About Today’s Efficiency Of Our Lights
Today, LEDs lighting dominate the lighting domain. They are efficient and manufacturers understand how to implement them for different lighting applications. While energy efficiency is rather well understood, the impact of the adoption speed is rarely discussed is.
He will have a look at the environmental cost of LED production versus the significant energy savings that a full transition to LEDs would bring. In a fictive scenario, he assumes that a transition takes place in a heartbeat today and compares that with the usually supposed scenario of a full transition to LED lights in 2025.
As of today, the total installed light sources of all sectors together can be broken down by lighting technology.
Based on the measured efficiency data, one can calculate the weighted average efficacy of the mix of all these technologies in lm/W. Gathering data from Caliper for LED flood light fixtures , and various manufacturer datasheets, we end up with the following weighted average: 38 lm/W as our world average, mostly raised by LEDs, HID and fluorescent technologies, and taken down by incandescent and halogens.
The same report gives a rough estimate of 30B fixtures. By multiplying the number of lamps with the efficiency using the calculation of EQ3 gives the amazing number of 11 Terra-lumens.
These calculations show that the average fixture consumes 10 W and produces 380 lm. It seems low for the power, but the order of magnitude is huge and the light output seems correct, given the large majority of halogen/ CFL/incandescent lights.
LED Fixture Production
Given our world statistics of the installed fixture base of 30B fixtures, the question here is: if we were to replace them all, what would be the impact?
NEMA in 2013 published a report in which the carbon footprint of several fixtures was analyzed. An interesting finding of this study was that the carbon impact comes mainly from four components: Ballast (driver), Heatsink (Al), potting materials in the lamp base, and LEDs themselves.
The semiconductor and electronics industries use a large amount of energy and water, and as the NEMA report shows, the overall carbon footprint and energy cost of manufacturing an LED product is approximately twice the conventional counterpart.
Derived from 30B fixtures into the relative energy cost, and now having to spend quite a bit of energy to produce the 86% missing “non-LED” fixtures.
How much energy does it take to produce an LED fixture?
– Unfortunately no exact data is available. Therefore a theoretical calculation based on some assumptions and published data from laptop computers was made, but fixture producers are welcomed to enlighten us with more accurate numbers.
An LED fixture in general does not have a battery or a screen, etc., and the electronics is simpler, but there is more and more PCB material involved for sensors, intelligence, communication and new features.
In the research paper “Economic-balance hybrid LCA extended with uncertainty analysis: case study of a laptop computer”, the authors found “Results show that manufacturing the computer requires 3010-4340 MJ of primary energy.” While LED fixtures have in general no screen, no battery, quite simpler electronics, the assumption was that it takes 1/10 of this energy consumption to produce a luminaire. In addition, the lower value from the cited research for energy consumption was used for the calculation, resulting in 300 MJ of energy.
To put things in relation, this 300 MJ equals 83 KWh or the equivalent of $10 of electricity in the US. To replacing all the fixtures, 172 GW of energy are necessary; that’s a lot for one year!
Circular Economy – Fixture Disposal
To see the whole picture, it is important to also have a look at the old fixtures. In the chosen scenario, the entire world is illuminated with LEDs. So apart from LED fixtures with the ability to replace the LED, everything must be replaced. In LED Lighting , replacing part of a fixture is an important debate, but very few solutions exist. This simplifies the calculation because the lifetime of any installed structure can be ignored.
Keeping the same “spherical cow” approach, there are currently about 30B “light points” in the world.
Data on large scale recycling varies quite a bit when reading through the literature. Our hypothesis is simply to add a “recycling factor”, a percentage of our new installed base that comes from recycling older materials. A study suggests that currently, between 20% and 40% of e-waste is recycled.
Even when assuming that proper recycling takes place with a recycling factor of 40%, this leaves a significant amount of waste. While the question of the waste raised many debates between the authors of this article, since the comparison concerns the scenario “change everything now” or “just keep going as it is”, in both cases, the waste will be the same, except there will new ways to deal with the waste that will be produced in the future. Then, maybe the second scenario might change.
The latest generation of fixtures in 2017 easily exceeds 100 lm/W for the complete range of applications; and efficiency is still increasing. It is worth it to mention that this is a very careful estimate. Figure 3 is a comparison of the two scenarios “change everything now,” and the scenario “just keep going as it is” with the assumption of changing +10% a year, leading to a complete change in 2025 for the latter.
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