Tesla Powerwall: Analysis of Its Use in Portugal and United States

The Tesla Powerwall battery solution provides the user with the option to control how and when the energy is used by storing energy from the photovoltaic (PV) system and/or from the grid to then be used when the electricity is more expensive. This option helps save money on the electricity bills and cut down on the PV system payback times. Since the Powerwall battery is perceived as being a cheap energy storage solution and energy usage can be controlled, three scenarios were considered to determine which is the most attractive to invest in. One is an on-grid PV system and Powerwall solution without grid injection incentives, then an off-grid PV system and Powerwall solution, and lastly a Powerwall solution without a PV system. The United States of America and Portugal were considered in this work in which the States of California, Hawaii, Alabama and the city of Aljustrel were chosen for comparison because of their different billing and grid injection schemes. The results show that over a 25-year period an off-grid solution in Hawaii can triple the investment and a Powerwall without a PV system solution in California can double the investment while all other scenarios are not viable investments.