If you were unlucky enough to catch Josh Frydenberg’s recent ‘car crash’ of an interview, where he tried to spin Australia’s fourth consecutive year of growing greenhouse emissions as nothing but good news, your ears might have pricked up at the claim that South Australia and Victoria have had to bring in ‘expensive and polluting’ diesel generators and that South Australia in particular is burning ‘80,000 litres of diesel an hour, just to keep the lights on’.

With so many half-truths floating about in the so called ‘energy debate’, it’s worth unpacking this claim.

For the 2017–18 summer, both the South Australia and Victorian governments have installed banks of diesel generators as part of efforts co-ordinated by AEMO to ensure grid security under their Reliability and Emergency Reserve Trader (RERT) arrangements

Australia’s National Electricity Market has for many years included diesel generators in the generation mix.

According to AEMO’s generator database, as of December 2017 there were 98MW of registered diesel generators in NSW, 31MW in Queensland and 266MW in South Australia, not including the new generators installed in late 2017.

In addition, there are many more diesel generators sitting ‘behind the meter’ in hospitals, data and telecommunications facilities, etc. that are not registered with AEMO.

Typically, diesel generators in the NEM run only for short periods during exceptionally high demand. With running costs generally in excess of $300/MWh, most diesel generators in the NEM run for well less than 1% of the year.

South Australian Diesel-Gas Turbines

The South Australian government has acquired nine General Electric ‘aero-derivative’ TM2500 turbines which can run on either diesel or natural gas. (The class of turbines is called ‘aero-derivative’ as the design is derived from GE’s CF6 aircraft engine.)

The trailer-mounted TM2500 turbines have been installed temporarily at two sites to form two power stations:

Temporary Generation North — 5 turbines (total 153MW) at the former Holden manufacturing site in Elizabeth

Temporary Generation South — 4 turbines (total 123MW) at Adelaide’s Desalination Plant in Lonsdale

For their first summer the turbines have been configured to run on diesel, allowing them to be in operation before the start of summer, however once a site with suitable electricity and gas network access is found, they will be moved and reconfigured to run on lower emissions and cheaper natural gas.

Initially the turbines were leased for $111.5m, but in late November then SA Government announced that the fleet had been purchased so that, in the words of Premier Jay Weatherill, “we can get on with the work of securing a permanent location”.

The total capital cost is $338.7m — which works out to be $1227/kW — and since they are no longer temporary, the SA Government is referring to them as the ‘state-owned generators’.

With the addition of this 276MW, SA will have 543MW of diesel capacity (not including the Hallett Power Station) for the 2017–18 summer.

From the first seven weeks of summer, from 1 December 2017 to 21 January, the engines only ran for short periods for testing and licensing purposes — i.e. over this period they have not run for a single minute to support the grid — and have generated just 157MWh, the equivalent of 35 minutes at full load, representing a capacity factor of only 0.05%.

Even when prices hit the market cap of $14,200/MWh last week the engines sat idle. While this might appear nonsensical at first glance, generators cannot both operate in the market and participate in the RERT.

In addition, the SA government has been careful not to distort the price signals in the market that will bring in new participants.

When running on diesel the generators emit 750kg CO2e/MWh (an emissions factor of 750), which is not only a much lower emissions factor than the now demolished Northern Power Station (1010), but lower than even the best coal power stations anywhere.

(Yes, even the so called ‘high efficiency, low emissions’ power stations that are neither highly efficient nor low emissions.)

Once converted to gas, the emissions factor will drop to 540, marginally lower than the Torrens Island gas power station (580).

At full tilt, the engines would burn at most 80,000 litres of diesel per hour, however those endlessly quoting the figure (looking at you Josh Frydenberg, Craig Kelly and Chris Kenny!) won’t tell you that they’ve used less than 47kL for the summer so far.

To put it into context, the state-owned generators have so far burnt less than 40 tons of diesel, while the Northern and Playford power station, before they were shut down by Alinta, consumed an average of 67 tons of brown coal every hour.

Victorian Temporary Generators (Morwell)

As part of the 1,150MW of strategic reserves secured by AEMO, 105 containerised diesel engine generators with a combined capacity of 105MW have been temporarily installed at the site of the old Morwell Coal Power Station (a.k.a. EnergyBrix), shut in 2014.

The equipment is owned and operated by international services company Aggreko and is contracted to be available for the three months starting 8 January 2018.

As RERT generators, it is estimated that there is a 61% probability that the power supply will not be required to operate at all.

According to Aggreko’s announcements, “there is a 19.5% probability that it will operate for up to 4 hours during the period January to March, and a 13% probability that it will operate for up to 8 hours over this period.

A condition of the Victorian EPA approval is that Aggreko must seek further approval from the EPA to operate more than 20 hours over the whole 3-month period.”

During last week’s heatwave, AEMO activated the RERT. While AEMO does no release details of which RERT panel members were called on to participate, an AEMO spokesperson has confirmed that the Morwell generators did not operate.

The diesel generators have an emissions intensity factor of 668 (ie. 668 kgCO2-e/MWh). This is less than half of Hazelwood’s factor of approximately 1,400, well below that of Millmerran Power Station (891), likely the lowest emissions coal power station in Australia.

While it is not accurate to say that the Morwell engines ‘replace Hazelwood’, it is arguable that they would not have been required if Hazelwood had not closed in March 2017.

Over a typical three-month period Hazelwood used to emit 4,308,000 tons of carbon dioxide.

If the Morwell generators operate at all they will emit 73.5 tons per hour. As such there is a 61% probability they won’t emit a single ton of CO2 outside any testing, a 19.5% probability of less than 293 tons and a 13% probability of less than 588 tons. The engines will need EPA approval to emit more than 1,470 tons of CO2, or 1/3000th of what Hazelwood used to emit over a similar period.

So while it is true that diesel generators have been installed to boost power security over the summer, it must be kept in mind that Victorias are temporary, South Australia’s will soon run on natural gas, both are much cleaner than coal and neither will get much, if any use. Anyone, politician or opinionista, who tells you otherwise is engaging in an act of deception.

As for the cost, we built our generation and transmission system to be 99.998% reliable. Politicians and our government agencies got the strong message through 2017 that this is not reliable enough.

So until we can have adult conversations about energy, we’ll have to pay for infrastructure that’s only called upon in extremely rare circumstances — you can consider that another form of ‘gold plating’.

Simon Holmes à Court is senior advisor to the Energy Transition Hub at Melbourne University and can be found on Twitter @simonahac