3 ms·
Your numbers are reasonable. 5-10x as many cycles on a flywheel versus best-available Li-ion tech was what we figured, too. The initial construction cost per kW
by eigenvector 8y ago
Your numbers are reasonable. 5-10x as many cycles on a flywheel versus best-available Li-ion tech was what we figured, too. The initial construction cost per kWh is much higher for a flywheel, though, basically enough to wipe out that advantage. Also, even if a flywheel is cheaper in the long run, it's a tradeoff of upfront capital cost vs long-term maintenance costs - and when you refurbish your battery in 10 years, cells are probably going to cost 20-30% less than they do today.
The other problem we had was that we were making 10s of flywheels per year and competing against Samsung and LG's battery manufacturing efficiencies. And buying an ultra-low-volume product from a startup that might not be around to maintain it in 20 years is also a tough sell in the risk-averse power industry.
- bigiain 8y agoThanks! As usual - the actual problem isn't reflected in "assume a perfectly spherical cow of uniform density" physics, or in the "Hey, I know a tiny bit about a related problem to this, I'll just extrapolate from there, WCPGW?" analysis. I reach towards both those oversimplifications way to often. Glad to see the guestimates/calculations I did bares at least an order-of-magnitude level of correctness. I _mostly_ do these quick calculations so I can rule out thinking harder about things that are 3 or 4 orders of magnitude away from possible. "Yeah boss, we can do that, it'll take <scrible scrible, estimate, google, calculate, double check> something like $800k of Amazon resource per month, maybe only half a mil if we commit to 12 months up front. How much did you say we could sell this for? To how many customers?"