Exhibit 99.1 PRESS RELEASE For Immediate Release Contacts: Michael W. Metcalf, CFO Powell Industries, Inc. 713-947-4422 Robert Winters or Ryan Coleman Alpha IR Group POWL@alpha-ir.com 312-445-2870 POWELL INDUSTRIES ANNOUNCES FISCAL 2024 SECOND QUARTER RESULTS HOUSTON — April 30, 2024 — Powell Industries, Inc. (NASDAQ: POWL), a leading supplier of custom- engineered solutions for the management, control and distribution of electrical energy, today announced results for the Fiscal 2024 second quarter ended Ma ...