Developing low carbon heat networks for cities and towns in Sussex and Kent

BHESCo are specialists in the decarbonisation of heat.

We have partnered with residential, educational, and commercial properties to develop affordable solutions for low-carbon heating and power.

This is achieved through a combination of energy efficiency improvements, shared heat networks and renewable energy generation.

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Heat Network Case Studies

Rural Village

Most properties in rural villages rely on fossil fuels as a source of heat, usually heating oil or liquid petroleum gas (LPG). 

BHESCo were invited to conduct a feasibility study on how to optimally decarbonise heating in the village.

BHESCo obtained grant funding from the Rural Community Energy Fund, administered by Greater Southeast Energy Hub, to conduct the project.

BHESCo designed a modern low-carbon heating solution combining heat pumps, resistive heating, and energy efficiency upgrades. Our plan included a community finance option where upfront costs would be raised through a community share offer, removing any financial barrier for village residents.  

Block of Flats

With support from the Heat Efficiency Networks Scheme (HNES), BHESCo have completed a feasibility study for a block of flats in Brighton & Hove. 

Following over a year of research, our recommendation is to install new pipework and HIUs (heat interface units) as an initial phase of upgrades. 

BHESCo also looked at the viability of air source heat pumps and and solar PV as an extension to this.

As part of our study we analysed the impact of solar power on heat costs if installing a heat pump. Heat costs at the site are currently around 11 pence per kilowatt hour. After upgrades to the heating network, adding a large ASHP and rooftop solar PV, this cost could be reduced to 4.5 p/kWh.

Rural School

In 2016 the Montessori Place School purchased a large site for a new school in the Sussex countryside, situated in Uckfield near Lewes. 

There was no connection to the mains gas. All of the buildings on the site were reliant upon Liquid Petroleum Gas (LPG) to provide heating and hot water.

Following a detailed site survey BHESCo designed, financed, and project managed the installation of an integrated renewable heat and power system that has reduced the carbon emissions of the school by a remarkable 79%.

Technologies installed include a 27 kW solar PV array, an 87kW ground source heat pump, and a 7kW air source heat pump.

Why we need to re-design the way we heat our homes and businesses

The majority of buildings in England are reliant on fossil fuels as a source of heat, usually from a gas fired boiler. 

There is already a policy in place which says no new building developments can be connected to the gas grid from 2025. It is clear that over the long-term communities will need to find an entirely new way to heat their homes and businesses.

Whilst converting the heating of a property is a big challenge, the transformation will deliver many significant benefits including:

The best solution will differ from location to location depending on the requirements of local residents and the unique geographical characteristics of each area.

The most effective outcome will typically involve a combination of  technologies, some of which which are outlined below.

What is a heat network?

A heat network is created by connecting a collection of properties together via a network of pipes which deliver heat from a central generating source.

Heat networks can be very small, consisting of only a handful of buildings, or they can be large enough to cover whole neighbourhoods and cities, such as in Copenhagen. Heat networks can be extended over time, and new properties or heat generating technologies can be added in correlation to demand.

We can divide heat networks into two types;

High temperature heat networks have existed for decades and are common in many parts of the world where urban accommodation will share heat in a district heating system.

These systems require highly insulated pipework to transport heat from the generation source to individual homes and businesses.

Low temperature (or ambient) heat networks provide a continuous supply of relatively low temperature water to buildings. Usually this water is the same temperature as the ground (around 10 °C ) and is used to provide a source of heat for heat pumps.

Although this may initially sound strange, a heat pump without a constant source of heat would quickly freeze it’s surroundings.

One of the advantages of a low temperature heat network is that the pipework does not need to be insulated in the ground and there are no heat losses with long pipe runs.

In circumstances where buildings require cooling then a low temperature network can be used to achieve this outcome. Any increase in water temperature will improve the heat pump efficiency for other buildings which are using the network for heating.

Being part of a heat network removes the need for properties to have individual boilers. Each property is fitted with a Heat Interface Unit (HIU) which transfers heat from the shared network to the system within the house. These units are similar in size to a modern gas boiler.

The development of heat networks is considered to be crucial to the decarbonisation of heat in the UK, as they are highly efficient and cost-effective and offer a particularly attractive and viable solution to the replacement of oil heating in rural communities.

What is a heat pump?

A heat pump uses cooled refrigerant to absorb heat from the environment. The refrigerant is then compressed to increase its temperature and the heat is transferred to a water system for use in radiators, underfloor heating, or hot water tanks.

The source of heat in the environment can be one of many things.

Heat from below ground is one of the best sources since the ground temperature (below 1m) remains at around 10°C all year round.

Heat from the air is the most available source, but has the disadvantage of being very cold in the winter.

Heat from water sources, such as lakes or sea water can also provide a relatively warm heat supply all year round.

air source heat pump sussex

An air source heat pump is a device which absorbs ambient heat from the air outside of your property and transfers it to a water system for use inside your property. The example above shows a 7kW heat pump that BHESCo installed at the Montessori Place School in Uckfield, East Sussex

A typical heat pump can provide 3 to 4 units (kWh) of heat for every unit (kWh) of electricity used to power the heat pump. This efficiency is affected significantly by the temperature difference between source and supply, so a warm source is good and the lower the supply temperature the better so systems like underfloor heating work very efficiently with heat pumps.

Carbon emissions from electricity production have fallen by 50% in the last 10 years and will continue to fall as more renewable electricity equipment is installed. Running a heat pump will already release less than a third of the carbon released by burning oil for heating, whilst delivering the same amount of heat.

low carbon rural heat network - sussex kent - brighton hove energy services

With a ground source heat pump liquid is pumped into a loop in the ground. Heat from the earth is absorbed into the liquid, before travelling back to the heat pump. The heat pump transfers heat into a refrigerant at low temperature which is then compressed to raise it’s temperature to deliver hot water to radiators and hot water cylinders

What is a 'shared ground loop'?

Ground source heat pumps draw the heat out of the ground through either a series of pipe loops 1-2m under the surface, or from boreholes drilled around 125m into the ground.

Installing these loops or boreholes is costly and requires a reasonably large area of ground. In order to minimize costs and give access to properties without much land it is more efficient to install boreholes at one location and share the heat through a low temperature heat network, or shared ground loop.

Each property has it’s own heat pump and retains the ability to control the temperature of individual rooms in just the same way as having a gas or oil fired boiler.

BHESCo urban heat network shared ground loop
An example of a heat network design where each property is fitted with an individual heat pump drawing heat from a shared ground loop and borehole array

The length of piping required for the ground loop will vary depending on the size of your property, the thermal efficiency of the building, and your unique individual power needs.

In circumstances where land available is limited, deep vertical boreholes can be drilled in order to access the heat stored in the earth.

The temperature of the soil remains almost constant throughout the year, meaning the heat pump can generate heat in all seasons.

Low-carbon heating for blocks of flats

There is a growing need for residents in blocks of flats to replace old, inefficient heating systems. 

Aging fossil-fuel powered heat systems are coming to the end of their natural life and people are looking for an affordable and sustainable alternative.

To meet this demand, BHESCo are working with residents from apartment buildings across Sussex on solutions which will deliver long-term reliability and environmental sustainability.

BHESCo’s years of experience and technical expertise guarantees that a robust system will be installed to deliver efficient and affordable heat for the benefit of all residents.

Energy Efficiency

When we talk about the ‘energy efficiency‘ of a property we are referring to how well it makes use of the energy that is required to heat and power the building on a day-to-day basis. In the UK the energy efficiency of a building is measured by its Energy Performance Certificate (an EPC), which also includes some suggestions on how to improve the property. You can find your EPC using the national EPC Register.

Upgrading the thermal and energy efficiency of a property will significantly reduce the amount of power that is consumed by the building on an annual basis, leading to a corresponding decrease in fuel costs.

In addition to lower energy bills, homeowners who make energy efficiency improvements can expect to enjoy much greater levels of warmth and wellbeing as well as achieving a significant reduction in the size of their carbon footprint.

Typical energy efficiency improvements include loft insulation, cavity wall insulation, low energy LED lighting, double glazed windows, and draught exclusion for windows and doors.

Bringing it all together to create a low-cost, low-carbon heating solution for communities in Sussex and Kent

BHESCo is working with a number of communities across the South East of England to support the development of locally owned, low-carbon energy solutions.

We want to empower people in Sussex and Kent to take control of their heating provision by creating their own heat networks powered by environmentally sustainable sources.

Similarly, we want to assist communities to take ownership over their electricity by supporting the development of microgrids and community-owned renewable energy generation.

By combining energy saving measures with heat pumps powered by renewable energy generation and battery storage, homes and businesses can achieve a tremendous reduction in the environmental impact of their heating, and in many cases a corresponding decrease in heat and power costs.

Heat networks and heat pumps are expected to form a fundamental pillar of the UK’s transition strategy towards a net zero emissions economy, and we expect to see a widespread uptake of these technologies over the coming years.

If you live in the Sussex and Kent area and are interested in partnering with BHESCo to investigate the economic feasibility of developing a heat network or microgrid in your community then please contact us using the form below.

Project Contact Form

If you are interested in working with BHESCo to revolutionise the way that your organisation or community sources it’s heat and power then please provide your details in the form below and a member of our Projects Team will get back to you to discuss next steps.

Sources

The Clean Growth Strategy 2017; Leading The Way To A Low Carbon Future, p.13

assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/696273/HNIP_What_is_a_heat_network.pdf