By Phil Kreveld
A recent opinion piece in a national broadsheet concluded that AI confirmed Australia’s transition to its 2050 target as being doomed to fail. Unsurprisingly, it also opined that 100% renewable electricity is an impossible thing—this also according to AI. It might well have based its conclusion on human-generated content and since much of this is critical of renewables, it is hardly surprising. However, AI is of no use in predicting the future of renewables because much of the associated technology requirements are at best still hazy, and subject to experimentation. The essence of the challenge is in managing power rather than energy. It is summed up by the equation below:
Pgen (t) and Pabs (t) are the instantaneous power being generated and absorbed, w is angular frequency, and dw/dt, the instantaneous rate of change of frequency. The factor K is a kind of ‘constant’, because in the real world, it is also time variant. Rather than delving into its formulation, K is essentially a summation of inertia, therefore including connected motors, mechanically driven generators—and the equivalent of mechanical inertia in power generating inverters. There are well over 3000 connection points (buses) in the south eastern grid. Thus, that kind complexity defies analytical predictions (other than by severe simplification) if generated power and absorbed power vary rapidly. And, that is the salient and challenging feature of the transition to renewables!
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Based on the current state of progress of the renewable transition the chances of meeting the 2030 and 2050 targets are doubtful. But, so what? We can declare the targets ‘aspirational’, and move on! The real questions on the renewable transition are:
- Will it reduce CO2 emissions, and by how much?
- At what cost?
- And will the grid be as reliable as in the first decade of the current century, and before?
For 1, we need to pick a period of energy accounting, and calculate net CO2 reductions. For 2, add subsidies plus energy pricing plus cost of capital over the same period. For 3… now that’s a tough one to answer!
There is a belief that reduction of emissions goes hand in hand with cheap energy because the marginal costs of photons and wind is zero. But there is no such thing as a free lunch. So, reducing emissions and getting cheaper electricity is a bit like doing away with the second law of thermodynamics because it is inconvenient.
The reliability question centres on how much capital we are prepared to throw at the national grids, thus feeding into 2 above.
Let’s answer the three questions in reverse order.
Will it be as reliable as the electricity system of 2020 and earlier? The answer is akin to ‘the length of a piece of string’ with the cost per unit length going at a billion bucks per. No one has been this way before us. That means we cannot address 2, Therefore, 1 becomes a rather artificial exercise. Political and AI prognostications can be safely ignored.
If security is paramount and we want the benefit of zero cost input of wind and solar, there is a dilemma because the two do not go hand in hand. That is because there are other factors in play, the cost of experimentation and availability of engineering talent and they come around with great cost.
We are already avoiding experimentation—unsurprisingly. For example, we are deliberately ignoring the dynamics of distribution networks; we are using traditional grid development in which generation is far away from load centres; and we are loath to let go of the last vestiges of synchronous generation; coal, gas and hydro. This is not to scorn the path we are taking nationally because it is in the nature of humanity to avoid great change—other than on paper! But what is the result: a belt and braces approach to grid augmentation, a refusal to utilise the self-generation in distribution networks, and brute force approach to increasing generation capacity essentially based on ‘more must be better’.
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All this results in capex, stimulated by subvention and capacity investment schemes, and transmission buildouts. The result is of course an addition to the national asset base, which will deliver electrical energy to the consumers and taxpayers of Australia today and in the future. And the cost of a kilowatt-hour? It will more than likely be heavily slanted towards the profits and interest rates associated with the hardware investment required for energy transport and reliability assurance.
However, we should not stop thinking about the science involved in the transition because at some stage that will benefit mankind. Australia is in many ways in the lead and rather than expending energy in ‘for and against’ debates, we are better off if that energy devises a ‘whole of grid’ engineering approach, taking it out of the hands of regulators and politicians because neither of those parties can solve grid security engineering problems. Yes, one way or another, the transition will be ponderous, but it will be less so and less costly if we take a wholistic approach. Future generations will thank us!
