Energy Storage Tax Incentive and Deployment Act of 2021 This bill allows tax credits for (1) energy storage technologies, and (2) battery storage technology. The bill expands the tax credit for investments in energy property to include equipment that (1) receives, stores, and delivers energy using batteries, compressed air, pumped hydropower, hydrogen storage (including electrolysis), thermal energy storage, regenerative fuel cells, flywheels, capacitors, superconducting magnets, or other technologies identified by the Internal Revenue Service; and (2) has a capacity of at least five kilowatt hours. The bill also expands the tax credit for residential energy efficient property to include expenditures for battery storage technology that (1) is installed on or in connection with a dwelling unit located in the United States and used as a residence by the taxpayer, and (2) has a capacity of at least three kilowatt hours.