Kilowatt to Megawatt

A typical Western household draws 1–5 kW on average, but peak demand can spike to 10–15 kW when the oven, dryer, AC, and water heater all run simultaneously. This peak is why electrical panels are sized at 100–200 amps (24–48 kW capacity). Adding an EV charger at 7–11 kW can push some older homes past their panel limits, requiring an upgrade.

EU directive 80/181/EEC mandated kilowatts as the official unit for engine power, making kW the legally required figure on vehicle documents since 2010. Manufacturers still advertise in PS (metric horsepower) because consumers are used to it, but the official registration papers always list kW. One kW equals about 1.36 PS, so a 100 kW engine is roughly 136 PS.

Home Level 2 chargers draw 7–22 kW, adding 30–130 km of range per hour. Public DC fast chargers range from 50 kW (older units) to 350 kW (latest ultra-rapid chargers). Tesla Superchargers V3 peak at 250 kW. A 350 kW charger can add 300 km of range in about 15 minutes on compatible vehicles — but your home wiring cannot deliver anywhere near that without industrial-grade supply.

When power returns after an outage, everything turns on simultaneously — fridges, AC compressors, water heaters, furnaces — creating an "inrush" spike 3–5× normal draw. A home that normally peaks at 10 kW might briefly pull 30–40 kW. This is why utilities restore grids in stages (rolling reconnection) rather than all at once: if an entire neighborhood surges simultaneously, transformers can overload and blow, causing a cascading failure that extends the blackout. Some smart thermostats now stagger restart to reduce this risk.

With modern 400 W residential panels, you need just 2.5 panels (so 3 in practice) for 1 kW of peak capacity. A decade ago, when panels were 250 W each, you needed 4. That 1 kW of panels produces roughly 1,000–1,600 kWh per year depending on location — enough to power a large refrigerator for a full year. A typical home installation is 4–10 kW (10–25 panels).

In the US, roughly 750–1,000 homes (average consumption ~1.2 kW per home). In Europe, where usage is lower, 1 MW can serve 1,500–2,000 homes. But this is average — on a hot summer afternoon when everyone cranks AC, that number can drop to 300–400 homes. Grid planners must size for peak demand, not averages, which is why installed capacity far exceeds average load.

A small data center uses 1–5 MW; a large hyperscale facility (Google, AWS, Microsoft) draws 50–200 MW — some exceeding 300 MW. The entire US data center industry consumed about 17 GW in 2023, roughly 4% of national electricity. AI training clusters are pushing demand higher: a single large GPU cluster can draw 50–100 MW, and planned AI-focused campuses target 1 GW or more.

Onshore turbines typically rate 2–6 MW; the latest offshore monsters reach 14–16 MW per turbine. Vestas' V236-15.0 MW turbine has a rotor diameter of 236 meters — wider than two football fields. A single sweep of its blades can generate enough electricity for a UK household for two days. Capacity factors run 25–45% onshore and 40–55% offshore, so actual average output is roughly half the nameplate rating.

Most operating reactors produce 500–1,400 MW of electrical power. The world's largest, at France's Gravelines plant, has six reactors totalling 5,460 MW. Small Modular Reactors (SMRs) being developed target 50–300 MW each. Nuclear plants run at 85–95% capacity factor — far higher than wind (~35%) or solar (~25%) — meaning a 1,000 MW reactor actually delivers about 900 MW on average.

MW tells you the maximum instantaneous power the battery can deliver (how fast it can discharge), while MWh tells you total stored energy (how long it can sustain that output). A 100 MW / 400 MWh battery can deliver 100 MW for 4 hours, or 50 MW for 8 hours. Grid operators care about both: MW for handling sudden demand spikes, MWh for sustained backup during extended outages or evening solar fade.