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Would the Proposed Baltimore-Washington Maglev Increase Greenhouse Gas Emission?

By Guest post by Owen Kelley

(This article was originally posted to the Prince George’s County Issues Forum on the Sierra Club website.)

The Sierra Club is devoted to fighting climate change, and it does not take kindly to companies greenwashing projects that would actually increase greenhouse gas emission. For this reason, Sierra Club members should take a close look at the magnetically levitated train that has been proposed between Baltimore and Washington DC. People call this train “the maglev.”

Proponents claim that the proposed maglev would be good for the environment because it would reduce greenhouse gas emission. This claim has been made for years by the companies that want to build and operate the maglev, namely Baltimore Washington Rapid Rail (BWRR) and its parent company, The Northeast Maglev.

As explained below, it appears that the proposed maglev would actually increase greenhouse gas emission, contrary to the assertions of BWRR and The Northeast Maglev. We care about greenhouse gases because scientists have determined that the modern economy emits so much of them that the Earth is warming. Carbon dioxide is the most important greenhouse gas emitted by construction, transportation, and power generation (e.g., EPA 2016, Table A1).

Carbon Dioxide from Constructing the Maglev

Constructing the Baltimore-Washington maglev would release a considerable amount of carbon dioxide. Constructing the 40 miles of tunnel and elevated track would cause significant emission largely because of the carbon dioxide released to manufacture the required amount of concrete and steel (IEA 2019, pg. 57). As estimated in Appendix A  of the present article, something in the neighborhood of 316 to 815 million kilograms of carbon dioxide would be released because of the construction.

Carbon Dioxide from Operating the Maglev

Operating the maglev would be responsible for additional greenhouse gas emission because carbon dioxide would be released to generate the electricity to run the maglev. Operating the maglev might result in a net decrease in emission, but only if a large fraction of the miles traveled on the maglev replaced miles that otherwise would have been traveled in gas-powered cars. Maglev technology is not carbon free–it just emits somewhat less carbon dioxide per passenger-mile than a gas-powered car does.

A large emission reduction is unlikely because BWRR anticipates that the maglev would greatly increase the number of trips made between Baltimore and Washington. A dramatic increase in travel is a necessary prerequisite for the economic boom that BWRR claims that the maglev would create in these cities (Rogers 2015).

Using BWRR’s ridership estimates, operating the maglev would either slightly decrease or slightly increase greenhouse gas emission, as estimated in Appendix B of the present article. Even in the most favorable scenario, it would take decades for maglev operations to make up for the massive amount of greenhouse gas emitted to construct the maglev’s track.

BWRR’s Carbon Dioxide Estimate

BWRR claims that the maglev would be good for the environment because it would reduce greenhouse gas emission by 2 million short tons (Rogers 2015, pg. 19).

BWRR does not explain how it arrived at its estimate, but one can speculate that the company did so by ignoring the massive amount of carbon dioxide that would be emitted to construct the track and to generate the electricity to run the trains. BWRR may have calculated merely the emission reduction that would occur from BWRR’s hypothesis that the number of car miles driven would go down if the maglev were built. Based on the estimates in Appendix C, this emission reduction could reach 2 million short tons after about 31 years, but only if many consumers really do find the maglev more attractive than driving. Figure 1 illustrates this attempt to understand the origin of BWRR’s mysterious 2 million short tons.

BWRR may be too optimistic about how many people would switch from driving cars to riding the maglev, and that could blow a hole in the advertised 2-million-short-ton emission reduction. For many people, taking the maglev would be more expensive and slower than driving. BWRR estimates that maglev tickets, Baltimore to Washington, would cost $80 to $160 per person round-trip (Romine 2015), but $8 in gas would be sufficient make the round trip by car. Looking at total trip duration, driving directly to one’s destination would be faster than detouring to take the maglev for many places within the DC beltway or a few m­­­iles from downtown Baltimore (Kelley 2020a,b).

Even if BWRR were correct and the proposed maglev were to reduce net emission by 2 million short tons (1.814 million metric tons), the maglev would still be an embarrassingly expensive way to fight global warming. According BWRR, it would cost $10 to $15 billion to build a maglev from Baltimore to Washington. Divide the construction cost by the emission reduction, and the result is a cost of $5,513 to $8,269 per metric ton of emission reduction. Effective ways to fight global warming cost under $100 per metric ton of greenhouse gas reduction, according to Griscom et al. (2020) and McKinsey (2007).


Constructing the tunnel and elevated track for the proposed Baltimore-Washington maglev would release in the neighborhood of 316 to 815 million kilograms of carbon dioxide, the primary greenhouse gas emitted by the construction, transportation, and electric-power generation industries.

In addition, it is unclear if there would be a net increase or decrease in carbon-dioxide emission specifically from operating the maglev, independent of constructing its track. The answer hinges on whether the maglev would cause car travel to decrease sufficiently to cancel out the carbon-dioxide emission from generating the electricity to run the maglev. Even if maglev operations and the hypothetical reduction in car travel were, together, to shrink carbon-dioxide emission slightly, the reduction during a single year would be so small that it could take decades to make up for the massive amount of carbon dioxide emitted to construct the maglev track.

Constructing and operating a maglev between Baltimore and Washington would be an extremely expensive project that would do little if anything to decrease greenhouse gas emission. Anyone concerned about global warming should think twice before supporting this project.


The three appendices referenced in the text are found in this PDF file: Appendices A, B, and C.  The documents cited in the text are as follows:

EPA, 2019: The 2019 EPA Automotive Trends Report. pg. 11. Available online at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100YVFS.pdf.

Griscom, B. W. et al., 2020: National mitigation potential from natural climate solutions in the tropics. Philosophical Transactions B, 375, http://dx.doi.org/10.1098/rstb.2019.0126. Available online at https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.2019.0126.

International Energy Agency (IEA), 2019: The Future of Rail: Opportunities for Energy and the Environment. 175 pp. Fig. 1.30 on pg. 57. Available online at https://webstore.iea.org/download/direct/2434.

Kelley, O. A., 2020a Sept 6: Economic Impact and Financial Viability of the Proposed Baltimore Washington Maglev. blog post, Greenbelt Online. Available online at https://www.greenbeltonline.org/economic-impact-and-financial-viability-of-the-proposed-baltimore-washington-maglev/.

Kelley, O. A., 2020b Sept 3: 15 Minutes to Baltimore? letter to the editor, Greenbelt News Review, pg. 2. Available online at https://www.greenbeltnewsreview.com/archives/.

McKinsey & Company, 2007: Reducing US Greenhouse Gas Emissions: How Much at What Cost? 107pp. Available online at https://www.mckinsey.com.

Rogers, W., 2015 April 17: Direct testimony of Wayne L. Rogers, case no. 9363, MD Public Service Commission, 23 pp. Quotes: “10.2 to 15.4 million” maglev trips (pg. 17), “165 fewer vehicle miles” (pg. 18), and “2 million short ton” reduction in greenhouse gas emission (pg. 19). Available online at https://www.psc.state.md.us/search-results/?q=9363&x.x=20&x.y=20&search=all&search=case.

Romine, Judge T., 2015 Oct 14: Proposed Order for Case #9363, Maryland Public Service Commission.

More from Owen Kelley about the Maglev

Read his September 2020 post about the Maglev’s Economic Impact and Financial Viability here on Greenbelt Online.

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