Energy and carbon dioxide
The cleanest kWh is the one that never needs to be produced.
It is known that it is not just the manufacture of a luminaire that affects the emission of CO2. During its 20-year lifetime, the product is expected to be used for 50,000 hours (according to the Energy Directive, office lighting is on for 2,500 h/year and we estimate 20 years of use) and now we come to the interesting part, because this is where the energy consumption comes in, which is directly related to CO2 emissions.
If we suppose that we are using a luminaire without control and a 70 % degree of efficiency, the luminaire will consume 2469 kWh during its 20 years. Using the Western European energy mix, this is 1272 kg of CO2 (according to EU 27, 1 kWh is equivalent to 0.515 kg of CO2). If instead we use a luminaire with a higher degree of efficiency (90 %), we will lower the energy consumption to 1,976 kWh and emissions to 1,017 kg of CO2.
In both cases, we can reduce consumption and emissions by 57 % if we use e-Sense luminaires with daylight, constant light and presence controls. Of course the luminaires can also be controlled in larger systems, but it is important for the environment that these are controlled!
Greenhouse gases are not just carbon dioxide
Greenhouse gases include carbon dioxide, methane, nitrous oxide and fluorine compounds. They all have different retention times in the atmosphere and show different degrees of “effectiveness” as greenhouse gases. The greatest threat is considered to be carbon dioxide, CO2, not because it is the most powerful, but because it is so common. Carbon dioxide is formed with all combustion, not only with the combustion of fossil fuels (oil, coal, gas). With the combustion of biofuel, it is estimated that the same amount of carbon dioxide that is formed during combustion is bound in the organisms that replace what was combusted. Thus the combustion of fossil fuel is considered to be the greatest threat.
Water vapour (H2O)
- Is responsible for about 2/3 of the natural greenhouse effect.
- Captures heat that the planet emits and forwards it in all directions.
- A part of the hydrological cycle.
- Human activities do not add water vapour to the atmosphere.
- Warm air can contain more H2O, so that increasing temperatures intensify climate change.
Carbon dioxide (CO2)
- Most problematic as it occurs in such large quantities.
- Responsible for 70 % of emissions (80 % in industrial countries).
- Binds in plants and is released during combustion, or degrading with access to oxygen.
- Use of fossil fuel releases the carbon dioxide which was previously bound in the plant..
Nitrous oxide (N2O)
- Responsible for 4 - 6 % of the increased greenhouse effect (about 6 % in industrial countries).
- Human influenced sources comprise fertiliser, combustion of fossil fuel and industrial chemical production.
- Naturally discharged by oceans and rain forests and by bacteria in the ground.
- 310 times more “effective” than CO2 in regards to heat absorption.
Methane (CH4)
- Responsible for 20 % of the increased greenhouse effect.
- Mainly created by mouldering, (i.e. degrading without oxygen).
- Emissions created by humans responsible for the majority (rice-plantation, refuse tips, stock-raising).
- Natural methane sources include: wetlands, termites, and oceans.
- 21 times more effective than CO2 with regard to heat absorption
Fluorine compounds
- 1.5 % of discharged greenhouse gases from industrialised countries.
- Can remain for thousands of years in the atmosphere. Does not occur naturally.
- Used in refrigeration plant, within the electronics industry and discharged during the manufacture of aluminium.
- Chlorofluorocarbons (CFCs) also deplete the ozone layer.
- Started to be taken out of use after the Montreal protocol 1987.
- Up to 22,000 times more effective than CO2 with regard to heat absorption.