Spain Blackout Shows Need for Batteries in Renewable-Heavy World

(Bloomberg) -- Last week, Spain’s power grid failed in mere seconds, blacking out the entire country and parts of Portugal. It was a stunning collapse that illustrates an inviolable law of the electric system: The heartbeat of the grid — known as frequency — must be stable at all times.

With more renewables on the grid and an ever-greater reliance on electricity to power everything from cars to heat pumps, the chances of that heart skipping a beat are rising. That has grid operators racing to find solutions to avoid the next Spain-sized blackout — and they’re increasingly turning to batteries.

Frequency is the force that keeps power humming from generators to homes and businesses. For a century, its cadence has been set by how fast turbines — those running on oil, coal, natural gas and nuclear energy — spin in a second. That rate is set at 60 rotations in North America and 50 hertz in Europe. 

There is little margin for error: exceeding just 0.2 hertz on either side of the threshold threatens instability. A deviation of 0.5 can be catastrophic, which is what happened in Spain last week and what investigators are trying to understand the cause of. 

To maintain the right frequency and stability, the grid needs kinetic energy called inertia, which is typically created by the spinning turbines of thermal plants. Wind turbines and solar panels can’t provide that, so Spain and Portugal need coal, gas or hydro plants connected to the grid.

Other blackouts have raised similar alarms, notably what happened in Texas when a February 2021 cold snap forced gas-fired generators to trip offline. That caused frequency to plunge and forced even more supplies to automatically shut down. The state grid was 4 minutes and 37 seconds away from a bigger failure that could have taken weeks to recover from, the grid operator said during public meetings at the time. The state, along with California and Utah, has also seen wind, solar and batteries trip during smaller frequency fluctuations, which then caused a bigger frequency dip and cascade into even more outages, including at gas plants.

One readily accessible way to address frequency issues on an increasingly renewable grid is by using different types of energy storage, installations of which have soared in recent years globally. 

“Batteries instantaneously correct frequency,” Arushi Sharma Frank, senior associate of the energy security and climate program at the Center for Strategic & International Studies in Washington. She added that grids will need bigger storage projects that can hold energy for longer periods of time. 

They’re particularly useful because they don't need any time to warm up like a gas plant. When there's a small deviation in frequency, they can rapidly be deployed to correct it by either storing excess energy or discharging it, providing what’s known as synthetic inertia. The increasingly complex grid means there needs to be more resources that can respond to sudden supply and demand changes.

Batteries now account for more than half of the supplies Texas’s grid operator uses to ensure stability through its ancillary services market, Jan Rosenow, energy program leader at Oxford University, said in a LinkedIn post earlier this week. Power plants running on coal and gas used to be the backbone of grid stability and now regularly make up less than 20% of the supplies procured, he noted.

Highview Power relies on liquid air energy storage technology rather than traditional lithium-ion batteries. Its systems can store up to six hours of energy, which can be deployed to supply power and manage inertia quickly. 

About 30 kilometers (19 miles) southeast of Hanover, Germany, Siemens is installing a new type of transient storage facility using supercapacitors, which act like super-fast batteries that can release or store 400 megawatts of power within one second. They can achieve this speed by building up electric fields — think of rubbing a balloon in hair — that absorb or deliver energy. 

Residential batteries have also helped manage stability: Home solar and battery company Sunrun Inc. manages a virtual power plant in Puerto Rico — no stranger to catastrophic blackouts — where electricity stored in about 4,000 home batteries is injected back onto the grid to keep supply and frequency stable, said Chris Rauscher, head of grid services and electrification.

Beyond physical batteries, grid operators also rely on software that can help speed up response to frequency variations. Spain’s Hybrid Energy Storage Solutions Ltd. relies on patented algorithms and models to control a storage system that can rapidly react to manage inertia and provide other grid-stabilizing services.

Markets and policies are also influencing storage deployment as a backstop to grid stability. The UK has been a leader following a 2019 blackout after lightning struck a large offshore wind farm, which tripped power plants on land as frequency fell, said Devril Celal, chief marketing and flexibility officer of Kraken Technologies, which provides artificial intelligence-based operating systems to utilities.

That event “evidenced the acute need for projects to provide stability to the grid,” said Keith Gains, managing director and UK lead at Quinbrook Infrastructure Partners. In response, the UK’s system operator has developed more mechanisms to procure stabilizing capacity by offering longer-term contracts to incentivize building new assets.

Quinbrook, which specializes in infrastructure needed to drive the energy transition, has focused on more traditional tools: Synchronous condensers, which are essentially motors that help stabilize the grid. They have three operational and are building four more to help stabilize the UK’s grid.

In the UK, as well as in large parts of the US, Ireland and Northern Europe, there are markets that have created pools of resources, especially batteries, that can ramp up or down within seconds to smooth out frequency oscillations. Spain doesn’t have such a market, and the country only has one gigawatt of battery capacity installed versus 64 gigawatts of solar, according to BloombergNEF. 

The UK has had to focus on grid resilience well before other nations having pivoted from traditional fossil fuel generators while becoming the second-largest market for offshore wind power behind China. This led the country’s electricity system operator to launch the Stability Pathfinder, the first program in the world to get some essential grid inertia from non-traditional sources, according to power analytics firm Aurora Energy Research.

Ultimately, to prevent another country-wide blackout, power hawks are waiting for details from the Spanish investigation to figure out what solutions to put in place. But Luis D’Acosta, chief executive officer of Uplight, an AI-powered software solution used to manage consumers’ energy usage, said one thing is clear with the growth of renewable power: “The system gets twitchier, and the time to respond has to be faster.”

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