The Energy Efficiency Paradox

The Energy Efficiency Paradox

We generally assume that if we use more energy-efficient machines we will use less energy. If we install energy-efficient light bulbs in place of incandescent bulbs, for example, it will take less energy to light our homes. But both economic theory and the historical evidence suggest that in long run the opposite is true: when we use energy more efficiently we actually tend to use more energy.


All else being equal, installing more energy-efficient machines should mean using less energy. We will use less energy, in other words, if we simply replace our old incandescent bulbs with newer, more efficient bulbs. But, as Terence Tao explains, the lower cost of energy also encourages us to make our homes even better lit by installing even more bulbs. And we’re likely to use any money we save on the cost of lighting our homes on something else that also consumes energy. The basic idea is that when we can do more with less energy, it may become worth it for us to use energy in new ways. The result may be that we actually end up using more energy when our appliances become more energy efficient.

As Cameron Murray explains—in an article that is well-worth reading—this is sometimes known as “Jevons Paradox,” after the 19th century English economist who noticed that as people began to use coal more efficiently, they began to use more coal, not less. Contemporary economists talk about what they call “the rebound effect." This occurs when the savings that come from using more energy-efficient machines are offset to some extent by the increased use of machines. Even if our individual energy savings more than make up for our new consumption of energy, greater energy efficiency may lead to faster economic growth, which in turn will lead to a greater demand for energy.

Economists argue about how large the rebound effect is likely to be in different economies at different times. But a new study led by Jeff Tsao of Sandia National Laboratories concludes that more efficient solid-state lighting could increase the consumption of lighting by a factor of ten by 2030, in much the same way as the introduction of electric lighting vastly increased the amount of light we consumed. That would more than offset the amount of energy solid-state lighting would save through its increased efficiency.

Of course, whether or not the rebound effect is actually large enough to offset the savings of from greater energy efficiency in any given case is an empirical question. If at some point the benefits of increased use of lighting diminish—or if we begin to value using less energy as a good in itself—then the rebound effect will get smaller. But as a general rule it’s important to understand that for all its other benefits energy efficiency doesn’t necessarily mean energy conservation. It would be nice if we never had to make any hard choices. For the foreseeable future, our energy use is likely to go down only if energy becomes more expensive or if we directly limit its use. But the sad truth is that no matter how efficient we make our machines, reducing our energy use is almost certainly going to mean foregoing some of the things we could be using energy on.

Photo: Sun Ladder

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.

BepiColombo

Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

Study helps explain why motivation to learn declines with age

Research suggests that aging affects a brain circuit critical for learning and decision-making.

Photo by Reinhart Julian on Unsplash
Mind & Brain

As people age, they often lose their motivation to learn new things or engage in everyday activities. In a study of mice, MIT neuroscientists have now identified a brain circuit that is critical for maintaining this kind of motivation.

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End gerrymandering? Here’s a radical solution

Why not just divide the United States in slices of equal population?

The contiguous U.S., horizontally divided into deciles (ten bands of equal population).

Image: u/curiouskip, reproduced with kind permission.
Strange Maps
  • Slicing up the country in 10 strips of equal population produces two bizarre maps.
  • Seattle is the biggest city in the emptiest longitudinal band, San Antonio rules the largest north-south slice.
  • Curiously, six cities are the 'capitals' of both their horizontal and vertical deciles.
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Surprising Science

Scientists discover why fish evolved limbs and left water

Researchers find a key clue to the evolution of bony fish and tetrapods.

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