kWh
A kWh, or kilowatt-hour, is the billing unit on your energy meter: one kilowatt of power drawn for one hour.
What does a kilowatt-hour measure?
It measures energy: power multiplied by duration. A 2,000-watt kettle running for thirty minutes consumes exactly one kilowatt-hour.
Every figure a solar installer quotes eventually resolves into this unit, because it is the only one your supplier charges for.
How does a kWh differ from a kWp?
A kWh is what a system produces; a kWp is what it is rated at. The rating describes capacity under laboratory conditions, the kilowatt-hour describes the electricity that actually reaches your meter.
Reading a quote as though the two were interchangeable is the most common mistake homeowners make. In the Netherlands, one kilowatt-peak on an unshaded south-facing roof yields roughly 850 to 950 kilowatt-hours a year — not one thousand for every kilowatt-peak installed.
Which consumption figure should I use when comparing quotes?
Use the annual total from your own bill, never a national average. A household with a heat pump or a car charger sits in a different bracket entirely, and sizing a system against the wrong figure produces the wrong system.
Take a full year rather than a single month. Dutch consumption swings hard between summer and winter, so a monthly figure extrapolated twelve times is misleading in both directions.
Why will one kilowatt-hour be worth more than another from 2027?
From 1 January 2027 a kilowatt-hour you consume yourself is worth more than one you export, because the Dutch net metering scheme ends on that date.
Electricity used at the moment it is generated saves the full retail rate you would otherwise pay. Electricity sent to the grid earns only the feed-in payment, which is lower by law and by design.
Common questions
Is a kW the same thing as a kWh?
No. A kilowatt is a rate — how hard something draws at this instant. A kilowatt-hour is a quantity — that rate sustained for an hour. A one-kilowatt appliance left on for three hours uses three kilowatt-hours.
How many kilowatt-hours does a single panel produce?
It depends on the panel’s rating and on your roof. One kilowatt-peak on an unshaded south-facing Dutch roof yields around 850 to 950 kilowatt-hours annually. Since a single panel is a fraction of a kilowatt-peak, calculate with the whole array rather than one panel.
Where do I find my own annual consumption?
On the yearly statement from your energy supplier, or in their app or customer portal. Look for the twelve-month total in kilowatt-hours.