It turns out unwarranted assumptions are the largest single source of renewable energy.

Take for example the Zero Carbon Australia, 2020 report which claimed that all of Australian energy could com from renewable energy sources by 2020. Ted (F.E.) Trainer, a well known Australian energy theorist pointed to some of the plans flaws,

To summarise, my back of the envelope impression is that when the foregoing points are added the ZCA conclusion is out by the following factors:

i. The efficiency gain assumed for electric vehicles should be perhaps halved.
ii. The assumed proportion of travel that can be transferred to electric vehicles is too high, in view of how well people and freight can be got to intended destinations by light vehicles and public transport, and in view of what people will accept.
iii. The embodied energy costs of plant might be much more than 10 times as high as has been assumed.
iv. Far more storage for solar thermal needs to be assumed, perhaps 96 hours, as distinct from 17.
v. The amount of solar thermal capacity might need to be trebled I am right about the peak vs average issue.
vi. Very optimistic assumptions and estimates have been made throughout, including regarding costs.

Trainer was not the only critic of the ZCA plan to point out its unrealistic optimism.

Dave Burraston has offered fact based critiques of the ZCA plans assumptions about wind implementation time, and solar facility construction times Martin Nicholson and Peter Lang, offered a long and detailed critique of the ZCA plan. They note, BZE make a number of assumptions in assessing the electricity demand used to calculate the generating capacity needed by 2020. In summary these are:

1. 2008 is used as the benchmark year for the analysis. BZE defend this by saying “ZCA2020 intends to decouple energy use from GDP growth. Energy use per capitais used as a reference, taking into account medium-range population growth.”.
2. Various industrial energy demands in 2020 are reduced including gas used in the export of LNG, energy used in coal mining, parasitic electricity losses, off-grid electricity and coal for smelting.
3. Nearly all transport is electrified and a substantial proportion of the travel kmsare moved from road to electrified rail including 50% of urban passenger and truckkms and all bus kms. All domestic air and shipping is also moved to electric rail.
4. All fossil fuels energy, both domestic and industrial, is replaced with electricity.
5. Demand is reduced through energy efficiency and the use of onsite solar energy.

Thus the net effect of these assumptions is to reduce the 2020 total energy by 58% below the 2008 benchmark and 63% below the ABARE estimate for 2020. The plan thus assumes that over 50% of energy demand will simply disappear by 2020 because of efficiency improvements.

The Nuclear Green Revolution site from which that comes is a left-wing climate alarmist site. But their analysis of the costs and practicality of so called renewable power is spot on.

If the whole disastrous anthropogenic global warming scary monster thing were true, and if reducing CO2 production by 20% would really do something to stop it (it isn’t and it wouldn’t), it would be possible to do so. But not with ‘renewable’ engery.

Reducing CO2 and other greenhouse emissions by 20% could be done if the pointless NBN was cancelled, and the $45 billion planned to be wasted on that was instead spent on nuclear power and the introduction of fuel cell technology for most land transport.

And that wouldn’t be a bad idea anyway.