Spinning Reserve

Spinning reserve is unused generating capacity that is already online and synchronized to the grid, ready to increase output within a short, specified window — commonly ten minutes — if a generator trips offline or demand spikes unexpectedly. Because the unit is already spinning, it can respond far faster than a plant that must be started cold, which is why operators hold a margin of spinning reserve at all times as insurance against sudden shortfalls.

How loads provide it

Spinning reserve does not have to come only from generators with spare headroom. A large, interruptible load can supply the equivalent service by standing ready to shed consumption on command: removing demand has the same balancing effect as adding generation. In several markets, Bitcoin mining facilities qualify as responsive reserve resources precisely because they can drop their entire draw within the required response time and verify it through metering.

Spinning vs. non-spinning reserve

Spinning reserve is distinguished from non-spinning (or supplemental) reserve, which comes from capacity not yet synchronized and therefore takes longer to deliver. Providers of spinning reserve are typically paid to hold the capacity available even when it is never called, with additional settlement for energy actually delivered during an event. For a miner, this is a way to be compensated for readiness — but the committed capacity must stay reservable, trading some hashing uptime for a steadier, hashprice-independent payment.

Spinning reserve sits within the ancillary services family alongside frequency regulation, and mines reach it through curtailable load and demand response programs.