In ‘Batteries’ 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.
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.
The lowdown on battery technology
Critical to any energy storage system is the battery itself. So what technologies are available and what are their pros and cons? Lance Turner takes a look inside the technologies available now and what’s in the offing.
IT SEEMS that almost every day a new domestic energy storage system is released onto the market. While manufacturers concentrate on the latest features like compatibility with existing systems, system monitoring, integrated inverters and even programmability, very little is mentioned about the actual storage medium itself.READ MORE »
What makes one battery better than another for a particular use, and which technology should you be looking at for your energy storage system needs? Let’s look at the current options in a bit more detail, including advantages and disadvantages of each, and then look at some newer technologies available now that you may not have seen.
This old faithful is the mainstay of the home energy storage industry. Lead-acid batteries have been in use for over a century and are a tried and proven technology.
They consist of plates made of spongy lead (negative plate) and lead dioxide (positive plate), with sulphuric acid as the electrolyte. During discharge, both plates are converted to lead sulphate, and the discharge reaction produces water which dilutes the sulphuric acid, changing its specific gravity. This change in specific gravity is what allows you to measure a flooded-cell lead-acid battery’s true state of charge using a hygrometer.
Lead-acid batteries have several advantages:
- reasonable resistance to overcharging
- lower cost than many other technologies
- readily available
- almost 100% recyclable
- almost all inverters and charge controllers are lead-acid compatible
- widespread knowledge of the technology in the industry.
They also have disadvantages, including:
- low energy density, which means high weight per unit of storage
- can’t be regularly deep cycled without reducing lifespan
- primary reactive materials are toxic and corrosive
- can produce explosive hydrogen gas when charging
- can’t be stored partially discharged without damage—must be fully charged regularly to prevent sulphation (where permanent lead sulphate crystals form on the plates)
- Peukert effect—effective capacity reduces with increasing discharge rate.
The full article looks at currently available battery technologies in detail, including:
- lithium ion
- salt water
- molten salt
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.
Neighbourly sharing: mini-grid in Mooroolbark, community battery in WA
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.
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.
Making batteries viable
Julian de Hoog and Khalid Abdulla explain how energy consumption and weather forecasting can improve the financial equations for domestic energy storage.
Many residential householders are now exploring the possibility of installing energy storage in their homes to reduce their electricity bills and better manage their energy needs (see ‘Energy Storage Market Heats Up’ in ReNew 135). This is true in particular for solar PV owners currently benefitting from feed-in tariffs that are due to expire: from January 2017, hundreds of thousands of customers (in particular in Victoria and New South Wales) will receive considerably less for any energy exported to the grid, making the idea of storing excess energy for later use more attractive.READ MORE »
The excitement and interest isn’t just limited to residential solar PV owners though—across the energy industry there is an expectation that large batteries and other forms of energy storage will be installed at increasing rates. Many industry analysts predict that the rate at which energy storage is taken up will be greater than the rate at which solar PV was taken up at the same stage of technology maturity, suggesting that an energy storage boom may be imminent.
However, energy storage still remains a fairly expensive proposition and householders looking to install a battery can expect to spend $10,000 or more, even for relatively small systems. As with solar PV, these costs will come down with increasing uptake and technology developments, but for at least a couple of years the cost of a battery will be hard to justify in most cases. The same is true for many utility-level and large-scale energy storage projects.
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 + 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.
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.
Going off-grid slowly: a DIY project
Stan Baker dreams of ditching his energy company and going off-grid. He explains how he aims to achieve this, one step at a time.
The well-documented ‘gold plating’ of the poles and wires networks has meant rising service fees for consumers despite falling demand for delivered energy. My own electricity bills reflected this and caused me to seriously consider leaving the grid altogether. A further consideration was the increasingly disruptive weather being experienced around the country resulting in power outages caused by high winds and electrical storms. When attempting to be energy independent, however, the problem is the high cost of the batteries and other equipment necessary to generate and deliver electricity.READ MORE »
Being something of a DIY type, I considered what bits I had sitting around in my garage and what expertise I might have that could be relevant. A passion over the years for converting hybrid cars to plug-in hybrids meant I had a reasonable understanding of lithium batteries, including the management electronics needed to ensure their longevity. I also had a 1.5 kW, 12 VDC Latronics inverter acquired years earlier for some long-forgotten project. Naturally, I had the usual nerdy stuff such as miscellaneous electronic parts as well as some understanding of microcontrollers.
In effect, I had much of what was needed to deliver 240 VAC off-grid, but with one question unanswered: where was the input energy to come from?
My house has a flexible pricing plan from Origin that provides cheaper electricity between 11 pm and 7am. This meant I had a lower cost source of electricity for charging the batteries, at least for initial trialling. So, about six months ago I put together a simple system using lithium iron phosphate (LiFePO4) batteries from an electric vehicle conversion that were down to around 50% of their original capacity and therefore unsuited for vehicular use.
The battery charger was a simple linear unit that used toroidal transformers. I had my fuse box modified so that the lights in the house could be powered either from the inverter or directly from the mains.
The original system was not particularly efficient and I estimated I was losing around 50% of the incoming energy, mainly due to the battery charger. However, it did keep my lights going during most nights and encouraged me to consider a more sophisticated battery storage system.
Read the full article in ReNew 131.