What Is ERS In F1? Energy Recovery Explained

ERS in 2026 is the system that recovers energy under braking through the MGU-K, stores it in the Energy Store, and redeploys up to 350kW (469hp) of electric power, nearly half the car’s combined output of close to 750kW (1,000hp) once the internal combustion side is added in. The MGU-H no longer exists, so braking is now the only recovery source, which makes energy management the defining strategic discipline of 2026 racing.

• The MGU-K produces up to 350kW (469hp) of electric power, roughly 47 percent of the car’s combined peak output of about 750kW (1,000hp).
• The MGU-K recovers up to 8.5MJ of braking energy per lap, plus up to 0.5MJ more under Manual Override Mode.
• The Energy Store can change state of charge by a maximum of 4MJ per lap, cycling energy through rather than storing a large reserve.
• Standard deployment tapers off from 290 km/h, while Manual Override Mode holds the full 350kW to about 337 km/h.
• The MGU-K is legally barred from propelling the car below 50 km/h at a standing start.
• The MGU-H was deleted entirely for 2026, ending the exhaust-heat recovery era that ran from 2014.

What Does ERS Stand For and What Is In It?

ERS stands for Energy Recovery System. In 2026 it is built from three parts: the MGU-K, the Energy Store, and the Control Electronics that govern the flow between them. The MGU-K is both a generator under braking and a motor under acceleration, the Energy Store is the battery that holds the harvested energy between corners, and the Control Electronics decide how much power moves where and when, all inside strict limits set out in the FIA’s technical regulations.

That three-part structure is simpler than it used to be. The MGU-H, the second motor generator that once sat on the turbocharger shaft and recovered energy from exhaust gas, was deleted for 2026. Every present-tense description of ERS in this guide covers what exists now: braking recovery through the MGU-K alone, with no exhaust-heat contribution. The MGU-H’s old job, what it did and why the FIA removed it, is covered further down in its own history section.

Fuel plays into this too, even though it is not technically part of ERS. The ICE’s fuel energy flow is capped at 3,000MJ per hour, a hard ceiling on how much energy the combustion side can ever contribute regardless of throttle position. With the fuel side capped, the electrical side is the only part of the power unit where clever management can still find a genuine advantage, which is exactly why ERS deployment has become the strategic currency of a 2026 Grand Prix rather than a background system nobody discusses on TV. That fuel cap is only one part of a wider regulation overhaul for 2026, and it sits inside the wider 2026 Formula 1 regulation overhaul that changed the car from nose to tail.

How Does the MGU-K Recover Energy?

Braking is now the sole harvest source for ERS. The MGU-K switches from motor to generator the instant a driver lifts and brakes, converting the car’s kinetic energy into electricity rather than letting it dissipate as heat through the discs. Under the FIA’s 2026 Formula 1 Power Unit Technical Regulations, the MGU-K can recover up to 8.5MJ of energy per lap this way, with an additional 0.5MJ available under override conditions for a driver who has qualified to use them.

The MGU-K only harvests from the rear axle, since it is mounted directly to the crankshaft rather than connected to the front wheels, so all of that recovered energy comes from the load the rear tyres are already carrying under brakes. That load is shared between the physical brake discs and the MGU-K’s harvesting, managed automatically through brake-by-wire so the driver feels a consistent pedal regardless of how much regeneration is happening underneath at any given moment. F1 Chronicle’s own measured braking g-force data puts the average peak deceleration at the calendar’s hardest stops between roughly 2.0G and 2.3G, the physical loads brake-by-wire has to blend with harvesting on every single stop of every lap. Teams also weigh brake cooling against MGU-K harvesting load when setting a car up for a given circuit, since a track with heavier braking demands, like Baku or Spa, asks more of both systems at once than a smoother circuit such as Suzuka.

Where Does the Energy Go?

Once the MGU-K harvests energy under braking, it flows into the Energy Store, the car’s battery. Regulation 5.4.9 caps the Energy Store’s state of charge change at 4MJ per lap, a tight ceiling that keeps the ES acting more like a flow battery than a reservoir: energy cycles through it every lap rather than building up a large stockpile for later use. What gets harvested on one braking zone is largely gone again by the time the car reaches the next straight, which is why deployment strategy has to be planned lap by lap rather than banked for a single decisive moment late in a race. The Control Electronics are constantly recalculating that balance, deciding how much of the available 4MJ swing to release on the next straight based on what has actually been harvested rather than a fixed pre-race plan.

That 4MJ figure is also a significant simplification from the previous generation. Under the 2014 to 2025 regulations, harvesting and deployment were governed by separate limits, roughly 2MJ of harvest per lap from the MGU-K and up to 4MJ of total deployment once the (now deleted) MGU-H’s contribution was folded in. Removing the MGU-H let the FIA collapse that split into the single 4MJ swing that governs the 2026 Energy Store, a cleaner rule that also happens to be far easier for fans to follow on a broadcast graphic.

How Do Drivers Deploy the Energy?

Deployment is where ERS becomes a strategic tool rather than just an energy-recovery system, and it works on two settings. In standard deployment, the MGU-K’s power output tapers from 290 km/h, so the electric contribution fades out well before the car reaches its top speed on a long straight. Manual Override Mode changes that: when a driver is within one second of the car ahead, the system holds the full 350kW all the way to about 337 km/h, plus the driver gets access to that extra 0.5MJ of harvest per lap, functionally the 2026 replacement for DRS as the sport’s primary overtaking aid.

Activating Override Mode is a driver decision, made through a steering wheel control once the one-second gap condition is met, and teams talk their drivers through exactly when to use it over the radio in the closing laps of a battle. Because the extra harvest and the extended power band both depend on being close enough to another car to qualify, Override Mode rewards drivers who can set up an attack rather than simply handing free lap time to whoever holds the button down longest.

Deployment is switched off entirely at the very start of a race. The MGU-K is legally forbidden from propelling the car until it reaches 50 km/h from a standing start, the same rule that governs how F1’s clutch is used: launches are combustion-only, with electric deployment only joining in once the car is already rolling past that threshold. Pit lane starts are exempt from the 50 km/h rule, since cars are already moving at a controlled speed when they leave the pit box.

What Does Energy Management Look Like in Real Races?

F1 Chronicle’s analysis of official F1 timing data from the 2026 season shows energy management reshaping how drivers brake, not just how they accelerate. At the 2026 Belgian Grand Prix, front-runners lifted for the first braking zone around 50 metres earlier in the race than they had in qualifying, a clear signature of harvesting changing braking points once the strategic picture opened up across a full grand prix distance. Our Belgian Grand Prix telemetry deep dive covers that finding in full.

The same measurement at the Hungarian Grand Prix produced just 5 metres of difference, a fraction of the Belgian gap. Two circuits, two very different answers, and whether harvesting reshapes braking everywhere or only at high-energy circuits like Spa is a question F1 Chronicle’s race analysis keeps measuring round by round rather than something we are willing to call settled off two data points. Our Hungarian Grand Prix deep dive has the detail behind that number.

Looking across a driver’s own race and qualifying performances, F1 Chronicle’s analysis found the median driver beats their own qualifying maximum speed by between 7.5 and 26 km/h depending on the circuit, largely down to slipstreams stacked with Manual Override Mode rather than raw deployment alone. Monaco and Spa are the exceptions, where the median driver is actually slightly slower in the race than in qualifying, a reminder that overtaking aids only help when there is a car ahead close enough to use them against, and that some circuits simply do not produce that opportunity as often.

Standing starts, measured independently of all of that, show just how little ERS has to do with a car’s initial getaway. F1 Chronicle’s timing data has cars reaching 100 km/h from a standing start in 2.79 to 3.04 seconds at Spa and 2.97 to 3.09 seconds at the Hungaroring, all of it on combustion power alone below the 50 km/h threshold where the MGU-K is allowed to join in. The closeness of those two ranges, despite the circuits having very different launch surfaces and gradients, says more about how tightly regulated the standing start rules are than about any single team finding an advantage there.

What Happened to the MGU-H?

The MGU-H existed from 2014 to 2025. It sat on the turbocharger shaft, recovering exhaust heat energy and using it to spin the turbo up on demand, which eliminated the turbo lag that had plagued forced-induction engines for decades and let engineers run smaller, more efficient turbos than would otherwise have been possible. It was, by most engineers’ own account, the single cleverest piece of the previous power unit generation, and also its most difficult to master.

The FIA deleted it for 2026 for reasons that had little to do with performance. The MGU-H was complex and expensive to develop, it had no equivalent in any road car a manufacturer might actually sell, and its technical difficulty was widely seen as a barrier stopping new manufacturers from entering the sport at a competitive level. Removing it also brought turbo lag back as a live engineering problem, one that the 2026 internal combustion engine and the wider power unit design now have to manage without the MGU-H’s help.

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Regulation figures verified against the FIA’s 2026 Formula 1 Power Unit Technical Regulations. Race data is F1 Chronicle’s own analysis of official F1 timing data from the 2026 season.

Reviewed by Jack Renn, July 2026

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