You live in one of the sunniest countries in the world. You might want to use that solar advantage and harvest all this free energy. Knowing that solar panels are rapidly becoming cheaper and have become feasible even in less sunny places like the UK, this should be a no-brainer.
Despite this, the Australian government has taken a step backwards at a time when we should be thinking 30 years ahead.
Further reading: Will the national energy guarantee hit pause on renewables?
Can we do it differently? Yes, we can! My ongoing research on sustainable urbanism makes it clear that if we use the available renewable resources in the Sydney region we do not need any fossil resource any more. We can become zero-carbon. (With Louisa King and Andy Van den Dobbelsteen, I have prepared a forthcoming paper, Towards Zero-Carbon Metropolitan Regions: The Example of
Sydney, in the journal SASBE.)
Enough solar power for every household
Abundant solar energy is available in the Sydney metropolitan area. If 25% of the houses each installed 35 square metres of solar panels, this could deliver all the energy for the city’s households.
We conservatively estimate a total yield of 195kWh/m2 of PV panel placed on roofs or other horizontal surfaces. The potential area of all Sydney council precincts suited for PV is estimated at around 385km2 – a quarter of the entire roof surface.
We calculate the potential total solar yield at 75.1TWh, which is more than current domestic household energy use (65.3TWh, according to the Jemena energy company).
Wind turbines to drive a whole city
If we install small wind turbines on land and larger turbines offshore we can harvest enough energy to fuel our electric vehicle fleet. Onshore wind turbines of 1-5MW generating capacity can be positioned to capture the prevailing southwest and northeast winds.
The turbines are placed on top of ridges, making use of the funnel effect to increase their output. We estimate around 840km of ridge lines in the Sydney metropolitan area can be used for wind turbines, enabling a total of 1,400 turbines. The total potential generation from onshore wind turbines is 6.13TWh.
Offshore turbines could in principle be placed everywhere, as the wind strength is enough to create an efficient yield. The turbines are larger than the ones on shore, capturing 5-7.5MW each, and can be placed up to 30km offshore. With these boundary conditions, an offshore wind park 45km long and 6km wide is possible. The total offshore potential then is 5.18TWh.
Altogether, then, we estimate the Sydney wind energy potential at 11.3TWh.
Turning waste into biofuels
We can turn our household waste and green waste from forests, parks and public green spaces into biogas. We can then use the existing gas network to provide heating and cooling for the majority of offices.
Biomass from domestic and green waste will be processed through anaerobic fermentation in old power plants to generate biogas. Gas reserves are created, stored and delivered through the existing power plants and gas grid.
Further reading: Biogas: smells like a solution to our energy and waste problems
Algae has enormous potential for generating bio-energy. Algae can purify wastewater and at the same be harvested and processed to generate biofuels (biodiesel and biokerosene).
Specific locations to grow algae are Botany Bay and Badgerys Creek. It’s noteworthy that both are close to airports, as algae could be important in providing a sustainable fuel resource for planes.
Using algae arrays to treat the waste water of new precincts, roughly a million new households as currently planned in Western Sydney, enables the production of great quantities of biofuel. Experimental test fields show yields can be high. A minimum of 20,000 litres of biodiesel per hectare of algae ponds is possible if organic wastewater is added. This quantity is realisable in Botany Bay and in western Sydney.
Further reading: Biofuel breakthroughs bring ‘negative emissions’ a step closer
Extracting heat from beneath the city
Shallow geothermal heat can be tapped through heat pumps and establishing closed loops in the soil. This can occur in large expanses of urban developments within the metropolitan area, which rests predominantly on deposits of Wianamatta shale in the west underlying Parramatta, Liverpool and Penrith.
Where large water surfaces are available, such as in Botany Bay or the Prospect Reservoir, heat can also be harvested from the water body.
The layers of the underlying Hawkesbury sandstone, the bedrock for much of the region, can yield deep geothermal heat. This is done by pumping water into these layers and harvesting the steam as heat, hot water or converted electricity.
Further reading: Explainer: what is geothermal energy?
Hydropower from multiple sources
The potential sources of energy from hydro generation are diverse. Tidal energy can be harvested at the entrances of Sydney Harbour Bay and Botany Bay, where tidal differences are expected to be highest.
Port Jackson, the Sydney Harbour bay and all of its estuaries have a total area of 55km2. With a tidal difference of two metres, the total maximum energy potential of a tidal plant would be 446TWh. If Sydney could harvest 20% of this, that would be more than twice the yield of solar panels on residential roofs.
If we use the tide to generate electricity, we can also create a surge barrier connecting Middle and South Head. Given the climatic changes occurring and still ahead of us, we need to plan how to protect the city from the threats of future cyclones, storm surges and flooding.
I have written here about the potential benefits of artificially creating a Sydney Barrier Reef. The reef, 30km at most out at sea, would provide Sydney with protection from storms.
At openings along the reef, wave power generators can be placed. Like tidal power, wave power can be calculated: mass displacement times gravity. If around 10km of the Sydney shoreline had wave power vessels, the maximum energy potential would be 3.2TWh.
In the mouths of the estuaries of Sydney Harbour and Botany Bay, freshwater meets saltwater. These places have a large potential to generate “blue energy” through reverse osmosis membrane technology.
To combine protective structures with tidal generating power, an open closure barrier is proposed for the mouth of Sydney Harbour. The large central gates need to be able to accommodate the entrance of large cruise ships and to close in times of a storm surge. At the same time, a tidal plant system operates at the sides of the barrier.
Master plan for a zero-carbon city
All these potential energy sources are integrated into our Master Plan for a Zero-Carbon Sydney. Each has led to design propositions that together can create a zero-carbon city.
The research shows there is enough, more than enough, potential reliable renewable energy to supply every household and industry in the region. What is needed is an awareness that Australia could be a global frontrunner in innovative energy policy, instead of a laggard.
The link below is to a media release concerning the Green and Golden Bell Frog, an endangered frog species in New South Wales, Australia.
For more visit:
The risk of more severe storms and cyclones in the highly urbanised coastal areas of Newcastle, Sydney and Wollongong might not be acute, but it is a real future threat with the further warming of the southern Pacific Ocean. One day a major storm – whether an East Coast Low or even a cyclone – could hit Sydney.
With higher ocean temperatures killing and bleaching coral along the Great Barrier Reef to the north, we could also imagine where the right temperatures for a coral reef would be in a warmer climate. Most probably, this would be closer to the limits of the low latitudes, hence in front of the Sydney metro area.
We should then consider whether it is possible to help engineer a natural defence against storms, a barrier reef, should warming oceans make conditions suitable here.
Ocean warming trend is clear
The oceans are clearly warming at an alarming rate, with the unprecedented extent and intensity of coral bleaching events a marker of rising temperatures. After the 2016-2017 summer, coral bleaching affected two-thirds of the Great Barrier Reef.
On the other side of the Pacific, sea surface temperatures off Peru’s northern coast have risen 5-6℃ degrees above normal. Beneath the ocean surface, the warming trend is consistent too.
With the East Australian Current now extending further south, the warming of these south-eastern coastal waters might be enough in a couple of decades for Nemo to swim in reality under Sydney Harbour Bridge.
On top of this, when we plot a series of maps since 1997 of cyclone tracks across the Pacific, it shows a slight shift to more southern routes. These cyclones occur only in the Tasman Sea and way out from the coast, but, still, there is a tendency to move further south. The northern part of New Zealand recently experienced the impacts this could have.
Think big to prepare for a big storm
If we would like to prevent what Sandy did to New York, we need to think big.
If we don’t want a storm surge entering Parramatta River, flooding the low-lying areas along the peninsulas, if we don’t want flash-flooding events as result of river discharges, if we don’t want our beaches to be washed away, if we want to keep our property along the water, and if we want to save lives, we’d better prepare to counter these potential events through anticipating their occurrence.
The coast is the first point where a storm impacts the city. Building higher and stronger dams have proven to be counterproductive. Once the dam breaks or overflows the damage is huge. Instead we should use the self-regenerating defensive powers nature offers us.
Thinking big, we could design a “Sydney Barrier Reef”, which allows nature to regenerate and create a strong and valuable coast.
The first 30-40 kilometres of the Pacific plateau is shallow enough to establish an artificial reef. The foundations of this new Sydney Barrier Reef could consist of a series of concrete, iron or wooden structures, placed on the continental shelf, just beneath the water surface. Intelligently composed to allow the ocean to bring plants, fish and sand to attach to those structures, it would then start to grow as the base for new coral.
This idea has not been tested for the Sydney continental flat yet. But in other parts of the world experiments with artificial reefs seem promising. At various sites, ships, metro carriages and trains seem to be working as the basis for marine life to create a new underworld habitat
The Sydney Barrier Reef will have the following advantages:
Over decades a natural reef will grow. Coral will develop and a new ecosystem will emerge.
This reef will protect the coast and create new sandbanks, shallow areas and eventually barrier islands, as the Great Barrier Reef has done.
It will increase the beach area, because the conditions behind the reef will allow sediments to settle.
It creates new surfing conditions as a result of the sandbanks.
It will protect Sydney from the most severe storm surges as it breaks the surge.
It will present a new tourist attraction of international allure.
Let’s create a pilot project as a test. Let’s start to design and model the pilot to investigate what happens in this particular location. Let’s simulate the increase of temperature over time and model the impact of a cyclone.
Let’s create, so when Sandy hits Sydney, we will be better protected.
The recent axing of five of the six senior scientists charged with protecting the health and safety of Sydney’s drinking water has understandably created concerns.
This follows last year’s merger of the New South Wales State Water Corporation and the Sydney Catchment Authority, creating a single body called WaterNSW to oversee water for the entire state. Later in the year the newly created agency suffered around 80 job cuts.
Domestic water supply systems are generally managed in ways that eliminate or reduce any possible risk to water quality. It appears to be problematic that the new agency loses its specific focus on Sydney’s water supply at the same time that it loses its most knowledgeable and experienced staff.
Water big deal
Sydney has Australia’s biggest and most complex domestic water supply network. In 2013-14 the city’s 4.5 million inhabitants used 536,607 million litres of water – roughly equivalent to an Olympic swimming pool of water every hour.
The challenge of supplying the greater Sydney population with clean, safe and reliable water has not always been met. In 1998, Sydneysiders were forced to boil their drinking water when the network was infected with Cryptosporidium and Giardia, after heavy rains washed these chlorine-resistant parasites into the water supply.
The pathogens were detected and nobody became seriously ill. Nevertheless the incident was a great embarrassment for the state government and tarnished Sydney Water’s coveted reputation for water cleanliness and safety.
The subsequent inquiry recommended that the catchments and water supply infrastructure become the responsibility of a separate agency, leading to the creation of the Sydney Catchment Authority (SCA) in 1999.
The inquiry also pointed to a lack of scientific certainty about the sources of water supply contaminants, and how they should be dealt with. So the SCA developed an in-house team of scientists, and commissioned others from CSIRO and universities, to gather the expertise needed to provide safe and reliable water in the face of factors such as droughts, deluges, pollution and pathogens.
This scientific effort was no mean feat, given the size of Sydney’s water infrastructure and the SCA’s modest workforce of fewer than 300 staff. Sydney’s catchments collect water from an area covering 16,000 square km of land west and south of the city. The water is stored in 21 dams, including the massive Warragamba Dam. These are linked to consumers by a complex array of pipelines, tunnels and other infrastructure.
What’s more, the catchments themselves are extensively developed. More than 100,000 people (and many domesticated animals) live in the region. Towns such as Katoomba, Lithgow, Goulburn, Moss Vale, Bowral and Berrima all discharge their treated sewage waste into catchment waterways.
As a result, Sydney’s water catchments have many potential sources of pathogens, including those from human and animal waste. A crucial part of the SCA’s research was to determine which of these contaminants poses a serious threat to humans.
The scientific research improved routine operational monitoring of the effectiveness of the multiple barriers that protect the quality of the water from the headwaters of the catchment through various storages, filtration and treatment systems, to the reticulated network of pipes to the consumer.
The SCA science team has undertaken and published some of the world’s most thorough research on the effects of subsidence from coal mining and its impacts on surface waters, such as Waratah Rivulet, an important waterway that feeds the Woranora Dam.
The research thoroughly documents the changes in surface water flows and chemistry as the mine subsidence fractures the sandstone strata. The freshly fractured sandstone “captures” some or all of the stream flow and a complex array of chemical reactions occur, resulting in increased salinity and concentrations of metals zinc, nickel and cobalt. It is less clear how mining was able to inflict such environmental damage in such well-protected catchments.
Other sources of catchment water pollution received less attention from the SCA scientists even though coal mining in Sydney’s water catchments continues to generate considerable community concern. One example is Springvale Colliery in the Warragamba catchment near Lithgow. The mine has just been extended despite having been identified as the largest source of salinity in the Coxs River catchment, the second-biggest waterway that flows into Warragamba Dam.
Although the SCA was a government agency, it earned revenues of just over A$200 million in 2013-14 by selling water to its customers, principally Sydney Water. Rather than costing the NSW government money, it paid the state a dividend of A$27.9 million in 2013-14.
It remains to be seen whether WaterNSW, with its significantly smaller scientific team, can continue this vital research to protect Sydney’s catchments and infrastructure. I expect that its biggest customer, Sydney Water, and NSW Health will demand that rigorous scientific standards continue to be upheld.
In its previous incarnation, the Sydney Catchment Authority had as its motto “Healthy catchments, quality water – always”. It’s an important principle to uphold, and regional areas could benefit if this guiding principle pervades WaterNSW’s operations across the state. It needs to ensure that the high standards that protected Sydneysiders’ water are not sacrificed.