Eight criteria that determine whether a waste heat recovery project is viable

Across the projects Calentix has assessed, commercial viability consistently depends on recurring criteria. No single factor is decisive on its own, and a project that is weak on one criterion can still succeed if others are strong. Taken together, they identify where the real work needs to happen to make a project viable.

1. High-temperature and stable heat source

Higher source temperature reduces the temperature lift required of the heat pump, improving efficiency and reducing electricity consumption per MWh delivered. A continuous and predictable heat supply is equally important: long-term contracts with district heating operators require a heat source that can be relied upon year-round, not one that is interrupted by planned or unplanned shutdowns.

2. Low investment in new district heating infrastructure

Connecting to an existing district heating network is the single most powerful driver of project economics. The network already has customers, revenue and a counterparty willing to invest in distribution pipelines. The heat recovery installation adds production capacity to a functioning system, and the required investment is typically limited to the heat pump station and a short connection pipe.

Building a new network from scratch is categorically different. It requires investment in distribution pipelines, customer connections and back-up heat production capacity, all of which must be financed before the first unit of revenue is earned. The risk profile shifts significantly, and the project is no longer primarily a heat recovery project but an infrastructure development project in which heat recovery is the enabling technology.

3. Short distance to nearest district heating network connection

Pipeline investment is a critical cost in most heat recovery projects, and whether it is financeable depends on two factors in combination: how far the pipe must run, and how much heat can be sold through it. Distance determines the capital cost; heat volume determines how many revenue-generating MWh that cost must be recovered across. A long pipe to a large and dense customer base may be viable, while the same pipe to a small or uncertain customer base typically is not.

4. Large and stable heat demand

Not all heat customers are equally attractive. What matters most is how evenly heat demand is distributed over the year. A customer base with stable, year-round demand allows the installation to operate at high utilisation, generating more revenue per unit of capital invested. A customer base that peaks sharply in winter and use little heat during the rest of the year requires high capacity for a small annual energy volume, which drives up cost per MWh.

New residential buildings are the most attractive customers. Offices, light industry and warehouses have a less favourable pattern. The difference is significant: a residential portfolio may deliver two to three times more annual energy per MW of installed capacity than an equivalent industrial one.

5. Attractive purchase price for the district heating operator

The margin available to a heat recovery project depends not only on what it costs to produce the heat, but on what the district heating operator currently pays to produce or procure heat by other means. This alternative cost sets the ceiling for what the operator can afford to pay while still benefiting from the switch. A project with a low production cost and a low alternative cost can still be commercially difficult, and vice versa.

6. Low and stable electricity prices

Since heat pump modules are driven by electricity and there is no fuel cost, the local electricity price directly determines variable production cost and shapes long-term project risk. Markets with low and stable electricity prices are structurally more attractive. In markets where heat prices can track electricity prices a portion of higher electricity costs can be passed through to customers, partially preserving margins. Where heat prices are more rigid, sustained elevated electricity prices compress margins directly.

7. Strong regulatory drivers and available public support

The EU Energy Efficiency Directive creates a direct obligation for data centre operators above 1 MW to assess and, where feasible, utilise waste heat. National legislation shapes the demand side: for instance, restrictions on fossil fuel-based heating in new and refurbished buildings create structural conversion pressure that strengthens the case for district heating customers. Public investment support can be decisive in borderline projects, both by improving returns and by providing third-party validation of the project's energy system value.

8. Committed counterparties with aligned interests

A heat recovery project involves at least three parties with different risk tolerances, investment horizons and commercial objectives: the data centre operator, the heat recovery developer, and the district heating operator. The project structure must allocate risk and return in a way that is workable for all three, requiring long-term contracts, clearly defined interfaces and counterparties with both the mandate and the financial capacity to commit. The weaker any one of the three parties are, the harder it becomes to close a bankable structure.