iii mass is more than 14 times greater and 1.2 times greater than that of the ISS and Starlink constellation, respectively. This study assessed lifecycle cost and emissions based on the following scenario: SBSP systems are developed on the ground in the 2030s and launched to low-Earth orbit (LEO), and then transferred to and assembled in geostationary orbit (GEO) in the 2040s. The SBSP systems are operated in GEO from 2050-2080, by transmitting energy to one or more stations on Earth. Maintenance, which entails developing, launching, and assembling new spacecraft modules, occurs between 2060-2080. SBSP systems disposal operations, which entail developing and launching debris removal spacecraft to GEO to transfer spacecraft modules to a graveyard orbit, occurs between 2060-2085. Lifecycle Calculations We developed a model to calculate the cost and GHG emissions for all aspects of the SBSP reference designs across the full lifecycle of development, assembly, operation, maintenance, and disposal. Including disposal or decommissioning of a system is a best practice when assessing its full lifecycle. The calculated lifecycle cost and GHG emissions are for first-of-a-kind systems delivering 2 GW of power to the electric power grid beginning in 2050. At the end of 2022, according to the Energy Information Administration (EIA), the United States had 1,160 GW of total utility-scale electricity-generation capacity.5 We calculated the lifecycle cost of electricity and lifecycle GHG emissions intensity for each representative SBSP design using common industry expressions: levelized cost of electricity (LCOE) and Economic Input Output – Life Cycle Analysis (EIO-LCA). The LCOE is the average cost of electricity over a generator’s lifetime and is a mainstay of energy sector analyses. The EIO-LCA is an established methodology for estimating first-order emissions intensity of economic activity. LCOE has several limitations. For example, it does not consider the variable value of energy at different locations or times.6 EIO-LCA also has limitations. This methodology often uses spend-based metrics to estimate emissions, which assumes a relationship between cost, efficiency, and emissions that may not always align with direct measurements of emissions by economic activity. All cost estimates are measured in Fiscal Year 2022 (FY22) dollars. EIO-LCA uses measured GHG emissions of producing goods and services by mass (like kilograms of steel), area (like square meters of solar cells), or cost (like dollars spent on services) by aggregating macroeconomic data. We then compared the LCOE and lifecycle GHG emission intensity (EIO-LCA) to alternative terrestrial renewable electricity production technologies using data from the National Renewable Energy 5 EIA, “Electricity explained,” last updated: June 30, 2023 https://www.eia.gov/energyexplained/electricity/electricity-in-the-us-generation-capacity-and-sales.php. 6 For more information on metrics, see NREL, “Competitiveness Metrics for Electricity System Technologies” 2021, https://www.nrel.gov/docs/fy21osti/72549.pdf.
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