@ysamjo I don't take comfort in *knowing* the future will be better. I do take comfort in a robust data-informed extrapolation that we have made the world better by most available metrics, and are highly probable to continue doing so.

Thanks for reading. If you want to read more of my SBSP takes, or see me go into more detail on the SBSP costing model I developed to analyze these concepts, I discuss it more here:.

In conclusion: Good analysis, but as long as it's based on NASA's 2024 SBSP results, I remain extremely skeptical. GBSP+Storage is being built *right now* that can make a green grid and a profit nearly anywhere. SBSP can only do that in marginal cases. Keep the panels here on🌍.

And the biggest assumptions that SBSP models need to make: We need to assume that conventional GBSP+storage is going to slow down and fall off its own learning curve soon. That's possible, but every time someone has made that bet so far, they've been dead wrong. 📈

So SBSP has a role in Europe 2050 green energy goals, provided***. * $10M/launch SHLV capable of 100 tonnes to GEO.* A big enough fleet to launch every ~hour for a ~decade.* Europe is willing to buy ~$1 trillion in launch services from them.

I admit I'm not an expert in the politics of European space launch, but do we really think Europe’s net-zero goals are so important that they would be willing to put a ~trillion $ into a non-European launch provider to make it happen? I very much doubt it.

Europe has made it pretty clear that it doesn't want to be dependent on US providers (like SpaceX) for its launch capacity. It hasn't yet succeeded in developing a launch vehicle that can compete on cost with Falcon 9, and it hasn't even *started* on a competitor for Starship.

At the end of the project, launch costs would be $1 trillion (with a T). The ~annual budget of the entire EU. But let's ignore that and assume the money can be found. The bigger question is this: Where is Europe going to procure that launch service?.

If we started building this European SBSP system *today* and wanted to finish by 2050, we would need to be launching one Starship every 2 hours. around the clock. for the next 25 years. Starting in 2040 would require a launch every *45 minutes*.

Building that much infrastructure in orbit would require 9,000 Starship launches to GEO, or 107,000 launches total (remember, the cost-competitive LCOE model requires Starship to go direct to GEO, which requires 12 tanker launches per payload launch).

NASA's assumed powersat design had a grid capacity of 2 GWe, and an all-in mass efficiency (including panels, converters, transmitters, control, etc.) of ~3 kg/kW. Assuming 100% up time, a constellation to provide ~300 GW to Europe would weigh in at almost ~900,000 tonnes 😐

I'm not going to get into what I think is a realistic price point for Starship to GEO, certainly not out in the 2040-2050 timeframe. But I do want to illustrate what a 300 GWe SBSP system built by such a rocket would look like.

How many things do we need to improve? Well. A lot. Most significantly, we need a SHLV with Starship levels of performance launching direct to GEO for just ~$10M a flight. That's just ~$100/kg_GEO. ~100x cheaper than we can do with Falcon Heavy.

NASA's study pegged the "baseline" LCOE of grid-scale SBSP on the order of ~1.00 $/kWh. So ~7x the cost of electricity in the US right now, ~20x the cost for new solar. Clearly, SBSP would need to improve some things to sell power at 0.06 $/kWh.

I'm not a civil engineer, so I can't really evaluate the power grid assumptions. But I am an aerospace engineer, and I think I'm qualified to say this paper's main weakness is how much it has to rely on the best-case scenarios from NASA's 2024 SBSP study.

If the price falls further, then SBSP supplements an even higher fraction, going beyond 20-30% seasonal baseload to ~100% of the supply if it reaches an even lower 100-200 €/kWyr [~0.02 $/kWh]

The model is that SBSP will provide a constant ~300 GW of Europe's power in 2050 (~4x the electricity consumption of modern Germany), picking up the slack for wind/solar+storage in the winter months.

I believe that. LCOE for new solar in Europe is ~30€/MWh [~0.04 $/kWh], so SBSP at ~0.06 $/kWh would definitely compete with conventional renewables, especially at high latitudes, and worth a bit of a premium since it's instantly dispatchable and can provide +99% uptime.

These authors conclude that SBSP remains uncompetitive with conventional renewables for most of the range of NASA's 2024 study. The price points where SBSP starts complementing/competing with conventional renewables is around 450€/kWyr [0.06 $/kWh]

The focus of this paper isn't so much on *how* to make SBSP economical, the focus is more on analyzing the impacts on Europe's electricity mix if we *assume* SBSP becomes as economical as the NASA study modeled it in 2024.

Overall, this is a solid piece of analysis that brings an appropriate level of skepticism and doesn't overreach. Too often, the SBSP community engages in motivated reasoning, but I don't see any evidence of that here.