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| Fig. 1: A restaurant gas stove turned on. (Source: Wikimedia Commons) |
In May 2022, the Los Angeles City Council passed a resolution that effectively banned gas stoves from all new buildings in their effort to reach a zero-emission city target in 2045. [1] This measure is supposed to affect new restaurants as well. Fig. 1 shows a restaurant gas stove turned on. The aim of this report is to shed light on the reasoning behind that measure applied to restaurants, by quantifying the new emissions that will come from new restaurants in Los Angeles in the coming ten years. We, therefore, aim to determine quantitatively whether an exception to that rule for restaurants would be reasonable.
Based on the Los Angeles Open Data portal, there are roughly 7216 active restaurants in Los Angeles County, most of which are located in the City of Los Angeles. We will assume the average number of new restaurants each year over the last five years has been 503, with a standard deviation of 65.
The amount of methane emitted by a stove gas burner was found to be 259 mg CH4 h-1. [2] We will assume each restaurant has the burners on for a third of a day, that is, eight hours. We will also assume each restaurant has ten burners, the standard number of burners for a commercial cooking unit. All 503 new restaurants, therefore, emit each year
| eCH4 | = | 503 × 259 mg h-1 burner-1 × 8760 h y-1 × 10 burners | |||
| = | 1.140 × 1010 mg y-1 | = | 1.140 × 104 kg y-1 | ||
Similarly, Lebel et al. also estimated the volumetric emissions of NOx to be 151.5 mL h-1 when stoves burn at high. [2] We take the density of NOx to be 1.912 mg/mL which comes from an average molecular weight for NOx. Following the same estimation process, we get that the total amount of NOx emitted by new restaurants will be
| eNOx | = | 503 × 151.5 NOx mL h-1 burner-1 × 8760 h y-1 × 10 burners × 1.912 mg/mL | |||
| = | 1.276 × 1010 mg y-1 | = | 1.276 × 104 kg y-1 | ||
So the total greenhouse gas (GHG) emissions of stoves in new restaurants in LA would be
Given the annual GHG emissions from Los Angeles goal of 9 MMT (9 × 109 kg of CO2) in 2035, we can estimate the percentage new restaurants would represent over a year period with that amount of emissions.[3] To do so, we will multiply our CH4 numbers by 80 because CH4 is 80 times more potent a GHG than CO2.
In light of the findings of this report, which has estimated the new restaurants' emissions for the next ten years in Los Angeles County to be 0.00147% of the targeted Greenhouse gas emissions goal for 2035, it seems reasonable to allow for an exception for restaurants on the ban on gas stoves, allowing restaurants to maintain their regular operations.
© Guillem Megias Homar. 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] S. Roth, "L.A. Is Banning Most Gas Appliances in New Homes. Get Ready For Electric Stoves," Los Angeles Times, 27 May 22.
[2] E. D. Lebel et al., "Methane and NOx Emissions from Natural Gas Stoves, Cooktops, and Ovens in Residential Homes," Environ. Sci. Rechnol. 56, 2529 (2022).
[3] "City of Los Angeles 2020 Community Greenhouse Gas Inventory," City of Los Angeles, April 2022.
