How could zero carbon be achieved?

8 April 2020


Zero carbon is a term used to signify that no carbon emissions, such as carbon dioxide, are being produced from a product or service.


The term zero carbon can be used in the context of a building to refer to the amount of carbon associated energy it takes for the building’s operation and can include a wide range of aspects associated with a building’s performance, including construction and mobility.


We use energy for heating, lighting, to produce food, for transport, entertainment, security, to make products, and to run the internet, our phones and other data services. Just about everything we do consumes energy in some form or other.


About 55% of the World’s energy supply comes from coal and gas, about 37% from hydro, solar and wind, 6% from nuclear and 2% from other types of renewables [1]. Unless all your products and services are powered and produced by renewables, a proportion of the energy you use will have some carbon associated emissions. The proportion of energy that will be produced by wind, solar and hydro is expected to increase to about 48% by 2030 but this is in the context of a rising population and a net increase in energy requirements.


A modern home, taking a 3-bedroom semi-detached home as an example, requires about 230 GJ of energy to make, considering the various materials such as wood, plastics, glass, metal, cement, bricks and blocks. To give a comparison a shower can take about 9 MJ to heat the water, so 230 GJ is equivalent to the energy of heating about 25,000 showers. The average energy consumption of a UK home is about 59 GJ a year of which about 35 GJ is associated with heating. If a home can be expected to last 60 years, then the energy associated with heating a home is ten times that associated with making the home. This provides justification for trying to reduce the energy we need for heating.


There are fortunately many things we can do to dramatically reduce heating energy requirements. These include:

  • Roof insulation
  • Energy efficient windows
  • Air tightness management
  • Wall insulation
  • Floor insulation
  • Ventilation management
  • Heat pumps
  • Solar panels
  • High efficiency boilers
  • Using hydrogen rich gas supplies
  • TRVs (thermostatic radiator valves) and smart management systems


15% of heat can be lost due to a poorly insulated floor in a home. By installing a high quality underfloor insulation solution you can not only reduce the heat-loss associated with the floor but also improve the performance of your windows and other home energy measures as the air permeability through the home can be dramatically reduced. The Q-Bot technology offers a means by which a high-quality application of underfloor insulation can be undertaken. Click here to find out more.


By Professor Peter Childs

The author is Professor Peter Childs FREng, FIMechE, FASME, CEng, PhD, Imperial College London. Peter is the professorial lead in engineering design and founding head of the Dyson School of Design Engineering at Imperial College London, professor at large for the Innovation Design Engineering programme run jointly by Imperial and the Royal College of Art, and a founder director at Q-Bot Ltd. His areas of interest and expertise include heat transfer, retrofit, sustainability and innovation.