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1) Renewable energy news articles (which sometimes read like romantic fan fiction) have a tendency to refer to capacity. This neglects actual generation capability, and I think the best analogy is found in this cartoon 
2) The important number is capacity factor, which tells you how often it is actually generating electricity. For wind & solar, this is usually much below 50%. This chart shows the US averages, although in NZ itâs quite different.
3) In 2017 NZ Geothermal had a 91% capacity factor, wind was ~35%. This was the lowest level since 2011, but still relatively high by world standards, and itâs usually around 40%. Some areas have turbines that are above 50% CF (hello Wellington!)
https://www.mbie.govt.nz/assets/d7c93162b8/energy-in-nz-18.pdf
https://www.mbie.govt.nz/assets/d7c93162b8/energy-in-nz-18.pdf
4) So in terms of a renewable grid, I find the best way to look at what actually *generates* a high % of electricity from low carbon sources. This graph is a little out of date, and in 2017 NZ was at ~82%. But it does show the two main global sources of low carbon electricity..
5) Which brings me to this. What are the proven technologies for the fastest deployment of low carbon electricity? Again, two pretty clear winners here. So as much as a headline might say âX capacity of wind/solar addedâ, think of capacity factor & proven low carbon deployment.
6) In addition to proven capability, another one to look at is gCO2/kWh & materials input. A hugely important aspect of decoupling prosperity from environmental degradation is just straight up using less stuff. Again, this graph is pretty unambiguous.
7) While this one shows just the materials requirements for different low carbon sources. One thing that jumps out for me for hydro & nuclear is the simplicity. If you want to decouple development from environmental degradation, just use less stuff.
8) So with decoupling. Another aspect is getting a higher return for a smaller input of energy. This is often referred to as energy returned on invested (EROI). Simple calculation of Energy Output/Energy Input, where a value of 1 means you get exactly what you put in.
9) The major published study on it was back in 2013, so numbers probably do need some updating and it is not a perfect metric by any means. But it is still a very useful one, as high EROI is important for high development.
https://www.sciencedirect.com/science/article/pii/S0360544213000492
https://www.sciencedirect.com/science/article/pii/S0360544213000492
10)This recent paper looked at what a wind/solar dominated grid could look like by 2060 (nuclear is assumed to only have a slight increase). Their results suggest this would decrease global EROI from current ~12 to between 3 & 5. Which is... https://www.sciencedirect.com/science/article/pii/S2211467X19300926
11) ...incompatible with high levels of development in current industrial complex societies. We would also need to overbuild capacity by ~35% and the materials requirement is so large that we would have to re-materialise the economy, counteracting efficiency trends.
12) As with anything, got to be careful about assumptions & limitations (as authors do say). But most of their limitations bias would actually increase constraints on the system. So it pays to bear this in mind, as high development is directly linked to human well-being...
13) ...as this beautiful set of graphs show. Now, are things perfect? Heck no, itâs a long way to go. But energy is so fundamental for building a more equitable and prosperous world, and a healthy biosphere is part of that. So we have to make sure we donât fuck that up.
14) So next time youâre reading about energy, please think about that. Because there is one source of energy that really is the best. Low carbon, minuscule space requirements, low materials cost, fastest proven grid decarbonisation, reliable. Wait, is it safe?!
15) Well, funny that. Because this will surprise you as much as it surprised the bouncer I yarned to at Ballroom last night. @OurWorldInData found that nuclear energy is by far the safest of the main (96% in 2014) sources of world energy production. https://ourworldindata.org/what-is-the-safest-form-of-energy
16) And before you come at me with cost, letâs take a case study. Germany shut down its nuclear plants and heavily subsidises renewables. And despite the falling cost of panels & turbines, they now have the highest electricity prices in Europe. Whereas France produces twice as...
17) ...much clean energy (cheers nuclear!) for nearly half the price. Germany could be basically carbon free if instead of shutting down their nuclear plants, theyâd built more, shut down coal, and even have enough left over for decarbonising transport. https://www.forbes.com/sites/michaelshellenberger/2018/09/11/had-they-bet-on-nuclear-not-renewables-germany-california-would-already-have-100-clean-power/
18) Well the next one is LCOE, but just because itâs widely used doesnât make it a good metric. Itâs the one that causes the âsolar cheaper than coalâ headlines, but it doesnât take into account wider system costs... https://www.sciencedirect.com/science/article/pii/S0301421518306645
18)...which are very low for nuclear, and intermittency/dispatchability
(electricity is produced when needed). Not only that, the discount rate of 10% used in latest IPCC report basically negates the future value of generated electricity. Nuclear plants go for ~60 years, but...
(electricity is produced when needed). Not only that, the discount rate of 10% used in latest IPCC report basically negates the future value of generated electricity. Nuclear plants go for ~60 years, but...
19) ...with that discount rate its longevity is worthless. Discount rates are useful for comparing financial investments sure, but weâre talking about a sustainable future. Discounting future generations is incompatible with that. We should be leaving the earth in a better...
20) ...place than we found it, and discounting is an economic mechanism that, in this case, makes it practically impossible. And heck, if weâre trying to build a more equitable, more prosperous, cleaner world & return land to nature, isnât that worth a higher capital cost anyway?
