Zero Carbon Homes Achievable Today
The UK and Ireland governments are committed to sustainable growth and increasing their ‘green’ credentials. They have signed up to various legally binding targets and standards such as the Climate Change Act 2008 (CCA), this act mandates that an 80% reduction in CO2 must be achieved from the levels recorded in 1990 by 2050.
Recent government policies require all new homes from 2023 to mitigate, through various measures, all the carbon emissions produced on-site as a result of the regulated energy use. The definition of regulated energy includes energy used to provide space heating and cooling, hot water and fixed lighting. It does not allow for energy used by consumer appliances.
These government policies are well aligned with European Policy, specifically the Energy Performance of Buildings Directive which requires all new Public Buildings to be nearly Zero Energy Buildings (nZEB) from 2020. It is noted that in achieving this mandatory nZEB standard the performance of the building fabric will need to be close to that of the Passivhaus Standard.
What is a zero-carbon / carbon neutral building?
A building must generate all its regulated energy without adding carbon dioxide to the atmosphere. If the building generates more energy that it requires, the surplus can be exported to the grid and if it is at a deficit, energy can be imported. The building emissions must however, taking these factors into account, be zero over the space of a year.
The energy used in dwellings accounts for more than a quarter of energy use and carbon dioxide emissions in the United Kingdom and Ireland. The amount of energy a home will need and the CO2 that it will produce each year can be calculated using SAP software and this allows architects to calculate the amount of renewable technologies that are required to offset the CO2 produced.
How to achieve zero-carbon / carbon neutral building?
To achieve a carbon neutral home, renewable technologies must be used to offset the CO2 produced from regulated energy use. The renewable technologies installed to produce on-site energy can vary depending on the circumstances, location of the property and the desired outcome. Solar PV or a wind turbine can be used to generate electricity, and when combined with the efficiency of a heat-pump can provide the space heating, hot water and electric lighting for the house.