Daniel sent us this one — he's been driving south in Israel, seeing the Ashalim concentrated solar plant dominating the skyline, this huge field of mirrors focused on a central tower that looks like it's straight out of Star Wars. And it got him thinking. Israel's drenched in sun most of the year, but our renewable share, and solar's slice of it, is nowhere near what you'd expect. So his first question is, what would total solar sufficiency actually require from a development standpoint? Is there a cutoff where it just isn't viable? And second — he grew up in Ireland where cloud coverage is heavy and sun is scarce — are there viable models for transmitting solar-generated electricity across continents, from sunny parts of the world to less sunny ones? Or is the better approach that different renewables get generated in different places? He's also got what he calls a dumb question, which is actually a good one — when we talk about solar generation capacity, are we talking about UV specifically, or what's the actual parameter being converted?
That's not a dumb question at all — it's actually where most people get tripped up. The quick answer is it's not UV. Solar panels primarily convert visible light and some near-infrared into electricity. The photovoltaic effect is driven by photons in roughly the four hundred to eleven hundred nanometer wavelength range. UV is below four hundred nanometers and most of it gets absorbed or reflected before it can contribute meaningfully. So it's not that hotter equals more powerful — it's about irradiance, the raw photon flux hitting the panel. In fact, panels actually lose efficiency as they heat up. The temperature coefficient on a typical silicon panel is about negative zero point three five percent per degree Celsius above twenty-five. So a hot Israeli summer day can knock a few percentage points off peak output compared to a bright cool day.
Which is one of those facts that feels backwards until you think about it for five seconds. The sun's energy isn't heat hitting the panel, it's light. Heat is just the waste product of the conversion.
And that distinction matters enormously when you start talking about total solar sufficiency. But before we get there, let me ground this in where Israel actually is right now. In twenty twenty-four, renewables supplied about fourteen percent of Israel's electricity. That's up from roughly ten percent in twenty twenty-three, so there's movement, but it's slow. Solar accounts for the vast majority of that renewable share. The government target is thirty percent renewables by twenty thirty, which the State Comptroller has already said Israel is not on track to hit. The actual projection is somewhere closer to twenty to twenty-two percent by twenty thirty at current deployment rates.
That fourteen percent figure — does that include the Ashalim plant Daniel's talking about?
It does, but Ashalim is an interesting case because it's not photovoltaic. It's concentrated solar power, C. , which uses mirrors to focus sunlight onto a receiver that heats a fluid — in Ashalim's case, molten salt — which then drives a steam turbine. It's fundamentally a thermal plant that uses sunlight instead of coal or gas. The Ashalim facility has three sub-plants. Two are actually photovoltaic fields, and one is the C. tower Daniel described, with fifty thousand mirrors. Combined capacity is about two hundred and fifty megawatts. For context, Israel's peak electricity demand is around sixteen thousand megawatts. So Ashalim covers maybe one and a half percent of peak demand.
The thing that looks like a sci-fi set piece is a rounding error on the grid.
In generation terms, yes. But it's not nothing. has one enormous advantage over photovoltaic — it can store thermal energy in molten salt and keep generating electricity for hours after sunset. The Ashalim tower can run at full capacity for about four and a half hours after the sun goes down. That's dispatchable solar, which is the holy grail for grid operators who need to match supply and demand minute by minute.
Which is the real bottleneck Daniel's asking about, right? Not can we build enough panels, but can we build a grid that runs on them?
And the grid challenge is the thing most public conversation misses entirely. Let me lay out what total solar sufficiency would actually require. Israel's annual electricity consumption is about seventy-five terawatt-hours and growing at roughly three percent a year. A terawatt-hour is a billion kilowatt-hours. To supply that entirely with solar, you'd need something like forty to fifty gigawatts of installed photovoltaic capacity, assuming Israel's roughly twenty percent capacity factor for solar. Capacity factor is the ratio of what a plant actually generates versus what it would generate running flat out twenty-four seven. For solar in Israel, the sun shines the equivalent of about seventeen hundred to eighteen hundred full-load hours per year, which is about twenty percent of the total hours in a year.
Forty to fifty gigawatts. For comparison, what's Israel's current installed solar capacity?
As of early twenty twenty-five, about seven gigawatts. So we're talking roughly a six to sevenfold increase. And that's just the generation side. The storage requirement is where it gets truly enormous. You need to get through the night, through cloudy periods, through the winter months when daily solar output drops by about forty percent compared to summer. If you assume lithium-ion battery storage, you'd need something on the order of three to five hundred gigawatt-hours of storage capacity to buffer a fully solar-powered Israel. For scale, the largest battery storage facility in the world right now is Moss Landing in California at about three gigawatt-hours. So Israel would need the equivalent of a hundred Moss Landings.
That's assuming a single country's grid. Daniel's second question is whether you could bypass some of that by moving electricity across continents. If the sun's always shining somewhere, can you just build the panels where it's sunny and ship the electrons?
This is one of those ideas that's beautiful in theory and brutal in physics. Long-distance electricity transmission exists — China has ultra-high-voltage direct current lines, H. , that push power over three thousand kilometers at voltages above a million volts. The losses on modern H. are about three percent per thousand kilometers. So if you built a line from, say, the Sahara to Ireland, you're looking at maybe four thousand kilometers and twelve to fifteen percent transmission loss. That's not the dealbreaker. The dealbreaker is the physical infrastructure. converter stations cost billions each. Undersea cables are fabulously expensive and vulnerable to damage. And you'd need to cross multiple national borders, each with its own regulatory regime, land rights, and geopolitical risk.
The geopolitical risk is not hypothetical. If you're routing Moroccan solar through Spain and France to Ireland, you've just made Ireland's electricity supply dependent on political stability across half a dozen countries and the goodwill of every government along the route.
There's a reason the most ambitious cross-border solar proposal — Desertec, which envisioned powering Europe from North African solar farms — basically collapsed. It wasn't a technology failure. It was an economics and politics failure. The cost of the transmission infrastructure alone was estimated at over four hundred billion euros, and that was a decade ago. Nobody could figure out who would pay for it or who would guarantee the security of the supply.
The continental-scale grid idea — it's not that it's physically impossible. It's that it's economically uncompetitive and politically fragile in a way that makes it a non-starter for any country that actually cares about energy security.
Which brings us to what I think is the more realistic framing of Daniel's question about different renewables in different places. The model that's actually emerging isn't one where you move electricity across continents. It's one where you build a diverse renewable portfolio locally, supplemented by regional interconnections that are modest in scale. Think about what works where. Solar in the Negev, obviously. Wind in the Golan Heights and along the Mediterranean coast. Offshore wind in the North Sea for Northern Europe. Geothermal in Iceland and East Africa. Hydropower in Scandinavia and the Alps. Each region builds what its geography gives it, and you interconnect within regions — not across continents — to smooth out variability.
For Israel specifically, what does that diverse portfolio look like? Because we've been talking solar, but Daniel's question implies he's wondering whether solar alone can carry the whole load.
It almost certainly can't, or at least shouldn't. Israel has some wind potential — there are wind farms in the Golan, and the government has been talking about offshore wind in the Mediterranean, but the wind resource here is mediocre compared to places like the North Sea. Israel's average wind speeds at turbine hub height are maybe six to seven meters per second in the best locations, versus nine to ten in the North Sea. That's a huge difference because wind power scales with the cube of wind speed. A ten meter per second site produces more than double the energy of a seven meter per second site.
Israel's renewable advantage really is solar. But you're saying we still shouldn't go all-in on solar alone.
Right, and the reason is seasonal. Israel's solar output in December and January is about forty percent lower than in June and July. That's not because of clouds — it's just fewer daylight hours and a lower sun angle. If you're a hundred percent solar, you need enough storage to bridge not just overnight but the entire winter. That's when the storage numbers become genuinely absurd. You'd be building battery capacity that sits idle nine months of the year. The economic case disintegrates.
There's a natural ceiling for solar penetration on any given grid, and beyond that ceiling, you need either a different renewable source with a different generation profile, or you need something that isn't renewable at all.
That's exactly where the conversation gets uncomfortable for people who want a pure renewable future. The realistic path to a decarbonized grid for most countries, including Israel, almost certainly includes some firm, dispatchable, zero-carbon baseload. That means nuclear, or it means natural gas with carbon capture, or it means something like green hydrogen used in gas turbines for the few weeks a year when renewables can't meet demand. The hydrogen pathway is being explored seriously — Israel has a national hydrogen strategy, and there are pilot projects in the Negev — but green hydrogen is still about three to four times more expensive than natural gas per unit of energy. That gap is shrinking, but it's not going to close in the next five years.
Let me pull on the nuclear thread for a second, because it's relevant to Daniel's question about what total sufficiency requires. Israel has a nuclear reactor at Dimona, but it's not a power reactor and it's not connected to the grid. Is there any serious discussion about nuclear power generation in Israel?
There have been feasibility studies going back decades. The Shimon Peres Negev Nuclear Research Center — that's the Dimona facility — is a research reactor, not a power plant. In twenty twenty-three, the Ministry of Energy commissioned a new study on nuclear power, and the conclusion was essentially that a small modular reactor could be technically feasible by the mid twenty-thirties but faces enormous hurdles. The capital cost would be in the range of five to ten billion dollars. The regulatory framework doesn't exist. And then there's the geopolitical dimension — any country pursuing nuclear power faces scrutiny, and Israel's unique position makes that particularly delicate.
We're not exactly in a position to join the N. and invite I. inspections of all our facilities.
That's the understatement of the episode. So nuclear, for Israel, is probably a non-starter for reasons that have nothing to do with engineering and everything to do with geopolitics. Which means the firm, dispatchable zero-carbon option for Israel is either imported electricity from neighbors — there's been talk of the Euro-Asia interconnector linking Israel, Cyprus, and Greece — or it's natural gas with carbon capture, or it's green hydrogen.
We haven't even mentioned the land-use question Daniel raised. He pointed out that the Ashalim tower is visually overwhelming, that you can't just stick these things everywhere. What's the actual land footprint of a fully solar-powered Israel?
This is where the numbers get tangible. A gigawatt of solar photovoltaic in Israel requires roughly fifteen to twenty square kilometers of land, depending on panel efficiency and spacing. To get to the forty to fifty gigawatts we'd need for total solar sufficiency, you're looking at six hundred to a thousand square kilometers. That's about three to five percent of Israel's total land area, or roughly the size of the entire Central District. And that's just the panels. That doesn't include the battery storage facilities, the transmission infrastructure, the access roads.
Three to five percent of the country covered in solar panels. That's not nothing, but it's also not as apocalyptic as some people make it sound. Israel's built-up area is already something like seven percent of the land. We're not talking about paving over the whole country.
The challenge isn't the raw acreage — it's where that land is. The best solar resource is in the Negev, which is also where the military does training exercises, where Bedouin communities live, where there are nature reserves and archaeological sites. Every square kilometer of solar development in the Negev involves a land-use conflict. The Ashalim plant Daniel mentioned — that was built on state land in the Negev, and it still took years of environmental impact assessments and negotiations. Scaling that up by a factor of fifty is not a trivial planning exercise.
This connects to something Daniel didn't ask directly but is implicit in his question. He's looking at Ashalim and thinking, this doesn't feel human-friendly. It's this alien structure dominating the landscape. If you're going to cover a significant fraction of the Negev in energy infrastructure, what does that do to the human experience of the place? Not just the environmental impact, but the aesthetic and psychological impact of living in a landscape that's been turned into a power plant.
It's a real question, and it's one the environmental movement has struggled with. There's a tension between the aesthetic case for preserving natural landscapes and the climate case for building renewable infrastructure. Some of the most intense opposition to solar farms in Israel has come from environmental groups who argue that the Negev's open spaces are ecologically valuable and shouldn't be industrialized. The Society for the Protection of Nature in Israel has opposed several large-scale solar projects on exactly these grounds.
Which is a fascinating tension. The same people who want to decarbonize the grid don't want to build the infrastructure to do it. It's not hypocrisy exactly — it's that both values are genuine and they conflict.
There are ways to mitigate the conflict. Agrivoltaics — putting solar panels above agricultural land — is being explored in Israel and elsewhere. The panels provide partial shade that can actually benefit certain crops in hot climates, and the land does double duty. Floating solar on reservoirs is another option — Israel has several pilot projects on water reservoirs in the north. Rooftop solar on commercial and industrial buildings avoids the land-use question entirely. But none of these solutions scale to the tens of gigawatts we'd need for total sufficiency. Rooftop solar in Israel could maybe get to five or six gigawatts if every suitable roof were used. That's a meaningful slice but not the whole pie.
Let's pull this together for Daniel's first question. Total solar sufficiency for Israel — technically possible, but the storage requirements are enormous, the land-use conflicts are significant, the seasonal mismatch means you're either massively overbuilding or accepting some other firm power source, and the economics are punishing compared to a diversified mix. Is there a cutoff where it just isn't viable?
I'd say the cutoff isn't a hard technical wall — it's an economic and political one. You could, in principle, cover ten percent of the Negev in solar panels and build a thousand gigawatt-hours of battery storage and run Israel on a hundred percent solar. The question is whether that's the best use of resources. And the answer, based on every serious grid modeling study I've seen, is no. The optimal solar penetration for Israel, assuming continued declines in battery costs, is probably in the range of fifty to seventy percent of electricity generation. Beyond that, the cost of the last ten or twenty percent of decarbonization becomes exponentially higher. You're building infrastructure that gets used a few weeks a year. The marginal cost per ton of carbon dioxide avoided goes through the roof.
The smart money is on a grid that's majority solar, backed by batteries for daily cycling, with natural gas turbines — eventually running on green hydrogen — for the long winter lulls. And maybe some regional interconnection to smooth out the edges.
That's exactly the consensus view among energy system modelers. And it's worth noting that even getting to fifty percent solar would be a massive achievement. It would mean roughly tripling current installed capacity, building tens of gigawatt-hours of battery storage, and fundamentally redesigning how the grid operates. The grid today is built around large rotating generators that provide inertia and frequency stability. Solar inverters don't provide that. You need to add synthetic inertia through advanced power electronics, which is a solvable engineering problem but one that requires investment and careful planning.
Let me shift to the second half of Daniel's question — the cross-continental transmission idea, and whether the better model is different renewables in different places. We've already touched on why moving electrons across continents is a tough sell. But I want to explore the alternative he's pointing at. If Ireland can't do solar at scale because of cloud cover, and Israel can't do wind at scale because of mediocre wind speeds, does the renewable future necessarily look different in different places?
And this is one of the things that makes energy policy so resistant to one-size-fits-all prescriptions. Ireland's renewable advantage is wind — specifically offshore wind. The Irish Sea and the Atlantic coast have some of the best wind resources in Europe. Ireland already gets about thirty-five to forty percent of its electricity from onshore wind, and the government's target is eighty percent renewable electricity by twenty thirty, with offshore wind playing a major role. Ireland's capacity factor for onshore wind is around thirty to thirty-five percent, which is among the highest in the world. For comparison, Germany's onshore wind capacity factor is around twenty percent.
Ireland's wind is better than Germany's wind. That's not something you'd necessarily guess if you just looked at a map of who's built more turbines.
Right, and it illustrates the point. Germany went big on solar early, despite having solar irradiance that's frankly mediocre — Berlin gets about a thousand kilowatt-hours per square meter per year, versus about two thousand in the Negev. Germany's solar capacity factor is around ten to eleven percent. Half of Israel's. So Germany ended up building a lot of expensive solar that generates relatively little electricity, while Ireland focused on its actual comparative advantage. The lesson is that renewables are not interchangeable. Each technology has a geographic profile, and getting the mix right means matching the technology to the resource.
Daniel's broader question — is the best approach one where different renewables get generated in different parts of the world — the answer seems to be yes, with the caveat that you're not shipping the electricity globally. You're shipping the energy-intensive industries to where the cheap renewable power is.
That's exactly the emerging model. There's a reason Morocco is positioning itself as a green hydrogen hub — it has excellent solar and wind resources, proximity to European markets, and existing port infrastructure. The idea isn't to send Moroccan electricity to Germany. It's to use Moroccan renewable electricity to produce green hydrogen or ammonia, and then ship that to Europe as a fuel or industrial feedstock. Hydrogen can be transported by pipeline or by ship, albeit with significant energy losses in the conversion. But it's more practical than trying to string H. cables across the Mediterranean.
Israel is thinking along similar lines with the hydrogen strategy you mentioned.
Israel's hydrogen strategy, published in twenty twenty-two, targets five to ten gigawatts of electrolyzer capacity by twenty thirty-five, mostly powered by solar. The vision is that Israel could become a hydrogen exporter to Europe, leveraging the same solar resource Daniel's been looking at in the Negev. Whether that's realistic depends on whether the cost of green hydrogen comes down as projected. Right now, green hydrogen costs about four to six dollars per kilogram. To be competitive with natural gas, it needs to get below two dollars. projects that could happen by twenty thirty, but those projections have been optimistic before.
Let's circle back to something Daniel mentioned in passing — the C. tower at Ashalim and the fact that it looks like it would give you a headache if you looked at it from twenty kilometers away. Is that a real concern with C.
It is a real concern. towers concentrate sunlight onto a receiver, but not all of the reflected light hits the target perfectly. There's spillage, and the glare can be intense enough to pose a hazard to pilots and, in some cases, to people on the ground at certain distances and angles. The Ashalim tower had to implement a glare management system that adjusts mirror angles during certain times of day to reduce the risk to aircraft approaching Ramon Airport, which is about thirty kilometers away. There have also been reports of birds being incinerated by the concentrated solar flux — the term "streamers" gets used, referring to birds that fly through the focal zone and literally catch fire in midair.
That's horrifying.
It's not unique to Ashalim — the Ivanpah C. plant in California had similar issues. The numbers are disputed, but the estimates range from a few thousand to tens of thousands of bird deaths per year at the larger facilities. For context, that's a tiny fraction of the billions of birds killed annually by cats and building collisions, but it's still a real environmental impact that C. developers have to mitigate.
It adds another layer to Daniel's point about C. not being the most human-friendly infrastructure. If you're also incinerating wildlife in the process, that's a harder sell to environmental groups who might otherwise support renewable deployment.
Which is one reason C. has largely lost out to photovoltaic on cost and deployment ease. Global installed C. capacity is about seven gigawatts, compared to over a thousand gigawatts of photovoltaic. The cost per kilowatt-hour from C. is roughly double that of utility-scale photovoltaic, and the gap isn't closing. The one advantage C. retains is the thermal storage piece we discussed, but even that is being eroded as battery costs fall. A photovoltaic plant paired with lithium-ion batteries can now deliver dispatchable power at a cost that's competitive with C. in most locations.
The Star Wars tower at Ashalim might end up being a historical curiosity — a technology that made sense for a brief window and then got overtaken by cheaper alternatives.
It's already happening. component at Ashalim was commissioned in twenty nineteen. Since then, no new C. plants have been built in Israel. All the new solar capacity coming online is photovoltaic. The market has spoken.
Let me ask you about something we haven't touched on. Daniel mentioned UV specifically, and you explained that it's visible and near-infrared light that drives photovoltaics. But is there any technology that does use UV? Are there panels being developed that capture more of the spectrum?
There's active research on multi-junction cells that stack different semiconductor materials to capture different parts of the spectrum. A triple-junction cell might have one layer optimized for UV and blue light, one for visible, and one for infrared. These cells can achieve efficiencies over forty percent in laboratory conditions, compared to about twenty-two to twenty-five percent for commercial silicon panels. The problem is cost. Multi-junction cells are fabulously expensive — they're used on spacecraft and in concentrated photovoltaic systems where you can justify the cost, but they're not remotely competitive for utility-scale power generation. Perovskite-silicon tandem cells are a more promising near-term technology. They add a thin perovskite layer on top of a conventional silicon cell to capture more of the blue and UV spectrum, potentially pushing efficiencies above thirty percent at a cost that's still within shouting distance of conventional panels.
That would change the land-use math considerably. If you can get thirty percent more power from the same area, the land footprint shrinks accordingly.
It would help, though the storage and seasonal challenges remain. Higher efficiency doesn't make the sun shine at night or in December. But it does reduce the total number of panels you need to build, which reduces cost and land-use pressure. It's one of several incremental improvements — better panels, cheaper batteries, smarter grid management — that collectively make high-renewable scenarios more plausible over time.
I want to go back to something you said about the optimal solar penetration being fifty to seventy percent. I think a lot of people hearing that would feel deflated. The vision of a hundred percent renewable future has a lot of cultural momentum. What do you say to someone who hears "fifty to seventy percent is the practical ceiling" and thinks that sounds like a failure of ambition?
I'd say that getting to fifty or seventy percent renewable electricity would be one of the great engineering achievements in human history. It would mean fundamentally transforming how we produce and consume energy, building out infrastructure at a scale that's hard to comprehend, and doing it all while keeping the lights on twenty-four seven. The last thirty percent is hard in a way the first thirty percent isn't. And my view is that honest conversation about what's hard is more useful than aspirational slogans that collapse on contact with engineering reality.
There's also the point that electricity is only part of the energy picture. When people say "a hundred percent renewable," they're usually talking about electricity generation. But total energy consumption includes transportation, industrial heat, shipping, aviation — sectors that are much harder to electrify directly. So even a grid that's fifty percent solar is a much smaller fraction of total energy.
Israel's total primary energy consumption is about three times its electricity consumption. Transport fuels, industrial processes, heating — those are mostly fossil-fueled today. Electrifying transport helps — if every car in Israel were electric, that would add maybe twenty to twenty-five percent to electricity demand. But you can't electrify everything. Jet fuel, maritime bunker fuel, high-temperature industrial heat — those need either hydrogen, synthetic fuels, or carbon capture. So the renewable electricity target is important, but it's not the whole story.
Which brings us back to Daniel's framing. He's looking at Ashalim and wondering, can we get to a hundred percent? And the honest answer is: a hundred percent solar electricity for Israel is technically conceivable but probably not the right goal. The right goal is probably a diversified mix where solar does the heavy lifting, batteries handle the daily cycle, and something else — gas, hydrogen, eventually maybe fusion or advanced nuclear — covers the gaps.
For Ireland, the answer is different. Ireland's renewable future is wind-dominant, with solar playing a supporting role, and interconnectors to the UK and European grids providing backup. The interconnector piece is important — Ireland already has a five hundred megawatt H. link to the UK, and a second seven hundred megawatt link is under construction. Those aren't continental-scale transmission projects. They're regional interconnections between neighboring grids that already trade power. That's a proven model that works, and it's the scale at which cross-border electricity trade actually makes economic sense.
The cross-continental solar pipeline Daniel was imagining — that's probably not the path. But regional interconnectors, shipping energy-intensive products rather than electrons, and matching the renewable technology to the local resource — that's the realistic template.
It's already happening. Look at the Euro-Asia interconnector I mentioned — it'll link Israel, Cyprus, and Greece with a subsea cable capable of carrying two thousand megawatts. That's not continent-scale, but it's enough to make a difference. If Israel has excess solar during the day, it can export to Cyprus. If Greece has excess wind at night, it can flow the other way. The grid becomes more resilient through diversity, not through any one country trying to be self-sufficient in a single technology.
That's a satisfying place to land on the technical side. But I want to give Daniel credit for his "dumb" question about UV, because it points to something bigger. Most people don't understand what solar panels actually respond to, and the public conversation about solar energy often conflates heat and light in ways that lead to muddled thinking. The fact that panels lose efficiency in extreme heat is counterintuitive.
It's one of those facts that makes you rethink things. The ideal solar location isn't the hottest desert — it's a place with clear skies, high altitude, and cool temperatures. The Atacama Desert in Chile, the Tibetan Plateau — those are actually better solar sites than the Sahara or the Negev, even though they're cooler, because the combination of high irradiance and low temperature maximizes panel output. Israel's solar resource is excellent by global standards, but it's not the absolute best.
Yet we're not building solar farms on the Tibetan Plateau, for obvious reasons. The best resource in the world doesn't matter if you can't build there or get the power to where people live. Which is a neat encapsulation of the whole episode — the physics is only half the story. The rest is economics, geography, politics, and the messy human reality of actually building things.
That's the energy transition in a nutshell. The technologies work. The challenge is deploying them at scale in a world that wasn't designed for them.
Now: Hilbert's daily fun fact.
Hilbert: The country of Liechtenstein has more registered companies than citizens. With a population of roughly forty thousand and over seventy thousand registered businesses, it is one of the few places on earth where corporate entities outnumber people by nearly two to one.
Liechtenstein is less a country and more a filing cabinet with a flag.
That explains a lot about the European banking system.
This has been My Weird Prompts. Thanks to our producer Hilbert Flumingtop. If you want more episodes, find us at myweirdprompts dot com or on Spotify. We're back next time.
