Here Come the Lumens
LEDs are great even if they won’t necessarily result in large net energy savings.
LED technology is exploding, enabling entire new categories of lighting. My favorite example is the new “bulbs” that screw into regular sockets (E26/E27), but use multiple LED panels to supersize the total lumens.
One of the best sellers on Amazon is a 120-watt “bulb” that produces 12,000 lumens. Let me pause for a second to let that sink in. An old-school 60-watt incandescent bulb generates 800 lumens, so this is 15x brighter! It is so bright that the instructions warn users to avoid looking directly at the light due to potential eye damage.
I’m sure it won’t be long before someone cries “rebound effect”. Indeed, these new bulbs are a perfect example of how an improvement in energy efficiency can spur increased use. Replace your incandescent with one of these and your energy consumption goes up, not down.
But even if LEDs don’t result in large net energy savings, they are still creating immense economic value. For today’s post, I want to celebrate all this LED innovation. LEDs are the latest example in a long history of humans finding ingenious ways to consume more lumens. More and brighter lighting inside and outside our homes and businesses, and throughout our communities can make us happier, more productive, and safer.
Falling Price of Lumens
LEDs are the latest chapter in a long history of technological innovation in lighting. In a pioneering 1996 paper, Nobel laureate economist Bill Nordhaus traces how the price of light has fallen throughout one million years of human history.
- When light came from open fires, the price of lighting was that you had to gather wood. Nordhaus calculates that it took 60 hours of labor to generate 1000 lumen-hours.
- The Greeks and Romans had wax candles. A typical wax candle puts out 13 lumens, and, according to Nordhaus’ calculations, wax candles require 5 hours of labor to generate 1000 lumen-hours.
- Oil, gas, and kerosene lamps were developed in the 1800s, pushing down dramatically the effective price of lumens. Depending on the source of fuel, Nordhaus calculates as low as 0.2 hours of labor per 1000 lumen-hours.
- Enabled because of the developments in electric power, carbon-filament, and tungsten-filament light bulbs were commercialized in the 1880s and 1920s, respectively. These innovations pushed the price lower still, to 0.01 hours of labor per 1000 lumen-hours, by Nordhaus’ calculations.
- Even with little additional technological innovation in light bulbs between the 1920s and 1980s, the effective price of lighting continued to drop precipitously as wages increased and electricity prices declined.
- By the time CFLs arrived in the 1990s, Nordhaus calculates that it took only .0001 hours of labor per 1000 lumen-hours, about 600,000 times cheaper than it was for prehistoric man gathering wood for open fires.
Rising Consumption of Lumens
At each step of the way, humans have increased their consumption massively. Economists Roger Fouquet and Peter J.G. Pearson calculated that lighting consumption per capita in the United Kingdom increased 6,500 fold between 1800 and 2000.
Over these long time periods, it is hard to perfectly disentangle falling prices and rising incomes, but there is no question that the rebound effect for lighting has been very large. Before the development of modern lighting, it was simply too expensive to consume much lighting so most people lived in near complete darkness except from the sun and the moon.
Thus, these new supersized bulbs and other innovations with LEDs are the natural next step in this long-running human thirst for ever increasing quantities of lumens.
The Department of Energy says that LEDs “use up to 90% less energy” than traditional incandescents. The DOE is not wrong. But, what they have in mind is very short-run: (1) unscrew an incandescent and (2) screw in an LED that puts out the same quantity of light.
Over the long-run, there are countless ways for people to use more lighting, just as they have responded to lighting innovations throughout history.
Just at the Beginning
My sense is that we are just beginning to see what is possible with LEDs. Yes, LED technology has been around for a long time, but it was not until the 2010s that LED prices started plummeting and consumers started buying them in large volumes.
It has taken time for LEDs to saturate the different lighting categories. Commercial bay lighting, recessed lighting, under the counter lighting, LED strip lights, rope lights, grow lights, ambient lights, flood lights. Across countless categories, there are smart entrepreneurs developing new LED technologies.
It will take time. We won’t all rush out immediately to buy a bunch of LEDs for every possible usage. But, over time, as homeowners, landlords, and business owners remodel their buildings, you can bet that they will add lighting.
Outdoor lighting is particularly ripe for price-induced increases in consumption, despite real concerns about light pollution. Maybe it didn’t make sense to have so many lumens in your backyard before, but now it probably does. And wouldn’t it be nice to have brighter street lighting, particularly in areas with lots of pedestrians and cyclists?
How much farther can this go? I don’t know. But historical precedent shows that humans have an almost insatiable appetite for ever larger quantities of energy services.
Keep up with Energy Institute blogs, research, and events on Twitter @energyathaas.
Suggested citation: Davis, Lucas, “Here Come the Lumens” Energy Institute Blog, UC Berkeley, March 27, 2023,
Lucas Davis View All
Lucas Davis is the Jeffrey A. Jacobs Distinguished Professor in Business and Technology at the Haas School of Business at the University of California, Berkeley. He is a Faculty Affiliate at the Energy Institute at Haas, a coeditor at the American Economic Journal: Economic Policy, and a Research Associate at the National Bureau of Economic Research. He received a BA from Amherst College and a PhD in Economics from the University of Wisconsin. His research focuses on energy and environmental markets, and in particular, on electricity and natural gas regulation, pricing in competitive and non-competitive markets, and the economic and business impacts of environmental policy.
Bright white LEDs have been around since the 90s, but ones that can be screwed into a standard E26 socket weren’t widely available until ~2010. Accepting 2010 as the start date, DOE predicts LEDs will save 348 terawatthours of energy through 2026, or a little over .5% of all electricity consumed by Americans.
So anyone who believes improvements in energy efficiency should be considered a “source” of electricity is kidding themself. Though LEDs only use 25% as much energy as incandescents on a per-lumen basis, they’ve only been able to reduce electricity consumption by a tiny fraction of that amount. The Jevons Paradox (or “rebound effect)” is real – and any efficiency gains from LEDs were the low-hanging fruit. If we expect electric ovens or water heaters to ever use 25% as much energy as they do now, we’re setting ourselves up for disappointment.
California population has grown 9% since 2005 but total energy use basically peaked in 2006, so energy efficiency has done something to dent energy use.
“California population has grown 9% since 2005 but total energy use basically peaked in 2006, so energy efficiency has done something to dent energy use.”
No, Richard. Californians are using 9% less electricity because “free” solar and wind have jacked up the cost of electricity seven times faster than the national average.
Is that the latest”renewable” solution to system reliability…make electricity so expensive that lower-income customers can’t afford it? Instead of Demand-Response, Demand – Do Without?
Yes, the price effect effect on demand has been substantial in California, but that’s the effect that creates the incentive for energy efficiency. You can’t say on one hand that growing electricity demand in inherent and unstoppable and then argue on the other hand that demand has stabilized or even fallen because the response to rising prices was to reduce demand. California’s gross state product has grown at a rate among the top 5 states over the 2006-2022 period so falling demand is NOT because of falling economic activity. The only explanation left is increased energy efficiency.
Advancements in LED manufacturing allowed LifeScan to pot them into an optics block back in the 80’s with sensitive electronic detectors enabling second generation blood glucose monitoring.
Controlling/limiting the wavelength(s) and intensity of the light that the LED’s emitted took a lot of coordinated effort by teams of folks back in the day. Thanks for reminding me of the role LED’s have played in lighting the world (and the bottom of chemistry/membrane matrixes).
Night-time lighting is terrible for wildlife, especially the cooler LEDs. We need to push back against unnecessary outdoor lighting at night.
Definitely this. No more light needed, or rather does nature have any more capacity to absorb light pollution? It’s already suffering greatly. See this excellent infographicky article from Reuters. I wish it was more explicit about the causes.
Good news and bad about lighting efficiency: the thermostat on the wall over there and the furnace it controls buffer savings in winter/cold climates, so you’re just trading watts for therms. But you save an extra 40% in summer if the AC doesn’t have to carry the lighting heat out of the house. Generally, energy efficiency in buildings is mostly about the exterior surface area of walls, roof, and windows, their R values (insulation), and leakiness.
One more plus for LEDs, though: they have occasioned a really revolutionary improvement in flashlights, which I realized forcefully during our two-day outage last week.
In economics, the Jevons paradox (Jevons effect) occurs when technological progress or government policy increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the falling cost of use increases its demand, increasing, rather than reducing, resource use. THAT explains why I drive my EV more than my ICEV.
Solar-and-battery-powered LED lights take advantage of all three dramatic cost reductions (solar, battery, and LED). Because it’s sensor activated, the battery is sized to be small and cheap.
Not the mention the main cost savings is likely the self-installation vs. wiring/electrician.
And let’s not forget the non-energy benefits of more efficient lighting: improved safety in homes and commercial and industrial buildings (e.g., less accidents), around sidewalks and streets (e.g., less accidents), and in health facilities (e.g., less accidents). In particular, we know better lighting in developing countries’ health facilities can lead to reductions in premature deaths (particularly at night where there is little or zero lighting).
You’ve missed the most important lesson illustrated by your lumen journey. Specifically, provide an investment structure that rewards innovation and entrepreneurs will often make use of technology to greatly improve services and the human condition. Your article did not even address the safety, health (moving from wood burning fires), and environmental benefits ( LED reduced use of raw materials and extended life) of LEDs which far improve the lifestyles and any increased use of lighting and energy .
So, the most important “lesson” Lucas could’ve made about the “lumen journey” is that it attests to the innovative virtues of capitalism? Are you suggesting that “an investment structure that rewards innovation”–which is generally true about all technological innovations in modern times–is more important than the gist of Lucas’s cogent blog post, which is that LEDs provide a “perfect example” of the rebound effect.
Applying an old saying to this new LED trend, it is possible to have too much of a good thing. In that regard, the most important lesson in this post is in its final words: “Historical precedent shows that humans have an almost insatiable appetite for ever larger quantities of energy services”–despite , I would add, technological innovations that may well have been designed, at least in part, to do the opposite.
“Are you suggesting that “an investment structure that rewards innovation”–which is generally true about all technological innovations in modern times–is more important than the gist of Lucas’s cogent blog post, which is that LEDs provide a “perfect example” of the rebound effect.”
My answer is yes.
I also believe the “rebound effect” with respect to LEDs needs to be clarified. First, there is no information presented to examine the total LED lighting energy usage compared to either incandescent or CFL usage. Based on the overall efficiency of LEDs my expectation is that a straight replacement would substantially reduce total lighting energy usage. Even with a significant increase in lighting applications it would still be difficult to show increased overall energy usage. So where is the energy usage rebound?
Second, if the rebound effect refers to an increase in lighting applications – so what? A determination of whether an increase in lighting is good or bad would require an assessment of how those applications impacted safety, energy and overall resource usage, education, health, and other services.
Great piece. This reminds me of Peggy Caswell’s work years ago. She showed that as irrigation got much more efficient by introducing drip irrigation, water useage went up in most farming areas, at least in the West.
An excellent, and dramatic, story! Along with McMansions, showers with six low-flow shower heads, massive personal trucks and so on, consumptive behavior seems to have little limits. Can energy or carbon pricing really ever fight the adverse climate impact of such trends? Perhaps it can to the extent that it aids a shift to low-GHG energy supply even if it might not do much for energy end-use behavior.