3 ms·
It's not X kWh of batteries for X kWh of flywheels, it's 0.01 kWh of batteries to provide enough power to run the flywheel's protection and control systems whil
by eigenvector 8y ago
It's not X kWh of batteries for X kWh of flywheels, it's 0.01 kWh of batteries to provide enough power to run the flywheel's protection and control systems while it 'freewheels'. Ideally, you don't want to brake the flywheel while the grid is down, because then you're losing all the storage energy and need several minutes to spin back up when the grid is back.
- robotresearcher 8y agoSurely you can power the control electronics from the flywheel, right? That should always work except when the thing is stopped, which is a safe state.
- hyperbole 8y agoin failsafe systems it's best not to depend on the thing you expect to fail to behave in a particular way when it... fails, redundancy is the key.
- robotresearcher 8y agoThe grid is the primary power source. Flywheel when no grid. Battery would be third. It might be enough to have a passive resistor load for the third option. But at the scale of these things, a battery to run a few hours of controller is not a big deal.
- eigenvector 8y agoSee my comment above on this: https://news.ycombinator.com/item?id=17071303 https://news.ycombinator.com/item?id=17071303