Servers generate a lot of heat, roughly as much as they consume in electricity. In most data centres worldwide, it is released into the outside air, cooled away and wasted. At a time when heating is expensive and CO₂ budgets are running short, that is absurd. Modern data centres in Germany are therefore increasingly planned so that the waste heat goes into the town, via the local public utilities, to residential buildings, schools and municipal buildings.
How it works technically
Four steps, explained in simple terms, from the servers to the home:
Why this solution is future-proof
Conventional heat generation (whether a gas condensing boiler in the basement, oil heating or even district heating from a gas-fired power plant) has two structural problems: it depends on external fuels and it causes CO₂ emissions. Data centre waste heat has neither the one nor the other problem.
In concrete terms: the data centre makes the waste heat available directly to the municipal heating company. This heat is a by-product that, without a buyer, would otherwise escape unused into the outside air. At the Philippsburg site, the energy needed to run the heat pumps comes entirely from the site’s own photovoltaic and storage infrastructure.
No fuel price
The heat is produced anyway. Fluctuations on the gas or oil market do not affect the price.
No CO₂ price
Server waste heat causes no CO₂ emissions. The political CO₂ price path from 2027 does not affect it.
Locally available
The energy is generated on site: no tanker lorry, no pipeline risk.
An option becomes an obligation
Until recently, using waste heat was a voluntary matter: some did it, many did not. That has changed. Since 1 July 2026, the German Federal Energy Efficiency Act has obliged new large data centres to use their waste heat: starting with 10 per cent of the heat, rising to 20 per cent for facilities that go into operation from 2028. An option has become an obligation, and Philippsburg starts above this minimum quota from the very beginning.
For citizens and municipalities this means: affordable, climate-neutral heat without fossil fuel, without CO₂ price risk.- Key statement on the use of waste heat in modern data centres
What this means for Philippsburg in concrete terms
The exact orders of magnitude depend on the expansion. In the first step, a heating network in Philippsburg alone, we are talking about an order of magnitude that can cover a substantial share of the households heated with gas or oil today. In the target scenario “Bruhrain”, that is, a network linking Philippsburg with the neighbouring municipalities of Waghäusel and Oberhausen-Rheinhausen, the amount of heat grows to around two and a half times that.
Heat from the data centre: what is possible
The exact figures will be worked out in the further exploratory steps with the town, the public utilities and potential connection customers.
What the heat is not
To avoid a false impression: a district heating supply does not reach every house “by itself”. It needs a pipe network that has to be built, and it sensibly connects the buildings that lie at suitable distances from one another, typically in more densely populated districts, not every isolated farmstead. Whether a particular house is connected depends on the route planning of the public utilities.
Nor is there a ready answer on tariffs: they are decided by the heating company, majority-owned by the municipality under the public utility model, not by the data centre. What we can promise: the structural cost advantage (no fuel, no CO₂) gives the municipal side room for manoeuvre that gas- or oil-based heat does not have.
More background on the project can be found in our first article “What is a data centre” and in the historical overview of the site.