Green shift brings blackout risk to world’s biggest power grid

As biting cold caused power demand to surge across western Europe on January 8, the continent’s power network came close to a massive blackout.

Europe’s grid, which is usually connected from Lisbon to Istanbul, split into two as the northwest and southeast regions struggled to keep the same frequency. The problem originated in Croatia and led to the equivalent of 200,000 households losing power across Europe. Supply to industrial sites was cut in France and Italy.

While this event hasn’t been linked to a surge in renewable electricity, as Europe replaces big coal and nuclear stations with thousands of smaller wind and solar units -- just as sectors electrify to reduce emissions -- incidents like this will become more frequent.

“It is not a question about if a blackout in more than one European region will happen, it is only a question of when it will happen,” said Stefan Zach, head of communications at Austrian utility EVN AG.

Transmission grids need to stay at a frequency of 50 hertz to operate smoothly and any deviations can damage equipment that’s connected. Had the frequency swings not been reduced within minutes, it could have caused damage across the entire European high voltage network, potentially causing blackouts for millions.

A fault at a substation that caused overloading on other parts of Croatia’s grid has been identified as the cause of the issue, network operators concluded Tuesday.

Large amounts of intermittent electricity create huge swings in supply which the grid has to be able to cope with. The issue isn’t confined to Europe. Australia has had teething problems in the transition to a cleaner grid. Wind power was blamed for a blackout in 2016 that cut power to 850,000 homes. The nation is looking to batteries as a solution and was the first country to install a 100 megawatt megabattery in 2017.

Read more about the race to build megabatteries here

California gets about a third of its generation from renewables. Last summer record-breaking heat gripping the state and electricity supplies grew strained in the evenings, as solar plants stopped generating for the day. Grid managers resorted to rolling blackouts for the first time since the state’s electricity crisis in 2000 and 2001. Utilities had begun installing big batteries to take up some of the slack, but not fast enough.

“The problem isn’t posed by growing green electricity directly but by shrinking conventional capacity,” said Eglantine Kuenle, chief electricity systems modeler at the EWI Institute of Energy Economics at Cologne University. “The upshot is a gap in secure power generation and grid balancing that must be fixed.”

Europe hasn’t come this close to a major blackout since 2006 when more than 15 million households were plunged into darkness for hours. Since that, Europe’s grid operators have put in automatic responses like splitting the grid and triggering standby generation or demand reduction.

Spinning turbines of thermal plants connected to the grid create kinetic energy called inertia which helps keep the grid at the right frequency. This spinning can’t be created by wind turbines or solar panels and policy makers need to find ways to incentivize other forms of energy storage or flexible output.

Germany is the biggest producer of green power in Europe. The nation is culling a quarter of coal and nuclear power capacity next year, a gap it will need to plug. Instead of building a huge fleet of batteries, Germany plans to rely more on more its neighbors, importing power along huge cables.

The event shows that problems in one nation will rapidly cascade between states as they become more reliant on their neighbors for power, said Wolfgang Kroeger, a professor at the ETH university’s Risk Center in Zurich.

Continental Europe was separated into two areas due to “outages of several transmission network elements in a very short time,” according to Entsoe, the association of grid operators. “Further detailed investigation” is ongoing.

“Longer, harder to fix disturbances that rip across countries are a real threat,” said Kroeger.