Did You Know?

We’ve been hearing a lot about how much energy we can save if we switch to compact fluorescent lamp (CFL) bulbs from ordinary incandescent or fluorescent tubes. However, the efficiency of CFL bulbs does not come without a cost – as is the case with most things. CFLs emit a small amount of mercury and according to a recent report in the environment magazine Down to Earth there are concerns that if there is large-scale adoption of these bulbs the amount of mercury emissions may be something to worry about.

The question to consider then is whether the potential harm from these emissions outweighs the huge savings in energy consumption that will result if we all move to using CFLs. First, let’s look at what we would save in terms of energy. Scientists estimate that for the same light output, CFLs use one-fifth to one-fourth of the energy of an incandescent bulb. Unlike an incandescent bulb which glows when the coil becomes hot and glows as it absorbs electrical energy, the light produced by a CFL is not a result of a heating process but due to the glow of phosphor. This is why it requires less energy to release light.

According to the Centre for Science and Environment, this means that if all households in a city like Delhi, for instance, switched to using CFLs, it would save up to 757 million units a year, translating into monetary savings of Rs 273 crore, apart from reduction in levels of several pollutants, including flyash, greenhouse gases, sulphur dioxide, oxides of nitrogen and particulate matter. Indirect savings from the reduced need for energy (again, in Delhi) include a reduction in water consumption (4.052 million litres per year) and coal use (5.4 lakh tonnes). And while there would be emissions of mercury, these would actually be 4.32 percent less than that emitted by conventional bulbs. Such savings are what has prompted some countries (Australia, Canada, Brazil and Venzuela) to introduce a phased move to CFLs and in time completely eliminate the use of incandescent bulbs.

Of course, there is still a lot we do not know about how used CFLs will impact the environment. India as yet has no laws relating to disposal and recycling of CFLs, and perhaps now is the time to work out these issues in a manner that allows us to make long-term, sustainable use of an eco-friendly technology.