In ‘Solar’ Category

An all-electric home can reduce your bills and ‘green’ your energy use, particularly if you run your house from the sun. And, as the grid gets greener, so too does your house. The roof of this Hawthorn, Melbourne extension was designed specifically to house the 4.5kW solar array that powers the house. Design by Habitech; read the full profile in Sanctuary 37.

Three steps to all-electric

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Thinking about going all-electric, but unsure what’s involved? Here we present an overview of the steps to going all-electric and where to find more information.

IN THE past, gas was seen as a cheap and clean option for winter heating, hot water and cooking. However, the efficiency of electric appliances has improved dramatically and solar PV has fallen so much in price (and can be used to power those appliances), meaning it can now be cheaper and more environmentally sustainable to go off gas and run an all-electric home.

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The ATA first looked at this in 2014 and the modelling results can be found at www.bit.ly/ATA-GVE. In summary, the results showed that even when paying grid electricity rates (i.e. without solar PV), for many Australian homes it would be cheaper over 10 years to switch from gas to efficient electric appliances, with appliances replaced as they fail or in some cases even before this. Greater savings can be found when disconnecting completely from the gas network as this eliminates the gas supply charge (costing several hundred dollars a year). The report also highlighted that new homes should not be connected to gas, as doing so would lock in higher energy costs than needed.

Savings will depend on the thermal performance of your home, the electricity price negotiated with your retailer, your gas tariffs and the efficiency of your appliances. The Grattan Institute found that a large home in Melbourne can save $1024 per year by disconnecting from the gas grid: www.bit.ly/GATCAHC

In addition, by using modern electric appliances, your home can be converted to use 100% renewable energy, whether you generate your own electricity with rooftop solar or purchase 100% GreenPower from your electricity retailer. The ATA’s latest modelling compares gas running costs to electric with solar; see p. 44 for preliminary results.

Three steps to all-electric

There are three main areas where many homes currently use gas: space heating, hot water and cooking (mainly cooktops, but ovens too). To switch to all-electric, there are now efficient options available for these uses. This article summarises the options and points to where to find more information.

Read the full article in ReNew 140.

Capture

Solar sizing: big returns

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Why it’s now advisable to ‘go big’ when installing a solar system, even if you don’t use much electricity: Andrew Reddaway presents the latest ATA modelling.

Many people ask us what size grid-connected solar system they should get. Traditionally, the ATA (ReNew’s publisher), has advised people to consider this carefully. If you primarily want to help the environment and cost is of little concern, it has always made sense to install as many panels as possible, as all their generation displaces electricity from dirty, centralised power plants. But most people have budgetary constraints, so their solar system needs to make economic sense as well as help the environment. To achieve this, we’ve previously recommended that people size a solar system based on their electricity consumption and maximise their other opportunities, such as energy efficiency. However, things have changed.

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Two big changes

1. Solar system prices

The last five years have seen significant price reductions, especially for larger solar systems. Prices vary with component quality and location, but on average a 5 kW solar system now costs around $6200 according to Solar Choice’s residential price benchmark data.

Let’s compare a 5 kW system to its smaller 2 kW cousin. To compare two different system sizes, the cost is presented in dollars per watt. Figure 1 reveals that since August 2012, the larger systems have halved in price, while the smaller ones have dropped by only a quarter.

Larger systems have always enjoyed economies of scale compared to smaller systems, because while the installer is on the roof it’s relatively easy for them to add more panels. One difference now is that the price of solar panels has fallen faster than other components. The industry has also become more familiar with larger systems, as they are now more frequently installed than small ones.

2. Feed-in tariffs

The Victorian government recently announced that solar feed-in tariffs will rise to 11.3 c/kWh from 1 July 2017, roughly double their previous level, and IPART has recently recommended a similar change in NSW. These changes are primarily due to wholesale electricity prices in the eastern states roughly doubling over the past year to around 10 c/kWh. We expect other states to follow suit, as feed-in tariffs below the wholesale electricity price are clearly unfair to people with solar. (In WA, a similar rise in wholesale rates hasn’t occurred, but prices might still rise due to the state government winding back its subsidy of electricity prices.)

What this means for solar system sizing

Given these changes, if you’re planning a solar system, is it worth it to upsize from, say, 2 kW to 5 kW?

The extra panels will be relatively cheap but more of their generation will be exported, which doesn’t help the economics.For example, depending on household consumption, a solar system rated at 5 kW might export 80% of its generation. Electricity exported to the grid only earns the feed-in tariff, ranging from 5 c to 14 c per kWh, depending on your location and electricity plan. Solar electricity used on-site, rather than exported, saves you paying the grid tariff, typically around 20 c to 35 c per kWh.

Surprisingly, our modelling of the economics found that a 5 kW system now has a shorter or equivalent payback time to the 2 kW system. We studied the economics by simulating a large number of scenarios in half-hour intervals for a whole year using Sunulator, ATA’s free solar feasibility calculator.

Our primary economic measure is payback time, the number of years until bill savings recoup the installation cost—the fewer years the better. Payback times shorter than 10 years are generally considered attractive to solar customers, as the system is likely to pay for itself before any significant expenses, such as replacing the inverter. The panels should last at least 20 years, so cumulative bill savings are large, especially for a larger system.

To do the modelling, we assumed a feed-in tariff of 11.3 c/kWh in Victoria and in other states a doubling of feed-in tariffs from current levels, phased in over the next five years. We considered common grid tariffs in each capital city, for a variety of household consumption profiles, along with likely tariff increases (we used AEMO’s retail tariff forecasts, but since they were based on Hazelwood closing in 2020, which happened this year, we pulled them forward by three years; this allows for annual tariff rises between 1.5% for Queensland and 3.4% for Tasmania). Panels are assumed to be north-facing with a 20-degree tilt. Our analysis also includes panel degradation over time.

Read the full article in ReNew 140The full report on solar sizing, including references, is available at www.ata.org.au/news/bigger-solar-is-better-ata-report

 

3-phase

One phase or three

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If your home has a three-phase power connection, there are a few extra decisions to make when buying appliances, connecting solar or adding batteries. Lance Turner explains.

ALL AC grid electricity is generated using a three-phase system. Because of their relatively modest power needs, most homes are only connected to one of those three phases. However, some homes, such as those that have larger loads, and most commercial premises, have a three-phase electricity connection.

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Larger loads can mean that a single-phase connection would be heavily loaded at times. A three-phase connection may be used as it spreads the power draw across all three phases instead of just one. Interestingly, some homes are connected to just two of the three phases.

If moving your home from gas to all-electric, you may also consider upgrading an existing single-phase connection to a three-phase connection. For an energy-efficient home this shouldn’t really be necessary, but for larger homes or homes with a single large load such as an EV fast charger, an upgrade to a three-phase connection may be desirable or even necessary.

At the very least, smaller (40 amp) single-phase connections may need to be upgraded to something larger, such as an 80 amp connection. Any grid connection upgrade will usually require cables between the residence and the grid to be replaced, which can be expensive, depending on your energy company, location, cable installation type (overhead or underground) and length of cable back to the grid, and may run to several thousand dollars. Shifting from single phase to three-phase will definitely need cable replacement—each phase needs its own cable, and will also require a meter upgrade.

Having a three-phase connection to a home does allow for greater flexibility with appliance selection as you can use either single-phase or three-phase appliances as desired. If you are upgrading to a three-phase connection purely to install a large solar system, then the cost of the connection upgrade must be added to the system cost when factoring in system payback times.

Read the full article in ReNew 140.

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Product profile: Optimised solar panels

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Many solar arrays experience partial shading for part of the day—even a large bird dropping on a single solar panel can reduce that panel’s output considerably.

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Until recently the solution for optimising output has been to use either microinverters or solar optimisers on each panel—ie, optimisation at the panel level. Because solar panels have multiple separate strings of solar cells, optimising at the string level produces energy output improvements for panels experiencing shading on one of the strings, as the other two strings may be producing maximum output. With a panel-level optimised panel, the underperforming string will drag down the other two, but with a string-level optimised panel, the third string can be optimised for maximum total output.

Maxim Integrated has developed a small IC for string-level optimisation of solar panels. At least two manufacturers that supply the Australian market incorporate the Maxim optimisers into their panels—Jinko’s Smart Module and Trina’s Honey Maxim (pictured). These panels incorporate three optimiser ICs per panel, giving three separate strings that can be individually optimised.

RRP: POA. Jinko and Trina modules are available from numerous solar installers and are distributed by Krannich Solar (as well as some other distributors), www.krannich.com.au. Also see www.jinkosolar.com, www.trinasolar.com and www.maximintegrated.com

Read more product profiles in ReNew 140.

Longyangxia Dam Solar Park

Largest solar farm in the world

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Snapped by NASA satellite in January this year, the Longyangxia Dam Solar Park in China’s Qinghai province now lays claim to the title of ‘largest solar farm in the world’. Covering 27 square kilometres, the solar farm has 850MW of capacity and nearly 4 million solar panels, eclipsing the next largest in Tamil Nadu in India with a capacity of 648MW.

The NASA website describes the title of ‘largest solar farm in the world’ as “a rather short-lived distinction”: In 2014, the Topaz Solar Farm in California topped the list with its 550 MW capacity. They were edged out by Solar Star, also in California, at 579 MW in 2015. By 2016, India’s Kamuthi Solar Power Project in Tamil Nadu was on top with 648 MW of capacity.

As well as largest solar farm, in 2016 China got to claim the title of world’s largest producer of solar power. China’s total installed capacity doubled in 2016 to 77 GW, pushing them well ahead of Germany, Japan and the USA– though NASA notes those other countries produce more solar power per person.

The NASA post concludes: it’s unlikely that Longyangxia will remain the largest solar park in the world for long. A project under development in the Ningxia region in China’s northwest will have a capacity of 2000 MW when finished, according to Bloomberg.

More on this, click here

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“Heartening” doubling of Victorian feed-in tariff

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The ATA (ReNew’s publisher) has welcomed the Victorian Government move to more than double the minimum solar feed-in tariff . From 1 July 2017, the feed-in tariff for rooftop solar in Victoria will increase from 5 cents to 11.3 cents per kilowatt-hour, benefitting about 130,000 households. The change follows findings by the Essential Services Commission (ESC) in its report last year on the energy value of distributed generation.

“It’s very heartening for solar households in Victoria to have a government that is serious about renewable energy,” says Damien Moyse, the ATA’s policy and research manager. “We also congratulate the ESC for its work on the issue over the past 18 months.”

The ATA contends that solar households and businesses across Australia provide greater value into the national electricity market than the narrow methodology used to calculate feed-in tariffs up until now. The new feed-in tariff is closer to recognising the full value that distributed generation brings to our energy market, which is important as solar and other demand-side technologies continue to play a greater role in our energy mix.

We at both ReNew and the ATA would like to see other states following Victoria and accurately reflecting the value of distributed generation through their feed-in tariffs.

For analysis by Jack Gilding on the best range for feed-in tariffs, see here.

Battery installation at Stucco

Battery bounty: saving students money

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This innovative project is demonstrating how a solar + battery project can work for both the student tenants and the managing co-op in a low-income apartment complex in Sydney. Robyn Deed talks to the project managers.

GETTING buy-in from all the apartment owners on a solar project in a new apartment building can be hard, but make that a solar + battery project for an existing heritage building used for low-income student housing, and an extra level of energy and commitment is required. But the residents and researchers behind the Stucco Co-operative Housing project in Sydney’s inner-west have achieved just that with a 30 kW solar + 42 kWh Enphase battery installation designed to reduce the 40 student residents’ energy bills and provide a roadmap for other such projects.

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Why is solar so tricky for apartments? “The main issue is the ‘split incentive’,” says Bjorn Sturmberg, a former resident of Stucco and one of the project managers. If the apartment owner isn’t the tenant, there’s little incentive for them to pay to install solar when the savings will go to the tenant.

How to get solar onto more apartment buildings is an issue the City of Sydney is currently grappling with, so Stucco “hit the bullseye” says Bjorn, when they put in an application for funding to find an approach that would work for the complex of eight units—with the opportunity to research a significant battery storage installation also in their favour. The result was a grant of $80,000 matched with $50,000 from the Stucco co-op. For City of Sydney, the ‘return’ on their grant is a report on just what the barriers are and guidance on how to overcome them.

Read the full article in ReNew 139.

Bringing nature back

Sub-tropical build – Bringing nature back

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Richard Proudfoot and his partner have brought nature in to their suburban block, at the same time as reducing energy and water use. He describes their house and garden build, and the satisfying birdsong-filled results.

IN 2008 we sold our small cottage in inner-city Balmain, in Sydney, and moved to Bribie Island, just off the Queensland coast between Brisbane and the Sunshine Coast.

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Why a life on Bribie Island? My partner Fiona was born and raised near Royal National Park, just south of Sydney. I was born and raised in the Australian outback. We both appreciate the bush and as we neared retirement, we looked for a simple, sustainable life in a leafy setting. While we loved the inner Sydney vibe, it could never be called simple, and true sustainability was always going to be difficult to achieve.

Bribie also has arguably Australia’s best climate. In summer, the temperature rarely exceeds 29 °C, while in winter the temperature range is 15 °C to 25 °C, and annual rainfall is 1.2 metres. It is a great environment to use passive solar design techniques to build a sustainable, more self-sufficient house.

We bought an ordinary suburban (650 m2) block (of sand!), 200 metres from the beach, bordered by neighbours on three sides. Much of the time, a cool sea breeze from the Coral Sea blows across our block. The block runs east-west and has many mature trees on the back boundary.

 

So what kind of house to build?

Working closely with the builder, we came up with a design based on their classic Queenslander kit home. The house is elevated to catch the sea breeze and there is always cool air flow under the floor. It has verandahs on all four sides. It has high ceilings with a fan in every room, essential for sub-tropical days and nights. Most of the windows are north facing. There is very little glazing on the south and west sides, to provide maximum protection from the many storms which come in from the south-west. Every room opens onto a verandah, including the bathroom.

We wondered about building on sand, but our builder allayed our concerns. He used about one metre (depth) of concrete per footing. He couldn’t go much deeper because the water table starts about two metres below the surface. To date we have not observed any cracks in the walls, so our initial concerns appear to have been unwarranted.

Read the full article in ReNew 139.

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100% renewables – how feasible is it?

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With ongoing discussion by government and media about the effect of renewables on the grid, the ATA’s Andrew Reddaway and Damien Moyse consider the feasibility of 100% renewables for Australia.

THE ATA (ReNew’s publisher) supports a transition from fossil fuels to renewable generation in Australia’s electricity grid.
As well as being important to meet our international commitments to fight climate change, this brings other benefits such as improved local health outcomes, greater energy security and more jobs.

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However, as this transition progresses we must ensure the grid remains reliable and avoid economic hardship. How can this be achieved as we approach 100% renewables? This article considers the challenges of relying on intermittent generation, ways to address those challenges and a plan for moving forward.

Read the full article in this month’s longform.

Read more articles in ReNew 138.

credits-onshore-wind-turbine-franseska-mortensen-and-samso-energy-academy

Island of energy: community-owned and renewable

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Denmark’s Samso Island went from complete reliance on imported oil and coal to 100% renewable electricity in just a decade. Jayitri Smiles and Nicky Ison explore the community and government partnerships that made it happen.

DURING the global oil crisis in 1973, Denmark began to think creatively about how to supply cheap energy to their population. As they built their first wind turbine, they were unknowingly establishing themselves as future world leaders in renewable energy.

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Today, Denmark aims to have renewable energy powering 100% of their country by 2050 and to eliminate coal usage by 2030. These targets build on a track record of success: since the 1990s Denmark has witnessed the quadrupling of renewable energy consumption.

The creation of the world’s first fully renewable energy powered island, Samso, is an exemplar of Denmark’s leadership. Not only has Samso become a carbon-negative region, but it has accomplished this world-first using community investment.

In 1997, Denmark’s Minister for Environment Svend Auken was inspired at the Kyoto climate talks. He returned home with a passion to harness the collective efforts of local Danish communities in a way that promoted self-sufficiency in renewable energy. Auken held a competition, which encouraged Danish islands to consider how their clean energy potential could be achieved with government funding and matching local investment.

The most compelling application came from Samso, a small island west of Copenhagen with a population of 4100. This island of 22 villages, at the time run purely on imported oil and coal, was suddenly thrust into the global spotlight and, through a combination of local tenacity, investment and government funding, transitioned to 100% renewable power in just a decade.

At the heart of this energy revolution sit Samso’s community-owned wind turbines. Onshore turbines with a generation capacity of 11 MW offset 100% of the island’s electricity consumption. Another 23 MW of generation capacity from ten offshore turbines offsets Samso’s transport emissions. Most (75%) of the houses on the island use straw-burning boilers via district heating systems to heat water and homes, and the remainder use heat pumps and solar hot water systems.

The extraordinary result is a carbon-negative island and community. The island now has a carbon footprint of negative 12 tonnes per person per year, a reduction of 140% since the 1990s (compare this to Australia’s footprint of 16.3 tonnes per person in 2013 and Denmark’s overall footprint of 6.8). Not only is the island energy self-sufficient, they now export renewable energy to other regions of Denmark, which provides US $8 million in annual revenue to local investors.

And Samso is not slowing down. Highly motivated, knowledgeable and passionate locals are aiming for the island to be completely fossil-fuel free by 2030. They plan to convert their ferry to biogas and, despite already offsetting their vehicle emissions via renewable energy generation, residents of Samso now own the highest number of electric cars per capita in Denmark.

 

Read about their transition in ReNew 138.

tau-pv-project-2016

Islands in the sun (and wind)

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The idea of moving to renewable energy generation is proving attractive to many smaller communities, particularly island-based communities. Here are some of them.

Kangaroo Island: Currently powered by a 15 km undersea cable from mainland SA which is nearing the end of its design life, one option, moving the island to renewable energy generation, has been examined by UTS Institute For Sustainable Futures. The outcome of the study was that the cost of replacing the undersea cable would come in at $77 m whereas a local wind/solar/diesel hybrid system was estimated at around $87 m. However, once ongoing costs such as network charges are factored in, costs for the new cable option rise to $169 m, compared to $159 m for local supply. The system would likely include doubling the existing 8 MW diesel generation capacity, installing between four and eight wind turbines, adding five hectares of solar farm and around 800 solar rooftops. The end result would be 86% renewable and 14% diesel generation.
www.bit.ly/KangUTS100

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Isle of Eigg, Scotland: In 2008, the island’s electrification project was switched on, providing 24-hour power for the entire island. Previously, electricity had been provided by individual households using their own generators, resulting in excessive noise, pollution and high maintenance burdens on individuals. The project included laying of 11 km of cable and installation of three hydroelectric generators—100 kW at Laig on the west side of the island, with two smaller 5 to 6 kW hydros on the east side. Four small 6 kW wind turbines below An Sgurr and a 50 kW photovoltaic array round out the system. There are also backup generators for periods of low renewable input. To prevent overloading of the grid, each house has a maximum power draw of 5 kW, and 10 kW for businesses. When excess renewable energy is being generated, the electricity is used to heat community buildings.
www.islandsgoinggreen.org

Bruny Island, Tasmania: As looked at in ReNew 136, the CONSORT Bruny Island Battery Trial is an ARENA-funded project to install up to 40 battery systems on the island, with the view to stabilising the grid and reducing the use of diesel generation during the peak season. Households that participate in the trial will be provided with a large subsidy to install solar power and a smart battery storage system. They will also be able to sell their stored energy into the electricity market via Reposit Power. So far, the first round of participants have been selected. www.brunybatterytrial.org

Rottnest Island: The Rottnest Island Water and Renewable Energy Nexus project involves the construction of a 600 kW solar farm to complement the existing 600 kW wind turbine, which was installed in 2005 and already produces around 30% of the island’s electricity needs, saving more than 300,000 litres of diesel a year. The solar farm is expected to push the renewables portion to 45%, further reducing the need for diesel fuel. Funding for the project will be jointly provided by the Rottnest Island Authority ($2 m) and ARENA, which will provide $4 m. www.bit.ly/RottnestSust

King Island: The King Island Renewable Energy Integration Project (KIREIP) aims to increase the island’s renewable energy generation to around 65%, and up to 100% at times, while reducing the reliance on diesel fuel. By adding energy storage and energy flow control, the system allows greater contribution of power from renewable sources. Integration of smart grid technology provides the ability to control customer demand to match the available renewable energy supplies. The storage system, the largest electrochemical battery ever installed in Australia, is capable of producing 3 MW of power and storing 1.6 MWh of usable energy.
www.kingislandrenewableenergy.com.au

Island of Ta’u: The island of Ta’u in American Samoa lies around 6400 km off the west coast of the USA. Until recently it was entirely diesel-powered, with diesel being delivered by ship. Disruptions to deliveries had at times resulted in severe electricity restrictions—not great when you rely on electric pumps for basic water requirements. Ta’u now has a solar power and battery microgrid that can supply nearly 100% of the island’s electricity requirements from renewable energy. The new microgrid has all but eliminated power outages and greatly reduced the cost of providing electricity to Ta’u’s almost 600 residents. The system consists of a healthy 1.4 MW of solar generation capacity from SolarCity, which feeds into 6 MWh of grid-grade storage from Tesla (Tesla recently aquired SolarCity) consisting of 60 Tesla Powerpacks. The project was funded by the American Samoa Economic Development Authority, the US Environmental Protection Agency, and the US Department of Interior. It is expected to offset more than 400,000 litres of diesel per year.
blog.solarcity.com/island-in-the-sun

Read more in ReNew 138.

fronius-hybrid-diag

Just add batteries

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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.

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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

Tassie off-grid home

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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.

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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.

powerwall

Australia’s first Powerwall home

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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.

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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.

Fronius Primo 5.0 Single phase 5kw inverter_1

An inverter buyers guide

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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*).

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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
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

Renewable energy courses guide

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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.

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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.

Download the table of renewable energy courses here (130KB).

Read the full article in ReNew 137.

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Finding value in sharing

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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.

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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.

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From engineer to activist: a renewables industry is born

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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.

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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.

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Solar sells: Australian PV research and innovation

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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.

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

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

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

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

Read the full article in ReNew 136.

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ATA member profile: Making sinewaves in Australia

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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.

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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.