. Author manuscript; available in PMC: 2022 Jan 4.

Published in final edited form as: Nat Energy. 2021 Jan 4;6:92–104. doi: 10.1038/s41560-020-00740-2

Table 1.

Scenario descriptions and model assumptions for each sector

	STEADY-STATE: business-as-usual trends	DEPENDENCE: slow decarbonization of the electric grid	REVOLUTION: fast-paced decarbonization of the electric grid
Objective	To model current trends in energy consumption and technology turnover in buildings and transportation within the city.	To analyse in-city technology investments in end-use sectors to achieve a total of 80% emissions reduction by 2050 in NYC, where New York State fails to achieve CO₂ per kW h reduction.	To analyse in-city technology investments in end-use sectors to achieve a total 80% emissions reduction by 2050 in NYC, while New York State reduces CO₂ per kW h in line with clean energy standards.
Emissions	Existing federal air regulations applied, such as Corporate Average Fuel Economy, the US National Ambient Air Quality Standards, New Source Performance Standards and Tier 3 standards on motor vehicle emissions. There is no greenhouse gas emissions reduction policy.	All air regulations applied in STEADY-STATE are included. Buildings sector target (45% CO₂ emissions reduction from 2005 levels by 2030 and 80% by 2050) and transportation sector target (58% CO₂ emissions reduction from 2005 levels by 2030 and 82% by 2050) are introduced into the model.	Air regulations applied in STEADY-STATE are included. Buildings sector and transportation sector emissions reduction targets in DEPENDENCE scenario are included. Power sector target (40% CO₂ emissions reduction from 1990 levels by 2030, and 80% by 2050 in New York State’s electric grid) is introduced into the model.
Power sector	Currently permitted and near-future planned coal, natural gas, nuclear and hydro power plants are added to the modelled capacity. Existing nuclear power plant capacity is kept operational throughout the modelling horizon. Electric sector capacity expansion is based on least-cost optimization of suite of technologies, which are available in the COMET-NYC database. We rely on Department of Energy, National Renewable Energy Laboratory, US Energy Information Administration and New York State Energy Research and Development Authority sources for future technology characterizations. All operational and in-progress solar capacity listed in City Solar is added⁵².	Electric sector assumptions in the STEADY-STATE scenario are included. A CO₂ constraint is not modelled for the electric sector; however, unit electricity intensity coefficients for end-use demand technologies are included to feed into the 80 × 50 target constraints (Supplementary Table 10). The capacity expansion decision is based on a least-cost solution.	Electric sector assumptions in the STEADY-STATE scenario are included. New York State Clean Energy Standard is included, which mandates 50% of electric generation from renewables by 2030. CO₂ emissions rate for electricity reported for New York State’s Reforming the Energy Vision goals (40% reduction from 1990 levels by 2030 and 80% by 2050) is used for electricity consumed by the city (Supplementary Table 10). A constraint for solar photovoltaic capacity expansion ensures the invested capacity level is greater than or equal to 250 MW by 2025 (ref. ¹⁴). A constraint for renewable energy capacity expansion ensures the installed capacity is at least 3.6 GW by 2020 (ref. ⁵³).
Transportation sector	STEADY-STATE assumptions on penetration of vehicle type, fuel and efficiency rates are applied. General assumptions are based on vehicle turnover and efficiency gains reported for the Middle Atlantic Census Division in Annual Energy Outlook 2016.	Assumptions for existing vehicle stock introduced in STEADY-STATE are included. Zero-emission vehicles are projected to compose 15% of new car purchases in 2030 and will be roughly half of all new cars sold in 2050.	Transportation sector in REVOLUTION scenario has the same technology assumptions valid for DEPENDENCE scenario. The difference between the DEPENDENCE and REVOLUTION scenarios is the emission coefficient of the unit electricity consumed by the transportation sector. Supplementary Table 10 presents unit electricity coefficients.
Buildings sector	Buildings sector includes the representation of existing building technology stock and is calibrated to actual reported energy consumption. Future energy demand forecast uses population projections and assumptions on the change in the floorspace reported for the Middle Atlantic Census Division in Annual Energy Outlook 2016. Annual Energy Outlook reports data at nine census divisions, and New York is in the Middle Atlantic Census Division. Equipment efficiency improvements and fuel shares reported in the Middle Atlantic Census Division of Annual Energy Outlook 2016 are incorporated into the model as lower bounds for future technology investments.	Assumption for existing building stock and technology characterization is the same as in the STEADY-STATE scenario. The future technology mix deviates greatly from STEADY-STATE due to faster technology turnover and fuel switching.	Buildings sector in the REVOLUTION scenario has the same technology assumptions valid for the DEPENDENCE scenario. The difference between the DEPENDENCE and REVOLUTION scenarios is the emission coefficient of the unit electricity consumed by the buildings sector. Supplementary Table 10 presents unit electricity coefficients.

Table 1 explains the objective and sectoral assumptions for each scenario. The first column presents the components of the model including objectives, sectors and representation of emission reduction policies, whereas each additional column contains a different scenario.