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With declining coral cover, poor water quality and the impacts of climate change, the future of the Great Barrier Reef has been under close scrutiny in recent years by the World Heritage Committee.

There are calls for Australia's onshore gas to flow much more freely. Glen Dillon, CC BY

With high gas prices partly to blame for the electricity blackouts that hit South Australia this month, and gas-fired generators caught short in New South Wales two days later, it is hardly surprising to hear calls for Australia to expand production.

Even the week before the latest crises, Prime Minister Malcolm Turnbull told the National Press Club that increasing gas supply is “vital” for Australia’s energy future.

Following bipartisan passage of the Victorian moratorium on onshore gas developments, federal Energy Minister Josh Frydenberg called on all governments to support unconventional gas. He has talked of an “urgent” need to increase gas supplies to improve energy security.

But how much extra gas do we need? And how do we square this with the equally pressing need to reduce our use of fossil fuels?

How much gas can we burn?

On average, the National Electricity Market (NEM) emits about 800 grams of carbon dioxide per kilowatt hour of electricity produced. This is almost double the OECD average of 411g per kWh.

According to the International Energy Agency (IEA), this average needs to fall drastically to 15g per kWh by 2050 to achieve the goal of limiting the global increase in temperatures to 2℃. Indeed, the IPCC Fifth Assessment Report shows that limiting global warming to less than 2℃ will require the electricity sector’s greenhouse emissions to reach zero by 2050.

By any measure that is a huge task, particularly for a country like Australia. Currently, around 11% of the electricity in the NEM comes from gas. Even if every coal power station were closed and replaced with zero-emissions technology, the NEM’s emissions intensity would still be three times this 15g per kWh limit.

Gas demand in the NEM states. GPG: gas-powered generation; LNG: liquefied natural gas. The amount of gas burned in the electricity sector would have to reduce to meet emissions reduction targets. Melbourne Energy Institute

This means that at current demand levels we need to burn roughly 70% less gas if we are to stay in this emissions intensity range. That’s a particularly small amount when compared with current total gas demand, as shown in the figure above.

Given this constraint, we need to think about how to maximise the amount of electricity we get from this limited amount of gas, and what new technologies can help us do it.

Technological options

There are several technologies for converting gas to electricity. Older power stations, such as Torrens Island in South Australia, are similar to coal-fired power stations. Energy from combustion is used to heat water, which in turn powers a steam turbine.

Today, gas is generally converted to electricity using two different technologies. First, there are open-cycle gas turbines (OCGTs). These work in a similar way to jet engines: the gas is mixed with air and burned, producing a stream of hot, high-pressure exhaust gas that drives a turbine.

OCGTs are very flexible and can ramp up and down very quickly. They are sometimes described as “peakers”, because they can respond rapidly to peaks in electricity demand. But because of this, they are typically not used very much – some OCGTs in the NEM run at full load for just a few hours a year.

Their thermal efficiency – the proportion of energy from combustion that is converted to electricity – is relatively low, at around 30%. This also means their emissions intensity is relatively high, at 580-670g per kWh.

A second type of gas power station is combined-cycle gas turbines (CCGTs). These power stations effectively recover extra energy from the exhaust stream of an OCGT turbine. This makes them more efficient than OCGTs, typically recovering 50% of the energy from the gas. As a result, their emissions intensity is lower, at roughly 400g per kWh.

One downside, however, is that CCGT technology is less flexible. It cannot stop and start as easily as an OCGT. Hence it tends to run for more of the time, operating more as a source of “baseload” power than as a response to peaks in demand.

Gas generators in the National Electricity Market (NEM) plotted by age and emissions intensity. The size of the markers indicates installed capacity, and the colour indicates technology type. Most installed capacity is flexible OCGT, which typically doesn’t use much gas over the course of a year.

As this chart shows, the efficiency of Australia’s gas power stations depends more on their technology than their age. CCGTs are more efficient. OCGTs are less efficient but more flexible, and typically use less gas overall because they are switched on more sparingly. OCGTs are also better suited to load-following and balancing renewable energy production and providing capacity to the market.

Burning questions

This is not necessarily a question of persisting with one type of gas-fired power station over the other. But it is important to think carefully about how we burn our gas as well as how much of it we burn. We also need to think about how that will help us meet our other energy objectives such as reducing greenhouse emissions and integrating more renewables into the grid.

Using more efficient technologies where possible makes sense. Several old and more inefficient plants are currently being used instead of newer, more efficient ones. Torrens Island and the newer Pelican Point in South Australia are a good example.

Pelican Point is a CCGT that is running considerably below its nominal capacity, while Torrens Island is running at high rates. While the decisions on operation of these plants are commercial and made by private companies, the same gas consumed by Torrens Island could be much more efficiently used by Pelican Point. A unit of gas burned at Pelican Point could theoretically deliver around 50% more energy than the same unit of gas burned at Torrens.

Torrens Island power station: less efficient, but more switched on. Adam Trevorrow/Wikimedia Commons

Part of the reason for this situation is that different companies own the plants. Engie has cut capacity at Pelican Point in response to high gas prices, whereas AGL has opted to keep Torrens Island running at full steam.

This highlights the difficulty, in a privatised market, of ensuring that power is drawn preferentially from the most efficient facilities. Solutions such as managed closures or forced divestment are politically unpalatable. The much-discussed “emissions intensity scheme” would theoretically help push the market in the right direction.

What about the competition?

Many of the services and capabilities that gas turbines provide are also available from other technologies. Flexibility, dispatchability and capacity (as well as other services such as inertia and frequency control) can be provided by storage, other renewable technologies and the cheapest – demand-side management.

Some of these technologies include concentrated solar thermal, battery storage and pumped hydro, which Turnbull also mentioned in favourable terms in his Press Club address.

Indeed, some of these technologies may be able to outcompete traditional sources of capacity like OCGTs.

Whatever the case, the role of gas will need to be carefully considered, and its use will necessarily be limited. In the longer term, the need to increase gas supply is far from certain.

Dylan McConnell has received funding from the AEMC's Consumer Advocacy Panel and Energy Consumers Australia.

UK academics say introduction of herpes virus could also cause ‘catastrophic ecosystem crashes’ in Australia

Scientists in Britain have raised concerns about Australia’s $15m plan to release a herpes virus in the nation’s largest river system to eradicate carp, saying it poses a serious risk to global food security, could cause “catastrophic ecosystem crashes” in Australia, and is unlikely to control carp numbers long term.

In a letter published in the Nature Ecology and Evolution journal this week, University of East Anglia researchers Dr Jackie Lighten and Prof Cock van Oosterhout say the “irreversible high-risk proposal” could have “serious ecological, environmental, and economic ramifications.”

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It’s worth asking who exactly would benefit from Andrea Leadsom’s suggestion that farmers should replace workers with robots (Farmers deliver stark warning over access to EU seasonal workers, 22 February; Letters, 23 February). Not the farmers, who would lose the freedom to exploit their workers while any cost savings associated with the robots would be swallowed up by competition and the supermarkets’ hold over the supply chains. Not the workers, who would lose their jobs, with nothing similar to go to. Not consumers, who would remain at the mercy of the supermarkets’ cynical “price wars”. Ah, I’ve got it: it must be the bankers, who have lent the farmers the money to buy the robots. The secretary of state for the environment, food and rural affairs used to work in banking, I believe.
Richard Middleton
Castle Douglas, Dumfries and Galloway

• Join the debate – email guardian.letters@theguardian.com

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Bumblebees can learn how to manoeuvre a ball by watching others carry out the task, researchers from Queen Mary University of London have discovered. Bees have already been shown to be able to learn how to pull on strings, push caps and even rotate a lever to access food. The Queen Mary study shows that bees are better at problem-solving than was previously thought

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National eNews - Time to Declare a Climate Emergency: Petition and Canberra Events this Weekend

Macquarie insists it is committed to renewable energy – but critics say it could invest in fossil fuels if its bid succeeds

The Australian investment bank on the verge of buying the UK’s publicly owned Green Investment Bank has launched a Westminster charm offensive after parliamentarians of all parties told Theresa May to halt the £2bn sale.

Green party co-leader Caroline Lucas, the Lib Dems’ Vince Cable and former Tory minister Lord Barker last month warned a sale to Macquarie would put the bank’s green purpose at risk and its most valuable assets, such as large windfarms, could be sold off.

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A new report says that using wood pellets to generate low-carbon electricity is a highly flawed policy.

The salt flats in Salar de Uyuni, Bolivia, are the largest in the world and contain 50-70% of the world’’s lithium reserves

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Is there a conservative case for climate change? Former Republican Congressman Bob Inglis believes so.

Protesters have been blocking construction of the pipeline for months, and maintain that they will continue to fight despite the eviction.

A world-first study has been conducted that tracks wild dolphins off the coast of New Zealand.

As politicians debate the causes of South Australia’s power failures, separating fact from rhetoric has become difficult. In this episode of The Conversation’s politics podcast, Michelle Grattan interviews energy expert Hugh Saddler.

Dr Saddler explains the complex mix of factors behind the power failures in South Australia and the stresses on the electricity systems elsewhere, and canvases what can be done to fix the problems.

With the government attempting to reinvigorate enthusiasm for coal, Saddler doesn’t believe the idea of subsidising the development of “clean coal” power stations will fly.

“There’s so many parties who would be involved in that sort of investment saying there’s no way they would invest in such a type of power station.

"One factor is that they have a long life. … That type of power station would take a very long time to build. Then it will have a long life and under that sort of life they would still be operating in 2050 when many countries have said we’ve got to be [at] zero emissions.”

A review into energy security by Australia’s chief scientist Alan Finkel is still underway. But the government has already ruled out establishing an emissions intensity scheme.

“In my opinion an emissions intensity scheme is just one of a number of different mechanisms which probably should be used. … I would suspect the sort of process that might go through is the Finkel report will come down with a whole suite of recommendations,” Saddler says.

Music credit: “Equestrian”, by Anitek on the Free Music Archive

Michelle Grattan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

New study reveals negative impact of climate change, human activity, acidification and deoxygenation on ocean and its creatures

The deep ocean and the creatures that live there are facing a desperate future due to food shortages and changing temperatures, according to research exploring the impact of climate change and human activity on the world’s seas.

The deep ocean plays a critical role in sustaining our fishing and removing carbon dioxide from the atmosphere, as well as being home to a huge array of creatures. But the new study reveals that food supplies at the seafloor in the deepest regions of the ocean could fall by up to 55% by 2100, starving the animals and microbes that exist there, while changes in temperature, pH and oxygen levels are also predicted to take their toll on fragile ecosystems.

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Keep the climate in mind when you're choosing what to plant. shutterstock

Since 1880, the average global temperature has increased by 0.8°℃, with large changes in rainfall redistribution. With these changing conditions upon us, and set to continue, gardeners will have to alter the way they do things.

As climate largely determines the distribution of plants and animals – their “climate envelope” – a rapid shift in these conditions forces wild plants and animals to adapt, migrate or die.

Gardeners face the same changing conditions. If you look at the back of a seed packet, there is often a map showing the regions where these particular plants thrive. But with a rapidly changing climate, these regions are shifting.

In the future we will need to be more thoughtful about what we plant where. This will require more dynamic information and recommendations for gardeners.

The shifting climate

Changes in altitude significantly affect the temperature. As you walk up a hill, for every 100 metres of altitude you gain, the temperature drops by an average of 0.8℃.

Changes in latitude obviously have a bearing on the temperature too. It gets cooler as you move towards the poles and away from the Equator. An accurate rule of thumb is difficult to derive, because of the number of interacting and confounding factors. But generally speaking, a shift of 300 km north or south at sea level equates to roughly a 1℃ reduction in average temperature.

This means that due to warming over the past century or so, Adelaide now experiences the climate previously found in Port Pirie, whereas Sydney’s climate is now roughly what was previously found halfway to Coffs Harbour. The temperature difference is equivalent to a northward shift of approximately 250 km or drop in altitude of 100 m.

At current climate change trajectories, these shifts are set to continue and accelerate.

The plants in your garden might need to change. Adaptation

Plants are already adapting to the changing climate. We can see that in the hopbush narrowing its leaves and other plants closing their pores. Both are adaptations to warmer, drier climates.

We have also seen some major shifts in the distribution of animal and plant communities over the past 50 years. Some of the most responsive species are small mobile insects like butterflies, but we have also seen changes among plants.

But while entire populations may be migrating or adapting, plants that grow in isolated conditions, such as fragmented bush remnants or even gardens, may not have this option. This problem is perhaps most acute for long-lived species like trees, many of which germinated hundreds of years ago under different climatic conditions. The climate conditions to which these old plants were best adapted have now changed significantly – a “climate lag”.

Using such old trees as a source of seed to grow new plants in the local area can potentially risk establishing maladapted plants. But it’s not just established varieties that run this risk.

The habitat restoration industry has recognised this problem. Many organisations involved in habitat restoration have changed their seed-sourcing policies to mix seeds collected from local sources with those from more distant places. This introduces new adaptations to help cope with current and future conditions, through practices known as composite or climate-adjusted provenancing.

The shifting climate and your garden

Gardeners can typically ameliorate some of the more extreme influences of global warming. They can, for example, provide extra water or shade on extremely hot days. Such strategies can allow plants to thrive in gardens well outside their natural climatic envelope, and have been practised by gardeners around the world for centuries.

But with water bills rising and the need to become more sustainable, we should think more carefully about the seeds and seedlings we plant in our gardens. The climate envelope we mentioned earlier is shifting rapidly.

We will need to start using seeds that are better adapted to cope with warmer and, in many cases, drier conditions. Typically, these plants have thinner leaves or fewer pores. This requires more information on the location and properties of the seeds’ origin, and a more detailed matching of diverse seed sources to planting location.

As the climate changes, we need to be more selective with what we plant.

As the climate continues to change we will also need to introduce species not previously grown in areas, using those that are better adapted to the increasingly changed climatic conditions. Plenty of tools are now available to help guide seed collection and species selection for planting. These include those offered through the National Climate Change Adaptation Research Facility and the Atlas for Living Australia, for instance.

But these resources are often aimed at expert or scientific audiences and need to be made more accessible for guiding gardening principles and plant selection for the public. The information needs to be intuitive and easy to understand. For example, we should produce lists of species that are likely to decline or benefit under future climate conditions in Australia’s major cities and towns, along with future growing areas suitable for some of our most popular garden species.

This won’t just be useful for a backyard gardener, either. Many exciting new gardening initiatives are being proposed, including rooftop gardens, which promote species conservation, carbon sequestration and heat conservation, and future city designs, which incorporate large-scale plantings and gardens for therapeutic benefits. All of these activities need to take the shifting climate into account, as well as the need to change practices to keep up with it.

Andrew Lowe receives funding from the Australian Government and not for profit groups for restoration research. He is a board member of Trees for Life and on the Scientific Advisory panel of Greening Australia.

Sandy Bedfordshire In an aerial tussle one raptor attacked from above until its opponent dropped so low it was grounded

By lunchtime the skies over rural Bedfordshire had become an arrivals and departures board. Thin white slashes criss-crossing the blue trailed over the horizon towards Barcelona, Rome and Salzburg. The 11.25 to Katowice had dissipated into a wispy smudge. Then, an intense arrowhead, like a cursor on a computer screen, might have been the 12.20 from Barcelona entering our airspace.

Birds of prey do not arrive; they simply appear in the sky, as if they had been lowered from heaven. So it was that three red kites came into view out of nowhere.

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Opposition leader Bill Shorten has accused the Coalition government of policy vandalism on energy, and committed to an emissions intensity scheme that he insists will deliver Labor’s target of 50 per cent renewables in the country’s electricity system by 2030. In a landmark speech at the Bloomberg headquarters in Sydney on Thursday, Shorten said Australia should […]

China's biggest EV and energy storage company targeting 25% share of Australian battery market, with new B-Box product range.

US EV and battery maker says mass-market Model 3 electric sedan on schedule to begin production in July.

As regulators consider strict new guidelines for Australian home battery installations, US battery maker SimpliPhi is making its move, keen to promote the key strengths of its proprietary technology – safety, reliability and flexibility.