Energy constraints are limits on how much power a system can draw, store, or reliably receive. In practice, they come from available electrical supply, grid capacity, cooling requirements, utility rules, and site-level consumption caps. For data centers and other critical infrastructure, these limits affect where equipment can be built, how dense it can be, and how much headroom exists for expansion.
In cyber security, energy constraints matter because availability is part of defense. If power is scarce or tightly regulated, operators may have to reduce server density, delay upgrades, or design stronger redundancy and failover plans. Attackers can also exploit energy pressure indirectly by forcing systems to consume more resources, triggering throttling, outages, or degraded services. Defenders use capacity planning, load balancing, backup power, and efficient hardware to stay resilient within those limits.