In ‘Solar’ Category
Just add batteries
There’s more to consider than just the brand or size when adding storage to a solar system. Damien Moyse and Nick Carrazzo highlight some of the issues to consider in a field with ever-evolving technology.
There are multiple ways that batteries can be added to an existing or new solar PV system. These different configurations will influence the system’s capabilities so it’s important to carefully consider the approach you take. This article covers the most common approaches currently available in Australia, but note that technology and options are developing rapidly so we will be updating this advice regularly.READ MORE »
The majority of solar PV systems currently installed in Australia are unlikely to be ‘battery-ready’—an existing solar customer cannot simply purchase a lead-acid, lithium ion, flow or sodium battery and have it retrofitted to their existing system.
The solar panels can be retained, of course, but an additional or replacement inverter and charging components will likely be needed to charge and use the batteries.
One approach (DC coupling) involves replacing the existing grid-interactive inverter with a new hybrid inverter; such inverters can both control charging of the battery and conversion of electricity from DC to the AC required for household use. As a cheaper alternative, in a fairly recent development, the replacement of the grid-interactive inverter can be avoided through fitting a DC to DC converter between the solar array and the battery bank—thereby negating the need to replace the existing grid-interactive inverter.
A second approach (AC coupling) requires installation of a second battery-dedicated hybrid inverter (with integral charger controller), with the existing grid-interactive inverter retained.
As such, almost all the new battery products currently on the Australian market are either sold with a new inverter (some as part of an integrated ‘all-in-one’ storage unit and some with the inverter separate from the battery) or require an inverter to be purchased separately.
Thus, most existing solar customers will need to replace their existing grid-interactive solar inverter, add a second inverter or add a DC to DC converter to their system. Which approach is taken depends on whether the system uses AC or DC coupling and the capabilities required of the system. Coupling refers to where within the system the batteries are connected.
Read the full article in ReNew 137.
Tassie off-grid home
Given their distance from the nearest power pole, it made sense financially as well as philosophically for this Sydney couple to go off-grid in their new home in Tasmania. Peter Tuft describes how they went about it.
As we approached retirement my wife Robyn and I knew we did not want to spend the rest of our lives in Sydney. Sydney’s natural environment is glorious but it is also much too busy, too hot and humid in summer, and our house was too cold and hard to heat in winter. We had loved Tasmania since bushwalking there extensively in the 1970s and it has a lovely cool climate, so it was an obvious choice.READ MORE »
We narrowed the selection to somewhere within one hour‘s drive of Hobart, then on a reconnaissance trip narrowed it further to the Channel region to the south. It has lush forests and scattered pasture with the sheltered d’Entrecasteaux Channel on one side and tall hills behind—just beautiful. And we were extraordinarily lucky to quickly find an 80 hectare lot which had all those elements plus extensive views over the Channel and Bruny Island to the Tasman Peninsula. It was a fraction of the cost of a Sydney suburban lot.
The decision to buy was in 2008 but building did not start until 2014 so we had plenty of time to think about what and how to build. We have always been interested in sustainability, and renewable energy in particular, even before they became so obviously necessary: my engineering undergraduate thesis in 1975 was on a solar heater and Robyn worked for many years on wastewater treatment and stream water quality. There was never any doubt that we would make maximum use of renewable energy and alternative waste disposal methods.
From the beginning we knew the house would be of passive solar thermal design. The house sits high on a hill (for the views!) and faces north-east. The main living room is entirely glass-fronted, about 11m long and up to 4m high with wide eaves. That allows huge solar input to the floor of polished concrete. A slight downside is that there is potential for it to be too warm in summer, but we’ve managed that with shade blinds and ventilation and so far it has not been a problem. All walls, floor and roof are well insulated, even the garage door, and all windows are double-glazed. Supplementary heating is via a wood heater set in a massive stone fireplace chosen partly for thermal mass and partly because it just looks awesome. Warm air from above the wood heater convects via ducts to the bathroom immediately behind the chimney, making it very cosy indeed.
Read the full article in ReNew 137.
Australia’s first Powerwall home
Nick Pfitzner and family are the proud owners of the first Tesla Powerwall home in Australia. Nick Pfiztner describes their configuration and the lessons they’ve learnt so far.
Our household had the privilege of the first Tesla Powerwall installation in Australia (maybe the world, they say). It has been a very interesting experience so far, and we’ve learnt a lot about what makes the house tick from an electricity point of view. I’ve also had the opportunity to discuss the energy generation landscape with several organisations developing similar energy storage technologies.READ MORE »
As a self-described Elon Musk fanboy, I became seriously interested in energy storage for our house after the Tesla Powerwall launch in 2015. I knew about other home storage systems, but mostly associated them with lead-acid systems and off-grid enthusiasts. We had previously got a quote for an off-grid AGM lead-acid system at one point, but we didn’t have the finance or space to make the BSB (big steel box) happen at that time.
However, by late last year with our finances more in order, we decided to take the plunge with the Powerwall. We chose Natural Solar as the installer. They had advertised themselves as the first certified installer of Powerwall in Australia and helped guide us through the options available.
We opted for 5 kW of Phono solar panels with a SolarEdge inverter and, of course, the Powerwall, for a total cost of $15,990 installed.
And add Reposit grid credits
Natural Solar also informed us about Reposit Power, a software package designed to maximise the benefits of home storage for the consumer. In a nutshell, Reposit is a software-based controller for the entire system. It learns the household usage patterns, gathers weather forecast data and interfaces with the inverter to make decisions about import or export of energy based on two important concepts:
Tariff arbitrage. This is the practice of switching to a time-of-use grid tariff and charging the battery at times advantageous to electricity pricing. This may occur when solar PV generation predictions for the next day are poor or where energy storage has been used up overnight. In either case, off-peak power can be imported for use the next morning.
GridCredits. This is an ARENA-supported project to investigate the use of intelligent storage and distribution of power via consumer-level battery systems, with the aim of reducing network infrastructure costs in future. Consumers are rewarded not through feed-in tariffs based on intermittent solar generation, but rather guaranteed power delivery from the battery. When the wholesale market for electricity is especially high, the electricity retailer discharges electricity from the battery into the grid, paying the consumer $1 per kWh.
These two factors could assist with the financial equation, so we figured it was worth the add-on cost of installing Reposit—an extra $800 at the time.
Read the full article in ReNew 137.
An inverter buyers guide
Whether you live off-grid or have a grid-connected generation system, the right inverter can make all the difference. We check out what’s available, where to get them and which one is right for you.
Choosing an inverter may not be the first thing that comes to mind when you’re thinking about installing a solar or solar + battery system. But every one of the 1.5 million solar systems already installed in Australia includes an inverter and, in fact, it can be thought of as the ‘heart’ of the system—if it’s not working, your solar generation is wasted or, if you’re off-grid, you’ll be without power (or at least without mains-equivalent 240 volt power*).READ MORE »
But what is an inverter and why is it so important? In a nutshell, an inverter takes electricity from a power source that produces DC electricity, such as solar panels or a battery bank, and converts it into mains-equivalent power (240 volt AC), ready to be used in your house.
It is important to have a good inverter. In off-grid systems, if your home relies solely on 240 volt power from a stand-alone inverter and the inverter fails, you will have no power, even though it is still being generated and stored. In grid-connected systems, an inverter failure means your solar panels are doing nothing until the inverter is repaired or replaced.
Which inverter for your needs?
The majority of currently installed grid-connected solar systems will be using a grid-interactive inverter. A grid-interactive inverter converts the energy from solar panels into mains power and feeds it into the house’s electrical wiring—no storage is involved. As indicated by the name grid-interactive, these inverters can export energy into the grid, and require a grid connection (or an equivalent 240 volt AC supply) to operate; they can’t operate in a stand-alone capacity.
When you bring energy storage into the equation it gets a little more complex, as the inverter needs to deal with both a generation source (like solar panels) and batteries; and possibly also the grid.
In off-grid systems, a stand-alone inverter can be used to convert the DC electricity from the battery bank into mains-equivalent power to run standard appliances. An inverter-charger is like a stand-alone inverter except that it has a mains voltage level input, which can be used to charge the batteries from the mains or a generator—it is not, however, grid-interactive, so can’t export energy to the grid.
The most complex inverter type is the hybrid inverter, which can feed energy into the grid from either the solar array or the battery bank. Many hybrid inverters can also power the house from the batteries during a power failure, in effect becoming a large UPS (uninterruptible power supply). They can also charge the batteries from the grid.
This makes many hybrid inverters true bi-directional devices, and many, if not most, can handle all of the energy flows in a home energy system. Some can even divert the excess solar energy to a particular load, such as a water heater, replacing the need for a separate device, known as a solar diverter (the SunMate is one example), for this purpose.
Let’s now look at the features of each type of inverter in a bit more detail.
Grid-interactive inverters are connected to both the power source (usually a solar array but sometimes a wind or hydro turbine) and the mains power grid. Energy generated by the power source is converted to AC mains power of the correct voltage and frequency and this supplements the power drawn from the grid by the home’s appliances. At times there will be more energy generated than being used and the excess is fed into the mains grid. At these times you will accumulate export credits, although how much you get paid for those depends on your feed-in tariff.
Grid-interactive inverters vary enormously in size, from 10 kW or larger units for big domestic and small commercial systems, down to tiny 200 watt models. Some, known as microinverters, are even designed to be mounted on the back of a solar panel to make the panel itself a grid-interactive module. These are ideal for those who want to start small and increase their system over time, or for systems where the array may be partially shaded—in a solar system using microinverters, each panel is independent of the others and not affected if other panels are shaded.
Read the full article in ReNew 137
For the full tables from this guide in PDF format, click here
Renewable energy courses guide
We’ve updated our renewable energy courses guide ready for enrolment time. You’ll find the table of courses—from TAFE certificates to postgraduate degrees—here. In the article, Anna Cumming has a look at what’s new in the industry.
IN the two years since we last published a review of the renewable energy courses available in Australia, things haven’t all been rosy for the renewable energy (RE) industry. Months of uncertainty at federal level over the national Renewable Energy Target, funding cuts to climate-related science, and the scaling back of feed-in tariffs for solar generation have all contributed to a reduction in the size of the industry.READ MORE »
The latest available Clean Energy Council (CEC) figures put the number of people employed in the wider RE industry at 14,020 for the financial year 2014–15, down a big 27% from the peak of 19,120 in 2011–121. However, the CEC puts some of this contraction down to a consolidation of the small-scale solar industry to more stable and sustainable levels. It also notes that RET legislation was passed right at the end of the reporting period, and since then confidence has grown: “The mood across the industry is upbeat in 2016, and it is expected that job figures will begin to grow once project development begins in earnest again under the RET in the coming years.”
David Tolliday, Renewable Energy Training Coordinator at Holmesglen in Victoria, shares this feeling. “The initial RE boom [homeowners taking advantage of rebates and premium feed-in tariffs to install solar PV] has passed, and the solar install industry has settled to around 4200 accredited installers—a good sustainable number,” he says. “The big opportunities now are in bigger-scale stuff like commercial solar, and battery storage on grid-connected systems.”
So, how to get involved? For those wanting to get into the industry or upskill, there is a wide variety of training and courses to choose from, from undergraduate and postgraduate university courses in engineering or focused on broader energy strategy, to hands-on solar design and install certificates offered by TAFEs and private registered training organisations (RTOs), and even free online MOOCs (massive online open courses). See our previous RE courses guide in ReNew 129 for a comprehensive look at the types of courses available, prerequisites and typical training pathways; here, we look at what’s new since 2014.
Read the full article in ReNew 137.
Finding value in sharing
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.
From engineer to activist: a renewables industry is born
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.
Solar sells: Australian PV research and innovation
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.
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.
ATA member profile: Making sinewaves in Australia
Long-time ATA member and software engineer Rod Scott continues to expand the work of Selectronic, his family business which 35 years ago created Australia’s first inverter. He talks to Kulja Coulston.
The success of the renewable energy industry has often tracked along a “sinewave sales curve”, according to Rod Scott, the products and business manager of inverter manufacturer Selectronic. “It’s standing on its own feet more now, but there were times when government program early announcements could dry up business for five months at a time,” he says of the ‘boom and bust’ cycle that has typified the renewable sector in Australia.READ MORE »
Together with his brother Ken, Rod Scott is continuing the work of his pioneering family business which has been part of the local industry from the beginning. Selectronic produced their first inverter in 1981: “It was a 360 watt DC to AC square wave inverter,” explains Rod. “We started small and it grew from there.” In 1990 Selectronic developed one of the earliest model sinewave inverters.
“It was then that our bigger models started to come out with energy-management functionality. It was all off-grid back then,with Australia being such a sparse country—storage for on-grid systems would have been a very strange concept!” It was in the early 2000s when they developed their first grid-interactive inverter, as that side of the market started to take off.
Rod’s parents established Selectronic in 1964 as a contract manufacturing business and ran it out of the Scotts’ backyard bungalow in Boronia, Victoria, before moving into a factory. The company cut its teeth custom-making transformers and inductors for the local electronics industry before launching its own electronics products division. Decades later, Selectronic continues to manufacture products locally, when most manufacturing has moved offshore.
“We were one of the first to make inverters in Australia, and we might also be one of the last.” Employing around 35 to 40 staff at its Chirnside Park factory in Victoria, Selectronic indirectly employs another 100 people in Australia through its supply chain, and will soon open an international office in Johannesburg. “We can’t get everything made here, particularly the specialist electronics, but we support local if we can, as it gives us flexibility and control over the quality of the product.”
Research and development has underpinned the company’s success for half a century, explains Rod: “Our future products look like what our customers demand, and it’s always been that way. When we developed the SP PRO in 2008, we already had 28 years of off-grid experience.” Selectronic’s continued commitment to the traditional offgrid market is also paying off, as the flexibility and reliability of those systems is relevant to the growing solar hybrid market. A few years ago a German company, KACO New Energy, rebadged Selectronic’s 5 kW SP PRO under their own label.
Rod has been an active ATA member and committed advertiser in ReNew. He is also personally committed to renewable technology at home, and is running off a 5 kW SP PRO with about 2.5 kW of solar photovoltaic panels. At a recent party none of his guests noticed the suburb-wide power outage: “I had to take everyone out onto the street before they believed me that we were the only ones still with power.”
This member profile is published in ReNew 136. Buy your copy here.
Store and deliver: Energy storage market heats up
The energy storage sector is heating up. Lance Turner takes a quick look at where the industry is heading.
A decade ago, seeing solar panels on homes was a rare occurrence, yet now you will find them on more than one million Australian homes. Indeed, solar has become completely mainstream, no longer just for greenies and those living remotely.READ MORE »
While solar power works well to reduce dependence on the grid at peak times, the recent or pending removal of decent feed-in tariffs for many solar owners has meant that many are now looking at energy storage. A battery system means that system owners can reduce their low-valued exports to the grid and instead store the energy for later use, offsetting expensive grid imports, and potentially saving money, or at least shifting the balance towards greater self-sufficiency.
Traditionally, solar battery systems have been designed to suit the individual installation, but for grid-connected storage that is no longer a requirement. All you need is a system that can store an appropriate amount of energy and be able to supply that to your house when needed—it doesn’t need to cover all demands of the home at all times.
To this end, we have seen a proliferation of domestic-oriented energy storage systems (ESS) of late. They vary in size, shape and features, but all are designed to allow the homeowner to take better control of their energy generation and use, reducing bills and, in some cases, providing a degree of backup against grid failure.
Not all systems are designed for grid backup, but this is becoming more common as manufacturers realise that customers want their systems to be as flexible as possible, even potentially allowing them to eventually go off-grid altogether.
Read the full article in ReNew 135.
How green is my solar?
How long does it take to pay back the energy used in the production of solar + battery systems and how much of an effect do they have on the greenness of the grid? The ATA’s Andrew Reddaway investigates.
By generating clean electricity, solar systems reduce the amount of coal and gas that’s burned in power stations. This reduces pollutants and greenhouse gases released into the atmosphere, which cause disease and man-made climate change. Fossil fuels also require extractive processes such as fracking and open-cut coal mining, which have led to negative effects on the environment such as land degradation, water contamination and mine fires.READ MORE »
It seems clear that installing a solar system will have a positive effect on the environment. But with several different types of system now available, including systems with batteries, how do they compare in terms of the environment?
Grid-connected without batteries
The vast majority of existing solar systems are connected to the grid and have no batteries. Your solar panels’ electricity is first used by on-site appliances, and any excess is exported to the grid to be consumed by your neighbours. Any shortfalls are supplied from the grid. This setup is relatively cheap and efficient, using a simple inverter that relies on the grid for its stability. However, it’s not very self-sufficient, because if a grid blackout occurs the inverter will switch off. (Although not always; some rare grid-connect inverters can use direct solar generation to supply household appliances in a blackout, even without batteries; for example, the Nedap PowerRouter.)
Since the grid has minimal energy storage, whenever your solar system is operating, a centralised power station will reduce its output to compensate. Each kilowatt-hour of solar generation reduces power station generation accordingly. In fact the benefit is even greater, as the power station must supply not only the end-user demand but also the losses incurred in the power lines, which can be over 20% for remote locations. Some people argue that because coal-fired power stations are inflexible, they’ll keep consuming coal at the same rate regardless of solar generation. Actually they are responsive enough; for example, Loy Yang A in Victoria can halve its output in less than an hour. Spread out over a geographically large area, solar systems’ overall impact is relatively gradual even when a cloud front arrives; this is forecast and managed by the grid operator in five-minute intervals.
With enough panels you can generate more electricity than you consume over a whole year, with your night-time imports more than compensated for by your daytime exports.
Read the full article in ReNew 135.
Solar panel buyers guide 2016
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.
Solar + battery trial in NZ
Combining PV and battery storage is often touted as a win-win for householders and energy distributors, eliminating peak demand and providing a way to better use the solar generation on-site. Lindsey Roke shares his household’s experience with a trial initiated by his local lines company in Auckland, New Zealand.
In late 2013, our power lines company initiated a PV and battery pilot scheme for households in the Auckland region. The aim was to test how PV combined with batteries could be made to work to the advantage of both householders (by reducing costs and providing backup energy in the case of grid outages) and the grid (by providing additional energy to the network, reducing peaks and providing a way to optimise PV integration into the network).READ MORE »
My wife and I decided to get involved in the scheme and in late January 2014, Vector (the lines company) installed a PV system with battery storage at our house. Almost two years on, there have been issues along the way, but overall it’s been a useful field trial, both for Vector’s and our understanding of the complexities of running such a system.
A new lease on energy
Vector offered the system with an installation cost of NZ$2000 and a monthly rental in proportion to the solar PV system size. Three PV system sizes were available—3 kW, 4 kW and 5 kW—each combined with a lithium iron phosphate battery of 11.6 kWh, and a 4.5 kW inverter (de-rated to 4 kW for enhanced reliability). We opted for a 3 kW PV system and a rental period of 12.5 years. For this sized system and rental period, the monthly rental (for 150 months) was NZ$70, covering maintenance and support. At the end of the lease we will own the panels, but Vector will remove the inverter and battery. Given the technology changes likely over that time, we thought this would be a reasonable option.
Of 290 installations in the pilot, ours was the 150th to be completed.
For us, the primary motivation was to shift to net zero energy (or better). Having designed and helped build our all-electric house in the 70s, we have since made a variety of efficiency upgrades including electric-boosted solar hot water (described in ReNew 97), energy-efficient lighting, a high efficiency space heating heat pump and upgraded under-floor and ceiling insulation (the walls were insulated from day one). Our average consumption is now about 7.4 kWh per day, for two of us and a some-time boarder (he’s a flight steward and often away).
When it came to sizing the PV installation, we wanted to cover this energy consumption, but weren’t necessarily expecting to save money over what we would otherwise have paid for electricity. Given our location in Auckland (at a similar latitude to Bendigo in Victoria), a correctly oriented unshaded PV array would be expected to generate an average of 4 kWh per day per kilowatt installed. Thus, we predicted that even the smallest system offered, 3 kW, would make us net exporters over a year, generating around 12 kWh per day on average.
Read the full article including issues and results in ReNew 134.
Off-grid wind and solar
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 double-glazed ceiling: Women in renewables
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 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 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.”
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.
The future of energy: Large-scale solar worldwide
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.
A recycling round-up
Lance Turner considers the evolving recycling options for some of the common technologies in households: solar panels, lights and batteries.
Solar panel recycling
Up until recently there have been no official schemes for recycling solar panels in Australia. However, as the number of broken and otherwise failed panels begins to grow, so has the need for recycling.
But how much solar panel waste is there at present, and what are we looking at down the track when the current explosion of solar panel installations come to the end of their working life?
Although figures are hard to come by, one typical example is that of Japan, which has seen considerable growth in PV installations in recent years. According to the Japanese Ministry of the Environment, by 2040 770,000 tonnes of solar panels will need to be recycled. The ministry has stated that, in conjunction with the Ministry of Economy, Trade and Industry (METI) and industry organisations, it will begin to implement measures for “removal, transportation and processing of solar power generation equipment” before the end of this fiscal year, in March 2016 (from www.bit.ly/1PwRFfC).
In Europe, requirements have already been added to the Waste Electrical and Electronic Equipment (WEEE) directive, bringing in a take-back and recycling scheme to deal with solar panel waste. The program, PV Cycle (www.pvcycle.org), provides fixed collection points, collection services for large quantities, and collection via distributors.
The WEEE directive means that solar panel manufacturers not only have to ensure collection and recycling of their products when they have reached their end of life, they will also be required to ensure the financial future of PV waste management.
Looking at Australia, there is currently (as of March 2015) 4.1 GW of installed capacity of solar PV. Assuming around 250 watts per panel (a common size), that’s around 16 million solar panels. With an approximate weight of 18 kg per panel, you are looking at 288,000 tonnes of solar panels, or around 11,500 tonnes per year (assuming a lifespan of 25 years) needing to be recycled. Of course, many PV panels will have a greater lifespan, while other, lesser quality panels will die sooner, so these figures are really just ballpark.
Regardless, that’s a great deal of materials needing to be recycled, most of which is glass, silicon cells (a glass-like material) and aluminium.
Aluminium framing is easily recycled in existing aluminium smelters. However, without a system of collection, transportation and dismantling of solar panels, these materials are currently going to waste, usually ending up in landfill.
Read the full article in ReNew 133.
Farming Renewably: Reaping the benefits
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.
Going hybrid: Adding batteries to grid-connected solar
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.
Low cost solar heating: Using free heat from your roof
After reading an article in ReNew, Alan Cotterill decided to design a closed loop heat exchange system to supplement his home’s heating with free heat from the roof. A couple of iterations later, he describes the resulting effective system.
In early 2014 I commenced efforts to use the heat from our roof cavity to contribute to winter heating. I decided on a closed loop system, which would take in room air, duct it through the roof and return it to the house at a higher temperature. A closed loop system avoids the issue of drawing down insulation fibres and dust from the roof cavity.READ MORE »
Useful attic temperatures
My home combined with our very cold but sunny winter days in Wagga seemed especially suitable for this system to run with reasonable efficiency. The house has a grey Colorbond steel roof and a large roof area relative to the internal floorplan, due to a high pitched roof and the wide verandahs and garage being included under the main roof structure. The east-west orientation of the long axis of the house and the north-facing roof area being covered with solar panels have not prevented useful attic temperatures. Measured 60 cm below the peak of the roof cavity, the average maximum attic temperature was 28 °C for the two weeks starting 16 July 2014 and 37.8 °C for the two weeks from 19 August 2014.
A first attempt
My first prototype forced room air through a system of ducts in the roof using a centrifugal exhaust fan mounted on its side on a shelf in the laundry. The air was distributed to three 12-metre runs of 100 mm flexible aluminium ducting before returning the air to the house. The returned air was reasonably heated but the total volume of returned air was inadequate to contribute significantly to winter heating.
Read the full article in ReNew 132.