Are we using less energy because of LED lighting, or more?

CC BY 2.0 gags9999/ no superfluous or unnecessary lighting here in Shanghai

It is wholly a confusion to suppose that more efficient lighting leads to diminished consumption. The very contrary is the truth.

LEDs use a lot less energy per lumen produced; according to IHS Market, a consultancy, LED lighting uses an average of 40 percent less power than fluorescents, and 80 percent less than incandescents, to produce the same amount of light. They determined that "the use of LEDs to illuminate buildings and outdoor spaces reduced the total carbon dioxide (CO2) emissions of lighting by an estimated 570 million tons in 2017. This reduction is roughly equivalent to shutting down 162 coal-fired power plants."

carbon emission savings© IHS Markit

They figured this all out by tracking the market share of all the LED companies, and suggest that every LED sold is a direct substitute for an older, less efficient light. From their press release:

The efficiency of LEDs is essentially what makes them environmentally friendly,” said Jamie Fox, principal analyst, lighting and LEDs group, IHS Markit. “Therefore, LED conversion is unlike other measures, which require people to reduce consumption or make lifestyle changes.... “LED component companies and lighting companies have transformed their industry,” Fox said. “They are fighting climate change much more effectively than other industries, and they should be given credit for it. Unlike in other industry sectors, workers at LED companies can honestly say that by selling more of their products, they are helping to reduce global warming.”

The evidence from space says otherwise

Well, maybe not. Because all IHS Markit appears to be doing is assuming that these companies are replacing inefficient lighting with LEDs. In fact, the evidence is pretty clear that thanks to LEDs we are using more energy than ever; as I noted a few years ago, we keep figuring ingenious ways to use them in places that we never did before, like with big LED monitors over urinals. But even if we just stick to lighting, a new study uses photos from space to show that we are using more lighting than ever. The study, Artificially lit surface of Earth at night increasing in radiance and extent. summarizes it all in the introduction:

A central aim of the “lighting revolution” (the transition to solid-state lighting technology) is decreased energy consumption. This could be undermined by a rebound effect of increased use in response to lowered cost of light. We use the first-ever calibrated satellite radiometer designed for night lights to show that from 2012 to 2016, Earth’s artificially lit outdoor area grew by 2.2% per year, with a total radiance growth of 1.8% per year. Continuously lit areas brightened at a rate of 2.2% per year. Large differences in national growth rates were observed, with lighting remaining stable or decreasing in only a few countries. These data are not consistent with global scale energy reductions but rather indicate increased light pollution, with corresponding negative consequences for flora, fauna, and human well-being.

change in lit area© Asolute change in lit area from 2012 to 2016

Essentially, lighting has become so cheap to run, thanks to the low cost of energy and the efficiency of lighting, that we are using far more of it, everywhere in the world, and particularly in developing countries with their dramatically improving standards of living. The study is primarily concerned with the effect of all this light pollution, but it also reflects energy consumption. And much of this is happening in parts of the world that generate most of their electricity with coal.

milan lighting© note the change in the quality of light in Milan

Major (factor of 2 or more) reductions in the energy cost and environmental impact of lighting should be accompanied by large absolute decreases in light emissions observable from space. The fact that the median country’s 15% increase in lighting from 2012 to 2016 nearly matched the median 13% increase in GDP suggests that outdoor light use remains subject to a large rebound effect on the global scale. Therefore, the results presented here are inconsistent with the hypothesis of large reductions in global energy consumption for outdoor lighting because of the introduction of solid-state lighting.

rebound effect© The Rebound Effect

It is environmentally incorrect to talk about the Jevons Paradox or the Rebound Effect, because it has been used by many to criticize attempts to increase energy efficiency, by noting that all those savings just get eaten up anyway. It is all very complicated and controversial, and there is some evidence that in products like cars and houses, we do buy bigger ones when they are cheaper to operate, but there is still a big saving of energy.

LEDs are an entirely different thing; we use them in entirely different ways that nobody ever dreamed of, and we use more of them. Lighting has become so cheap that it has turned into a bauble, into decoration. When it comes to lighting, to paraphrase Stanley: it is wholly a confusion to suppose that more efficient lighting leads to diminished consumption. The very contrary is the truth.

Just look at Shanghai.

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