!00% renewables = 100% unaffordables

100% renewables, plus 100% battery 'firming', is an unaffordable pipe dream.

Batteries are the weakest link in the 100% renewables supply chain. Their capacity to store dispatchable power is puny, weather-dependent, unreliable, inefficient and extremely expensive.

Consider small changes in seasonal weather only. Assume 100% reliance on batteries for 'firming', smoothing dispatchable power supply across seasons. Batteries store power for half the year, and dispatch it all in the other half. The required battery supply is enormously costly.

Suppose solar power smooths seasonality in the NEM. Assume battery costs fall to just 10% of SA's Hornsdale 'big battery' costs. The back-up batteries for reliability would still cost A$1.2 to A$2.3 trillion dollars. On average, that's about the current A$ value for Australia's entire GDP.

That finding is based on the published performance and cost of SA's Hornsdale 'big battery'. It uses a very simple numerical calculation assuming minor seasonal variations in average solar intermittency. Reality is worse. It must cover larger seasonal variations in solar intermittency.

For solar, see 'Reliable' renewables: What cost battery storage and structural inflation?. For wind, see 'Reliable' wind power: What cost battery storage?

Suppose wind power smooths seasonality in the NEM. Again, assume battery costs fall to 10% of SA's Hornsdale costs. The reliability-required back-up batteries would still cost A$0.6 to A$1.2 trillion dollars. On average, that's about half the current A$ value for Australia's entire GDP.

Why are wind power's seasonal smoothing battery costs less ruinously expensive than for solar power? On average, wind is less intermittent than solar power. It's still a long, long way from 24/7 reliable base-load power across the seasons.

Reliance on solar and wind, plus batteries,for seasonal smoothing alone, is unaffordable.

Back-up batteries for 100% reliance on solar and wind, for seasonality smoothing alone, would eat up the equivalent of 50% to 100% of the value of Australia's entire production.

This is just for the cost of batteries to smooth small seasonal renewables intermittency variations.

Reality is more costly. The conclusions above ignore other renewables costs.

They don't allow for costs of additional renewables generation capacity needed to cover day-to-day renewables intermittency fluctuations, new specialised transmission capacity everywhere, and more battery storage to smooth day-to-day fluctuations in intermittency. They ignore extra costs to ensure the grid can cope. They don't include the costs of disposal and site remediation when solar panels and wind turbines reach the ends of their relatively short economic lives.

100% reliance on renewables plus batteries is neither politically nor economically acceptable.

Allocating most production to batteries and renewables would boost currently-rising cost of living pressures a lot more. Links between Australian production and real incomes would be distorted.

Nevertheless, many governments have promised to get to 100% reliance on renewables (plus battery storage only) by 2050 or thereabouts.

In practice, how?

If reliability and affordability are important energy policy objectives (are they?), how can the required 'firming' of power supply be achieved in this renewables-only, batteries-only, world?

For renewables enthusiasts, the answer seems to be: faith and hope. That is, faith in 'cheap' renewables. And hope something will turn up to cut battery costs, etc, enough to prove it.

I've already assumed battery storage costs are slashed to just one-tenth of Hornsdale's. Is it realistic to assume even further storage cost reductions are feasible? What's the evidence?

Others, letting facts or known/likely future changes determine their views, might pursue a different path. This might include the following steps.

The first step is the most urgent. Currently-feasible base-load power sources, including gas, other petroleum products (including diesel), and coal (coking and steaming) must be secured quickly. These are our only hopes for quick answers to 'firming' intermittent power for the NEM. Without them, lights out. Look at Europe. Look at South Australia (esp, 2016). Victoria soon?

The second step is to halt growth of unreliable renewables. Battery back-up is less needed then.

We can't unscramble the renewables omelette already in place. Governments have added a very sour taste even to these scrambled eggs. Cash-strapped, they've reneged on, or slashed, incentive 'schemes' for private investment in renewables. Yet they charge private power customers for government large scale 'investments' in solar, wind, and 'pumped hydro' schemes. Energy investment expectations in general have been destroyed. Power prices continue to rise.

The third step is to put energy policy changes currently under contemplation on hold. If we want to get to Dublin, best we don't start from here. We need a better road map to a clear destination.

The fourth step is to compile independent evidence for power choices needed in the long term. This won't be easy. Bipartisan support is needed to 'firm' investment expectations themselves.

Who should be members of an independent review panel? Private sector engineers with relevant experience should dominate. Maybe one or two economists knowledgeable in the field to keep an accurate eye on energy source costs, properly and comparably measured. Ideally, no, or few, official agencies financed by the taxpayer. These days, these agencies' independence is affected by political pressures from their ministerial masters, whether they admit it or not. Last, neither politicians of any tribe nor their advocate supporters should be included.

Getting clear advice will still be difficult in practice. As Michael Crichton concluded in his reference-thick climate change novel State of Fear (Harper Collins, 2004):

Everybody has an agenda. Except me.

Quite so.