An energy shortage occurs when there is not sufficient electrical power generation or transmission to serve a particular population. This can be caused by high energy prices, old infrastructure, and increasing demand. Hot temperatures, for example, can add stress to the electric grid as people turn on air conditioners all at once. The result can be a shortage, leading to brownouts or blackouts. Another cause can be a disruption to oil or other energy imports, due to geopolitical events, natural disaster, or similar crises.