November 2011
Our most recent event at Mold was a very lively presentation with a good deal of debate and discussion promoted. Our thanks go to Chris Jones of MES energy services who provided our CPD seminar on the Road to Carbon Zero. Chris provided an overview of what currently meets Part L and how change is needed to achieve carbon zero buildings for 2016. Go to www.mesenergyservices.co.uk for details of sustainable building solutions and how MES energy services can help. By 2050 it is proposed by government targets that there will be an 80% reduction in CO2.
With nearly half of emissions from existing stock this target is going to be a challenge. The driving factor to reduce missions is to prevent fuel poverty, provide fuel security and try to obtain energy security. Fear is that the rising costs of fuel and the increasing demand for fuel will lead to reduction in supply so we need to stem this by reducing the need of a building to be heated by fuel. As buildings produce around 45% of emissions, Part L of the building regulations has been applied to limit the heat loss from buildings and currently Part L 2010 forces a 25% reduction from the previous 2006 version. However in 2013 Part L is demanding a 44% reduction from the 2006 and in 2016 100% reduction (zero carbon) for dwellings with a later date of 2019 for non-dwellings.
The definition carbon zero has recently changed to reduce the building day-to-day use as it was unfair that the building industry had to try to achieve compliance in building when the building use and consumer choice could not be controlled. There is confusion caused as there is also the code for sustainable homes (CSH) which also provides different targets to meet that do not relate to just construction and efficiency.
How to build an energy efficient building
Design: looking at shape, orientation, fabric, air tightness, services, renewable technologies and use of the building. The siting of properties is predominantly going to be south facing to get maximum energy through PV etc. so planning will have to change to assist in the target to get to carbon zero. Terraces also work better than detached properties and larger schemes can benefit from getting better discounts and community energy schemes. There are already schemes and test homes – Bedzed in London and Innovation Park at Nottingham University. The BRE also has test homes to record and show how factors influence design and help the building to meet the requirements. Shelter: issues of trying to get sunshine to a building and for solar panels and PV. If the property is in the middle of a large or high rise building will there be a right to sunshine similar to the right to light?
Example of post-2016 specification (CSH level 6):
- Very few north facing – south facing in majority of buildings
- Simple rectangular shape
- Triple glazing
- Walls – brick/block (thermal) with 250mm insulated cavity (rigid insulation)
- Floor – 200mm rigid insulation
- Roof – 450mm mineral wool
- Boiler – Biomass boiler or community heating
- 100% low energy lighting
- Whole house ventilation with heat recovery
- Air permeable less than 2m3/m2/hr.
- 4m2 solar panels for hot water
- 3.5kwp solar PV (depends on orientation/pitch and shading issues but could be 10-15m2)
- Very low thermal bridging – accredited details scheme.
The above caused a bit of debate with the approximate costs involved as if the cost of current 2010 build is £2-6k, and is estimated to be £6-9k for 2013 and £25-35k for 2016, a lot of smaller infill buildings will probably not be cost effective as larger developments may get the best costs for bulk buying.
On larger sites wind turbines or micro hydro may be options and with the renewable heat incentive coming in ground source pumps, air source heat pumps and biomass are all options to come.
Current feed-in tariffs on offer provide up to 25 years of income for solar PV or wind with best prices between 9-37p dependent on type, but from next year prices will be reduced.
The road ahead for construction will change the way we design, build and use our buildings.
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