Before connecting Barrel OS to hardware we tested it in a simulator that reproduces battery, PV, compute and variable weather. We chose the hardest case: a Planet with 250 kWp in Northern Italy, in the worst month of the year, with more compute than the battery can sustain (22 kW instead of the roughly 12 we recommend for that climate).
| 14 days | Without control | With Barrel OS |
|---|---|---|
| Blackout hours | 68 | 0 |
| User demand served | 88.6% | 96.6% |
| Minimum state of charge | 5% | 29% |
Without control the system runs at full power until the battery empties, then shuts down every night. With Barrel OS the GPUs slow down in the evening as needed and service never stops.
The trade-off is clear: deferrable jobs run less (358 kWh against 817), and they run by day, when energy is available.
How much compute can a Planet hold?
We repeated the test varying installed compute from 8 to 30 kW, with three different weather sequences. Up to the size we recommend (about 12 kW in Northern Italy in winter) the two systems are equivalent. Above that, the uncontrolled site starts shutting down at night; with Barrel OS blackouts stay at zero. Beyond about 25 kW, the uncontrolled site serves a little more demand overall, but by shutting down every night. Barrel OS chooses continuity: no interruption, at the cost of slowing down.
Five climates, same rule
We ran the same test across the five climates in our configurator, with twice the recommended compute for each. Without control, from 30 to 79 blackout hours in two weeks. With Barrel OS, zero, serving about 95–96% of demand.