Greenhouse Gas Emissions

Lighting is responsible for an estimated 7% of industrial greenhouse gas emissions, 33% of commercial and 10% of residential sector emissions. Total greenhouse emissions due to lighting in Australia at present are in the region of 22Mt CO2-e per annum. A breakdown of greenhouse emissions by lamp type is shown in the Fig. 1 below.

The implementation of electric lamp conservation standards in Australia could, depending on the assumptions made, potentially deliver annual CO2-e savings of 68kt in 2006, 231kt in 2008 and 418kt in 2010. Accumulated savings between 2005 and 2010 are estimated to be 1,190kt over business as usual scenarios.

It is estimated that 80% of the electricity used for lighting is ultimately removed by building air conditioning systems. The increased lighting efficacies and the associated reduction in lighting heat will reduce this air conditioning load. The lower energy use by air conditioning systems is estimated to produce a further 27% saving in CO2-e (ie an additional 322kt in the period 2005 to 2010).

Fig 1: Greenhouse gas emissions by lamp type

กก

Lamps are referred to by their colour temperature to indicate their 'coolness' or 'warmth'. The human eye can detect radiation in the range of 400nm (violet) to 700nm (red), which is considered to be the normal range of visible light. White light sources will generally be characterised in terms of their colour temperatures as follows; 

> 5300K*  cool (bluish white)

3300 - 5300K intermediate (white)

< 3300K warm (reddish white)

At most working illuminance levels white light is preferred, and warm light is preferred at lower illuminance for living and amenity areas. Artificial light sources vary widely in their colour rendering indices (CRI). The CRI is a measurement of a light source's ability to allow the human eye to perceive colours in the same way as it does under daylight at the same colour temperature. A higher CRI means that colours are rendered closer to their daylight appearance. A lamp with a high CRI does not necessarily have to have continuous light output across the visible spectrum, but there needs to be a range of output wavelengths which are in relative balance for this to be achieved. For example, incandescent lamps achieve a CRI of 100 while most high-pressure sodium lamps have a CRI of about 22. Although rendering of colours by high pressure sodium lamps is not accurate, each colour can be recognised. They are widely used in certain commercial and many industrial applications. A lamp's colour rendering ability is not directly related to whether it is a cool or warm colour.

 * K is kelvin, the absolute temperature scale - 0^oC is 273K.

Typical Efficacies

The efficacy of a lamp is measured in terms of its light output, in lumens, divided by the nominal power in watts. Depending on the technology, various lamp efficacies are obtained (values below are after 100 hours burning). The table and figure below show typical values:

Residential

Total domestic electricity use for lighting was estimated as 4,760GWh/a in 2000. In 1998 there were 7.0 million households in Australia (ABS, 2000b) and total annual consumption per household for lighting was therefore around 680kWh.

Straight fluorescent tubes
On average, each household is assumed to have one tubular fluorescent lamp (often in the kitchen), according to industry sources. The stock of tubular fluorescents in this sector is therefore estimated at 7 million, with replacement sales of about 1 million to 1.5 million per year. Given that there may be many tubular fluorescent lamps in residential applications such as garages where utilisation is much lower than normal (commercial sector) levels, the stock could be considerably higher than 7 million. However, the running hours, and therefore contribution to energy consumption, of these additional fluorescent tube lamps would be relatively small.

The fluorescent tubes that are assumed to be distributed one per household on average would consume about 300GWh/a. It is assumed that the remaining energy consumption is by incandescent lamps and compact fluorescents.

According to industry sources, in 1998, 15% of households owned compact fluorescent lamps The number of compact fluorescents is estimated as 2 million (2 for each compact fluorescent-owning household), with annual replacement sales of 500,000. The total energy consumption of these fluorescent lamps is about 60GWh/a.

The remaining lighting energy consumption in this sector is by incandescent lamps. The total energy consumption by incandescents is 4,400GWh/a, and the total stock (average 60W/lamp, 1,000 running hours per year per lamp) is about 73 million lamps. With an average lamp life of 1,000h (or one year of running) annual sales would be expected to be in the region of 73 million.

Recommended lighting levels for most commercial/industrial applications [AS 1680].

¹A lux is the measure of illumination: when 1 lumen falls on a 1 metre square surface it is called a lux. The more efficient lamps deliver the most lumens per watt (energy consumption).

Standards

Existing Australian Standards cover incandescent lamps (AS2325-1993, except incandescent reflectors, but IEC 61341 relates to these) and tubular fluorescent lamps (AS1201-1989, except compact fluorescent, but IEC 60901:1996 relates to these). From the perspective of any minimum energy performance standards or mandatory labelling, some minor amendments would be required to provide better coverage of energy efficiency issues and to provide a credible basis for service life claims. 

Some countries have also implemented voluntary programs, such as labelling schemes and public guidelines, for these and other products, including HID lamps (US Federal Energy Management Program). Several countries are also proposing to introduce energy efficiency regulations in the future (eg. Thailand, New Zealand).

The UK government announced the introduction of investment incentives (tax allowances) for certain energy efficient technologies. In the area of lighting, compact fluorescent lamps, T8 straight fluorescent tubes and efficient luminaires will qualify for the incentives. Higher power discharge lamps (eg sodium or mercury vapour, metal halide) appear not be directly regulated. This may be because their efficiency is usually quite high and their use is more restricted than the other types of lighting.

Despite their widespread and increasing use, quartz halogen systems tend not to be regulated.