Planning to fail: how 'percent renewables' policy threatens the energy transition

Let's see how national and NEM outputs and growth rates compare. In the table below generation in gigawatt-hours from OpenNEM is converted to petajoules and annual growth for solar and wind deduced, as above.

The patterns for both "% renewables" and numerical increments in solar plus wind outputs (bottom rows) in the two tables are similar. Both can be reliable sources for drawing conclusions about Australia's clean energy performance. One such conclusion is that the "% renewables" metric flatters the real contribution of solar and wind energy as measured in physical units per annum. To borrow from Australian Consumer Law, it is "misleading and deceptive".

Consumers are also influenced by excited renewables commentary, especially about periods of unusually high renewables content over a narrow interval or region. For example: "Australia's main grid reached a new record for renewable energy production on Friday – for the second working day of the week – with a peak of 71.3 per cent, according to the Australian Energy Market Operator" (21 October 2023)". These cherry-picked data seem intended to raise morale about renewables within the electorate.

Overall there is a pattern of exaggeration of clean energy progress, supported by governments, regulators, media and industry.

How can true progress be established? Can Australia's energy policy succeed?

The answers lie in the proper setting of clean energy targets.

The current target is simply "100% renewables". Using the above data this means that for 2022 if Australia's total renewables had reached 983.8 PJ it would have hit its 100% target. Actual clean output was 317.5 PJ, just under one third of that target. Not bad. But as already noted 983.8 PJ cannot possibly be the amount of electrical energy that would replace all 5249.6 PJ fossil fuel energy Australia consumed in 2021/22 (see Australian Energy Update 2023). The correct amount for that purpose must be far greater.

The crucial question is, how much greater? What quantity of electricity would we need to replace, or displace, all of Australia's fossil fuel consumption? That's much the same as asking "how much electricity would a fully electrified Australian economy require?" Let's call that the clean electricity target.

At the moment there is no shortcut to answering that question directly. We need an educated guess. Here is one approach.

A key fact is that fossil fuels are now converted to electricity by combustion in thermal power stations. The laws of thermodynamics require that all such energy conversion processes suffer losses. That is, efficiencies must be less than 100%, usually far less. Losses appear mostly as heat.

In 2022 the world average thermal generation efficiency was 40.7% according to the latest Statistical Review of World Energy. Australia's is probably lower because it relies more than others on coal, especially brown coal.