This article discusses the issue of excessive lighting in buildings, highlighting how our actions, rather than the actions of the affluent, contribute to energy waste. It challenges us to recognize our role in this problem and urges a change in mindset.

The inspiration for this topic came during my recent visit to London. While strolling through the city on a weekend evening, I observed numerous office buildings illuminated despite being unoccupied. Passersby could see cluttered desks and empty chairs through the ground-floor windows. I counted many such structures, each brightly lit, almost as if there were incentives for showing off their lighting. This phenomenon starkly contrasts with the common complaints about rising energy costs. It exemplifies a troubling inability to think critically about our energy usage.

Modeling the Problem

To understand the extent of this issue, I developed a model evaluating various scenarios using the following key parameters:

A. Reference Building Characteristics:

1. Dimensions: 30 x 30 meters (900 m² or 9,688 sq ft)
2. Total Floors: 6
3. Overall Area: 5,400 m² (58,125 sq ft)
4. Use: Office spaces

B. Lighting Reference Values:

1. Ceiling height capped at 3 meters with white walls.
2. Average light level for commercial offices set at 40 foot-candles (fc).

C. Calculating Bulb Requirements:

I created a performance table based on various light bulbs and their luminous output. The total required light output for the entire building amounted to 2,714,250 lumens. For example, with each bulb providing 450 lumens, the calculation revealed that 6032 bulbs would be necessary to achieve adequate lighting, thus consuming significant electricity, regardless of whether they were incandescent or LED.

Subsequently, I analyzed the energy consumption of different bulb types based on their luminous output:

Checkpoint 1:

To ensure the number of bulbs was reasonable, I evaluated bulb density, determining how much area each bulb would cover.

D. Estimating Unnecessary Lighting Hours

Next, I calculated the hours during which the building was unnecessarily lit. Using a baseline of 12 hours, I established the following parameters:

• Work hours: 7 am to 7 pm
• Annual working days: 255
• Weekend days: 104
• Holidays: 6

This led to a shocking estimate of 5,700 hours per year of excessive lighting, equivalent to 237.5 days, or 65% of the yearly total hours.

Can you grasp the impact? That translates to over 15.6 hours of unnecessary light each day. This figure served as a basis for final consumption calculations.

E. Estimating the Number of Buildings in London

Starting with an estimate of 10,000 buildings, I assessed:

• Total area of London: 1572 km²
• Area occupied by these buildings: 9 km²
• This accounts for only 0.6% of London's total area, which seems plausible.

F. Electricity Production in the UK

As previously noted in my blogs and analyses on Academia.edu, I cannot solely rely on commonly cited sources. For instance:

• BP Energy Outlook: UK 2021 electricity production at 309.9 TWh
• Our World In Data: UK 2021 electricity production at 324.07 TWh

Checkpoint 3:

I rely on the most accurate source, DUKE, which reported 308.659 TWh for UK electricity production in 2021. Unfortunately, many academics reference less reliable statistics, perpetuating misinformation.

Household consumption in the UK for 2021 stands at 109 TWh for comparison.

G. Calculating Energy Usage for Unnecessary Lighting

Armed with the necessary data, I calculated the electricity consumed unnecessarily due to excessive lighting. The results were astonishing.

Scenario 1: 1600LM per bulb

Scenario 2: 450LM per bulb

Interpretation of Scenarios

Using only LED bulbs rated at 1600lm, the total annual consumption across 10,000 buildings would be 1,644 GWh, accounting for 0.5% of the UK's total electricity production in 2021. If only 450lm LED bulbs were used, the consumption would rise to 3,094 GWh, representing 1.0% of total UK production.

In a mixed lighting scenario of 15% halogen, 35% CFL, and 50% LED, the results indicate:

• For 450lm per bulb: 1.4% of total UK electricity production.
• For 1600lm per bulb: 0.9% of total UK electricity production.

While this model could explore many more scenarios, time constraints limit further investigation.

In Conclusion

During my research, I uncovered data indicating a decline in UK electricity production since 2005.

This decline may relate to the adoption of more efficient energy-consuming devices. For instance, the transition from incandescent to LED bulbs could lead to savings of up to 83% in energy consumption, showcasing the vast potential for improvement.

Final Thoughts

I simulated whether it would be feasible to generate sufficient energy for unnecessary consumption with current photovoltaic technologies. Theoretically, it is possible with 550Wp panels and a 12% conversion factor. However, various challenges arise, including:

• Flat roofs are essential.
• No competing structures or obstacles on those roofs.
• Sufficient energy storage must be available for nighttime and low-production days.

Given these hurdles, it's more practical to simply turn off lights when buildings are unoccupied, reallocating resources for more meaningful energy initiatives.

In summary, our excessive lighting habits reflect poorly on us, not the wealthy. We must confront the reality of our selfishness and negligence regarding energy use.

If you think this is just a minor percentage of the UK's electricity production, consider the implications of 9 km² in London alone. The scale of this issue extends far beyond just one city. How many buildings across the UK—and the globe—contribute to this waste daily?

One Last Note:

China accounts for 39% of global CO2 emissions from electricity generation, with production reaching 8,534 TWh in 2021. We must consider how much of that energy is squandered daily. Every speaker at the next IPCC COP should bear this in mind, yet the discourse often veers towards empty platitudes rather than actionable solutions.

The unnecessary lighting we produce compels us to:

• Extract excessive resources for energy generation.
• Generate vast quantities of energy.
• Create distribution systems that incur losses reflected in our bills.
• Address decarbonization challenges tied to this energy.
• Produce resources for technologies aimed at generating this energy.

Yet, how many individuals benefit financially from this cycle?

If anyone still insists the blame lies solely with the affluent, it’s time for a personal reckoning. Are we truly so wealthy that we can afford to illuminate vacant buildings?

It's high time we clarify our priorities.