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23 April 2019
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Analysis: Which projects are actually energy-efficient?


10 March 2016 | Herpreet Kaur Grewal


Commercial buildings in the UK may be producing an average of 3.8 times more carbon than estimated at their design stage, according to research from a government-appointed body. 

Innovate UK is a government body made up of about 250 staff, drawn mainly from energy consultant businesses and based in Swindon. The organisation is charged with determining “which science and technology developments will drive future economic growth”.

Its latest study examined six years of data from its £8 million Building Performance Evaluation (BPE) Programme. Only one of the 50 buildings studied produced the amount of carbon specified by its design. Researchers looked across the entire first wave of non-domestic evaluation projects funded by Innovate UK, including schools, supermarkets, offices and health centres. They analysed the emerging data and drew early conclusions that will also apply to other commercial and public buildings.

Although two-thirds of the buildings studied used renewable energy, a large proportion of these experienced problems that had a negative effect on their energy use and carbon emissions, says the report, published last month.

The study examined “50 leading-edge buildings” including 201 Bishopsgate, described as a high-specification office in the City of London with a floor space of more than 37,000 square metres over 14 storeys; the 2,500 sq m Blue Bell Health Centre in Liverpool; Cheshire Oaks on the Wirral, Marks & Spencer’s second-largest store at 19,400 sq m, which uses CO2 as a refrigerant to cool food, with heat recovery from the refrigeration and a biomass boiler for use in winter; Bourne Hill Offices in Salisbury, which provide office space for Wiltshire Council; and numerous schools based in London and in other regional areas.

Higher emissions
The study examined projects where data was available, focusing on the buildings’ fabric and systems, and how satisfied occupants are with the properties.

Almost every building in the BPE had higher carbon emissions in use than expected during design. Some had only slightly higher emissions while others were up to 10 times higher than the Building Emission Rate (BER). The Building Regulations require designers and developers to calculate a BER for every new building. This gives the estimated rate of CO2 emissions per square metre of floor area for emissions from regulated energy use (heating/cooling, ventilation and lighting).

The study found that projects faced big problems integrating new technologies, especially configuring and optimising building management systems (BMS).

Some teams also had maintenance, controls and metering difficulties with their biomass boilers, photovoltaic arrays and solar water heaters.

Additionally, one air-source heat pump had problems operating in cold weather. There were also problems with automatic window controls to support natural ventilation.

This is partly inevitable when people start using new technologies, because of installers’ lack experience of fitting systems in different buildings.

The study analysed carbon emissions and the procurement route, which indicated that average emissions are lower for projects with a traditional contract.

Success stories
But the team did come across some success stories. 
For instance, it was found that Staunton on Wye Primary School, with electricity and fuel use both below 30 kilowatts per hour per square metre (kWh/m2). Similarly, Mayville Community Centre, with electricity use of 47 kWh/m2 and no fuel use; and Angermering Community Centre, with electricity use of 49 kWh/m2 and no fuel use.

The report concluded that meeting the government’s 80 per cent carbon reduction target by 2050 will be “an unattainable goal, unless there is a revolution in how the country constructs and operate buildings”.

The report added: “The past 10 years have allowed the industry to experiment cutting energy use in buildings in many different ways. It is rare to find independent evaluation of how much energy buildings actually use when developers hand them over. As such, there is still no consensus about the best approaches for achieving true low-carbon performance.”