We already see the large areas involved even in existing industrial-scale wind and solar farms. We can't see the sizeable equipment costs but relatively puny intermittent energy outputs these actually deliver compared with fossil fuels and nuclear power.
This opinion piece is not about renewables intermittency and the multiplied generation/storage capacity needed to offset that. I dealt with that in my 22 August 2017 opinion piece entitled: Does Australian renewable energy save the earth – or just cost it?
The very low energy density of renewables and man-made batteries is an additional, even larger, capacity multiplication problem. If renewables and man-made batteries are much less energy-dense than nuclear and fossil fuel power sources, then we need to compensate for this energy density disadvantage as well as intermittency, if we want to use them. This means investing in even more generation and storage equipment:
- The capacity, and space, required for a reliability-equivalent investment in renewables generation plus storage is many multiples of that required in nuclear or fossil fuel electricity generation.
- Huge dollar investments in at-scale generation and battery storage will be needed. These multiply as renewables penetration increases.
For example, could an equivalent-power, totally renewables-based, electricity generation/storage plant be developed, whatever its cost, within the geographical footprint of the current 2,000 mW (plate-rated) Liddell coal-fired power station?
With current technology, I don't think so. There are lots of other examples suggesting huge tracts of land (or ocean) will be needed to switch from more energy-dense fossil fuel and nuclear energy sources to very diffuse energy sources (and batteries) to do the same job. (I'll assess the land-use economics of renewables in my next piece on 'poles and wires'.)
Energy density issues, and the trade-offs between their implications and other considerations, should explicitly be recognised and dealt with.
A policy perspective
Recently, the conservation argument against energy-dense fossil fuels was that supplies would run out ('peak oil', etc). We're still waiting for 'peak oil'; still longer for 'peak gas' and 'peak coal'.
Now it's claimed we can't use existing deposits of such fuels because they'll increase global warming, local atmospheric pollution, etc. They won't run out at all. Those remaining must be left in the ground.
Fossil fuel prices are rising as emissions standards increase costs. Renewable energy costs are falling. However, the multiplied capacity and storage requirements of reliable renewables will increase total costs and/or slow cost declines.
Even so, many – including the Commonwealth Government – now assert renewables don't need any subsidies.
If so, Australia's small global emissions (1.4% of global anthropogenic emissions and falling), and pusillanimous total overseas efforts to reduce emissions, raise the obvious question.
Why do we need Renewable Energy Targets (RETs) at all? These add to system-wide costs and kill affordability.
Let's abandon RET-type measures, and let technology, energy density, and their costs, sort out the energy mix we use.
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