Blar Mhor Air Source Heat Pump and Heat Battery Project

Demonstrating this ‘home-grown’ heat battery will help to create a valuable showcase so other public and private housing developers can see the environmental and financial benefits being delivered in over one hundred houses. The whole system will help contribute to the national effort to decarbonise the provision of heat. Several other Scottish suppliers are using their low carbon expertise to help deliver the project and it provides another demonstration of the growing market opportunity offered by low carbon heat to Scottish businesses.

Helping reduce fuel poverty with low carbon heat technology

A combination of an air source heat pump (in this case Daikin or LG) and a Sunamp phase-change heat battery replaced existing heating systems to demonstrate reduced carbon emissions and lower heating costs. Using the heat battery to store energy enabled the opportunity to change electricity consumption from peak to off-peak charging tariffs, which was a major contributor to reduced costs.

The benefits of the new system are:

— Reduced energy consumption and domestic heating costs for tenants
— Reduced fuel poverty
— Reduced carbon emissions from domestic heating

Further, the trial has enabled an innovative Scottish company to successfully demonstrate its low carbon technology.

Where is the project located?

The Blar Mhor housing development is being constructed in Fort William. The residential site is part of a wider development to include a new hospital and a college. The Blar Mhor project will provide low carbon heating technologies to the 117 homes being constructed in the first phase of the overall Blar Mhor housing development. This will more than double in size to 250 homes at a later stage. It is understood the element of the project funded by the Low Carbon Infrastructure Transition Programme should be complete in March 2022, though the overall build completed by Summer 2022.

Combining low carbon heat and electricity systems to achieve big savings

The homes in the Blar Mhor development were originally planned to be heated using a liquified petroleum gas heat network. The Highland Council’s commitment to addressing fuel poverty and decarbonising head led to them identifying an opportunity to replace the proposed fossil fuel-based heating system with low-carbon and renewable heating systems. Shifting from the initial plans to a system combining air source heat pumps, solar panels and heat batteries provides an immediate reduction in carbon emissions. The air source heat pump and heat battery operate using either electricity from the solar panels or from the grid. As the electrical grid continues to decarbonise in the future, the carbon savings will continue to grow.

It is estimated that the combination of low carbon heat and electricity technologies used at Blar Mhor will reduce running costs for householders by between 40-60% compared with the originally planned liquified petroleum gas system. The total capital expenditure was £2,160,261 with the Scottish Government’s Low Carbon Infrastructure Transition Programme providing grant support of £895,680.

Thirty flats to be built on the site will be connected to a centralised heat pump system. This will result in income being generated through the Non-Domestic Renewable Heat Incentive (RHI) scheme, for the first 20 years of operation. The homes that are part of the development are new builds with individual heat pumps at each home. These do not qualify for Renewable Heat Incentive.

How do the different technologies work?

Air Source Heat Pumps
Air Source Heat Pumps capture low temperature heat energy from outside air and then concentrate this energy to increase the heat so it can be used for heating and hot water. The heat pumps can also be used to charge the heat batteries in each home, which enables the renewable energy to be stored for peak time usage. The housing development consists of a mixture of detached houses, semi-detached houses, and flats. The detached and semi-detached homes will each have their own heat pump system and the flats will be served by a number of shared heat pump systems, which will serve up to five properties each.

Solar PV Panels
Roof-mounted Solar Photovoltaic (PV) – solar PV panels convert the sun’s energy into electricity when they are exposed to direct sunlight. Each home in the Blar Mhor development will be equipped with roof-mounted solar PV panels which will provide renewable energy and reduce the homeowners’ electricity bills. Electricity from the solar PV panels will be used to either power the air source heat pump (which provides heating to the home) provide power for general needs (TV’s, lighting etc) or charge the heat batteries in each home.

Heat Batteries
Phase-change heat batteries –will be installed in each home. The batteries store heat generated by the air source heat pump and/or can be charged by electricity generated by the solar PV panels. This allows energy which is generated at off-peak times to be stored and used by the household at a time when heating or hot water is required. A typical example of how the heat battery would be utilised: the air source heat pump is powered by the solar PV panels and charges the heat battery during the daylight hours. This renewable energy is stored until it is required later to provide heating and hot water during peak times in the evenings, when there is little or no sunlight.

How are Scottish low carbon heat and renewables companies benefiting?

The design and development of the Blar Mhor development involves a broad team of professionals and suppliers who are based in Scotland (further information provided below). The project is expected to provide an economic boost to the area by developing the workforce in the renewables sector and by increasing construction-based apprenticeship opportunities.

The project will enable a range of Scottish based suppliers to demonstrate and develop their low carbon heat capabilities and skills. The main Scottish based companies that will contribute to the project are:

The Benefits Expected

Carbon emission savings
— Predicted annual savings of 85 tonnes of CO2e annually, compared with the originally planned liquified petroleum gas systems. This is equivalent to:

- Taking 45 average petrol cars off the road
- 626 aircraft flights from Glasgow to London

For Users
— 40% to 60% reduction in household energy costs
— Reduced levels of fuel poverty

For Stakeholders
— Regeneration and economic development for the local community.
— Local job creation and upskilling.
— The absence of liquified petroleum gas combustion, results in improved air quality due to removal of local carbon dioxide and nitrous oxide emissions..

The project is being supported by the Scottish Government’s Low Carbon Infrastructure Transition Programme.
This case study has been developed with support from: