District Energy

The Climate Change Act 2008 established a legally binding target to reduce the UK’s greenhouse gas emissions by at least 80% below 1990 base year levels by 2050.

District energy, including private wire, heating and cooling has an important role to play in future sustainable energy systems, whether through the operation of smart electricity, or the development of thermal grids.

District heating comprises a network of pipes connecting buildings in a community together; this can be individual groups of buildings, a campus or a city neighbourhood. These can be served by centralised energy centres or a range of distributed heat producing units, including renewable energy systems. this central plant may also incorporate combined heat and power (CHP) plants to offer co or tri-generation.

One of the future challenges will be to integrate district heating and cooling with the existing building stock and more energy efficient buildings, as well as the electricity sector to achieve optimal efficiencies.

District energy comprises three main elements:

A central energy plant that produces heat and power in the case of (CHP) plants.
A network of pre-insulated distribution pipes to transfer the thermal energy from the energy centre to the buildings connected to the network.
Heat interface units at the customer buildings, to connect to existing space heating, domestic hot water services, cooling and process heat systems.


Heat Mapping

To establish a district energy scheme requires genuine knowledge of the commercial market and its stakeholders, along with a strategic understanding of how decentralised energy business opportunities can be sustained over time, to deliver a sound commercial basis for investment.

Heat mapping is a key first step in a scheme’s development and allows clients to identify energy demands from existing buildings and evaluate future demand from potential developments to plan a coherent long term strategy.

Using the UK Heat Map as a starting point, energy demand clusters can be located and potential growth in energy demand identified, quantified and recorded using GIS mapping tools.

energy masterplanning

Heat load clusters and routes for connecting heat mains can be identified and a constraints assessment undertaken to establish optimal network routes. These can then be analysed based on whole life costs, to establish the most commercially viable networks and cost-effective means to deliver carbon reductions.

An energy master plan can be prepared identifying key areas suitable for district energy networks, including potential locations for decentralised energy centres. The master plan provides a robust evidence base that can be used to support community regeneration and the development of local planning policy.

feasibility studies

A district energy feasibility study will incorporate a detailed technical analysis and economic evaluation of the proposed project to assess the viability of the scheme, prior to the development of a detailed business case. The study will also consider the impact of future policy and economic changes that may affect the scheme and identify appropriate funding and financial models as well as procurement routes.

The scope of the feasibility work may include:
Assessing the potential location of energy centres and distribution network
Developing detailed cost estimates and financial models to assess the viability of schemes
Initial hydraulic analysis of network route options
Assessing energy centre planning implications: space requirements, noise, and flue gas dispersion modelling
Quantifying carbon savings
Evaluating potential low carbon technology supply options as a means of promoting the development of a ‘path to zero carbon’
Selecting schemes to take forward for business case development
Providing support and advice on the procurement strategy
Development of a ‘private- wire network’ to enhance the economic viability of CHP projects.

design & specification

A holistic design approach is required to optimise the overall performance of the system and ensure the delivery of the cost and carbon benefits envisaged at feasibility stage. Although gas-fired CHP is often seen as the preferred heat source, district heating offers the potential for a broad range of low carbon heat sources to be incorporated into the system, such as biomass, geothermal energy and recovered industrial heat.

Following the initial feasibility study, the technical design, financial model and contractual arrangements should be further developed. This will include the design and sizing of the proposed heat network, distribution pumps, filtration and water treatment and temperature operating characteristics, transient and static pressure design, and the requirement for thermal stores.

The velocity and temperature profiles in the pipework are critical to ensure there is sufficient energy available to be transferred to the users, whilst avoiding excessive velocities that will increase the required operating pressures, with a consequential increase in energy consumption.

Our approach is to use 3D CAD modelling tools to optimise the design of the pipe network and allow both thermal and stress analysis of distribution network route options to be carried out. Selection of key plant such as the CHP unit or boiler plant, thermal store and pumps can then be specified for the energy centre and distribution network.

scheme delivery

The energy sector is subject to frequent policy and economic changes creating a complex environment for anyone looking to effectively develop and deliver district energy business models that reduce risks and increase the competitiveness of district heating.

By working closely with owners, operational management and contractors we have gained a broad experience in the energy sector and understand the market and what is needed for long term success.

We can help you select the most appropriate approach that reflects your priorities. Many Local Authorities recognise that either wholly-owned public sector or public / private ESCOs will provide them with greater control, however the establishment of such models may not be their area of expertise, and can be complex and time-consuming.

As a result Local Authorities may tender the development of the project to private sector ESCOs, thereby transferring project risks and reducing their involvement in the long term scheme operation.

Case studies

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