All critical infrastructure uses buffers to hedge fluctuations in supply and demand. Water, for example, uses reserves and reservoirs to collect supply when it is in excess, and then releases it when demand is in excess.
This buffering allows for smooth consistent delivery of a critical resource to users. For energy this is not the case. Energy has no large scale storage mechanism.
Meaning energy must be produced at the same time as demand requires. Under supply leads to black outs and over supply leads to a loss of stability in the delivery infrastructure.
Connections
Saudi Arabia Can Control The Price of Oil With Not A Lot Of Market Share
Reference
� The Beauty of Batteries