If you follow the various high profile 100% renewable energy advocates, Mike Cannon-Brooks, Simon Holmes a Court and anybody in the Greens, you'd probably be wondering why the Australian Energy Market Operators (AEMO) is bothering with a Renewable Integration Study. Isn't it a done deal that renewables can power the grid? Isn't it easy? Adam Morton wrote about RIS in the Guardian back in April, and the take home message conveyed in his opening paragraph was precisely that ... and totally different from the tone of the actual study ... or even of the AEMO press release.
Given that the article was published on the same day as the press release and the report with its appendices comprises some 260 pages of sometimes very complex material, it's unlikely Morton read much of it. That's the thing with journalists, they have far too much to read and everybody wants the story on the day it "happens". Even if he got an advance copy, his opening paragraph tells me he didn't read much of it.
Here's what Morton started with. It's a great opening, well designed to suit readers who won't finish the article; those in love with TLDR.
Australia already has the technical capacity to safely run a power grid in which 75% of the electricity comes from wind and solar and, if it gets regulations right, should occasionally reach this level within five years.
Seriously, after that start, who would bother to read the rest? We are it says, on track for 75% wind and solar, the grid will be just fine, all it needs is a little regulatory tweaking.
The RIS study has a subtitle of "Stage 1". Gosh, does that mean there's more? Perhaps they'll cancel the other stages after reading Morton. How hard can it to tweak some regs?
It's Stage 1 because AEMO has a vast mountain of work to do to try and work out how to deal with the quivering steaming mess that politicians have dumped in its lap.
If you read the report and its appendices, you'll find bits like:
... resulting in increasing contingency sizes following transmission faults due to the potential mass disconnection of DPV systems.
"Mass disconnection" sounds disturbing? Even if you don't understand all the jargon.
And how about:
AEMO has identified an urgent need for DPV generation shedding capability over a sufficient proportion of the DPV fleet as a critical back-stop mechanism for maintaining power system security in the South Australia region as daytime operational demand continues to reduce.
What does this mean? It means that AEMO urgently needs to be able to shut down large amounts of rooftop solar to prevent blackout risks in the late afternoon in SA.
I could list many more. The RIS is 260 pages of warnings about problems in our grid. Complete with examples of near misses and serious failures.
Translate all that dry technical jargon into normal language and you'll detect an organisation under siege. It's tough being continually told to solve some really tough problems while being in a state of near panic; because this isn't a game, people can die during blackouts. On the other hand there is also the excitement of living on the edge and doing some really complex, interesting and geeky engineering. It's like going downhill on a bicycle at 80 kph feeling both the exhilaration and the terror of there being just 2mm of rubber between you and disaster.
Let's unpack Morton's paragraph starting with a graph from the study itself. The RIS has some very complex graphs, and the one below is one of the more simple ones, but it comes from a family of related graphs with its own separate fact sheet to help you understand it; the "Instantaneous penetration summary graphic"
The RIS study does not say, as Morton claims, that the grid will cope with 75 percent of it's electricity coming from renewables, rather it says that given a massive technical effort which may well involved dumping and replacing substantial amounts of hardware, plus a substantial research effort to solve problems that nobody else in the world has yet solved, then yes, it should cope with a peak of 75 percent coming from renewables ... meaning wind and both rooftop and big solar farms. So now look at the graph ... don't just glance at at, but read all the text around it and think about it. My explanation will mean more if you've made an effort yourself before you read it.
Each dot represents half an hour. Pick a grey dot on the graph. It represents an actual half hour in 2019. There will be 17720 of these half hour bits during each year. The dot's position on the x-axis tells you how much renewable energy was available as a percentage of what was required. Some of the grey dots are close to the 50% line. But what about the preceding and following half hour? How do you know where they are? You don't. You'd expect those pre and post half hour dots would be close to the first dot, but the fact that there are big gaps between some of the dots tells you how volatile the electricity system is.
Now look at the cloud of red dots. Notice please that their is more space between them than the grey dots. And the orange dots? There's more space again. Think about that for a minute ... keep thinking ... I'll come back to it.
What AEMO says is that with plenty of hard work, they can cope with some red dots (half hour chunks) on or below the 75 percent line. But the red cloud is AEMO's best guess prediction of the state of the power supply in 2025; and some of the red dots are on the other side of the 75 percent line; the side they are not confident of handling. So the RIS study is telling you to prepare for blackouts in 2025, even if they succeed in achieving all the changes they outline in the RIS report.
If you read the AEMO fact sheet about this graph (and a more complex cousin), you won't find them talking about blackouts. Instead, they talk about regions on the graph "where inertia and system strength limits impact secure operation" ... meaning times where they have to take dramatic action ... perhaps "load shedding" ... where some people are blacked out in order to prevent everybody being blacked out. Perhaps "curtailment" ... taking some wind farms off line ... in addition to selective blackouts. Rest assured AEMO will move heaven and earth to keep the lights on for as many people as possible, but the public and our politicians are making this incredibly hard.
The cloud of orange dots represents a scenario where renewables are rolled out far faster than they have been to date. It's called the "Step Change" scenario because that's what it represents ... a dramatic shift in policy. And now you can see that the number of dots on the other side of the 75 percent line is considerable.
Note the orange cloud is more sparse than the red cloud. Have you thought about it? Where two dots representing two adjacent half hours are a long way apart, then that means the output from the renewable sources is very different. But what you need in an electrical system is smooth gentle changes. Big changes bust things. Rate of change of frequency (RoCoF) is one of the jargon terms for measuring potentially damaging changes. .
But what about the other end?
Morton focused on what he thought was good news, the fact that the grid may be able to cope with dots on the 75 percent line. But what about the other side? Look at that orange cloud of dots ... those on the left are largely underneath the grey cloud, but there are clearly plenty down there. Even with a massive increase in renewable rollout, there will still be times when they provide very little energy. Which means we actually need two electricity generation systems of much the same size ... the renewable one and the one for when the renewable one isn't producing much or anything ... the windless evenings and nights and those dark winter days.
Will that other system be gas or batteries (including hydro)?
Miners in many countries are scrambling to scale up output of battery materials, meaning more children in the Congo engaged in what is euphemistically called artisanal mining to get more cobalt ... and many mines are ramping up for more lithium, graphite, nickel, copper and vanadium; to name but a few. But China has a monopoly on the downstream processing of many items on the supply chain and she isn't happy with Trump's hi-tech trade war. Will she retaliate in the battery sector?
In any event, the answer in Australia is clear; the second system will be gas. While the Greens have spent decades fixated on opposing nuclear power, the gas industry has been beavering away unimpeded ... building 39,000 kilometres of gas pipelines and terminals and opening gas fields. Those who have spent hundreds of billions in infrastructure will not crawl quietly away into the dead of night. Globally the picture is also clear, there are already 1.89 million km of gas pipelines and growing fast. Tipped to hit 2.03 million km by 2024.
AEMO's challenges and risks
Morton talked in his opening paragraph about getting regulations right. This totally misrepresents the challenges AEMO faces. Here's another image from the body of the main report that gives you a more accurate idea of the problems.
Let me explain what goes on in our electricity grid so that you can make sense of this graph.
Every 5 minutes, yes 288 times each day, software on the NEM generate a stack of equations that represent the state of the system and the things that need to happen during the next 5 minutes. Do you remember simultaneous equations from high school? It's a bit like that except that there may be hundreds of equations and thousands of variables. That system gets solved by linear program software and adjustments are made in grid operations for the next 5 minutes. This happens over and over again ... 12 times every hour.
The graphic shows the difference between the current problem (down in the yellow region) and the change in complexity as you add more intermittent power sources to the system. The program that solves the equations in a few minutes every few minutes will take hours to solve the more complex problems with more equations and variables ... except that nobody has hours ... all they have is 5 minutes. I used to work in the transport industry and our problems were even bigger ... they'd run over night, or over the weekend.
Take careful note of the vertical axis of the chart. It starts with seconds at the bottom but it finishes with hours at the top! This tells you that something serious happens as the problem grows. Perhaps it's structure changes, or perhaps the number of equations blows up ... that's a technical term mathematicians like to use when something gets really big really quickly.
The three boxes on the right represent three levels of problems and the expanding quarter of a circle shows how the time to solve the problem goes up very very rapidly with the complexity.
So the NEM engineers may actually have two really tough problems. The first is to generate the equations required for an increasingly complicated system. It's difficult to explain in lay language but sometimes in this kind of mathematics, a seemingly small structural alteration can change the nature of the problem and make it either unsolvable or impractical to solve. In which case you have a second problem ... to find a method to simplify the problem back into one you can solve ... in 5 minutes. And of course ... the solution to your simplified problem had better also solve your actual problem. This complexity is why engineers and mathematicians all over the planet are publishing papers and research on the various facets of the renewable integration problem.
To pass this off as "getting the regulations right" is just wrong.
Here's an example of two similar sounding problems being very computationally different.
Suppose you are a postman and you want to go along every street in an area and do it as efficiently as possible. Ideally, you'd go along every street just once. That's an easy problem, meaning that a brilliant mathematician has already come up with a good method that can produce an answer quickly, even when you have a huge number of streets. Here's a similar sounding, but really hard problem. Suppose you are a postman and you have a bunch of postboxes to visit to collect mail. You want to visit all the boxes while travelling the least distance. It sounds really similar to the first problem ... but the first is easy while the second is hard! Being "hard" means that finding an optimal solution soon becomes impractical as the size of the problem grows. Being "hard" also means that some really brilliant mathematicians have shown the it's extraordinarily unlikely that anybody will ever find a method that will solve the problem quickly.
One of the (many) reasons there is so much money being invested in quantum computing is because of the promise of quick solutions to the second kind of problem ... which is usually called the Traveling Salesman Problem.
One of the complexities AEMO is struggling with is that when you connect inverters to a grid, whether on a wind farm or a rooftop solar system, it isn't only a matter of "how many"; nor can you simply aggregate them ... because, according to the RIS, exactly where they are in relation to each other can effect how the system behaves. Calculating how these will respond when a wind farm goes off line is difficult. And connecting a thousand inverters may result in a problem that is more than a thousand times harder to solve. As a consequence the RIS explains that AEMO is actively working to change the standards on inverters. Change how they are made. RIS also speculates that it may be necessary to replace or retrofit all (or perhaps just most of) the current inverters on the grid.
And that's just the beginning
The RIS doesn't use the word "blackout" at all in its 260 pages of study + appendices. But the much scarier term "black system" get plenty of use in Appendix A of the RIS. Under normal conditions, the software churns out solutions every 5 minutes, and the system is adjusted in accordance and everybody can relax. But when there are problems outside the norm, then skilled operators have to step in and take control ... start giving orders to bring one or more generators on line or take some off. Here's a RIS chart showing the number of times this has been happening since 2014. You can see that as the complexity has grown, so have the number of times people had to step in and override the automatic processes. There are 8,760 hours in a year, so having the NEM subject to manual intervention for over 1,600 is quite extraordinary and demonstrates how increasingly fragile the system is becoming.
But the problem with rooftop solar, is that most of it is behind the meter and can't be turned off. Victoria is the exception with its smart meters. These were rollout between 2006 and 2014 at a cost of over $2 billion, but an Auditor General report in 2015 said that only 0.27 percent of people had enrolled in the "flexible pricing offers" that was one of the big advantages touted for these meters. As a result of this failure, no other state has rolled them out. The real reason d'etre of smart meters isn't really to help consumers, its because they can act as a bandaid for a fragile grid. They can help you at least see why your system is
crashing. All kinds of economic commentators panned smart meters because they thought it was interfering with the God-like capacity of markets to solve problems. Markets don't keep the grid reliable and safe, engineers do.
AEMO wants to mandate changes to inverters and meters to help them control the system. But the big issue with consumer grade solar systems is the price. They are built to be cheap.
Industrial level electrical gear has heavy filtering to withstand large voltage fluctuations which can occur when something like a pylon collapses in a high wind. Consumer level inverters may simply turn off. So imagine you have large amounts of rooftop solar powering away and you get a fault ... then inverters can just shut down! This isn't a big deal with low levels of penetration, but at high levels, it's a serious matter. Oops ... suddenly the grid has to find a huge chunk of power from somewhere. To avoid a black system ... AEMO jargon for a massive state wide blackout ... AEMO has to ensure more backup power is available than would otherwise be required. The RIS appendix A is devoted to the problems caused by high levels of rooftop solar ... and that's just one of them. Here is a list of others ... I won't explain them all, that would take too much space. So here's a quick list of problems: over voltage, inverter settings issues, under voltage, power quality, voltage regulation, phase balance, thermal capacity, tap setting, thermal capacity (there are two problems in different parts of the grid with the same name), voltage regulation (again), voltage set point, fault discrimination, low background fault level.
It's worth talking about fault discrimination. As levels of rooftop solar rise, they can change the direction of current flow in ways that were never anticipated by earlier power engineers. This can lead to "simple" problems like breaking devices that weren't designed to have current flowing both ways, but other problems are worse. Finding faults becomes far more difficult. Imagine water flowing down a pipe. If it doesn't come out the other end you can work your way back up the hose, opening and closing inspection holes until you find the blockage or hole. Now connect taps to the pipe and start pushing water in. Push in so much that it starts flowing in both directions. Now try finding your blockage or hole!
In my experience, AEMO puts some of the most important stuff in the appendices of its various reports so as not to frighten the Morton's of the world with anything unpleasant. The people at AEMO write carefully worded press releases and executive summaries and put the important stuff where it won't get too much attention. But, of course, the appendices are absolutely essential for the many people who need (or want) to understand what is actually happening rather than what is politically expedient to expose to the deep investigative scrutiny of the renewable cheer squad sometimes posing as journalists in Australia.
The people shouting cheap, cheap, cheap about renewables rarely talk about the full price of trying to make a reliable grid out of unreliable intermittent sources, including consumer level junk electronics. But of course, the gas industry just loves these people, they have made it indispensable.
There is an alternative
There is an energy source which is both clean and far more environmentally benign than wind, solar, biomass or hydro. It also avoids further complexity in our grid. It is of course nuclear power.