General Forum

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francis Subject: Next generation CCGT Date: 2011-06-09 (at 18:33:09)

This next generation CCGT is designed for a renewables heavy grid:

"The FlexEfficiency 50 plant using GE's advanced 9FB Gas Turbine is rated at 510 megawatts with greater than 61% efficiency, significantly reducing the amount of fuel needed to create power. The plant achieves a ramp-rate of more than 50 megawatts per minute, twice the ramp-rate of today's industry benchmarks. The technology allows the plant to turn down to 40% of its load while maintaining emissions guarantees and it starts in less than 30 minutes. It can be integrated with a concentrated solar power field to achieve more than 70% efficiency and it offers a 10% smaller footprint than existing combined cycle power plants with equivalent output."

http://www.ecomagination.com/technologies/flex-efficiency/

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Francis Subject: more scene setting Date: 2011-08-16 (at 12:39:07)

Following from [68] above, here I make some brief comments to flesh out points 1-5, after a little more scene setting.

OzEA is sitting on plans to develop work to date (i.e. here) to achieve a spatial and monetised high-level model of the NEM. When implemented, this will provide a basis for quantitative analysis of high penetration renewables, both in terms of supply variability dynamics and electricity cost. Before proceeding to implement the necessary machinery, it is necessary to justify the work in terms of the results it can provide. Here, we are engaged in this process; an open process where interested stakeholders are encouraged to contribute and comment.


1. Transmission system analysis from a renewables perspective
The aim is to explore the economic trade off between transmission and dispatchable supply capacity. That is, for given 50% renewable supply configurations, want to find the combinations of transmission links and gas-turbines that give the required system reliability at least cost.

2. Renewables, smart grids and system stability
We set aside the problem of very short time scale variations, as from clouds passing over PV, and focus on the peak shaving and smoothing capabilities of putative and reasonable smart grid scenarios. To avoid get bogged in the detail of residential and industrial demand management, we use a comparatively simple demand-smoothing heuristic (somewhat like that already used to model Pumped Hydro Storage). The benefit derived from a given level of demand smoothing can be valued from the simulation runs. It is then a separate analysis to compare this benefit against a concrete smart-grid configuration that would be needed to achieve the modelled level of demand shifting.

3. Evolutionary paths to 50% renewables (via 20%, 30% and 40% 'stepping stones')
To start, we take a nominal timeframe for 50% renewable electricity in 2040, with 20%, 30% and 40% stepping stones at around 2020, 2028, and 2035 respectively. Keep in mind that this exercise is complicated with many known unknowns, including in technology development (e.g. geothermal, ocean power). The approach remains to work with wind and solar. Using reasonable constraints and projections, sketch out plausible deployment of renewable supply to the 50% level. The task is then to critically analyse scenarios in relation to the demand-remainder dynamics (i.e. the cost of ensuring that supply and demand remain balanced).

4. Identifying potential 'market failures'
Don't want to overstate this. Following from above, and supposing OzEA has identified important aspects of an attractive path to high-penetration renewables, the question turns to the market incentives that attract or repel the system from taking on these aspects.

5. The cost of achieving 50% renewables
Two levels are apparent here. The first is using cost learning curves (for example, for solar thermal with storage) to inform (3), and to otherwise give a high-level exposition of the tension between timeframes, costs, and the difficulties of looking ahead several decades. In contrast, with an established scenario, pathway, and analysis of market mechanisms, it can be possible to estimate an overall cost. This sort of headline cost figure can be fraught, but can also provide a basis for considered debate and discussion.


On a slow rhythm I will proceed to work through these aspects in some more detail, and to otherwise engage and respond to questions and comments.

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Francis Subject: response to #70 Date: 2011-08-30 (at 13:07:16)

Thanks Ben -- it is interesting what you say about rapid transitions from strong wind to little wind; I suppose that such events are reliably forecast, thus allowing the transition to be managed.

4GW of fast acting reserve is also well within the available hydro (7.8 GW installed capacity according to ABARE), and less than double the existing Pumped Hydro Storage capacity.

My thinking, based on what we've done and seen to date, is that 50% renewables is quite possible to integrate into the NEM without needing too much extra redundancy in the fuelled supply. The first task is showing this in black and white, and requires some months dedicated work. Then, the issue becomes the trade-off between cost and timeframe, along with intelligent big picture analysis of the various cost tradeoffs that need to be considered in searching for least cost paths. The aspects that trade off include: transmission, smart grid / demand management, storage (including use of hydro and thermal storage within CSP plant), peaking gas turbines, and perhaps within-distribution-network PV.

More or less whatever happens with OzEA funding, we need to wrap what we have and whatever we can manage on top, into an academic paper. You've certainly earned a place in this. Part of what I am doing here is balancing the need for forward plans with the need for certain follow on work that will cap off what we have.

More thoughts from me in about ten days -- I have a boating adventure to go and do.

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francis Subject: NT Green Energy Taskforce reports Date: 2012-01-16 (at 19:32:03)

The NT Green Energy Taskforce reports have finally been made public. Local copies here: Report 1: Roadmap to Renewable and Low Emission Energy in Remote Communities, and Report 2: An evaluation of the relative merits, feasibility, and likely costs of the potentially available renewable energy technologies to be used in the NT, including geothermal, solar, biomass and tidal.

The first report recommends particular action, the second recommends only research and capacity building. Here I provide a few comments on each.

The first report recommends that 10 MW of solar (flat plate PV) be installed in 46 remote communities that currently generate electricity from diesel. The solar power component is not to exceed 30% of peak load, thus enabling straightforward integration. Cost is estimated at $60 M ($5.50 per Watt installed + planning overheads), with displaced diesel to save some $90 M over 20 years in todays money (17% saving on diesel use gives 4.5 M litres displaced annually, priced conservatively at $1 a litre).

This would provide the NT's Power and Water corporation with 7% of the RECs it needs through to 2030. The report also recommends development of options for 100% displacement of diesel in remote communities.

Such a roll out can act to build capacity in the NT for mid-scale solar installations. Also, some of these communities may be suitable and willing to be test sites for demand management and other systems that enable higher solar penetration.

The second report looks more broadly at how the NT Power and Water Corporation (PWC) might meet the MRET by 2020 (i.e. around 300 GWh per annum of eligible renewable generation). The upshot is recommendations for the NT government to hold off on any sort of direct subsidy and instead work around the edges to remove barriers, promote and attract research and capacity, and see-what-happens up to 2015. There's a fair bit in there, and perhaps I'll comment again after further digestion.

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Peter Lang Subject: Simplified transmisison analysis for interstate interconnectors Date: 2012-02-18 (at 19:06:39)

Ben McMillan @ #70, you said:

"I could do a highly-simplified version of my transmission analysis, with only state-to-state links, and no automatic optimisation of links, if that would be useful. That would be more amenable to producing a bunch of graphs to get a feel for what is going on."

Would you be in a position to do your simplified transmission analysis for the case I've attempted to estimate very crudely (see Appendix 2 here: http://bravenewclimate.files.wordpress.com/2012/02/lang_renewable_energy_australia_cost.pdf
And spreadsheet showing my calculations here:
http://bravenewclimate.files.wordpress.com/2012/02/renewable-electric-nem-the-cost-v0-05.xls

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francis Subject: Re: Peter Lang (#74) on EDM-2011 Date: 2012-02-22 (at 11:14:58)

Re: http://bravenewclimate.files.wordpress.com/2012/02/lang_renewable_energy_australia_cost.pdf

Peter, thanks for dropping by. As I emailed you a few days ago (so for the benefit of others) I've had OzEA on life support since July 2011, but hope to have a new academic appointment soon that will allow me some time for picking up key OzEA threads as you identify. So, no, there has not been tangible progress here on the balancing act between transmission and gas turbines in a high-renewables NEM.

Before making other comments, it is hopefully no surprise to anyone that I contend 100% renewable scenarios to be primarily polemic and not especially useful technically, except perhaps as limiting cases. For those who have not read it, I refer back to The First Story - Scoping the Problem, and specifically the point that "looking ahead forty or fifty years is really difficult ..." The interest here at OzEA is the 30%, 40%, 50% levels, as an evolutionary integration into the existing systems.

That said:

The Elliston et al. paper (EDM-2011) is a fairly rough cut, or "hello world", take on high-penetration renewables. Ben Elliston is a PhD student cutting his teeth, and I expect we'll see refinement and evolution. While your critique makes its point well, it is unsurprising that costing their scenario ends up at over $300 per MWh for the electricity. Of course, as you spell out, there are other more specific issues that need to be appreciated.

In terms of transmission analysis, and noting Ben McMillan's comments above, I think the important point is that one does not run individual radial transmission lines at rated capacity for each renewable plant to major load centres. Some sort of daisy-chain or other more networked approach gives better utilisation of the transmission capacity, and (as Ben McMillan worked through) you get a distribution of putative flows with a tail for chopping. A larger number of renewable plant sites, strategically selected and intelligently wired up, will require much less new transmission than your current critique involves.

Peter Lang's critical analysis of the cost implied by the Elliston scenario is a valuable contribution, and I read it very much in that way. The challenge (for those of us exploring renewable energy scenarios) is to appreciate the issues raised, and to incrementally develop and refine renewable scenario-ing into more and more tangible propositions. I'm keen to see if I can get a 'Lang costing' to come in at less that $100 MWh (for 50% renewables) before anyone else does. (-;

A plug: I've recently been getting familiar with the BoM gridded solar data, and am now looking to pull together ~100 putative sites where we might include solar plant in scenarios, or otherwise have some interest in irradiance time series. See here. This will in time lead to an improved OzEA scenario.