Execution within a power budget
Given a power budget in terms of watts, the runtime should be able to adaptively adjust resource usage (e.g. DVFS) to keep within that budget. This ability to do this will depend on the quality of information available - external meters or internal measurements from IPMI (motherboard / power supply) or hardware counters (on CPU die). In the latter cases, some estimation or safety factor will need to be applied, or the user could specifically say "power budget for CPU/RAM" rather than for "the whole system".
Performance issues arising from this distinct from in temperature-constrained execution should be identified and subsequently addressed.