.png)
Guest post by Dr Mark Diesendorf, Institute of Environmental Studies, UNSW.
Click here for a printable 6-page PDF version of this response.
——————-
This is a personal response to Lang’s (2012) article critiquing the peer-reviewed paper Elliston, Diesendorf and MacGill (2011) ‘Simulations of scenarios with 100% renewable electricity in the Australian National Electricity Market’, referred to hereinafter as EDM (2011).
I appreciate the large amount of work that Lang has done in attempting to assess our work. However, I think his critique is premature, because he has misunderstood the intent of our work, which was clearly identified as exploratory. It is the first of a series of planned papers that will pick up on some of the issues that he has raised (and others) and step by step prepare the ground for an economic analysis. Several other questions that he raises are simply repetitions of questions that we have already raised and in some cases answered in EDM (2011).
Lang appears to be confused and mistaken in some key issues, such as the reliability of generation, where his conclusions are incorrect and potentially misleading.
Reliability of generation
Lang misunderstands and hence misrepresents our result that, in its baseline scenario, supply does not meet demand on six hours per year. He draws an incorrect conclusion from this result to claim that ‘renewable energy cannot realistically provide 100% of Australia’s electricity generation’. However, he overlooks the fact, clearly stated in the abstract, the main body and the conclusion of EDM (2011), that all our scenarios meet the same reliability criterion as the existing polluting energy system supplying the National Electricity Market (NEM), namely a maximum energy generation shortfall of 0.002%. This criterion inevitably means that any energy supply system, including the existing fossil-based system, is likely to fail to meet demand on at least several hours per year.
This is simply realistic, because no electricity supply system has 100% reliability. To achieve this ideal would require an infinite amount of back-up and hence an infinite cost. For this reason, electricity supply systems have reliability criteria such as Loss-of-Load-Probability (LOLP, the average number of hours per year that supply fails to meet demand) or energy shortfall. The NEM uses the latter. Since Lang refers to LOLP later in his article, he presumably partly understands this fundamental principle of electricity supply, yet somehow forgets this when critiquing the principal conclusion of our paper.
His oversight invalidates his conclusion. Hence our conclusion stands: namely that, subject to the conditions of the model, a 100% renewable electricity system is technically feasible for the NEM based on commercially available technologies.
Filed under: Emissions, Policy, Renewables | 67 Comments »
