The situation with telecommunications satellites is less clear, although ground stations are certainly vulnerable. The Internet too is something of an unknown. Most electricity generating stations, whatever fuel they use, including hydroelectric, will have more than one millennium vulnerable unit. There are many other applications which use this sort of moving average as a safety check, e.g. engine controls, flight controls and life support kits. Whether all nuclear power stations would fail safe is not clear.
Automated systems are probably millennium vulnerable and by no means certain to fail safe.
Millennium testing is crucial. Some types of valves are typically known to fail to shut, others fail to open. Accidental oil contamination cannot be ruled out. Water supplies and drainage Water mains and reservoirs suffer from the same potential problems with valves and pumps as oil and gas pipelines. Water companies may disagree over the scale of the problem, but few deny its existence.