simple system of passing air through wet filter pads, known as direct cooling. While this does cool the air somewhat, it also increases the humidity of the air, something often undesirable in hot weather.

Other options in the pipeline 

An alternative system, the Climate Wizard (a domestic model will be available in 12 to 18 months), is an indirect evaporative cooler that uses a counter-flow heat exchanger to cool the air without adding moisture. The system uses a heat exchanger, which has both dry and wet channels isolated from each other, to keep the evaporating water and the airflow into the house separate. Air passes through the dry channels in the heat exchanger, while some of that air passes back through the heat exchanger via the wet channels, where evaporative cooling removes heat. This cools the air in the dry channels without adding moisture. The dry air then flows into the home, while the moist air is expelled outside. Seeley International, the supplier of the system, claims that this system results in cooler and drier air entering the home compared to a conventional evaporative cooler, and can provide cooling performance similar to a heat pump air conditioner, with lower energy use.

While not common in Australia, there is a combined solar heating and cooling system known as a Combi+ system. It uses a solar ‘combi’ system (which uses solar thermal collectors, backed up by another heat source, to provide both space heating and hot water) combined with a sorption chiller for summer cooling. Combi systems are common in countries such as Austria, Switzerland, Denmark, Sweden and Norway, although Combi+ systems are less so, due to the lower cooling requirements in much of Europe.

PV-powered economics 

CSIRO has recently conducted research into the economics of PV-powered air conditioners. As presented at All Energy Expo 2014, their provisional results demonstrate that using PV to power the whole house, including the air conditioner, has a much better return on investment than using the PV to power only the cooling system. Systems with batteries could become cost-effective as battery prices decrease. The research is being published soon; watch out for it on their website.

Read The State of Solar Cooling in ReNew 130 for a look at the solar cooling market.