Natural Gas as a Bridge Fuel

Frank Voris
October 3, 2018

Submitted as coursework for PH240, Stanford University, Fall 2017


Fig. 1: Projections for nominal labor costs required to convert the U.S. electric grid to renewable sources, assuming wage growth rate of 3.22% per annum beginning in 2017. [3] (Source: F. Voris)

Few opinions come without a valid counter-argument, and this paper hopes to explore the potential that many scientists see in natural gas as a bridge fuel during the transition to renewable energies. [1] Natural gas production in the United States has boomed since 2005 in large part thanks to technological advances in Hydraulic Fracturing. [2] While natural gas is a fossil fuel, it burns cleaner than coal, and academics argue that in a world not ready for the complete adoption of renewable resources natural gas could ease the burden of coal on the environment.


In order to understand the need for a bridge fuel, one must understand the scope and timeframe of the transition from fossil fuels to renewable energy. Jacobson et al. published a study which presents a roadmap for the United States to convert its all-purpose energy systems (for electricity, transportation, heating/cooling, and industry) to a completely renewable grid powered by wind, water, and sunlight. [3] Although the paper does not make claims about the total cost of the project, conclusions can be made based on assumptions about labor and land required to accomplish the goal.

Jacobson et al. estimate that labor alone would require 3,900,000 40-year construction jobs, and 2,000,000 40-year operations jobs. [3] Paying these workers involved in this specific project a very conservative $10/hour in the first year would cost $1.72 trillion. At the project's termination in 2056, the nominal compensation would reach $5.92 trillion (Fig. 1.) In 2056, when looking back the summation of 40-years of labor costs would be $13.66 trillion in nominal dollars. These labor costs surely would be just a fraction of the entire cost of the project.

The described plan also requires a total of 2.02% of the land of the United States. The United States of America has a land mass of 3,797,000 mi2. 2.02% of this is 77,000 mi2. Of this 77,000 mi2, 21% would be used for infrastructure and 79% for spacing between wind turbines. [3] In other words, the project would require converting a piece of land the size of South Dakota into a renewable energy production site. While the economic and social justification for the may exist, a project of such scale has little precedent. It would likely require a new era in American politics on a similar scale as the New Deal.

Benefits of Natural Gas

Fig. 2: Coal as a percentage of energy production per year in the USA. Chief driver of decrease in proportion of coal production is the rise in natural gas production. [2] (Source: F. Voris)

While there is no denying that the idealistic solution to climate change and energy crises is renewable energy, considering the scale of the project, pragmatic solutions must be considered. This is where scientists believe that natural gas can have a beneficial impact on the environment. In fact, the analysis of life-cycle greenhouse gas emissions from different fossil fuels shows that shale gas and natural gas emit about 33% fewer greenhouse gases than coal. [4] Simply put, it is possible to significantly reduce greenhouse gas emissions without overhauling the entire power-grid of the United States. The rise of fracking in the United States has brought natural gas to the forefront, and already diminished the market share of coal energy production. (Fig. 2.) While this energy generation emits fewer greenhouse gases than coal, it comes at the expense of fracking-induced seismic events, polluted groundwater, and increased water consumption.


While the long-term goal is to have a grid completely powered by renewable energy, a transition to a cleaner option than coal should not be scoffed at, but embraced. The challenge here is to not settle for natural gas as good enough. In order to continue forward, we must ensure that natural gas truly is a bridge fuel.

© Frank Voris. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] D. P. Schrag, "Is Shale Gas Good for Climate Change?," Daedalus 141, No. 2, 72 (2012).

[2] J. A. de Gouw et al., "Reduced Emissions of CO2, NOx, and SO2 From U.S. Power Plants Owing to Switch From Coal to Natural Gas With Combined Cycle Technology," Earth's Future 2, No. 2, 75 (2014).

[3] M. Z. Jacobson et al., "100% Clean and Renewable Wind, Water, and Sunlight (WWS) All-Sector Energy Roadmaps For the 50 United States," Energy Environ. Sci. 8, 2093 (2015).

[4] A. Burnham et al., "Life-Cycle Greenhouse Gas Emissions of Shale Gas, Natural Gas, Coal, and Petroleum," Environ. Sci. Technol. 46, 619, (2012).