In ‘Batteries’ Category

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Store and deliver: Energy storage market heats up

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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.

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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.

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How green is my solar?

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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.

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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.

The system is entirely contained in one cabinet - except for the solar panels, of course!

Solar + battery trial in NZ

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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).

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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.

Motivations
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.

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

Off-grid wind and solar

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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.

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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.

PV panels - pvcycle

A recycling round-up

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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.

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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.

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

Farming Renewably: Reaping the benefits

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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.

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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.

 

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Going hybrid: Adding batteries to grid-connected solar

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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).

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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.

14-11-30 3 Batt charger inverter

Going off-grid slowly: a DIY project

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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.

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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?

First attempts

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.