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CP1 - Heat Networks

Why use Heat Networks?

CP1 Heat Networks

Heat Networks

The Heat Networks Code of Practice has been produced by CIBSE and ADE with extensive participation from AECOM, Cofely, DECC, GLA and many others. The introduction to the Code states that:

The development of heat networks (or district heating) in the UK is increasingly recognised as an important component in the UK's future energy strategy (DECC, 2013).

Heat networks can address the 'energy trilemma' by meeting the following strategic aims:

Why are gas-based Combined Heat and Power Networks not being adopted?

There are a number of barriers to the uptake of gas-based Combined Heat and Power Networks. The reasons can be categorised under the headings of Cost, Legal, Environmental and Customer resistance:

Cost

There are some important reasons why it is expensive to install a CHP-based district heat network:

Legal

It is not easy to get all parties to commit to the binding long term contracts to take heat that are needed before finance can be agreed and construction can begin.

Environmental

Air quality is an increasing concern, especially in city centres, and all CHP engines rely on combustion which emits NOx and SOx as well as CO2.

Customer resistance

Consumers have traditionally been resistant to signing long term contracts, with a concern that they may have to share costs of heating provided to others.

CHP based heat networks do not provide any cooling.

What is the alternative to using CHP?

Energy Trilemma

There is an attractive alternative to gas-based CHP district heating which is more effective in resolving each of the three facets of the Energy Trilemma. To avoid emitting CO2 from heating it is important to avoid combustion. This can be done with the electrification of heating and utilising:

These can all be achieved using ground source heat pumps which can also concentrate heat.

The alternative to using CHP is a Heat Sharing Network

Instead of an expensive central energy centre sending hot water through an expensive steel pipe network, a small diameter flexible plastic pipe network connects each building with water close to ground temperature. Each building employs a heat pump to extract heat if it needs heating, or reject heat if it needs cooling.

This radically simpler mechanism yields no carbon emissions on site – nor any other product of combustion – and allows for incremental expansion of the network at marginal cost. Each building is in control of its own costs and its own temperature controls.


Traditional Gas-Powered District Heating Heat Sharing Networks
High cost of insulated steel pipework Low temperature flexible plastic pipe network
No cooling without separate additional circuit Cooling from heat pumps
Large additional cost for cold circuit Separate cold circuit not required
High cost of central heat generation Low cost local heat pumps borne by tenants
High running costs of central heat generation Local heat pumps under tenants' control
Admin cost of metering, accounting, collecting revenues Tenants pay their own electric cost directly
Heat Sharing dividend
CHP systems emit CO2 and other noxious gases No on-site emissions at all
Can use waste heat
No heat recycling Provides Seasonal Thermal Energy Storage
Uncertainty of future heat demand Allows incremental expansion
Uncertainty of future heat sources
Legal cost of agreements to share capital costs Legal cost of agreements to share (lower) capital costs
Legal cost of agreements to share high running costs Low central running cost minimises risk
Legals need to meet changes of tenants during the scheme Fewer barriers to new tenants - low risk to existing tenants