Matt Chester calculates increase to transportation-related carbon emissions when late-night games and early-closings of the public transit system require fans to find alternative ways home, including taxis or ride-sharing services like Uber or Lyft.  Photo Library/Getty Images photo by Tim Santimore.

Could carbon emissions be offset by public transit operating later, taking fans home instead of cars?

By Matt Chester

This article was posted on Chester Energy and Policy  on May 21, 2018.  

For those of us in the Washington, D.C. area, much has been made in the past week at the intersection of the National Hockey League (NHL) Playoffs and the local public transit system.

In an issue that seems only possible inside the Beltway, continuing conflict has arisen between the much maligned DC Metro system and all-too-often late night overtime games for the Washington Capitals.

In the past few years, local teams (also including the area’s baseball team, the Nationals) have resisted fronting the $100,000 per hour fee required by the Metro to keep the trains running past their normal closing times of about 11:30 PM on weeknights, prompting fans to choose between watching the conclusion of playoff games or catching the last train home.

While teams like the Capitals have played the game of chicken to avoid setting the precedent that they’ll always pay for the Metro to stay open, the fees have been fronted instead by the likes of Exelon, the nation of Qatar, and (just announced for tonight’s Game 6 of the Eastern Conference Finals vs. the Tampa Bay Lightning) Uber in order for the public metro trains to remain open for the later-than-normal hours that would be required should the playoff games go to overtime.

While I’ll leave the political implications of a foreign nation subsidizing the operation of the public transit system in the U.S. Capital and the general public transit issues to those who are better positioned to write on such topics.

One angle to this story I haven’t really seen is the assumed increase to transportation-related carbon dioxide (CO2) emissions when late-night games and early-closings of the public transit system require fans to find alternative ways home– namely, taxis or ridesharing services like Uber or Lyft.

While the $100,000 per hour price tag required to keep the Metro system open late is typically framed on the basis of fan convenience, civic morale, and the letdown of the existing taxes and other funds not being enough to keep the trains running, would the discussion be altered at all if we instead framed the costs as opportunities to offset carbon emissions of cars taking fans home instead of public transit?

Let’s run the numbers and find out!

Paying for the extra hour

Before starting down this pathway of rough calculations, it is important to first lay out exactly how paying to keep the Metro open later works.

Last year, General Manager of the Metro System, Paul Wiedefeld, announced a return to a policy that allowed Metro to stay open late for special events as long as the organizers of those events put down money up front (this return coming after over a year of a no-exceptions policy that the Metro would not alter its hours).

However, this return required organizers to front Metro a $100,000 per hour deposit, a massive increase from the previously required $29,500 deposit in years past.

This $100,000 per hour, though, is just a deposit. If during the extra hour(s) of service the Metro ends up collecting at least $100,000 in revenue per hour, then the company/organization that put down the deposit gets their money returned. If, however, revenues fall below $100,000 per hour, then the entity that put down the deposit only receives back the fare revenue raised during that time and the Metro pockets the rest.

This protocol set up by the Metro can apply to the actual organization who wants the Metro open later for its event (e.g., the Washington Capitals due to a critical playoff game) or to a third party who opts to put down the deposit.

Calculating emissions savings

According to Lew Blaustein of the Green Sports Blog, the part of a sporting event that contributes the most to CO2 emissions and climate change is fan travel to the event itself.

As he detailed in my interview with him, Blaustein emphasizes that the most effective way to minimize CO2 emissions associated with sports is thus to ensure fans are able and encouraged to take public transit to events.

But in instances like the transit mess in late-night DC, fans may no longer have a choice. So what is total effect on CO2 emissions associated with an event if all the fans that would have traveled to the game by the Metro are now forced to hire a taxi, Uber, or Lyft to take them home?

We can find some publicly available data to get a fairly rough, but entirely back-of-the-envelope, estimate.

Number of fans traveling by Metro

The Capital One Arena, where the Washington Capitals play their home games, has a capacity of about 20,000 fans. Of those fans, about 6,700 (over a third) took the Metro home from Game 3 of the Eastern Conference Finals last Tuesday.

Let’s use that as a tentpole for about how many fans would be taking the Metro home from any given playoff game.

Additional cars needed if Metro is closed

The data available is not in great enough granularity for us to know exactly how many cars would be needed to take all 6,700 of these fans home in the Metro’s absence.

While some groups surely meet at the game and return to separate homes afterwards (meaning each would take an individual vehicle home), other groups of people attending the game are likely families, roommates, or neighbours who can split an Uber or Lyft home.

Without knowing for sure, a fair estimate  to balance these single riders and multiple riders might be to just say the average additional car (Uber, Lyft, or Taxi) needed once the Metro is closed will take two people.

While this may vary from the actual number, it’s a reasonable estimate we can grab to put on the back of our envelope:  3,350 additional cars needed to drive fans home from Capital One Arena

Distance traveled by these cars

Here’s where things get tricky and we really have to understand the limitations of our estimates.

During the extra hour(s) of Metro service after Capitals games, only the nearby Gallery Place and Metro Center stations are open for fans to get on a train– all the other trains are ‘exit only’ during these extended hours.

The issue, though, is the data for how far on the Metro system groups of fans travel after a Capitals game is not available. So we need to make some hand-waving estimates here.

We can calculate the distance, by car, from Gallery Place and Metro Center to the end of the line of each line of the Metro system.

These distances represent the furthest points the Metro might have carried passengers, but obviously many riders are getting off before reaching the end of the line– so we can assume riders get off the train evenly distributed along the route estimate that the average distance traveled by car in the absence of the Metro is just half the distance to the end of the line.

After calculating that average distance along each line, we can also distribute the 3,350 cars evenly through each of those routes (likely not reflecting the exact true distribution, but the best we can do without more granular data and still likely to get in the ballpark).

By multiplying the number of cars driving each Metro line by the average distance along that Metro line and summing the results all up, we arrive at an estimate for total vehicle miles driven:

25,628 additional miles driven by cars

Carbon dioxide emissions associated with these additional miles driven

From here, the calculations are fairly straightforward. According to the Energy Information Administration (EIA), the average light-duty vehicle in the U.S. fleet (which includes cars, light trucks, vans, and SUVs) was 24.0 miles per gallon in 2016.

Further, the Environmental Protection Agency (EPA) reports that a car burning a gallon of gasoline releases 8,887 grams of CO2.

Combining these data points with the 25,628 miles driven gives an approximate CO2 emissions from the additional cars on the road due to Metro closing of 9.5 metric tons of CO2 (for reference, this total is about the amount of CO2 emissions from two cars over the course of a year on average, according to the EPA).

What about the CO2 emissions from running the Metro?

Before declaring that keeping the Metro open for these fans saves 9.5 metric tons of CO2, you must also account for the CO2 emissions that are associated with the Metro staying open late.

Unfortunately, after much research I was unable to really find a satisfying way to calculate this figure. The Metro runs on electricity, and the amount of CO2 associated with electricity use is directly tied to the fuel used to generate it.

Coal creates the most CO2 per unit of energy and natural gas generates less than half the CO2 emissions of coal, while renewable energy sources are considered carbon-neutral. The electricity of the Metro system comes from Maryland, Virginia, and the District of Columbia, all of which have a unique energy mix, according to EIA:

So how do we compare the 9.5 metric tons of CO2 from the cars after a Capitals game without the Metro staying open late? The best I could find was a tool created by someone at the Metro in 2014 that would calculate the greenhouse gas emissions saved by individuals opting to take the Metro instead of driving.

By entering a starting point of Gallery Place Metro Station and an ending point of Branch Ave Metro Station, it gives the following output:

According to this tool from the Metro, taking the Metro instead of driving would save 2.9 kilograms of CO2-equivalent (kg of CO2e).

The small print indicates this calculation is using ‘standard rates of GHG emissions per mile to the different modes used,’ though it is unclear what those standard rates are and how they would inherently vary if the Metro car was half full vs. completely full– as the CO2 emissions of the car are constant regardless of how many additional passengers it is carrying.

So there are serious limitations to this tool, but we can use it in a similar manner of our calculations before– calculate the emissions of driving to the end of each line, assume the average distance traveled is actually half that, and distribute the 3,350 cars evenly along those routes. When doing so, the total emissions from driving compared with using the Metro are as follows:

In short, this tool suggests that the 3,350 car trips would have accounted for about 12.7 metric tons of CO2e, 8.8 metric tons of CO2e greater than if those cars were instead replaced with riding the Metro.

Again, though, it is ambiguous how the Metro CO2 emissions are calculated– this calculation assumed 3,350 cars displaced correlated with 3,350 additional ‘transit rides,’ rather than 6,700 for each of the passengers (otherwise a single car driving three people from Gallery Place to Branch Ave would account for 4.4 kg of CO2e, but those three people taking the Metro would account for 4.5 kg of CO2e).

Taking these calculations at face value, though, would result in an estimate that the Metro taking passengers home after a Capitals game instead of a car would reduce total emissions by almost 70%. 

Cost of carbon avoided

So to bring this all back to the original question– would it be effective to frame the question of whether or not an organization should pay to keep the Metro open after the Capitals playoff games in terms of costs to eliminate CO2 emissions?

If we run with the listed assumptions and calculations, then the cost to keep the Metro open would offset 6.6 metric tons of CO2 (70 per cent of the 9.5 metric tons of CO2 from driving the 3,350 cars home).

The $100,000 per hour for this, though, is just a deposit, and that cost would be reduced by the total fares collected. During late night hours, a fare on the Metro can run anywhere from $2.00 to $3.85. Let’s assume the 6,700 riders pay about $3.00 each, bringing the total cost to keep the Metro open an extra hour to $79,900.

$79,900 to offset 6.6 metric tons of CO2 comes out to over $12,000 per metric ton of CO2. Compared with the typical cost to offset a ton of CO2 on the open market, anywhere from $0.10 to $44.80 per metric ton, that price tag is astronomical.

Even if we adjusted our calculations for a complete worst-case scenario, where:

  1. Without the Metro, all 20,000 fans at the game would drive a car home from the game,
  2. Where each car would have to drive 24.1 miles (the longest driving distance from arena to end of the Metro, from Gallery Place to Shady Grove),
  3. But instead the Metro was open and running on entirely carbon-neutral fuel, and
  4. All 20,000 fans in the Capital One Arena would be paying $3.85 to ride the Metro to their final destination;

then even in that scenario, the cost ($100,000 minus fare revenue) of $23,000 would offset 178.5 metric tons of CO2 for a price of almost $130 per metric ton.

Still not a good deal compared with the open market costs of offsetting/cutting carbon. So that’s likely why, as I stated in the introduction, you haven’t heard the question framed this way– when taking an economic approach to CO2 reductions, the cost the Metro is charging is too much for it to make sense in financial terms of cutting carbon.

However, that would certainly be different if Metro adjusted their model and reduced the financial burden on the organization seeking to keep the Metro open later.

Other considerations

Just because the monetary value of CO2 reductions to keeping the Metro open later are not enough to justify the costs being asked does not mean that doing so for the CO2 and climate-related reasons are not worthwhile. When Exelon announced they had paid to keep the Metro open for game three of the Capitals-Lightning series last week, they noted:

We want to make sure our customers can be there for every play and get home safely and emissions free by powering the Metro’s extended hours

Reducing emissions doesn’t always need to come down to economic terms, and sometimes it is about doing what’s right and preventing climate changing emissions. Exelon seems to get that (though they surely also appreciated the boost in good will and advertising, as well).

Additionally, there are other factors for which this analysis could not account: increased activity at bars and restaurants in the area by fans who want to be near the action but don’t have tickets to the game, how the figures would adjust if the Capital were to reach the Stanley Cup and fan enthusiasm was at a peak, return trips needed by the taxis or Ubers, how the uncertainty around the Metro’s status influences how people plan to get to/from the game in the first place, etc.

Further, all of this analysis is assuming that the game goes late and the Metro staying open later than usual is necessary for fans, though this was not the case after Game 4 and reportedly only 1,000 people actually took advantage of the Metro running an hour later than usual.

In the end, public transit is always an extremely valuable tool for cities and organizations to reduce the carbon footprint of their events, regardless of the specific carbon cost considerations.

Though as a Capitals fan attending game 6 on Monday, I do not expect these CO2 impacts of travel to the game to be on the mind of many others in the arena. Instead, we’ll be hoping to keep the series alive and reopen the debates about Metro staying open later during the Stanley Cup Finals– LET’S GO CAPS!

Matt Chester is an energy analyst in Washington DC, studied engineering and science & technology policy at the University of Virginia, and operates this blog and website to share news, insights, and advice in the fields of energy policy, energy technology, and more.

For more quick hits in addition to posts on this blog, follow him on Twitter @ChesterEnergy.