Category Archives: Renewables

Is nuclear a good investment?

In the much belated follow up to the eligibility criteria post on nuclear power, I consider the first merit criterion; is nuclear power a good investment? Is building a nuclear power plant a good way to turn a pile of money into a bigger pile? Or are there better ways of doing that?

Imagine you’ve been saving for a while and you have $50 billion burning a hole in your pocket and want to invest it in some clean electricity production. Nuclear looks okay, people keep telling you it’s clean and reliable, and everyone in the neighbourhood seems to have solar now as well, so might look at that too.

There’s a bit to consider; nuclear takes a long time to build, but once it’s running it produces electricity almost all the time. Solar is very quick to build, but only produces power when the sun shines. Which will give you more electricity from your investment?

In the first post I assumed an 8-year construction schedule, the Nuclear Energy Agency allows 4-8 years depending on where you are, and excluding permitting, finance raising and design. As this would be the first ever nuclear power plant built in Australia I think ten years is reasonable. It’s taken Hinkley Point, with full government support, at least two years to even decide if they’re going to build it and they’re expecting electricity in 2022 or so.

$50b is about the expected cost for the Hinkley Point reactor. For that price you get 3200MW, provided by two steam turbines. These will generate power almost all the time, for a modeled capacity factor of 85%. This might be a touch low, but it doesn’t make much difference in the model; the US hit about 91% capacity factor last year, a record, and their long term average is around 90%. France in comparison was closer to 80%, but nuclear makes up a much higher proportion of generation in France, so has to ramp up and down to follow the load. The construction period is about ten years, so construction costs are around $5b each year.

How much solar would that buy? I’ve been using $2/Watt as an estimate for about 18 months, and it’s probably a bit high now for rooftop where the installation market is very competitive. I’ve seen commercial systems go in recently at $1.1 – $1.4/Watt, but they have all been on flat rooftops. If you spend $5b a year on solar it will require more space than some factory roofs, so the cost of installing in a field is more accurate. These tend closer to $2.4/Watt, which is what I’ve modeled.

Solar’s capacity factor is quite easily determined using climate data, driven by maps like this from  the Bureau of Meteorology. Find the insolation, multiply it by the panel efficiency and it’s possible to calculate the average energy output per kW. Like this table. For the model I have assumed 4kWh/kW/day, slightly more than Sydney’s average, but a lot less than Brisbane, Cairns and Alice Springs. 4kWh/kW per day is an implied capacity factor of 17%.

Solar is much easier to build. Australia has been adding about 800MW each year for the last 5 years, without really trying. At $2.40/Watt, $5b will buy a touch over 2GW of capacity. That represents a pretty big increase in current installation rates, so maybe 2GW in the first year is a bit ambitious. If this were an actual 10-year program then your installation capabilities would ramp up and should easily install 2GW/year by the third or fourth. I have modeled a constant program of 2GW per year to keep it simple. Again this doesn’t make much difference to the result.

I also haven’t modeled any change in the price of solar, which is extremely generous to nuclear. Installed prices have roughly halved in the last 5-years, continuing the trend of the last 40-years. It would be quite reasonable to assume that the cost of solar would halve again during this period.

The price of nuclear hopefully doesn’t change during the build, although these plants have a bad record of hitting their construction quotes and timelines. This excellent article in Grist gives a summary of some studies into power projects and how often they run over time and budget. Nuclear is the worst, on average being more than 100% over budget, and almost 100% of projects running over time. Of generating technologies, solar is the most reliable, with average cost overrun of less than 10%, with 40% of projects running over schedule.

First the graph of capacity over time. Solar installs just over 2GW a year, nuclear installs nothing for ten years. This is just peak output though, nuclear can provide that around 90% of the time, solar less than 20%.


The interaction between capacity and capacity factor are shown in the annual output graph. Solar’s output increases each year for the first ten as new capacity is added, then decays over time as the panels degrade. I’ve modeled 1% reduction in capacity each year. Nuclear generates nothing for ten years, then 3200MW forever. Degrading at 1% solar’s annual output falls to match nuclear’s some time after year 30. The solar array would have replaced some panels and inverters by this time, but many of the original panels would still be working.

Annual MWh

Solar gets a massive headstart through easy construction and modular design, which theoretically generates electricity from day 1. Even with the panels degrading and nuclear power’s famous high capacity factor, it doesn’t generate as much electricity as solar until about 80 years into this scenario.

Cumulative generation

I’ve just realised that I graphed Year in all three. MWh 

There’s a gentle curve in solar as the panels wear over time, but in anything less than a 50-year investment solar is going to make more electricity per dollar than nuclear, by some margin. Solar provides returns much faster and with much lower risk than nuclear, with the strong chance that construction will get cheaper throughout a program, rather than more expensive. The numbers used above are extremely favourable for nuclear, assuming that the nuclear project will be delivered on time and on budget, which is demonstrably unlikely, and assuming that solar will not experience any cost improvement, despite doing the same thing every year for ten years, with a product demonstrated to lower its manufactured price over time. Nuclear produces nowhere near as much electricity as solar on conservative estimates and it’s only going to get worse.

The absurd complexity in manufacture and design of nuclear power plants is a weakness that leads to severe cost and timeline uncertainty, while the opposite is true of solar. No one will build a nuclear power plant in Australia without significant government intervention. And it won’t just require money, but the political stamina to commit to a project of staggering cost and no discernible output for over a decade. It won’t happen. Nuclear has already lost.


A letter to the Federal LNP

I got angry about climate change again this week, in particular this stunt by NSW Liberal MPs. With my blood up after my first coffee for the day I wrote the below and sent it off. Maybe there are some points in there you’d like to take to your local members? Politics aside, the ACT’s response to climate change is the most appropriate in the country. It only appears radical because everyone else, particularly federal politicians, are doing so little.


Good morning Ms Goward,

I note with disappointment your media event and associated opposition to the ACT’s ambitious renewable energy plan. Two things in particular are disappointing and I would have thought below you. First, the idea that electricity should be produced in the region it is consumed, or any other product for that matter, is absurd and not how we have ever operated. Do the people of Lithgow complain about hosting our power plants? Do you drive out there and apologise from time to time? Do you feel guilt that the cheap power that has driven our economy is killing the residents of Morwell? A functioning economy has always depended on distributing costs and benefits and electricity generation is no different.

What I am most disappointed about though is the argument against the ACT’s principled stand. It appears from the article in the Canberra Times that you said “Ninety per cent by 2020 is really quite outrageous – it’s pandering totally to a green movement. It’s unrealistic, it’s impractical and wind turbines are notoriously unreliable as well.” This amounts to you asking the ACT to stop being ambitious. Their action is making you and the laggards in the LNP look bad. Rather then try and work harder on your own response you try and bring others down. It is disgusting and will be viewed with utter contempt in years to come.

You have an opportunity to do the right thing by your electorate and their children, by being ambitious and taking action. Yet you choose to bring others down instead. Party unity is one thing, doing the right thing something else entirely.

Why not think about the jobs in your region? Or the health benefits that come from reducing coal use and mining? The Goulburn region has a stunning wind resource, that can bring jobs and money to the region. While climate change ruins farms and rain patterns, you choose to do nothing and stand in the way of a new income stream for these properties.

I hope you change your mind and support the most ambitious and appropriate government response to climate change in Australia at the moment. I have not read a report yet that thinks Direct Action will work, and there are no penalties if it doesn’t. If you are serious about addressing climate change you can stand up and say something. If you are not, history will judge you very harshly.

I am available to speak further about this on [mobile number] and happy to discuss more appropriate policy responses to climate change if you desire.

Evan Beaver

More like Urgh Hour

I’ve been complaining loudly this week about how ineffectual Earth Hour is and as a result how much I hate it. I despair that this massive, well organised and well funded marketing machine has set their sights on getting people to turn their light off for one hour, once a year. Anyway, this is an old hobby horse of mine, and if you want to hear more, follow this link to my TEDx talk from last year.

What can we do then? What concrete actions can we take, and could Earth Hour promote, that would contribute to de-carbonising our economy and making our lives more energy efficient?

Buy GreenPower. This commits your electricity retailer to purchasing enough renewable energy to cover your use. This is a cost and effectively subsidizes renewable electricity sources. It is additional to the mandatory renewable energy target and audited by a federal government agency. I trust it absolutely, noting GreenPower is a product, and many electricity retailers have “green” supply options, which might not all be renewables. If everyone was on GreenPower Australia’s decarbonising job would be done.

Contribute to a community renewables project or put solar on your roof. Community renewables include: Hepburn Wind, SolarShare who I volunteer with or this excellent project in Freemantle. If you want solar on your roof use an accredited installer sourced through the Clean Energy Council.

Buy more efficient appliances. Chances are if your fridge is more than ten years old you should replace it, and the energy saving will cover the cost of a new fridge in 6-10 years. You can compare the efficiency of all sorts of new appliances here and there are calculators to work out how much you can save. I encourage you to leave the sticker on these appliances, or move it to the back, so you can make comparisons later and understand how much energy different things use. The star system is an indication of how efficient a unit is compared to a standard, which is updated periodically. To get a feel for how much different appliances use, compare the kWh figure, the number printed in the middle of the sticker. As an example, our fridge uses 320kWh a year, while a big plasma TV is closer to 450.

Ride your bike more!

Make your house more efficient. I’ve got a blog post here on how to make a Canberra house more efficient, and here at the Conversation on how to control heat flows in your house.



If the answer is nuclear you don’t understand the question.

When selecting technology to solve a problem, a common method employed is to have “eligibility criteria” and “merit criteria”. Eligibility criteria are the must haves; if you are selecting a new machine to generate electricity “does it generate electricity” is the obvious one. Eligibility criteria are all pass/fail tests. Merit criteria are what you use to split all of the options that pass. Say you’re comparing a diesel or natural gas engine to power a remote site, a merit criteria could be “is fuel available all year round?”

In this post I will focus on the eligibility criteria for powering Australia while reducing the greenhouse gas emissions associated with electricity production. I will spend a long time arguing that, no, nuclear should not be considered, because it is utterly incapable of solving the problem. In later posts I will discuss the merit criteria, where again nuclear falls down.

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Levelised Cost of Electricity: What is this?

Levelised Cost of Electricity, or LCOE is a means of comparing generation technologies, by considering the cost of the electricity that comes out over its lifetime. Simply put it is the lifetime sum of all the costs; construction, planning, maintenance, land purchase, waste disposal, pollution charges, mining, divided by the amount of electricity produced during it’s lifetime. Choosing some non-indicative numbers, if you spend $2000 installing solar panels, and they generate 4000kWh over their life time, your LCOE is 50c/kWh.

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Climate Change Reporting and the Truth

I’d wondered previously how much “cherry picking” goes on among those who report on climate change, in particular those unique individuals who do not believe that climate change is a real thing and no we really shouldn’t do anything about it.

The “windmills don’t stop coal being burnt” report doing the rounds this week has been an astonishing example. Here’s my take on it from last week.

The centre of the story is Hamish Cummings, retired engineer, who made some phone calls and used some AEMO dispatch data to conclude, fairly ambitiously, that when the windmills come on the coal plants don’t turn down, so the windmills aren’t doing anything. This showed conclusively, using “real data” that the windmills weren’t contributing. It was seized upon enthusiastically by Jo Nova, Independent Australia, Andrew Bolt (whose comment moderators deleted my link to the post where I strongly disagreed), Australian Climate Madness, and of course The Australian.

All of these outlets thought a story on the carbon intensity of the grid and whether or not windmills influenced it was worthy of a story.

No doubt then all of these people will be happy to know there is an index of carbon intensity, published monthly by Pitt and Sherry, who like Hamish, are engineers.

It shows pretty clearly that in about 2009 emissions stopped following the pattern of demand and started decreasing. It also shows a corresponding decline in black coal and an increase in renewables. Brown coal is probably not the first to go in the bidding order because it is the cheapest. The recent carbon price will have an impact on that though.
So a retired engineer releases a report, based on phone calls, letters and publicly available network data (read very low resolution) completely disagrees with an index which has been published monthly for years, and they publish the retired engineer. I suppose I shouldn’t be surprised.


Tristan over at Climate Spectator has a good post on this as well.





Sigh. Windmills Don’t Work Because Coal is Baseload

I suppose I shouldn’t be so despondent about this article; nonsense like this is why I started this blog. I am referring to an article in the Australian yesterday, which talks about a study which suggests that wind-farms don’t actually save any emissions, because the coal fired power which they are displacing is baseload.

It ran in the Australian, so to engage with this “debate” you’ll need to follow this link, then click on the first article “Hopes of slashing greenhouse emissions blowing in the wind.” Go and read the whole catastrophe and come back.

While you’re at it, if you haven’t read the first baseload post here that will provide some background.

The thrust of it is some research conducted by Victorian mechanical engineer Hamish Cumming, who has looked at “publicly available data” and determined that because there is no evidence in these data that the coal plants are burning less coal, then obviously the windmills aren’t abating any carbon.

I will leave aside the carbon permit and subsidies claims, that will take another post to tackle properly, and concentrate on this analysis. How right is he? What assumptions support these findings? Is the data actually available to make this determination?

From the article: “A forensic examination of publicly available power-supply data shows Victoria’s carbon-intensive brown-coal power stations do not reduce the amount of coal they burn when wind power is available to the grid.”

Is evidence of whether or not the coal fired power-stations are ramping down when wind comes on, evidence that the turbines are abating carbon? No.

The only reliable measure of how much carbon is abated by renewables and whether or not they are making a difference is in the long-run averages; by looking back over a year of data and comparing the MWh generated across the network with the tonnes released. If we start generating more electricity per tonne of CO2 then both renewables are contributing and the carbon price has had an impact. The data that is being described above does not include any hard data about tonnes emitted; this is a closely kept secret of the generating companies as it directly affects their competitiveness in the market. Note too that he has only considered Victorian power-stations; there is no requirement that the stations that power down are the ones near by, nor any requirement that the most polluting ones power down. Sure, it would be good if that did happen, but current thinking is that with a carbon price the most polluting plants will be proportionally less competitive, and so will be dispatched less frequently. If abating carbon was the only goal of the market then the bidding order would be based on carbon intensity and Hazelwood would only get dispatched a couple of times a year. But, the market is based on cost, with the addition of a carbon price a pollution proxy and so the most expensive generation is turned off first. Not the most polluting.

“Cumming says surplus energy is wasted to make room for intermittent supplies from wind.”

I have considered a whole post on this idea previously, but we can tackle it now. This statement show a disturbing lack of understanding for how electricity and the network actually operate, with a fair degree of entrenched baseload thinking to really skew the statement . What on earth is surplus energy? Our grid operates on alternating current (posts on this are at my old blog, here, here and here) and is managed to maintain frequency. Demand loads come and go during the day and generation is tuned to meet demand. If the frequency drops that means more demand has come on and so more generation will be dispatched. Obviously the reverse applies as well. The frequency is managed extremely tightly; if it gets too far from the 50Hz that equipment across the grid is designed to use, that equipment starts breaking. So frequency is managed to 50Hz, +/- 0.15Hz and if it goes beyond that emergency protection settings are enacted and loads get dumped. Note that nowhere in here is any mention of surplus energy (actually electricity, but that distinction doesn’t seem to matter to many). We always generate exactly the same amount of electricity as we use. Always. So while the signal of Victorian brown coal generators turning off at exactly the same time as wind turning on is not visible, it is wrong to use this information to make claims about whether or not any greenhouse emissions have been saved.

“Cumming’s findings have been confirmed by Victoria’s coal-fired electricity producers and by independent energy analysts who say it is more efficient to keep a brown-coal power-station running than turn it down and then back up.”

There is some ambiguous language here, but I am sure that the coal-fired power-stations would have confirmed that they prefer not to change load. That’s what baseload means. That doesn’t mean that they can’t or don’t change load and nor does it confirm the findings. A fairly typical 250MW turbine can change generation down to 30% of its rated load, at increments of about 5MW per minute, and a typical power-station will have 4 of these turbines. These generators have always had the capability to change loads; demand has always been changeable, and there is no network difference between an decrease in demand and an increase in generation. So wind turbines or other intermittent generators are just another element dragging the grid frequency away from 50Hz, but it is entirely manageable.

Here is the reference for the coal data used in this study:

In a letter to Victorian Attorney-General Robert Clark, Cumming said the owners of Yallourn, Hazelwood and Loy Yang power stations had confirmed in writing that the power stations combined consume about 7762 tonnes of coal an hour.

“They have confirmed that the power stations do not change the coal feed intake 24 hours a day, seven days a week, 365 days a year. The coal consumed by these three power stations alone makes base-load power available at a rate of 6650 megawatts,” Cumming wrote.

Given that Yallourn is partially under-water we know this is not true.

Beyond that though, this is an extremely technical field and I would expect this sort of analysis would have to include actual feed-rates of coal, compared to output, correlated across a wide number of sites, to have any hope of making the claim that wind-turbines do not displace coal fired generation. This seems to be an anecdote, aggregating across four (Loy Yang A and B) major power-stations and based on the assumption that output is constant.

There is one extremely technical point that is a possible mechanism for wind power not abating emissions, and I would be reluctant to say which way this fell. Baseload plants have a Best Efficiency Point, when their electricity produced per tonne of coal is maximised. Any deviation from that point means slightly less efficient generation. But there are two problems with this; the change in efficiency is minute and it assumes that the plant was already operating at its best efficiency point. The whole-cycle efficiency of a plant might be 30% plus or minus just a couple of points, until the extremes of their operating range. The question then is does efficiency move so far that it wasn’t worth turning the wind turbine on at all? Only long run data will confirm or deny this. Ditto with the operating point assumption. There is just no point commenting on the electricity network unless you have reams of data. It’s too complicated not to.

This study has been quite widely covered, getting a run with Andrew Bolt, Jo Nova and the piece above in the Australian.

One hopes that those mentioned would like to discuss an alternative viewpoint. I am also a mechanical engineer and I’ve got a bit of an idea how electricity works. While Hamish Cummings analysis is a valuable contribution to the debate, I think it is a starting point only, and would strongly benefit from some more data. It is not possible to make those findings from the data presented.

I’ll post this on their blogs and we’ll see how it goes. Maybe if you see someone else running this line you could point them here. I think we could have a more nuanced discussion than this.
And big hat-tip to reader @andrew_hedge who pointed the Oz piece at me.
PS I’ve had some twitter discussions since this about what the actual abatement is: this report is a good starting point. But, these are modeled values which will upset a lot of people. Like I said, long run data is the only way to crack this one.