The frog and the scorpion arrived at the edge of a river at the same time. Both wanted to get to the other side. The scorpion asked the frog for a ride on the frog’s back because the scorpion could not swim.
The frog objected, saying that the scorpion might sting him if he was on the frog’s back.
The scorpion replied that he would not do that because if he stung the frog as they crossed the river he would drown himself.
So they set out, and midway across the river the scorpion stung the frog.
As they both went down the frog said “Why did you do that?”
“Because I am a scorpion.”
Consider the relationship between renewable energy and the energy from conventional sources, mostly coal. As the installed capacity of RE increases on the back of subsidies and mandates it erodes the financial viability of coal power. We are told that it is so much cheaper that coal can’t compete, and indeed it will be a great benefit if the old coalers close well in advance of their normal lifetimes.
Why is RE so much cheaper than coal power?
Quite simply because solar and wind providers are not covering the cost of “firming” that is, filling the gaps on windless nights between the peak levels of RE supply on sunny and windy days.
RE is like the scorpion, getting a ride on the back of the frog.
As long as the frog is strong enough to carry the scorpion, that is, to provide all the power that is demanded by the grid on windless nights, the lights will stay on and nobody will be alarmed
However the scorpion is slowly and steadily killing the frog by undercutting the price of coal in the market.
When the scorpion has killed a little more of the “frog”, say a couple more coal-fired power stations, there will be a tipping point when there is not enough conventional power left to keep the lights on through windless nights, or dinnertimes during a wind drought.
The analogy is imperfect because the wind and solar providers don’t die when there is not enough conventional power to keep the lights on, it is the grid that dies, or large parts of it, with all the services that the grid supports.
The RE “scorpion” is supposed to want to keep the grid alive, in the same way the scorpion in the story ostensibly wanted to get to the other side of the river. But RE cannot keep the grid alive through windless nights without the help of the conventional power “frog”.
And as the grid dies on a windless night, someone might ask the “scorpion” why it killed conventional power and hence the grid, to which RE would reply “because that is what I do.”
Far from being cheaper, the real cost of RE plus firming is much more expensive than conventional power. This is demonstrated in an elaborate model of the NEM – the electricity system of SE Australia, with estimates for the cost of power from different sources and combinations of sources. The existing (base) case 1 and also 2, replacing brown coal with nuclear, costs between $60 and $80 per MWh.
The options 3 (replacing all coal with nuclear) and 5 (replacing all coal with nuclear) would cost between $60 and $80 per MWh.
Case 4 that they described as the AEMO plan at the time would cost in the order of $250 per MWh in 2040.
Case 6 shows a 100% renewable mix comprising solar PV, wind and hydro with support from pumped storage and some battery storage. Because of low capacity factors, solar PV and wind require a combined total of 110,000 MW of capacity. There is also a need for 30,000 MW of pumped storage capacity for 3 days. To this must be added high-cost additional transmission to get the power to points of high consumption where it is needed, making a total SLCOE of $ 415.50 / MWh.
Of course all the assumptions in the model can be disputed but the fact remains that the RE enthusiasts have not yet come to grips with the full implications of turning aspirational RE goals into reality. Up to date they have been able to ignore the value of the free ride that they are getting on the back of conventional power (the frog) that provides the “firming” or backup to cover the gaps in wind and solar supply (the scorpion).