As electric power demand varies during the day, peak power is met by running plants that can quickly be brought on-line and then shut off. Oil is suitable. Natural gas is even better.
Historically, gas was more expensive than petrol. But that changed at the end of the 20th century as fracking took off.
In 2009 in the US, natural gas provided 23.4% of electric power generation, while petroleum was only 1%. Hydroelectric power generation, by damming rivers, contributed 7%.
Electric power transmission is the bulk transfer of electrical energy from a generating power station to electrical substations located near demand centers. Electricity is then distributed locally to customers via distribution lines.
Transmitting electricity at high voltage over long distances is not especially efficient: 6–10% is lost to resistance, turning electricity back into heat.
As power lines may be loaded from various plants, transmission lines form an interconnected grid. The transmission grid system embodies a self-organized criticality. Excess load may be overcome by shifting electrical flow, but a large, sudden loss in supply or surge in demand can bring down an entire system, causing a blackout (power outage).
Failure protection is built into grid systems to prevent, or at least localize, blackouts. But the physical components behind electricity grids are surprisingly fragile, and hard to come by.
The US runs on roughly 2,500 large transformers, most of unique design. Only 500 or so can be built per year globally. It typically takes a year or more to receive an ordered transformer. Some transformers exceed 400 tonnes. The average American transformer is 40 years old.
Downing the transformers at just 9 critical substations could shutter America’s electricity grid down for months. The easiest way to do so would be shooting them with a high-caliber rifle. Which 9 substations are crucial is secret.
A surge of energy from the Sun took down Quebec’s electricity grid for 9 hours on 13 March 1989. Had such a solar storm hit America, it may have destroyed a quarter of the high-voltage transformers, knocking out power for quite some time.
An electromagnetic pulse, which can be prodigiously produced by a nuclear bomb designed to maximize gamma radiation, could knock out electric power for years.
More mundanely, a country’s electricity grid can be knocked out by cyber-attack. Hackers cut power in the Ukraine for a few hours in December 2015. The same could be achieved elsewhere with determined effort, though power outage would likely be measured in hours, not days.
Despite the risks and consequences, startlingly little has been done to protect the electricity grids in most countries, including the United States. The electric power industry expects the government to take the lead in protecting its assets. It took a decade for the North American Electric Reliability Corporation to draw up a vegetation-management plan after an Ohio power line sagged into tree branches and cut power to 50 million northeasterners at a cost of roughly $6 billion.
National security in many countries amounts to bullying foreigners, harassing dissidents, and maintaining a war machine, not looking after economic well-being beyond subsidizing favored corporations and industries.