Tom Murphy’s paper reveals something I also fell for back in the day

I again owe this next post to Mike Stasse’s indefatigable efforts to quote the dishonest (Michaux) or irrelevant (Murphy). With Mike, it goes like this. I show a fundamental error in one of Mike’s heroes – an error so blatant even Mike doesn’t have a comeback. So rather than discuss it any further, Mike just diverts attention from that error and moves onto another one!

Mike – if you showed me a massive error like Michaux “Painting the world Singapore” – and basically pretending the whole world’s stock of hills and mountains was no more than 15 metres high like Singapore’s – then I would eat humble pie and publicly apologise on my blog for quoting a bad source. For example – In June 2022 I changed my mind about renewables, saying I now thought they had a shot. Mike – you should try it. Now you know Michaux’s a fraud – you really should pop back on to the Ecomodernist show and recant “following Michaux”.

But I must be honest – I shared Tom Murphy’s opinion back in the day. It was a different world with wind and solar an order of magnitude more expensive than they are today. I even wrote about it here – (but I have since deleted those posts in shame). My concern back then was about the sheer COST of OVERBUILDING a renewable grid to make it reliable!

What a difference a decade makes. Lazard now shows solar has come down 90% since 2009 and is now 4 times cheaper than nuclear, with wind almost as cheap. Also, depending on geography but generally speaking, solar works well during the day and wind can be fairly reliable at night. They complement each other well, so you’ll generally get a 100% renewable grid with wind and solar – but 100% is not what we’re aiming for. Why? Winter! As Tom Murphy argues:

“Note that 7 days of storage does not literally mean that we are prepared to experience 7 days with zero input from the renewable infrastructure. Operating at 30% of the break-even amount over a period of 10 days also leaves the system with a 7-day energy deficit, for instance. This circumstance is not too difficult to imagine: a cloudy winter week over the southwest while the wind speed over the country is half its average value (means eight times less power) over the same period.”

But that’s irrelevant in a world where we really can afford to Overbuild renewables. If your grid drops to 30% – it’s not rocket science to ask if you can just multiply your renewables three times to get you through winter? So the aim becomes not a 100% renewable grid – but actually something more like 300% – spilling the excess during summer. (Shutting down excess wind and solar so it doesn’t fry the grid.) Or even doing seasonal jobs like desalinating extra water or making extra hydrogen or even running a garbage Gasification plant – as long as they can be redirected back to supporting the grid during winter.

It’s as Tony Seba says – we’re really bad at estimating cost curves. A year is a long time to us – and we have trouble estimating what is happening across 10 years. This is where a little history can help. While it took 20 years to go from the horse and car to the car – 80% of that change happened in 10 years. Cost curves are a thing – an economic law almost like the law of gravity.

With renewables so cheap, it’s not just Overbuild – but other grid services that are now affordable. Renewables grids are so cheap you can now afford to build extra HVDC lines to the West and South of America where snow is irrelevant or at least very rare. Maybe these Western and Southern States should be prioritised for solar and the windier areas around the coast prioritised for wind – and they could optimise a grid that ‘only’ needed to be Overbuilt twice, not thrice? I’m sure there are better models than Murphy’s by now. Also, there’s an interplay between existing HVDC and storage. Sometimes it’s better to build new power lines, and sometimes it’s better to build new pumped hydro. EG: If a solar farm expands to 2 GW output but the local HVDC line can only carry 1 GW – do you build a new line – or build a local pumped hydro dam to store the extra solar during the day? Then it’s pumping only 1 GW solar down the line during the day, and using the spare GW to pump water up a hill for sending down the line at night. Your 2 GW farm is now a firmed 1 GW line to the grid. That’s the concept. Don’t ask me to evaluate a particular site or needs of a particular grid. That’s way above my pay grade – I’ll go with whatever experts like Andrew Blakers and Matthew Stocks recommend.

Not only this, but pumped hydro electricity storage is also good for restarting a grid. In a bad blackout like the terrible Texas snow storm of a few years ago the grid is so shut down it loses frequency control. Frequency control is the speed at which AC zips back and forth down the grid lines – and getting it out of sync does all sorts of bad things – like frying equipment or even shaking an old coal fired generator out of it’s housing, destroying the power station! It’s called a Black Start (wikipedia) – in that there’s no existing electricity frequency to help sync new supply coming onto the grid. It’s enough for now to know that pumped hydro stations can help start the grid up, as well as store it.

This is where I again must mention Tony Seba. Key technologies are converging – but I think Seba omits pumped hydro as one of the important ones. But he’s great on the cost curves of all the others – and the implications are simply STUNNING for a world threatened by climate change and food insecurity. Start with this talk – there are 5 in the series.

The Murphy argument above reminds me of how lucky we are in Australia. David Osmond is an Australian renewable engineer who modelled one of Australia’s worst years for renewables weather – 2022’s La Nina weather. He analysed the weather on a daily basis and had a very public conversation about it all on his blog. The weather was so bad it needed some Overbuild to reduce pumped storage to what Australia ALREADY HAS today. (And we’re building more with Snowy 2.0.) What kind of Overbuild fixes this? According to Osmond – just 70%! This link is also where I reference a Griffith University study into 4 decades of Aussie whether that also concludes that Overbuild can help firm the grid. Blakers et al just plan the most economised grid, with plenty of wind and solar but also HVDC between Queensland and Victoria and enough storage for 2 days. They’ve tested the model with years of weather data – and it works.

Now to be fair to nuclear – there have been some really bad project management, public sabotage and legislative changes that have done everything from delay builds to have the government interfere with the technology half way through a build. The Western world has forgotten how to build nuclear in a big way. South Korea can still build them affordably – but that seems to be a lost art in America. IF some bold government in the West got their act together and started something like the French 1970’s Mesmer plan, we could standardise the best Gen3.5 reactor today and arrange to build 30 or so. Then the prices would come crashing down and the grid would be simpler to manage. But even then – would it be as cheap? Apparently solar is still getting learning curve benefits – and has maybe another 7 years of cost drops before it finally levels out!

Reading Michaux and Murphy reminds me to be grateful for the smart people and governments that both invented this new tech, and offered government rebates to help bring the costs down. Where I used to quote cost comparisons of Germany’s high historical renewables costs vs nuclear, I now see them as essential investments in getting the wind and solar prices to where they are today. To where we can Overbuild with confidence that there will be enough wind and solar to keep society ticking over – and have pumped hydro to start the grid up again after a day if we get some little bit of the math wrong. 😉

This entry was posted in 100% renewable energy papers, Hydro, Nuclear, Solar, Storing energy, Wind. Bookmark the permalink.

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