Light Up the Night

Safeco Field is brighter now that LED lights are used there. (via Isabelle Minasian)

The 1912 World Series was an epic battle between the Boston Red Sox and the New York Giants. The Giants featured the great Christy Mathewson who was bested by Smokey Joe Wood’s efforts, winning two of his three starts and coming in to relieve in the eighth game. Yes, the eighth game. The Series was scheduled for the usual best-of-seven. However, after 11 innings the second game was declared a 6-6 tie due to darkness. Darkness!

Thomas Edison won his patent on the light bulb in 1879 only three years after the founding of the National League. Almost immediately the idea of playing baseball at night arose. By the mid-1930s the technology had advanced to the point where night games were not uncommon in the laboratory of baseball innovation – the minor leagues.

May 24, 1935 was the date of the first night game in major league history between the Cincinnati Reds and the Philadelphia Phillies at Crosley Field. Most teams added lights and night games rather rapidly. However, the Chicago Cubs, who have always been late to every party, held out until Aug. 9, 1988 before they played their first night game in Wrigley Field. (For more on the history of night baseball see “Though night may fall, play ball!” here at THT.)

Believe it or not, we are in the midst of another lighting revolution in baseball. Many parks are converting from metal halide lamps to LED panels. The Seattle Mariners were the first, completing the transition at Safeco Field in time for the 2015 season. The Yankees also debuted LEDs in the same year. Rumor has it the San Francisco added LEDs over the last offseason.

If you’re like me, you’ve gone to your local big box home improvement center to get a light bulb and stood dumfounded at the immense selection. The information on the packaging seems to make finding a bulb harder, rather than easier. Let me take a stab at simplifying matters.

There are basically three types of consumer bulbs on the market; incandescent, fluorescent and LED (light-emitting diode). All three have advantages and disadvantages that range from eco-friendliness to spectral distribution. Just to stay focused here, let’s just deal with the cost of the bulbs that produce equivalent amounts of light.

The amount of light output is measured in lumens. The table below shows the relevant data for each of the three types of bulbs that produce around 800 lumens – equal amounts of light.

800 Lumen Light Bulb Stats, by Light Bulb Type
Bulb Type Lifespan Power Used Cost per bulb
Incandescent  1,200 hours 60 Watts $1.00
Fluorescent  8,000 hours 15 Watts $1.50
LED 50,000 hours 10 Watts $5.00

If all you think about is the price of the bulb, the incandescent is the way to go. However, if you were vying for the services of a ballplayer you wouldn’t just worry about the signing costs. You’d also keep in mind the annual costs as well. The easiest way for us to think about it is to imagine we will use each type of bulb for 50,000 hours (about six years).

Notice, we’ll have to buy only one LED to last that long. Over the same span, we’ll need several fluorescent bulbs and a freaking case of incandescent globes! Here’s a table with the results.

800 Lumen Light Bulb Stats, per 50,000 Hours
Bulb Type No. of Bulbs Cost per bulb Cost for bulbs
Incandescent 41.7 $1.00 $41.7
Fluorescent  6.3 $1.50 $9.45
LED  1.0 $5.00 $5.00

The tables have clearly turned. Now the LED is the winner. So, even with the higher signing bonus, if you purchase a durable player you’ll get your money’s worth over time. However, we still haven’t considered the costs to actually use the bulbs. Again, let’s assume we use them for 50,000 hours.

Now we have to pay our local utility company for the energy to run them. You pay around 10 cents for a kWh (kilowatt-hour or 1,000 Watt-hours) of electricity. Looking back at the first table we can multiply the power used for each bulb by the 50,000 hours to get the energy used. Here are the results in a table.

800 Lumen Light Bulb Electricity Costs
Bulb Type Energy Used Cost for Energy
Incandescent 3000 kWh $300
Fluorescent  750 kWh  $75
LED  500 kWh  $50

Putting this all together, you can see the savings for an 800-lumen bulb running for 50,000 hours.

800 Lumen Light Bulb Total Costs
Bulb Type Total Cost Percent $ Saved
Incandescent $342   –
Fluorescent  $84 75%
LED  $55 84%

Switching from the traditional incandescent bulbs to LED lighting saves 84 percent of the cost! The basic physics explains the increased efficiency. Incandescent bulbs require heating a filament until it glows. As a result, most of the energy goes into heating the filament not making light.

Fluorescents directly excite gas atoms causing them to give off light. This process does produce some heat, but nothing like a hot filament. That’s why you can touch a fluorescent bulb while it is running but don’t try that with an incandescent. Meanwhile LEDs almost directly convert energy into light using the same technology that creates computer chips.

The metal halide bulbs used in major league parks are actually a bit more efficient than household incandescent bulbs. So, the switch to LEDs will only save about 65 percent of the cost.

Safeco saved about 800,000 kWh in 2015 compared to 2014. Since the Mariners buy electricity in bulk, they pay less than we do per kWh. They saved only about $50,000 annually. I know that’s not much compared to a player’s salary, but it might pay for an analytics person! Or at least an intern or two!

Stadium lighting with LED has other advantages, according to the firm that did the installation, PLANLED:

  1. The estimated lifespan of the LED panels is more than 30 years, compared to about three years for the metal halide bulbs saving maintenance costs.
  2. The infield was found to be 39 percent brighter and the outfield 28 percent brighter.
  3. TV broadcasts look better because the frequency distribution in the LEDs is closer to daylight than the metal halide bulbs.
  4. Metal halide lamps go on and off 60 times per second while the LEDs don’t. So, super-slow motion cameras don’t show any flickering.
  5. The amount of light pollution exiting the top of the ballpark is greatly reduced.

So, next time you’re standing in front of the dizzying array of lighting options at your local big box store feeling like a “dim bulb,” do what the pros do – go with the LEDs. You’ll feel so much brighter!

David Kagan is a physics professor at CSU Chico, and the self-proclaimed "Einstein of the National Pastime." Visit his website, Major League Physics, and follow him on Twitter @DrBaseballPhD.
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Kevin Rusch
6 years ago

You should also factor/price the cost of physically replacing a spent bulb. It’s probably inconsequential in your house, but in that panel full of them hanging from the top of the ballpark, it’s significant.

Jetsy Extrano
6 years ago
Reply to  Kevin Rusch

Yes! If you have any contacts, it would be interesting to hear what fraction of a full-time position it is to go around changing halide bulbs.

Now they can spend that headcount on a fire Tweeter.

6 years ago

Interesting article. I guess they’ve fixed the problem that older LEDs used to contain lead, arsenic and a dozen other potentially dangerous substances. I recently watched the Mets play in Milwaukee where they quickly dimmed the lights when a Brewer hit a homerun. I guess they can do that with LEDs. At least I think it was Milwaukee, the Mets pitching staff have given up a lot of homers lately.

Jim Detry
6 years ago

Unfortunately, you set up a straw man.
Nobody is going to light a stadium with 60 watt incandescents, pretty much the crappiest light source available.

Outdoor metal halide bulbs (commonly used in street lights) are as efficient (Lumens per Watt) or better than LEDs. However light from LEDs is more directional. That’s bad for indoor use, as the LED fixtures have to build in a way to scatter the light in a room. However, for outdoor use such as a stadium, directionality is a good thing and the metal halides have to use reflectors to get the light onto the field. Since the reflectors are not perfect, give the LEDs a 2x advantage.

Metal halides have a lifetime of around 20,000 hours. So give the LEDs a 2.5x advantage in lifetime.
As to cost, you can buy a 36,000 Lumen metal halide bulb for less than $10. That’s equivalent to 45 bulbs of 800 Lumens @$5, or $225 total. (Yeah, the original comparison used 800 Lumen LEDs which are not going to be used in a stadium–they would use much larger modules). Let’s guess larger LED modules would cut the cost by another factor of 2 to about $110 for the same lumens as the metal halide.

So on cost the metal halide has at least a 10x advantage. On lifetime and efficiency combined the LEDs have a 5x advantage.

That puts lifetime costs within a factor of two in favor of the metal halides with all the estimates rounded off. However, including labor to change bulbs etc. and the fact that LEDs continue to drop in price and rise in efficiency makes the comparison fairly close.

It is not the slam dunk you show in your straw man calculations but prices are close enough that other preferences can enter (size of the fixtures, esthetics of the lighting, color spectrum, bragging rights for having LEDs etc.).

I’m not saying teams should not convert to LEDs, just that, if your local team choses not to, there’s no reason to ridicule them.

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priya misra
6 years ago

Thanks for sharing nice post please do share