High voltage station connectors. Image: Shutterstock
Picture a pile of sand. As you pour more sand on top of it, the pile will gradually get higher and higher, until a breaking point where the mound will cascade and sink down. It's just a demonstration of the basic laws of physics that govern the universe, and a team of physicists believe the same principle can be applied to the America's strained energy grid.
Researchers led by David Newman at the University of Alaska spent 20 years studying the principle to determine the optimal size for the power grid—big enough to efficiently distribute electricity but not so big it's vulnerable to collapse at the slightest trigger. And our aging infrastructure is increasingly vulnerable to a widespread failure, like the infamous 2003 blackout that killed power to 50 million buildings in North America for two days and dealt a serious blow to the economy.
The point of a huge centralized infrastructure is to ensure that power is evenly distributed among regions—a rural area in some backwoods town far from a power plant needs to be able to turn the lights on too. It also serves as a backup if one part of the grid goes down, by drawing on a surplus in one place to meet the excess demand of another.
But the energy grid has ballooned in size over the years as demand continues to skyrocket. Renewable energy sources, like solar and wind, along with the growing prevalence of electric vehicles put strain on the grid, which often operates at capacity. When it's maxed out—on, say, a hot day when thousands of people are running their air conditioners—it may not be able to borrow power from elsewhere if a region goes down, and that could spark a massive failure.
"If the grid is already near its critical point and has no extra capacity, there is a small but significant chance that it can collapse like a sandpile," researchers wrote. That tipping point—like that single grain of sand—can be something as simple as a tree branch falling on power lines. Or even more nerve-wracking, a malicious attack; the lucrative energy sector is a very attractive target for hackers.
"The US could suffer a coast-to-coast blackout if saboteurs knocked out just nine of the country's 55,000 electric-transmission substations on a scorching summer day," the Wall Street Journal reported last month.
To find the sweet spot, researchers studied the Western grid, one of the three major interconnected grids in the US, which has 16,000 nodes—generators, substations, and transformers that convert high-voltage electrify to low-voltage suitable for homes. They tested how well different sizes responded to blackouts and found the Goldilocks size was 500 to 700 nodes.
"The question 'Is there an optimal size?' seems to have at the least a qualiﬁed 'yes' as the answer in our model of a power transmission grid," the study concludes. The results were published today in the scientific journal Chaos published by the American Institute of Physics.
"These considerations become even more interesting as the grid and its reliability changes due to the increasing penetration of highly variable renewable generation," researchers wrote. The growing strain has spawned the much-hyped, booming push for microgrids and a rethink of the entire energy paradigm.
The microgrid goes like this, as Motherboard's Brian Merchant explained: Instead of giant power plants supplying the electricity for all our homes, and utilities cashing in as the middle man, consumers can create their own energy with to small-scale solar and wind power and waste-to-heat systems and distribute it among a local community. It's more reliable, cleaner, and democratizes the energy system.
The most recent example of this is Honda's Smart Home prototype, which is powered by solar PV and is supposedly so efficient that it feeds excess power back into the central grid. It comes with a lithium battery just like the one found in an electric vehicle to store power for a rainy (or rather, cloudy) day. It's not the first time the idea has been floated, and it's spurring the suggestion that Tesla isn't an electric car company at all, but rather an grid-storage enterprise.
In a similar realm, 'smart grid' innovation is also gaining traction as a solution to the nation's vulnerable energy infrastructure. The idea is that automated, digitized grid technology that can monitor energy use would also manage supply and demand more efficiently, and self-heal in the event of a disaster or attack.
And so the pattern goes these days: If you can't work with the laws of nature, parade out the latest technology to work around them instead.