Refurbishing to cut carbon footprint

A 450 kW biomass boiler in Sainsbury’s Dartmouth store is one of the keys toward providing at least 10% renewable energy on site.

Reducing a building’s carbon footprint during refurbishment is essential to meeting long-term Government targets. And it need not be a risky business — as Mark Northcott explains.

Refurbishment offers a perfect opportunity to help mitigate the effects of climate change by installing technology to help reduce the carbon footprint of a building. And you do not have to take on high risk or unproven technologies to complete a low-carbon refurbishment.


According to the Carbon Trust, the key to success in most projects is a corporate commitment to cutting emissions, coupled with effective project management to ensure this is translated into action at every stage.

In its guide ‘Low carbon refurbishment of buildings’, the trust says: ‘Non-domestic buildings account for nearly a fifth of the UK’s carbon emissions. Given that 60% of the buildings that will be standing in 2050 have already been built, low-carbon refurbishment of existing buildings will be essential to hit Government targets for reducing carbon emissions.

‘Nearly all building refurbishments offer opportunities to reduce carbon emissions, but conventional projects often miss the opportunities available, leading to unintentional and unnecessary increases in energy use and associated emissions.’

The Carbon Trust’s Low-Carbon Building Accelerator (LCBA) focuses on gathering data and demonstrating expertise in the energy-efficient refurbishment of non-residential buildings. It involves the Carbon Trust’s specialist consultants working with a range of building projects in the retail, hospitality, Government and education sectors.

It says: ‘Significant focus has been placed on energy use in new buildings. However, new build represents only a small fraction of the available opportunities (about 1.5% of the UK building stock is new builds each year)…

‘Buildings experience a number of refurbishments throughout their life, with a major refurbishment every 20 to 30 years. These refurbishments represent an opportunity to reduce carbon emissions through refreshing a building’s fabric and services equipment.’

The Carbon Trust has produced a detailed process to ensure low-carbon refurbishment of buildings.* The need to reduce carbon emissions is increasingly pressing as the Government introduces new regulations that have potentially enormous cost implications.

For example, up to 20 000 large organisations are racing to avoid huge potential losses, and even jail terms, under the new mandatory Carbon Reduction Commitment (CRC) carbon-trading scheme.

The CRC comes into force in just a year from now. Any organisation with an annual electricity bill of around £500 000 and above (more than 6000 MWh of electricity) is automatically included.

The CRC is a UK mandatory cap and trade scheme proposed to cut carbon emissions by 1.2 Mt a year by 2020.

As far as heating is concerned, there is a wealth of proven energy and carbon-saving equipment available. The UK is committed to reducing carbon emissions by 80% by 2050, and biomass heat production in particular has a potentially enormous role to play in achieving this aim.

For example, a biomass boiler using wood pellets as its fuel produces around 50 to 60 kg of carbon dioxide per MWh. If the fuel is wood chips this figure is even lower — 35 to 40 kg of CO2 per MWh. Compare this with natural gas (230 kg of CO2 per MWh) or oil (380 kg of CO2/MWh).

Biomass will hold, and can even reduce, atmospheric carbon-dioxide levels because replanting trees to replenish the fuel burnt takes the carbon-dioxide released back in from the atmosphere during our lifetime, thus locking as much carbon already in the atmosphere as we can into the existing carbon cycle.

So, by investing in biomass, a building owner can considerably reduce his or her property’s carbon footprint, while also supporting local fuel suppliers.

But biomass does even more than this; it also has the potential to dramatically cut costs.

The Carbon Trust puts it this way: ‘Biomass heating offers most significant cost savings in parts of the UK which are not currently on the gas grid. For example, using wood or straw can provide cost savings of 2 to 4 p/kWh (pence per kWh) relative to use of heating oil.

‘A biomass system generating 1600 MWh of heat (roughly equivalent to the annual heating requirements of a typical school) could therefore save up to £50 000 per year on fuel costs relative to an existing oil-based heating system. The costs of biomass fuels also tend to be much less volatile than fossil fuels.’

A real example hammers home this important point. A new ‘eco-store’ operated by a major supermarket chain in Dartmouth, Devon, is benefiting from a biomass boiler supplied by Broag UK. The installation of this boiler is expected to help it become one of the first supermarkets in the UK to achieve a BREEAM ‘Excellent’ rating.

The 450 kW boiler burns wood pellets made from sustainable forested trees.

The biomass boiler was selected because it reduces waste heat and uses renewable energy. This fits with the supermarket’s goal to reduce the carbon footprint at the Dartmouth store by 20% and provide at least 10% renewable energy production on site.

Mark Northcott is director — commercial products with Broag.

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