Bloomberg has a crackerjack video production unit.
The piece above is a great historical overview of global grid development, and includes a discussion of last year’s Iberian blackout – which have spotlighted a vulnerability of renewables on the grid – the lack of spinning mass to even out fluctuations on the grid.
The spotlighted solution includes adding in some equipment to replace that mass – and below, Undecided has a nice discussion of Flywheels – a technology with a long history whose time might have come again.
Below, there are other solutions as well, involving Batteries, which seem to be good for damn near everything.
Synchronous generators, the heavy rotating turbines in coal, gas, nuclear and hydropower plants can provide control room engineers with the inertia needed to maintain frequency for the electrical system. Replace coal with solar and the control room must find inertia somewhere else. It’s a significant problem.
Initial studies in the United Kingdom from 2012 already revealed that if the volume of non-synchronous generation exceeded about 65% of total generation capacity running, the transmission system could not be secured against some credible potential faults. Proponents argue power electronics can bridge the gap.
Grid forming vs. grid following
Grid-following inverters track voltage phase and frequency from the grid as a reference to synchronize and inject power. Grid-forming inverters use internal control algorithms to set their own voltage – often by emulating the behavior of a spinning generator to create a virtual synchronous machine.
Field work
In a field roughly 70 km northwest of Aberdeen, once known as Europe’s oil capital, the Blackhillock BESS provides Great Britain’s electricity grid with synthetic inertia – the kind that doesn’t require any spinning mass. Grid-forming technology has been deployed in northeast Scotland to provide synthetic inertia and stability services to a part of the network where renewable generation from wind farms is abundant.
Developed by Zenobe and using energy storage provided by Wärtsilä Energy Storage, the 200 MW/400 MWh phase-one section of Blackhillock BESS was commissioned in early 2025, becoming the first battery in the world to provide full active and reactive power services connected to the transmission system. The landmark project is paid to provide grid stabilisation services to Great Britain’s National Energy System Operator, having passed various technical tests in the system operator’s Stability Pathfinder 2 procurement round. It’s able to offer these stability services due to innovative grid-forming technology provided by German inverter manufacturer SMA.
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Here, from an Australian Broadcasting report several years ago – brief description of how new Battery Energy Storage Systems can adjust instantly to voltage fluctuations and stabilize grids.
Lots of cool changes under way in the grid and we’ll all be better off when it’s done and the growing pains are finished. I remember fifteen years ago there was still a widespread assumption that the grid “couldn’t” operate with 20% variable generation, but that number kept going higher and higher and now we’ve got multiple states (and there are multiple nations) that operate every day with far higher fractions. And increasing costs of dealing with damage to old transmission and distribution lines and gear means that more and more small remote towns will find it very smart to invest locally in battery, solar and islanding capabilities when lines drop.
Batteries have changed the equation a lot, and I think there have already been successful demonstrations of black-start abilities (which natural gas plants have fairly often failed to succeed at). Power electronics and software also increase the manageability and resilience of the grid – while the overall complexity also goes up.
For spinning reserves, I think it might make sense wherever a thermal plant is being shut down to do a real evaluation of whether the generators should be retained and left hooked to the grid to keep that extra inertia. Batteries respond faster and more accurately, but if a plant’s structure can be partially retained, and some jobs with it, that could also cushion some of the impacts as the grid inevitably shifts far more towards distributed everything. Shutting down a coal plant in a city is not as locally damaging as loss of the same number of jobs in less-populated areas.
They listed three reasons for the increase in demand:
(1) gas cars to EVs
(2) converting furnaces to heat pumps
(3) AI datacenters
The big one they left out—surprise, surprise—is the increasing need for air-conditioning as the planet warms. Watch for a super El Niño near you!