Time for 2026 updates to my annual “opinions about solar” thread, now with storage.
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10. We oughtta be building more wind, especially in seasonal climates like Europe. Solar will get built anyway, it’s cheap, but wind blows at night and in the winter. We’re going to need something to charge the batteries in winter, especially with rising heatpump use.
11. How mismatched is European seasonal solar supply and electricity demand? Well, here is the situation for my fully electrified house in Switzerland with 13.2kW of solar, a heatpump and an EV. I would have needed about 122kW of PV to be self-sufficient across December.
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11. How mismatched is European seasonal solar supply and electricity demand? Well, here is the situation for my fully electrified house in Switzerland with 13.2kW of solar, a heatpump and an EV. I would have needed about 122kW of PV to be self-sufficient across December.
12. Sometimes the story is the dog that doesn’t bark in the nighttime. European grids would once have struggled in a 2026-level heatwave, but they had only a few problems and high evening prices. CAISO and Ercot, which also have lots of batteries, had good reliability years despite record loads.
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12. Sometimes the story is the dog that doesn’t bark in the nighttime. European grids would once have struggled in a 2026-level heatwave, but they had only a few problems and high evening prices. CAISO and Ercot, which also have lots of batteries, had good reliability years despite record loads.
13. Europeans shouldn't feel guilty about using electricity for airconditioning (or reversible heatpumps), it already mostly comes from the sun, especially if you pre-cool. This is good news for hot countries as well. Heat is deadly.
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13. Europeans shouldn't feel guilty about using electricity for airconditioning (or reversible heatpumps), it already mostly comes from the sun, especially if you pre-cool. This is good news for hot countries as well. Heat is deadly.
14. Data center power demand increase is significant, but localised, and probably not as high as clean power developers would like. BNEF estimates that data center electricity use will more than triple by 2035, reaching 5.4% of global demand, though it makes up 23% in the US PJM market, 18% in Malaysia and 15% in the UK.
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14. Data center power demand increase is significant, but localised, and probably not as high as clean power developers would like. BNEF estimates that data center electricity use will more than triple by 2035, reaching 5.4% of global demand, though it makes up 23% in the US PJM market, 18% in Malaysia and 15% in the UK.
15. Data center / Big Tech firms are by far the largest corporate buyers of clean power under power purchase agreements worldwide. They are also signing expensive deals for clean firm power, like nuclear and solar-and-storage, seeking to meet hourly matching targets. Non-paywall:
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15. Data center / Big Tech firms are by far the largest corporate buyers of clean power under power purchase agreements worldwide. They are also signing expensive deals for clean firm power, like nuclear and solar-and-storage, seeking to meet hourly matching targets. Non-paywall:
16. It is relatively easy to run a baseload power load, like a data center, *mostly* on solar and batteries. Especially somewhere like Saudi Arabia where the solar resource is quite constant all year. However, to get to the reliability needed, you need something else – either gas backup, or some bonkers long-duration storage tech.
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16. It is relatively easy to run a baseload power load, like a data center, *mostly* on solar and batteries. Especially somewhere like Saudi Arabia where the solar resource is quite constant all year. However, to get to the reliability needed, you need something else – either gas backup, or some bonkers long-duration storage tech.
17. One good thing about data centers is that they drive some investment into the scale-up of bonkers long-duration storage tech, eg Form Energy’s iron-air batteries (link). They care much less about the cost of power than about speed-to-power, which honestly is a new term for me this year.
https://www.canarymedia.com/articles/batteries/gigantic-form-energy-battery-google-minnesota
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17. One good thing about data centers is that they drive some investment into the scale-up of bonkers long-duration storage tech, eg Form Energy’s iron-air batteries (link). They care much less about the cost of power than about speed-to-power, which honestly is a new term for me this year.
https://www.canarymedia.com/articles/batteries/gigantic-form-energy-battery-google-minnesota
18. Lithium is going to continue to be the main technology for batteries for the foreseeable future, although China does have some policy support for sodium-ion.
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18. Lithium is going to continue to be the main technology for batteries for the foreseeable future, although China does have some policy support for sodium-ion.
19. After extensive complaints from me, BNEF now defines long-duration storage correctly: not in hours, but as technologies where “the cost and scale of energy capacity (GWh) are largely decoupled from those of power capacity (GW)".
It's where you have a big tank of some cheap storage medium, basically.
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19. After extensive complaints from me, BNEF now defines long-duration storage correctly: not in hours, but as technologies where “the cost and scale of energy capacity (GWh) are largely decoupled from those of power capacity (GW)".
It's where you have a big tank of some cheap storage medium, basically.
20. Long-duration storage deployment by BNEF’s definition was just 2GW / 9.6GWh in 2025, mostly in China. The main technologies getting built so far are compressed air and flow vanadium redox.
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20. Long-duration storage deployment by BNEF’s definition was just 2GW / 9.6GWh in 2025, mostly in China. The main technologies getting built so far are compressed air and flow vanadium redox.
21. The Hormuz crisis is having relatively little direct effect on solar panel sales, because solar doesn’t usually replace liquid fuel. The crisis is boosting EV sales, particularly in Europe where they reached 36% of car sales in Q2 2026 (China’s figure was 60%, though the car market overall slowed down). This does eventually support solar.
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21. The Hormuz crisis is having relatively little direct effect on solar panel sales, because solar doesn’t usually replace liquid fuel. The crisis is boosting EV sales, particularly in Europe where they reached 36% of car sales in Q2 2026 (China’s figure was 60%, though the car market overall slowed down). This does eventually support solar.
22. It should be all over for the new internal combustion engine car market. The only reason it doesn’t seem to be is that a lot of people don’t seem to realise how times have changed, and still repeat old talking points.
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22. It should be all over for the new internal combustion engine car market. The only reason it doesn’t seem to be is that a lot of people don’t seem to realise how times have changed, and still repeat old talking points.
23. Balcony solar: sure, you can put solar on anything. It works at any scale. But the amounts are tiny - this is not really an alternative to building large amounts of rooftop or ground mount solar.
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23. Balcony solar: sure, you can put solar on anything. It works at any scale. But the amounts are tiny - this is not really an alternative to building large amounts of rooftop or ground mount solar.
24. “But you can own your own power plant!”.
No normal person wants to own their own power plant. Apart from us weirdoes, most people want to buy affordable, reliable power from the grid and have someone else make the investment and worry about the details.
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24. “But you can own your own power plant!”.
No normal person wants to own their own power plant. Apart from us weirdoes, most people want to buy affordable, reliable power from the grid and have someone else make the investment and worry about the details.
25. Agrivoltaics: sure, you can put solar on anything. It may even help, eg in this blistering summer a bit of shade would have helped many European crops. But it’s looking for preferential support, because there are reasons farmers currently prefer open, machine-accessible fields.
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25. Agrivoltaics: sure, you can put solar on anything. It may even help, eg in this blistering summer a bit of shade would have helped many European crops. But it’s looking for preferential support, because there are reasons farmers currently prefer open, machine-accessible fields.
26. Grazing sheep under solar panels should not qualify for agrivoltaics support. Solar subsidising sheep farming is not particularly an environmental plus. (Some crops do work well with PV, for example shade-tolerant berries, and in some climates, growth isn't limited by light availability).
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26. Grazing sheep under solar panels should not qualify for agrivoltaics support. Solar subsidising sheep farming is not particularly an environmental plus. (Some crops do work well with PV, for example shade-tolerant berries, and in some climates, growth isn't limited by light availability).
27. For 7 years I have been refusing to get excited about perovskites. Still not. Crystalline silicon is honestly pretty great, and perovskites won’t solve the basic problems for solar, which are unrelated to efficiency or price.
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27. For 7 years I have been refusing to get excited about perovskites. Still not. Crystalline silicon is honestly pretty great, and perovskites won’t solve the basic problems for solar, which are unrelated to efficiency or price.
28. The US and India are locked into having high-price local solar module markets, due to trade wars.
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28. The US and India are locked into having high-price local solar module markets, due to trade wars.
29. As a consequence of trade barriers, US solar module buyers are now paying more than 38 US cents per Watt, for generally worse products than free trade markets are getting for 12 US cents per Watt.
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29. As a consequence of trade barriers, US solar module buyers are now paying more than 38 US cents per Watt, for generally worse products than free trade markets are getting for 12 US cents per Watt.
30. The rest of us, if we want to be less dependent on China for solar modules, should buy from southeast Asia, India or Turkey, which will be happy to sell them at much less cost than setting up a domestic industry.
