This post was written by Keith Dawson for UBM Tech’s community Web site All LED Lighting, sponsored by Philips Lumileds. It is archived here because the All LED Lighting site has gone dark. This material is Copyright 2013-2015 by UBM Americas.

2014-01-10

What If We Don't Need SSL to Save Energy?

Home electricity use in the US has fallen 6% over three years. What does this fact do to the case for solid state lighting?

The Associated Press reports with numbers from the US Energy Information Administration (EIA) that the average US household finished 2013 having used about the same amount of electricity as in 2001. Usage has dropped about 2% per year since 2010 and is expected to fall another 1% in 2014.

What's going on? It's not solid state lighting (SSL) making the difference -- residential penetration rates for SSL are not much above 1% so far. Compact fluorescent lighting might provide a small part of the answer. But according to the AP, the big gains in energy efficiency have come from other initiatives.

First, many states have tightened energy-saving requirements for new-home construction in this century. While new homes represent only a small fraction of the total housing stock, the efficiency gains there are large enough to move the needle on overall residential energy consumption.

Miniaturizing electronics play a big role. Hardly anyone still has a computer at home with a big, energy-guzzling CRT monitor. Flat screens are up to five times more efficient. And the Electric Power Research Institute calculates that it costs $1.36 to power an iPad for a year, while the old-style desktop computer used to set you back $28.21 in electricity. Millions of CRT TV screens have been replaced with ones based on efficient LCDs and LEDs.

(I'll note in passing that in the commercial sphere, server virtualization and cloud computing are already saving large amounts of energy.)

Then there's the increasing efficiency of electric appliances, from refrigerators to washers and dryers to air conditioners. The AP quotes the Association of Home Appliance Manufacturers as noting that a room air conditioner purchased today is going to be 20% more efficient than a 2001 model. There is also a trend toward more central air conditioning vs. room-sized units, again resulting in greater efficiency (partly offset by a tendency to use the central air more).

Who needs SSL?
If we're already 6% ahead of the game by the end of 2013, and 7% in another year, doesn't this fact take some of the wind out of the arguments for energy-saving SSL? After all, the total potential energy savings if all residential incandescent bulbs are replaced with LED wares is of the same order -- and all this saving won't be seen until after 2025.

According to the EIA, 13% of US residential electricity goes for lighting. If SSL promises eventually to save half of that as it replace low-efficiency lighting over the next couple of decades, that's "only" 6.5% saved.

The trends that have been dropping residential energy use should accelerate, if anything, as greater percentages of inefficient housing stock and electric appliances and consumer electronics are replaced by newer models, and as federal energy efficiency standards become more stringent over time.

True, every little bit helps, but doesn't the overall success of the greater energy-saving push in the US take some of the luster off of the contribution our industry can make?

— Keith Dawson Circle me on Google+ Follow me on Twitter Visit my LinkedIn page, Editor-in-Chief, All LED Lighting