Did ClimateWorks vary assumptions between scenarios?


As part of my research reviewing all 100 % renewable electricity studies, I am revisiting the work of ClimateWorks for the Deep Decarbonisation Pathways Project. You can find the report here.


The report includes three scenarios:

  • 100 % renewable grid (of interest to my meta-review, and the major scenario presented by ClimateWorks)
  • Nuclear
  • CCS

In the latter two scenarios, “permission” is effectively given in the model for those energy sources to compete. As a result, each of these energy sources comes to make a significant contribution to the least-cost finding (23 % and 14 % respectively).

The limitation on nuclear to only 14 % seemed surprising to me. It is based (primarily) on the following assumptions:

  • Only a few large nuclear plants can be accommodated in the eastern states before connection limitations are met
  • Western Australia remains separate from the NEM (despite the scenario suggesting it will become the largest electricity user)

On the first point they say “ESM (CSIRO’s Energy Sector Model) only allows nuclear power in the larger states of New South Wales, Queensland and Victoria, since nuclear power stations generally have to be a minimum size, which would preclude their deployment in the smaller states”.

The authors acknowledge that consideration of smaller reactors is important and worthy of further work. They also tested the WA connection in the nuclear scenario and found the nuclear share increased to 27 %. That alone is an interesting signal.

They state further that “with the use of small-scale nuclear plant or a more interconnected grid [we will return to that] there is no technical reason why nuclear power could not supply a major share of electricity consumption”.


In light of these sensible remarks, I am concerned that the assumptions about transmission network limitations and may not have been understood and applied equally. I am not certain of my findings here. All of the following is to be read as open investigation, not conclusion.

The authors state:

“Within the scope of this project, it is not possible to fully resolve the changes to the network that would be required to support the reliable market balancing of the generation mix in each scenario. The relatively high demand growth will necessitate significant transmission network growth and the need to extend the grid to remote renewable resources, given their high contribution to the generation mix”.

Ok… they know it’s essential, it was out of scope. Fine. I have no problem with that. What did they do?

“As a guide, in the absence of detailed transmission network modelling, the transmission cost results from the existing ‘Renewables thrive’ scenario of the Future Grid Forum project have been applied, which is a 100 percent renewable grid scenario, as outlined in Graham et al. (2013)… Under ‘Renewables thrive’, taking into account the required changes to the transmission network, the cost was projected to increase to 4.3c/kWh by 2050”.

So, no modelling, but an effort at costing based on someone else’s modelling. That, again, is fine with me as long as it’s disclosed.

Now, let’s look at the mix for 100 % renewable grid.


It is evident that this mix will require the “significant transmission network growth and the need to extend the grid to remote renewable resources” that the authors discussed. So, I strongly suspect the transmission was assumed to be unconstrained, simply costed in on a per kWh rate on the basis of “we will build what we need”.

Here are the network augmentations proposed by Future Grid Forum. 

Future Grid 1

Future Grid 2

That’s a lot of investment that could be put towards improvements tailored for nuclear generation.

So…why was transmission assumed to be constrained in the nuclear scenarios such that only a few reactors in the eastern states were assumed to be possible? Renewable units are smaller than nuclear units, but that renewable scenario is (much) more dispersed than a nuclear-based system would be. Stronger transmission networks (and other investments) is an answer to both problems. The authors acknowledge that very fact (“with the use of small-scale nuclear plant or a more interconnected grid there is no technical reason why nuclear power could not supply a major share of electricity consumption”).

Every progressive transmission enhancement that would be necessary for the 100 % renewable grid scenario would, just as effectively, contribute to new threshold that enables the connection of more large nuclear units. Has this modelling settled for assuming nuclear connections based on the network of today, but enabled levels of renewable penetration based on the network of “whatever we need tomorrow?”. If so then an assumption that should be uniform across all scenarios is, instead, differentiated between scenarios.

DDPP-au 2

The transmission enhancement requirements for nuclear (which can be close to load and existing transmission) are likely far more discreet than for the needs of the renewables system shown above. I posit dollars invested in transmission upgrade for nuclear would deliver connection capability much more efficiently than dollars spent in transmission upgrade for geographically dispersed renewable overbuild. If spending on networks was applied rationally and even-handedly, nuclear should do well.

The result is that the contribution from nuclear in the scenario where it was permitted would be, at 14 %, a false low. This suggests that the wholesale price of the nuclear scenario (Figure 2.18) is a false high, as more nuclear, earlier, would displace more of the higher-priced renewable electricity that enters the mix later: enhanced geothermal and wave (capital costs, Figure 2.7) and solar thermal (which, while dispatchable, is still variable). It’s likely not delivering an optimised system from the available options.

I find this report is overall clear, well written and offers some important potential directions, as well as giving one of the more even-handed treatments of nuclear generation in Australian literature (my criticisms not withstanding). However I cannot get clarity on this issue. I welcome comments from all including the report authors if they can shed some light on how this assumption was managed.


A step forward in a shared responsibility: shortlisted sites announced

OPAL Reactor

Today the Federal Government Department of Industry, Innovation and Science announced a shortlist of six nominated sites for consideration for the establishment of Australia’s national low-level waste and intermediate level waste disposal and storage facility.

The Public Notice announcement is here with all sites listed.

Here is list of Frequently Asked Questions. I’m not sure how frequently they could have been asked since it was only announced today… but I think we all know what they mean: here is a list of answers to the basic range of issues that will be coming up for discussion.

As I have discussed once before, I am a member of the Independent Advisory Panel that has worked with the Department to get to this point. I believe the process is on a very good footing thanks to what has been an excellent process. There were 28 nomination through the voluntary process, a much stronger response than anticipated. This goes to show just how well Australians can deal with these issue when we approach it maturely and fairly.

Inevitably, this day comes: the day when people in many communities are made aware that locations close to them are under serious consideration. It happens all at once, since the only other way is basically leaking information, which helps no one.

There will be concerns, there will be some outrage, there will be some statements made that are false and misleading. This is normal, can be addressed and cannot be avoided right out of the gate. I encourage everyone who feels they understand these issues to be very patient with fellow Australians because many of us don’t; most Australians have had little or nothing to do with the back-end of our active nuclear medicine and research activities.

To those who hold concerns, I would say please try to move to a position of curiosity: this facility will not be imposed on unwilling communities and there will be a great deal of information and credible sources available to you to learn about everything involved. I say with no hesitation that the eventual facility will be world-class and safe to people and the environment. In fact, compared to the type of waste facilities most people may have been exposed to, not to mention any other industrial facilities, I think most Australians will be pleasantly surprised (perhaps even astonished) at just how neat, well organised, well contained and inoffensive this facility will be.

I look forward to continuing to assist with this process. I invite media to contact me to ensure a perspective from the Independent Advisory Panel is represented.

Join me at Adelaide Sustainability Drinks

Next week I will be the guest speaker at Adelaide Sustainability Drinks.

Wednesday 18 November 2015, from 6 pm, Kings Head Hotel, Adelaide.

After 14 years of involvement, study, work and outreach in sustainability, I will be reflecting on how my perspectives have altered from then to now, with particular reference to my changed understanding of both human population and nuclear energy. I will describe what I think sustainability needs to mean for the challenges of the 21st century in what I hope will be a thought provoking presentation. Entry is free.

Not humbled, angered: The response to Fukushima is an ongoing mistake. Part 2

This is the second part of my recount of my visit to Fukushima from earlier this year. For part 1 see here. It has been a long time between part 1 and part 2. Apologies, much important work has come up in the meantime.

A word on Australia’s domestic waste responsibilities

The OPAL research reactor, Lucas Heights, near Sydney. This reactor produces much of the global supply of diagnostic nuclear medicine, dopes silicon for the high-end electronics industry, and uses the neutron beams to undertake a wide range of research.

The Adelaide Show podcast, coming tonight!

Last night I had a blast with Steve and Nigel from The Adelaide Showa long-running local podcast.

We chatted about climate change and a little bit of my journey on that subject, before I blew their minds with some of the possibilities of nuclear energy in South Australia.

I did the Is that news? quiz, where Steve and I had to guess the fake nuclear-themed news story from Australian history, sat on the Visa Council, where we decide whether someone can come to Adelaide or not based on a disparaging tweet, and helped polish off the Drink of the Week, a 2010 Gramps shiraz from the Barossa.

Here is a promo video, the podcast goes out tonight, listen in and share widely!