What Is ERS in F1?

F1 ERS by the Numbers

• 2014: the year F1's hybrid ERS era began, pairing the MGU-K with the exhaust-heat-recovering MGU-H for the first time.
• 120kW: the maximum MGU-K output under 2014-2025 rules — about 161bhp, deployable for roughly 33 seconds per lap.
• 350kW: the maximum MGU-K output from 2026 onward, nearly three times the old figure.
• 2MJ: the old per-lap MGU-K harvest cap (2014-2025); the MGU-H had no harvest limit at all in that era.
• 9MJ: the new 2026 per-lap harvest cap — now generated entirely through the MGU-K, since the MGU-H is gone.
• ~1,000bhp: combined power-unit output stays roughly the same across both eras, per Motorsport.tech's breakdown of the 2026 rules — it's the engine-to-electric split that flips from roughly 80/20 to close to 50/50.

How F1's ERS Actually Works

ERS is short for Energy Recovery System — the hybrid half of a modern F1 power unit, sitting alongside the internal combustion engine. Its job is simple in concept: capture energy the car would otherwise waste, store it in a battery (officially the "Energy Store"), and let the driver call on it as an extra burst of electric power whenever it's needed.

The system centres on the MGU-K, the Motor Generator Unit-Kinetic, mounted directly on the crankshaft. Every time the driver brakes, the MGU-K switches into generator mode and converts the car's kinetic energy into electricity instead of letting it bleed away as brake heat. That electricity flows into the battery. When the driver gets back on the throttle, the MGU-K flips roles and acts as an electric motor, adding its own power directly onto what the combustion engine is already producing — the same basic principle as a hybrid road car, just deployed at 300+ km/h.

Why the MGU-H Got Scrapped for 2026

Until 2025, F1 power units carried a second hybrid motor: the MGU-H, or Motor Generator Unit-Heat, which recovered energy from the turbocharger's exhaust gases. It was remarkably effective — unlike the MGU-K, the MGU-H had no per-lap harvest limit at all, so manufacturers could pull essentially unlimited energy from exhaust heat and use it both to charge the battery and to spin the turbo up instantly, eliminating turbo lag.

The catch was cost and complexity. The MGU-H spins at extraordinary speeds — over 100,000rpm — and required exotic materials and years of development to perfect, making it one of the most expensive single components on the car while contributing almost nothing that road-car manufacturers could actually use. For the 2026 rules, the FIA cut it entirely, betting that a simpler, cheaper power unit built around a single, far more powerful electric motor would attract new manufacturers without sacrificing performance.

F1 ERS Rules, Era by Era

2026 Update: A Much Bigger Battery Boost

The 2026 power unit rewrites the balance between engine and electricity. Combustion output drops from roughly 550-600kW to around 400kW, while MGU-K output nearly triples from 120kW to 350kW — pushing the power unit from an engine-dominated ~80/20 split toward something close to 50/50 between combustion and electric power, while total output stays close to the same ~1,000 horsepower F1 fans are used to, according to Motorsport.tech's technical breakdown of the new regulations. The per-lap harvest cap doubles to 9MJ, and instead of one continuous deployment window, drivers can now fire off multiple 4MJ bursts across a lap depending on how much charge the battery has available — a much more tactical, moment-to-moment version of the strategic "save it for the straight" deployment calls that defined the MGU-H era.

Frequently Asked Questions

What is ERS in F1?

ERS stands for Energy Recovery System, the hybrid component of an F1 power unit that captures energy the car would otherwise waste — mainly from braking — stores it in a battery, and lets the driver deploy it as an extra electric power boost on demand.

How does the MGU-K work?

The MGU-K (Motor Generator Unit-Kinetic) sits on the crankshaft. Under braking it acts as a generator, converting the car's kinetic energy into electricity that's stored in the battery. Under acceleration it flips to acting as an electric motor, adding its own power on top of the combustion engine's output.

Why did F1 remove the MGU-H for 2026?

The MGU-H recovered energy from exhaust-gas heat with no per-lap harvest limit, but it was mechanically complex, expensive, and had almost no relevance to road cars. The FIA dropped it for 2026 to cut cost and complexity, shifting all energy harvesting onto a much more powerful MGU-K instead.

How much power does F1 ERS add?

Under 2014-2025 rules the MGU-K added up to 120kW (161bhp) in a single continuous deployment window of around 33 seconds per lap. From 2026, MGU-K output nearly triples to 350kW, deployed in bursts of up to 4MJ that drivers can use multiple times per lap instead of just once.

The Bottom Line

ERS turns every braking zone into a chance to bank power, and every straight into a chance to spend it — the same push-to-pass logic that makes F1 strategy calls so tense on the radio. The 2026 rules don't just tweak that system, they rebuild it: dropping the exhaust-heat-recovering MGU-H entirely and nearly tripling what the MGU-K alone can do, all while keeping total output close to the roughly $10 million hybrid power unit's familiar ~1,000bhp ceiling. It's a companion piece to the car's other big mechanical systems — see our F1 gearbox explainer for how that power actually reaches the wheels, and our F1 top speed and G-force breakdown for what it all adds up to on track. Then head to the team radio archive to hear engineers and drivers actually talk ERS strategy in real time.