Renew Magazine

The thought that, after my solar feed-in tariff ended in ten years, my system would become merely a cheap generator supplying all the local air conditioners at a profit to my power company annoyed me. Especially as I would have to fund any maintenance to the solar PV system from my pension.

So I decided not to invest further in additional grid-connect panels but rather, to put my dollars into making my home office totally independent of the grid. I built an off-grid solar power system with 12 volt battery storage, supplying a 240 volt inverter at the lowest cost possible.

Online shopping for parts
I sourced a pair of new 6 volt deep cycle lead-acid batteries from a local retailer. The brand was Interstate Batteries model GC2-HD-UTL, with a capacity of 216 amp-hours each. I purchased a 200 watt, 12 volt monocrystalline solar panel for $500 from eBay store LHP Power, which came with a 25-year warranty, and found a low cost 10 amp solar controller from a Chinese eBay supplier.

The solar controller has three sets of connectors, one for the PV panel, one for the load, and the third for the battery bank. The solar controller prevents overcharging the batteries, unwanted discharge of the batteries through the PV system at night, and disconnects the load to prevent battery damage if it becomes run down.

After purchasing a couple of low cost 800 watt 12-240 volt inverters from another Chinese eBay store I was ready to roll with my first system.

Photovoltaic panels produce electricity directly from sunlight in a solid-state process—there’s no moving parts to wear out, just large inert panels that have very long lifespans. The most popular use of PVs nowadays is to supplement mains grid power and reduce electricity bills. However, solar PVs have many other uses including to power off-grid houses, water pumping systems and remote communications systems, as well as in large commercial solar power installations.

The different technologies
There are three common types of solar cells: monocrystalline, polycrystalline and thin film.

Both mono and polycrystalline cells are made from wafers cut from blocks of silicon. Monocrystalline cells start life as a single large crystal known as a boule, which is ‘grown’ in a slow and energy intensive process. An example can be seen at right. Polycrystalline cells are cut from large cast blocks of silicon rather than single large crystals.

The cells are then modified by a process known as ‘doping’. This involves heating the cells in the presence of boron and phosphorus, which changes the structure of the silicon in such a way as to make it a semiconductor. This is the same method which is used to make integrated circuits.

Once the wafers have been doped, they then have a fine array of electrically conductive current-collecting wires applied to each side of them.

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

In recent years, other types of thin film materials have started to appear. These include CIGS (Copper Indium Gallium (di)Selenide) and CdTe (Cadmium Telluride). They tend to have higher efficiencies than amorphous silicon, with CIGS cells rivalling crystalline cells for efficiency.

The grid-interactive system was installed with future fires in mind, with a battery backup to ensure electricity supply during a blackout. The system now fulfils most of their energy needs in the new house, although the true status of their bill, and usage, remains a mystery due to Tru Energy’s long billing delays.

The improvements don’t stop there, with the entire rebuild showing a greater resilience to future bushfires with the bonus of improved energy efficiency.

Learning from the past

The old home was a single-storey brick veneer with a W-roof profile that Janet describes as a perfect ember trap, single-glazing to the west and was like an oven inside in summer. “We had a big wooden deck which probably went up in flames quite nicely. We knew it was a risk but we were a bit naïve perhaps and didn’t think a fire would come through, or that it would be that severe.”

After losing everything it was difficult to know where to start with rebuilding. Two things helped shape their rebuild though: a meeting with architect Ian Weir and visiting open days at other sustainable homes.

They’d first seen Ian on television and discovered that he offered free consultations to people affected by the Black Saturday bushfires. His advice was to keep the building shape as simple as possible with few nooks and crannies to limit the places for embers to gather.

Visiting a house in Healesville, Janet grew to love a unique construction duo of rammed earth and scyon, a thick but lightweight cement composite cladding which looks just like weatherboard. “The house felt solid and inside it felt grounded and safe.” The couple engaged the designer of that house for their rebuild, heeding Ian Weir’s advice to simplify the shape and opting for a flat, slightly angled roof profile that the embers would slide off. After all, the roof had been a weakness in the old house.

In reality, finding out how long a system takes to pay off is a complex equation. Location is one of the biggest variables, due to the differing levels of sunshine across this wide country. However, sunshine levels are probably more predictable than the other location-specific variable – the eight different feed-in tariffs across Australia’s states and territories. Darwin residents, for instance, enjoy the highest levels of sunshine in Australia, yet have no feed-in tariff to celebrate this rich resource. The ‘Sunshine State’ of Queensland, by comparison, currently has one of the highest feed-in tariffs available.

Then there is the question of the up front Federal Government incentive, the Solar Credits Scheme. Did you manage to access the five-times multiplier for your STCs (Small-scale Technology Certificates), or did you miss out and only receive an STC multiplier of three, thinking that it was only meant to drop to four in mid-2011 anyway?

In February this year the Alternative Technology Association’s Energy Policy Team crunched the numbers on just how long a standard 1.5kW grid-connect solar power system would take to pay off around the country. The study was carried out in the midst of a solar installation boom, spurred on by the Federal Government Solar Credits Scheme, where households were able to receive five times the amount of STCs that their system generates. At the time, many states had strong feed-in tariffs, with a number of these being gross, including NSW and the ACT, with 60c/kWh and 45.7c/kWh paid to solar households for all their electricity generated. With estimated payback times as low as four years in New South Wales at the time, it’s little wonder solar power systems were in demand.

Only six months later ATA’s Solar Payback Calculator has been revised showing a significant increase in the payback time of grid-connect solar power systems in most states.

What’s happened?

Since the beginning of 2011, feed-in tariffs in SA, WA, NSW and ACT have been reduced or scrapped, with at least one other state currently considering its feed-in tariff options. Last year these governments were applauded by clean energy advocates for their progressive solar feed-in tariffs. In turn, payback times in these states have increased by up to 15 years, while the reduction in the Federal Government’s Solar Credits STC multiplier from five to three means payback times in all states have increased.

In February a 1.5kW grid-connect solar power system installed in the ACT had an estimated payback time of five years based on a gross feed-in tariff of 45c/kWh and a STC multiplier of five. The scheme is now closed to new customers so the same system could take over 20 years to recoup.

Similarly, in NSW the payback time has increased from around three to four years under a 60c/kWh gross feed-in tariff before the mid-year STC multiplier drop, to in excess of 20 years today with the closure of the feed-in tariff.

Payback times are expected to increase to at least 11 years in SA with feed-in tariff changes in October. In WA, the net feed-in tariff of 47c/kWh reached its capacity and was closed to new applications. Electricity retailer Synergy will pay a 7c/kWh hour net feed-in tariff to WA customers under that state’s Renewable Energy Buyback Scheme, yet payback times for new customers will be around 20 years.

Where’s the potential?

Victoria, Alice Springs and Queensland currently offer feed-in tariffs to new customers in the 45c/kWh to 66c/kWh range, with payback times around seven to eight years on a 3kW system, based on only exporting half the electricity produced to the grid. Increase that grid export to 75% and a system in Queensland might pay back in six years.

The last six months show that feed-in tariffs can change overnight, so get in quick. In fact, ATA’s Solar Payback figures for Victoria include a second, lower feed-in tariff of 23c/kWh, which has been in place for many years now and will hopefully remain in place, despite potential changes to the premium tariff of 60c/kWh.

Price of PV

Ultimately one of the biggest factors in payback time will be the price paid for a system. While feed-in tariffs are disappearing, the retail price of a solar power system looks set to drop, says ATA Energy Policy Manager Damien Moyse.

“PV prices are one of the good news stories with regards to this technology. The history of solar PV prices over 30 years has seen a halving of system price with every doubling of global installed megawatts. The current word from China, where most panels are currently manufactured, is that global silicon prices are likely to drop again in 2012, meaning that off-the-shelf prices for solar PV systems should again reduce further next year.”

The STC factor

Household solar prices are also affected by the STC price paid as part of the Solar Credits Scheme. To make it easier for everyone selling and buying a small-scale renewable energy system, the Federal Government fixed the STC price at $40. Yet, the price the consumer receives is actually less than that, probably closer to mid to low $20s and unfortunately this is unlikely to increase.

“The large electricity retailers, who buy the certificates direct from solar PV installation companies, use their significant purchasing power to offer these companies faster purchasing, but at a much reduced price than the $40 stipulated by government. Given the unwillingness of the Federal Government to force electricity retailers to purchase only through the dedicated STC ‘Clearing House’, it is unlikely that consumers will see prices close to $40 per certificate any time soon,” says Damien.

Does it matter?

To make a system pay off earlier, as always, it comes down to how energy efficient your home is in the first place. “Reduce your electricity consumption first, then install a small PV system. Get your consumption down to less than 10kWh per day and then all you need is about a 1.5kW system,” says Damien.

Most people investing in household solar have already travelled the energy efficiency path and are switching to solar to help the environment, not for financial reasons. ATA member Stephen Whately says: “We don’t need to justify the payback times of our cars or holidays, why should you justify sustainable improvements to the home?”

In other words, don’t dwell too long on ATA’s latest solar payback modelling below, the figures are likely to change, and solar households are in it for the love, not the money.

Solar Payback Calculator

Assumptions

The calculations above are based on the following details.

Size and Price
• System size: 1.5kW and 3kW
• Installed cost, fully installed, before value for STCs is recouped: $4.50 per watt, or $6750 for a 1.5kW system
• System Retail Price to customer. This is calculated using the Capital City STC Zone. In SA for instance, a system is expected to produce 31 STCs over 15 years. Multiply this by the Solar Credits multiplier of three to get 93 STCs worth $2325. This makes the retail price in SA $4425 for these calculations.

Small-scale Technology Certificates (STCs)
• STC price for above modelling: $25
The fixed $40 price for STCs from small renewable energy systems is the price that liable parties (i.e. electricity retailers) are mandated to purchase these certificates for. The actual price received by the end PV consumer is currently significantly less than $40 due to off-market transactions established between certificate traders and liable parties that occur outside the SRES ‘Clearing House’, which provide greater liquidity to solar PV suppliers /installers but less value to the end consumer.
• STC multiplier: x 3 for first 1.5kW of system size (current from 1 July 2011).

PV Generation
• System degradation rate: 0.5% per annum
• 20% generation losses are accounted for within the PV system
• Panels are assumed to be unshaded, facing north and tilted at the latitude angle ± 5 degrees. Generation from panels not within this optimal range would need to be derated to account for lower generation
• PV generation has been defined using Peak Sun-Hours (PSH) as defined by the Bureau of Meteorology (1990-2008 averaged data, converted to tilted angle of panels, tilted to latitude angle). The final ranges within each are attributable to there being more than one PSH zone within that state, with the lower end of the range reflecting the PSH zone for the capital city and the higher end of the range being reflective of regional locations with reasonable population density. Annual generation for the two locations within each state are calculated using the formula:
Annual generation [MWh] = System Size [kW] x PSH x 365 x (100% – Generation Losses) / 1000
Where: Generation Losses was 20%.

The results for capital city and regional locations are presented as a payback period range in each scenario in the tables. As it turned out, for all states, the longer payback period in the range for each scenario represents the capital city for that state.

Feed-in Tariffs (FiTs)

FiT rate assumptions are outlined in the second column of the tables.

NSW: Given the NSW FiT was scrapped for new entrants in June 2011, ATA has modelled three scenarios for NSW; one involving the original rate (60c/kWh); one using the interim rate (26c/kWh); and one involving no FiT.

SA: Given the recent changes to the FiT scheme in the South Australian Parliament, ATA has modelled two scenarios for the SA FiT; the first involving the original rate of 44c/kWh (due to cease for new entrants on 1st October 2011); and the second involving the adjusted rate from the 1st October 2011 of approximately 22c/kWh (16c/kWh plus retailer ‘fair and reasonable’ contribution for the value of the electricity).

ACT: Given the cancellation of the ACT FiT in early 2011, ATA has modelled two scenarios; the first involving the original rate (i.e. 45c/kWh), and the second involving no FiT.

VIC: Given the uncertainty around the future of the Victorian Premium FiT, two scenarios have been modelled; the first involving a Premium FiT of 66c/kWh, with the second involving the traditional standard FiT of 23c/kWh (in case the Premium FiT is soon closed).

WA: Given the recent closure of the WA government FiT scheme, two scenarios have been modelled; the first involving the previous total rate of 47c/kWh, with the second involving only the ‘Synergy’ buyback rate of 7c/kWh.

Other Model Assumptions
Electricity export rate

For net feed-in tariff jurisdictions (NT, QLD, SA, Tasmania, Victoria and WA), ATA modelled two scenarios assuming a household exports 50% and 75% of the total electricity generated from their solar PV system into the grid.

For gross feed-in tariff jurisdictions (NSW and ACT), ATA modelled 100% export of the total electricity generation from their solar PV system into the grid.

Zones

The following Zones were used for the purpose of STC calculation:
• NT: Zone 1 to 2
• QLD: Zones 1 to 3
• SA: Zone 3
• Tasmania: Zone 4
• Victoria: Zone 3 to 4
• WA: Zone 2 to 3
• NSW: Zone 3
• ACT: Zone 3

Value of grid electricity

See electricity price column. The ATA’s calculations assume a 5% increase in retail electricity prices, yet it could be higher. If grid prices go up, you’ll pay back a system in a net feed-in tariff zone faster. This is irrelevant in gross feed-in tariff states, as you are not offsetting your household consumption with your PV generation in a gross metered situation.

• The inverter is replaced after 15 years at a cost of $900 per kW.
• Discount rate: 6%. This is an allowance for the reducing value of money over time.

Article by Jacinta Cleary. Solar Payback Calculator and assumptions by Damien Moyse and Dominic Eales of the ATA Energy Policy team.

This article appears in ReNew 117.

But there is another way.

Woodlawn Bioreactor

It’s not perfect but it’s an option that is better for the environment and can also be used to produce electricity. It’s called a bioreactor and is more than just theory: a bioreactor is currently being used to dispose of 400,000 tonnes per year of Sydney’s garbage.

Located near Goulburn in New South Wales, the Woodlawn Bioreactor is run by Veolia Environmental Services. Based on a disused open cut mine, the 6000 hectare site is currently being used to dispose of municipal waste and generate electricity. Aquaculture and horticulture facilities are in trial phases.

The site was originally a copper, lead and zinc mine with major open-cut and underground mine workings. The mine closed in 1998 and Veolia took over the lease for the site in 2004. In addition to the workings, the site is extensively degraded with large tailings dams and unvegetated areas that once housed crushers and other industrial facilities. The underground shafts are abandoned but the huge 25 million cubic metre open-cut pit is being used as the new rubbish repository.

But how does the garbage get to the Woodlawn site, 250 kilometres from Sydney? The major transport component is by train. The garbage is compacted into purpose-built shipping containers at Clyde Transfer Terminal in Sydney. Each container takes the equivalent of three garbage trucks of material. The containers are then placed on railway wagons—no less than 56 of them carrying 1500 tonnes of waste per train.

The train, hauled by three diesel locomotives, leaves Sydney early each week-day morning, arriving at the Crisps Creek Intermodal Transfer Station, near the hamlet of Tarago, at 6am. At the transfer station, built specifically for the bioreactor, large forklifts place the containers on trucks that transport the garbage to the bioreactor, about 10 kilometres away.

Read the full article in ReNew 114

The inquiry

The Social and Economic Impact of Rural Wind Farms Senate Inquiry was launched last year by departing Family First Senator Steve Fielding, in response to claims people were suffering adverse health effects from living too close to wind farms.

“There is an obvious cluster of health issues ranging from sleep disturbance, headaches, and problems with concentration and memory in the Waubra area,” he said when seeking community support for the inquiry last year.

“Once we know what we’re dealing with then development can continue under new guidelines…given the mounting physical evidence from those living near wind farms I think it’s only fair for the Parliament to have a look at what is happening.”

The senate inquiry aimed to examine any adverse health effects for people living close to wind farms, concerns over excessive noise and vibrations emitted by wind farms which are close to people’s homes, the impact of rural wind farms on property values, employment opportunities and farm income, and the interface between Commonwealth, state and local planning laws as they pertain to wind farms.

The issues

Although there are four distinct questions listed above, the most divisive and controversial issue surrounding the Australian wind industry today is the health debate. The vast majority of people who live near wind turbines feel fine, but some people who live near wind turbines feel ill. A lot of the controversy has originated near the Waubra Wind Farm in Central Victoria, where a number of local people have formed a group called the Waubra Foundation and have appointed a medical director, Dr Sarah Laurie.

Many scientists in the international community have written about the audible and low-frequency sounds emitted by turbines and how they do not affect people’s health. However, there is no denying that some people are genuinely ill, and so the senators rightly began asking questions.

What is infrasound?

Audible sounds are vibrations carried through air or other media to your ears. Human ears can generally detect vibrations between the frequencies of 20 Hertz (Hz), the equivalent of 20 vibrations per second, and 20,000 Hz. Infrasound is sound that is lower in frequency than 20 Hz.

Infrasound can be caused naturally by severe weather, surf, earthquakes, volcanoes and waterfalls among other sources. Infrasound can also be generated by machinery such as diesel engines and wind turbines and by large subwoofer loudspeakers.

An independent Australian report was commissioned by Pacific Hydro and written by acoustic consultant Sonus in November 2010. The report concluded that wind turbines do generate infrasound, however, it is well below the levels allowed by established guidelines. These levels were measured both outside and inside at a variety of distances significantly less than separation distances between wind farms and houses. They also noted that infrasound levels measured in both a rural coastal and an urban environment are of the same order as levels measured within 100 metres of a wind turbine.

Submissions

The Senate received over 1017 individually written submissions and 1154 form letters (all of which were positive). Of the individual submissions, 535 were pro-wind power, 468 were anti-wind power and 14 were neutral. Many of them were written by individuals but others were written on behalf of organisations with an interest in either promoting or resisting wind farms. There were even submissions from international anti-wind farm groups such as The Alliance to Protect Prince Edward County (submission 24), a citizens’ advocacy group in Ontario Canada whose stated mission is to “challenge wind energy development” in that province.

One of the most famous international wind farm sceptics is Nina Pierpont (submission 13), an American doctor who self-published the book Wind Turbine Syndrome. Dr Sarah Laurie refers to Pierpont’s work in her submission (390) and says: “There is an urgent need for further independent medical, acoustic and scientific research, looking specifically at the populations affected by the currently constructed and operating wind developments in Australia.”

Mr Noel Dean, a farmer from the Waubra area, writes in his submission (647) that “[o]ur health, emotions, finances, sense of well being and quality of life have suffered enormously because of the operation of the Wind Farm.”

There were also many submissions from supporters of wind energy, including Codrington Wind Farm Tours (597): “Noise is possibly the principal issue discussed in the media, to an extent that it has reached ‘urban myth’ proportions! One consequence however, is that when people actually visit the wind farms and discover the lack of noise, they tend to become cynical of other information from the media and realise that much of the negativity around wind farms may not be accurate,” they wrote.

Dr Peter Seligman, who was a member of the team that developed the Australian Cochlear Implant, also made a submission to the inquiry (353). “It is not doubted that under some conditions wind farms can be heard at a distance. It is unlikely that any vibration can be felt at a distance. As far as infrasound is concerned, the body is naturally exposed to high levels from internally generated sources,” he wrote.

In my own submission (273) I mentioned research by The American and Canadian Wind Energy Associations who established a scientific advisory panel comprising medical doctors, audiologists and acoustic professionals from the US, Canada, Denmark and UK. The panel concluded that ‘wind turbine syndrome’ is not a recognised medical diagnosis but rather reflective of symptoms associated with annoyance. Factors culminating in annoyance include the nocebo effect defined as “an adverse outcome, or worsening of mental or physical health based on fear or belief in adverse affects.”

The Senate Panel Hearings

Having received hundreds of written submissions, the Senate Community Affairs Committee hit the road to meet with people and hear their thoughts first hand. There were four panel hearings held in Canberra, Ballarat, Melbourne and Perth in late March. I was fortunate to attend hearings in both Ballarat and Melbourne, which both had a very different atmosphere. The transcripts of the presentations are available online at the inquiry website.

Before arriving at the hearing I prepared a few dot points for my chance to speak. I started with the standard comment that wind farms are a progressive and clean energy technology that needs community support for Victoria to meet its renewable energy targets. I also touched on my thoughts on the health debate, which are that turbines themselves do not directly cause illness but that unwanted development, combined with inadequate community consultation had created fear and anger that was causing illness.

When I arrived I was genuinely surprised by the amount of emotion in the panel hearing room, and after half an hour of listening to people share their experiences of illness, I completely changed my mind on my own presentation. The people in the room were genuinely distressed.

Rather than speaking about illness from the point of view of a pro-wind city-based observer, I decided to keep my three-minute time slot entirely personal. Instead I spoke specifically about why I work in the wind industry and how I had attended the Hepburn Wind turbine construction picnic only days earlier. I told the senators how I had seen an example of a wind farm being joyous, inclusive and beneficial for the local community—very different from the accounts being heard that day.

The next day in Melbourne the mood was entirely different, and distinctly less emotional. As well as wind farm developers, there were presentations from the Clean Energy Council, Friends of the Earth, the Country Fire Authority and Hepburn Wind.

The health debate continued with further input from Dr Sarah Laurie. “There is absolutely no doubt that these turbines, particularly at some developments, are making nearby residents very sick, and that their symptoms worsen over time. This is resulting in people abandoning their homes and farms, if they can afford to.”

Professor Simon Chapman, (submission 605) from the University of Sydney’s Public Health Department, spoke as a representative of the Climate and Health Alliance. “There is always a relationship between energy supply and health, but these impacts are different depending on the type of energy supply. For example, there are obvious health effects from nuclear, that we are seeing played out in Japan at the moment; we are not going to spend time talking about them today. Coal, which contributes a lot of the current energy supply, makes a definite contribution to death and disease. Then we can look at renewables, like wind, which have the least impact of those three and a very small health impact compared to the others,” he said.

Professor Chapman also criticised Nina Pierpont’s wind turbine syndrome research on the basis that it lacked scientific rigour. He said that Dr Pierpont “has not done any research which has been published in peer-reviewed journals”, and that “she has produced case reports on just 10 families…my understanding is that there are something like 100,000 turbines worldwide. So the first observation I would make is that interviewing 10 families is a sample of such low representativeness…it is incredibly small.”

The Senate’s report

The Senate Committee’s final report into the Social and Economic Impacts of Wind Farms was released last week, after two extensions due to the large volume of material submitted. The report states seven recommendations, which cover noise, health and complaints processes.

On the topic of noise, the report recommends that National Acoustics Laboratories conduct studies into the noise and infrasound impacts of wind farms, and noise standards for planning should include calculations of low frequency noise and vibrations indoors at impacted dwellings.

Regarding complaints processes, they suggest that responsible authorities should ensure that complaints are dealt with expeditiously and processes should involve an independent arbitrator.

Regarding health, the report recommends that the National Health and Medical Research Council should continue to review the research into wind farm health effects. They say the Commonwealth Government should undertake studies into the effects of wind farms on human health, and the National Wind Farm Guidelines should be redrafted to include any adverse health impacts found. They also recommend that further consideration be given to the development of policy on separation criteria between residences and wind farms.

The wind industry and environment organisations have generally received the report positively. Further studies are encouraged as it is anticipated that they will arrive at the same conclusions as the international studies; that is that wind farms do not affect human health.

Clean Energy Council Policy Director Russell Marsh said the report raised some issues to consider, but it was critical the industry got on with the job of building clean energy in Australia. “The Senate inquiry process was a way for the silent majority of wind farm supporters to have their voices heard,” he said.

Friends of the Earth campaigner Cam Walker pointed out the many positive aspects of the report: “The committee should be commended for their careful and balanced approach to this issue. They have considered the complaints put forward by a small number of people living near wind farms, but balanced this against the weight of scientific evidence that wind farms have no proven adverse health impacts on people living nearby.”

The Herald Sun even ran an article Wind farms’ noise found to be safe which stated “A senate committee has been unable to establish a direct link between ill health and the noise generated by wind farms.”

The setback issue is of particular interest in Victoria where Planning Minister Matthew Guy has stated an intention to give residents within 2kms of any wind farm development a right to veto. The Senate committee comment on page 20 of the report that “A difficulty with a prescribed setback distance is that, in term of noise and shadow flicker, the distance may either be too great or too little. If the setback is too great then this could limit the industry and possibly affect the amount of renewable power generation in Australia. If the distance were too little, residents affected adversely would not have any redress’.

“We’re pleased that the committee did not support a mandatory setback distance around wind farms, calling them arbitrary and saying it’s preferable to decide setback distances using scientific measurements of sound effects,” says Cam Walker. The Victorian Government should listen to this advice, and drop its proposed mandatory 2km exclusion zone around wind farm developments.”

My thoughts
While there is widespread international and Australian scientific evidence that wind turbines do not directly affect human health, there is no denying that there are a small number of health problems in rural Australia.

As I understand the issues, it appears that a lack of understanding of the nature of noise, vibrations and health is creating fear among some members of the community. It also appears that there are problems that need to be addressed in the way that community consultation is undertaken. It’s my hope that the outcomes of this inquiry will result in reassuring communities of their safety while also addressing the development processes that have arguably contributed to distress among a few community members.

Alicia Webb works in the wind industry however she attended the Senate Panel Hearings independently and these opinions are her own.

More information
The Social and Economic Impact of Rural Wind Farms website
Pacific Hydro Wind Farm Infrasound Report
Canadian Wind Energy Association Report on Wind Turbine Sound and Health Effects

This article was first published in ReNew 116

The nickel metal hydride battery packs that came with the drills had been given a good run already and refused to accept charge after I’d used them for about a year. My preferred replacements, lithium ion batteries, would have cost so much that I could have purchased a whole new drill with new ni-cad batteries. This option being against my principles—I wanted to keep these perfectly functional drills working—I ended up buying two NiMH batteries online at a competitive price.

Two years of drilling went by and my replacement NiMHs were suffering the same fate. Using any one of four similar chargers, the charging period would only last for 15 minutes or so. Lifting the battery up and dropping it into the charger again soon became futile.

I decided to have a go at charging the batteries using solar power. A couple of years ago I was the happy winner of a 17 volt, 20 watt solar panel in ReNew’s Sustainable Sheds competition. [Ed note: read all about John’s super sheds in ReNew 107.] The output terminals of this panel were connected to the positive and negative terminals of the NiMH battery packs. They were given just a few hours each of high quality East Gippsland sunshine and wow, they have all taken the charge, although admittedly at less than their initial capacity. I now have four very functional battery packs again. The solar panel puts about one amp into the battery, so the 3Ah battery needs a good three hours to complete its charge. I’m a little unsure how the battery will respond to being left on the solar charger all day, such as if you fail to time it right. I try to start the charge mid afternoon, so the fading light tapers the charge.

Thanks ATA—what a saving in cost and resources!

Crank it up
For hot water, the Your Home Technical Manual for example suggests to tilt the (north-facing) solar panels at an angle corresponding to the latitude of the location and “in some cases, it may be desirable to increase the angle somewhat to improve winter performance and reduce overheating in summer”. Despite this, it’s uncommon in my experience to see solar collectors tilted above 35°.

My interpretation of the situation is that it’s more than merely “desirable in some cases”—it’s really important to increase the tilt of solar collectors for hot water, but not PV. To appreciate why, we need to recognise the key difference between solar hot water and solar PV, namely, that solar hot water systems cannot make use of their surplus energy. Indeed excess summertime solar gain can be a problem as discussed in ReNew 113 (DIY Solar Hot Water Cover page 72). On the other hand, urban PV systems have the benefit that excess generation is simply exported to the grid.

Grid-connected PV systems are best configured for maximum annual solar gain. However, we need to apply a different rule of thumb for hot water—to configure for the maximum number of days with sufficient solar gain. This means cranking up the solar collectors to a much steeper angle. This is done to maximise solar gain in winter and to help reduce overheating problems in summer. To optimise for winter noon, the angle should be latitude plus 23.5°, which in Melbourne is 61°. Given that the angle of the sun is lower than its noon angle for most of the daylight hours, it follows that the collector angle should be even a little higher than this. I chose to tilt my collector at 64° from the horizontal.

Western Australia is thought to be an ideal geological location for developing local geothermal energy, with a number of geothermal exploration projects already planned for some areas.
There are also several examples of smaller urban projects which are attracting a wider interest in geothermal applications, such as the use of geothermal energy to heat five community pools and leisure centres in Perth.

Pools are particularly suited to geothermal heating, which not only benefit from a constantly available heat source, but also from significant savings in operating costs and carbon dioxide emissions due to less reliance on fossil fuel.

Aimed at scientists, technical experts, policy makers and potential end-users, the WAGES event will be supported by the West Australian Geothermal Centre of Excellence and will feature international guest speaker John Lund, who has over 30 years experience in the geothermal industry and is one of the world leaders in direct use applications and ground-sourced heat pumps.

The conference will also feature technical sessions on direct use geothermal applications and ground-source heat pumps, while other sessions will seek to provide a forum on issues critical to the success of the industry.

For more information go to www.wageothermalsymposium.com.au. ReNew is pleased to be a supporter of this event.

Agriculture is one such example. Agriculture contributes 16% of Australia’s gas emissions, second only to the energy sector (75%). Of this 16%, livestock contribute to about 70% of Australia’s agricultural emissions. The predominant livestock emissions are enteric fermentation (fermentation that takes place in the digestive system of ruminants) and manure.

Between 1990 and 2007, livestock related emissions declined by 7.5%. This reduction was predominantly a function of changes in stock numbers due to the fluctuating market, rather than smarter farming techniques to reduce emissions. Therefore, an upward trend in the ruminant industry is likely to increase the number of animals, and hence emissions.

To support world populations, the agricultural industry will continue to grow. And as such, emissions are expected in increase. Although Australia’s population is declining, other populations such as China, Mexico and the United Arab Emirates are expanding. And it is these countries which buy our produce. Whilst agriculture in Australia only accounts for 3% of the GDP, agriculture accounted for 35% of Australia’s merchandise exports from 2004 to 2008, compared to imports a fifth of this value.

Smarter farming
Increasing agricultural production doesn’t necessarily mean clearing more land for farming, but smarter farming techniques. Maximising production, increasing yield and above all, sustainable agriculture. Sustainable farming has been, in some minor form, a part of agriculture since agricultural practices began. The technique of inter-cropping to stave off weeds and pests was at the forefront of native American agriculture. Yet the importance of the techniques and intense research have only been the focus for the last 30 or so years.

Today, common and simple measures such as fallow stages, crop rotation, planting of leguminous crops, no-till farming, retention of native vegetation, water use efficiency and stubble retention are widely adopted practices halting the demise of the already degraded Australian land. These initiatives are, for the most part, easily adopted with little cost to the producer.
But there are newer technologies making their way onto the world’s technology carpet.

Anaerobic digestion is just one example. Anaerobic digesters essentially work by reducing waste to gas, solids and liquid stream. During  anaerobic digestion, aerobic micro-organisms ferment biodegradable matter to a variety of usable products, the most popular the biogas mixture of methane and carbon dioxide.

The use of this technology is becoming more popular, particularly in the United States and Europe, where below freezing temperatures cause a sizeable electricity bill. With the ability to not only produce their own heat and power, but to also sell excess power back to the electricity company, anaerobic digesters are gaining considerable favour.

The beauty of the process is that each of the by-products can be utilised in some way. Biosolids can be used for bedding or as a soil amendment, and the liquid stream as a fertiliser or if treated, for animal consumption. As the process removes the odour from the waste, the solids and liquid stream can be spread during the warmer summer months without the resulting unpleasant smells. Finally, if production is on a large enough scale, the process can provide enough biogas power to run the property. In the case of excess, this can be sold back to the power company for a profit.

The biogas produced offsets carbon dioxide emissions by displacing fossil fuel combustion i.e. reducing the dependence on fossil fuel for energy. As with any alternate energy, anaerobic digestion reduces the use of the finite and continually depleting fossil fuel stores.

Berrybank Farm Piggery, Victoria, is home to 15,000 pigs, producing 275,000 liters of sewage effluent each day. After installing a Total Waste Management System in 1989, the farm is now saving $435,000 a year by converting the effluent into biogas and fertiliser.  The process consists of seven steps, from waste collection to biogas conversion to heat and electricity.

Once collected, the waste is subjected to sedimentation to remove grit, thickened, then sent to the primary and secondary digesters. Here the waste is broken down into the gas, liquid and solid forms. Scrubbers, trappers and dehumidifiers then remove sulphur from the biogas, before it can be used for electricity and heat. Through this process, Berrybank Piggery produces a daily output of 2900 kW of electricity, equivalent to $125,000 per year.

An example of outputs and use from anaerobic digestion

Why such a low uptake?

As a seemingly self-sustaining process, the question persists—why doesn’t every ruminant property in the country have a digester? The high initial cost is probably the biggest factor holding back this technology. The capital start up required is close to $400,000, not including the costs of maintenance and general day to day running expenditures. Berrybank Piggery spent $2 million dollars setting up their Total Waste Management System. However the costs can be recovered in as little as five years, providing the scale of operations is large enough.

Risk is the second critical issue with the technology. Biogas produced is typically 40% methane and 60% carbon dioxide, but small amounts of water vapor, hydrogen sulfide, carbon monoxide and nitrogen are also produced. As biogas does not contain any oxygen, asphyxiation is a potential danger, as well as the danger of fire and explosion. The hydrogen sulfide converts to corrosive sulfuric acid at low temperatures, and engines must be designed accordingly to cope. And overall, it’s a biological process. Changes in the system, such as animal feed, can upset the process.

Anaerobic digesters are not suitable for every ruminant enterprise. The system relies on waste being easily available. In intensive enterprises, such as feedlots, where waste is easily collected from the one point source, the labour required to run the digester is minimised. However if the animals are kept across a vast area of land, collation of waste will be labour intensive.

Naturally occuring process

The concept itself is not new. Anaerobic digestion is a process which occurs naturally, and is well known in the bottom of ponds or lagoons. The process has also been used for over a century to process sewage biosolids. As such, anaerobic digestion is not limited to ruminant farm use. Any composting can be essentially utilised for biogas production, from vegetable and wine process, other livestock such as chickens and pigs and municipal waste.

Though relatively unknown now, anaerobic digesters, in some form, are filtering their way into the Australian market. For now, yes, it’s expensive, but the same thing was said about solar panels 40 years ago. Further research and development fine tunes the processes and technology, resulting in a safer, cleaner and often less expensive product.

A good diet…

There are other methods available to reduce livestock gas emissions, such as controlling diet quality and quantity. The higher the fiber content of the feed, the higher the gas emissions. Cattle grazing low quality pasture are likely to emit higher amounts of methane and cattle on greener higher quality pasture. This highlights the importance of high quality agriculture, and sustainable farming to maintain quality land.