Diwali Special: The science behind lighting up your home

Given a choice between diyas and LED (light-emitting diode) lights, many would opt for the former to light up their homes on Diwali. But if seen from a scientific angle, it’s a choice between particulate emissions or power consumption.

Even the smallest thing you do this Diwali could increase your carbon footprint. Diyas and candles give out emissions. Installing lights requires continuous power consumption. But while it might seem that residential energy consumption should increase in the week of Diwali, experts suggest otherwise. “The relationship between Diwali and household electricity consumption is difficult to draw," says Radhika Khosla, research director, Oxford India Centre for Sustainable Development, on email. Diwali arrives closer to winter, when air-conditioners, the primary guzzlers of power in residential areas, are barely used.

A look at the possible emissions and power consumption from some commonly used lighting sources.

Given a choice between diyas and LED (light-emitting diode) lights, many would opt for the former to light up their homes on Diwali. But if seen from a scientific angle, it’s a choice between particulate emissions or power consumption.

Even the smallest thing you do this Diwali could increase your carbon footprint. Diyas and candles give out emissions. Installing lights requires continuous power consumption. But while it might seem that residential energy consumption should increase in the week of Diwali, experts suggest otherwise. “The relationship between Diwali and household electricity consumption is difficult to draw," says Radhika Khosla, research director, Oxford India Centre for Sustainable Development, on email. Diwali arrives closer to winter, when air-conditioners, the primary guzzlers of power in residential areas, are barely used.

Vaibhav Chaturvedi, a research fellow at the Council on Energy, Environment and Water, a Delhi-based not-for-profit policy research institution, says there are two ways of looking at a household’s footprint, depending on the lighting source one opts for: material and operational components. “Material component means that if I buy a strip of lights, there are certain (manufacturing) materials that go inside it. These materials are emission-intensive. The wires, bulbs, they all create some emissions during manufacturing," explains Chaturvedi. There are negligible emissions in the manufacture of diyas as they are made of clay and not necessarily in factories.

The other angle is operational emissions. “When you look at the operational emissions for lights, one will need to compare the additional electricity (and its emissions intensity) that is being consumed because of these lights. Diyas use oil. So, oil burning will lead to some emissions. But one would need to measure the emissions from one diya and then see how much emissions would, say, 100 diyas give out as a replacement for equivalent lights," he adds.

Khosla says reducing energy demand is “central" to mitigating climate change and the early decisions that households make regarding “the technologies they purchase and how they use them" are essential to creating path-dependent low-carbon consumption trajectories. “Households are a key part of the solution to reducing energy demand—domestic energy use already accounts for a quarter of global final energy demand and a significant portion of greenhouse gas emissions. Most of the growth in future household energy demand is projected to be in urban areas in developing countries, such as in India," she adds.