Heat networks and district energy

District energy and heat network feasibility, modelled to a standard funders accept

Software for the feasibility stage of a heat network or district energy scheme. Compare sources, network routes, phasing and cost, against CO2, to the CP1-grade evidence standard that heat network zoning and the Green Heat Network Fund expect. This page explains the category, the problem it solves and what to look for.

The category

What district energy planning is, and what it is not

District energy planning is the process of comparing and selecting the supply system for a heat network zone, district or campus: which sources (heat pumps, waste heat, geothermal), how the network is routed and phased, and what it costs to run and to build across many buildings.

It is not building energy modelling, which looks at a single structure's demand and services. And it is not the zoning assessment that designates where a network should go. It is the engineering layer between them, the work that turns a designated zone into a costed scheme.

District energy planning sits where infrastructure investment decisions are made, on the timeline of feasibility studies, option appraisals and funding applications, and to the rigour CP1 and the Green Heat Network Fund expect. The underlying method is multi-energy hub modelling, which evaluates every source and network in a single optimisation model.

Where district energy planning fits

Building energy modelling

Single structure: thermal performance, demand, building services

District energy planning

Heat network zone or district: sources, network routes, phasing, shared storage, cost against CO2

National energy system modelling

Wholesale prices, generation mix and grid investment at national scale

The problem

Without purpose-built software, most feasibility studies are under-analysed

The number of feasible supply configurations for a zone is large. A study with ten source candidates and a few network options runs to hundreds of combinations. Working through them by hand in spreadsheets is slow and hard to audit, and under deadline pressure the breadth of options is the first thing to go.

Sector-coupling interactions, where a choice in the heat system changes the economics of the electricity system, are almost impossible to model reliably without one computational framework. The heat pump size depends on the network temperature, which depends on the waste-heat source, which depends on the tariff. These cannot be settled in sequence.

The result is that the chosen scheme often rests on two or three calculated cases, which is thin when it has to satisfy a CP1 review or a Green Heat Network Fund application. The lower-cost option may never be evaluated. This is the gap that purpose-built district energy planning software addresses.

What the software does

What district energy planning software does

Purpose-built software for this category gives you a structured place to define the source candidates, load in demand profiles, set the network and site constraints, run the optimisation across a large design space, and compare results on cost, CO2, space and operation. It replaces the patchwork of spreadsheets, scripts and hand-built charts that most teams still rely on for feasibility work.

Multi-energy capability

Models heat, cooling, electricity, gas and hydrogen together, not separately. That is the prerequisite for capturing sector coupling: the heat pump, the waste-heat source and the network all sit in one model rather than three.

Scenario and Pareto comparison

Puts the optimised options on the same axes. A Pareto front of life-cycle cost against CO2 tells a council or a funder more than a separate report per option, and it shows what each step up in ambition costs.

GIS integration

Places the scheme in real geographic context: building footprints, network routes, heat-source locations. Site context drives network cost and heat demand, so it belongs in the model from the start, not bolted on at the end.

Auditable outputs

Results trace back to inputs, not a black box. When a council, a CP1 reviewer or the Green Heat Network Fund asks why a configuration was chosen, the answer is in the model, not in a separate spreadsheet or an engineer's memory.

Client-ready exports

Outputs you can share without rebuilding them in PowerPoint or Excel. Sankey energy flows, Pareto charts, capital breakdowns and monthly profiles come straight out of the tool, with the underlying data exportable for a funding submission.

Optimisation across large design spaces

Evaluates combinations spreadsheet analysis cannot reach. The underlying method, MILP, searches the full design space and finds the configurations that meet cost and CO2 targets at once, including ones a practitioner building scenarios by hand would not construct.

For the mathematical method behind the search across large design spaces, and the deterministic, auditable basis a CP1 review expects, see the page on MILP optimisation for energy systems.

In practice

Sympheny is a cloud platform in this category

Sympheny is built by Urban Sympheny AG, a spin-off of the ETH Domain (Empa). It combines GIS-enabled multi-energy hub modelling, a MILP optimisation engine that evaluates 50,000+ technology combinations per run, Pareto comparison of cost against CO2, and in-browser outputs (Pareto fronts, Sankey diagrams, dashboards) with Excel export of the underlying data.

The platform has been used across 40+ projects, including city-wide decarbonisation studies, campus energy master plans, district heating network evaluations and industrial site energy concepts. The same modelling rigour underpins the feasibility and option-appraisal work UK heat network schemes are assessed on.

Sympheny's optimisation engine is a commercial application of research published over ten years at Empa and the ETH Domain, the same methods set out in the peer-reviewed literature on multi-scale MILP energy system optimisation.

Common questions

Frequently asked questions

What is district energy planning software?

District energy planning software gives engineers a structured way to model, optimise and compare the heat and energy supply options for a district, zone or campus. It handles multiple energy carriers (heat, cooling, electricity, gas, hydrogen) in one model and evaluates large numbers of source and network combinations, so a heat network feasibility case rests on calculated options rather than two or three by-hand scenarios.

Who uses district energy planning software in the UK?

Consulting engineers and energy teams running feasibility and option appraisal, usually to CP1 standard, for local authorities, developers and ESCOs. The work sits behind heat network zoning under the Energy Act 2023 and behind Green Heat Network Fund applications. The economic buyer uses the outputs to see what each level of ambition costs and to justify the spend.

How does it differ from building energy modelling?

Building energy modelling looks at a single structure: its thermal performance, demand and services. District energy planning software works at the scale above, modelling how heat is supplied to many buildings from shared infrastructure, networks, district heating, generation and storage. The two address different stages of the design process.

Can it replace a heat network consultant?

No, but it changes what the consultant spends time on. The software does the computational work of searching a large design space and comparing cost against CO2. The engineer brings the judgement: which sources are realistic on the site, which constraints bind, and how to defend the chosen option to a council and a funder.

What outputs does it produce for a funding case?

A Pareto front of life-cycle cost against CO2, technology sizing and capital breakdowns, hourly energy flows, network and storage sizing, and dashboards. Sympheny renders these in the browser for live review, and the underlying data exports to Excel, so the evidence base behind a zoning assessment or a Green Heat Network Fund application is traceable.

See it on your scheme

See Sympheny on a heat network or district energy scheme like yours

Book a 30-minute demo. We'll walk through how a feasibility study is set up, how sources and network options are compared on cost against CO2, and what the funding-ready outputs look like before you commit.

Book a demo