Exhibit 99.1 Hyliion Holdings Corp. press@hyliion.com (833) 495-4466 ir@hyliion.com HYLIION HOLDINGS REPORTS FIRST-QUARTER 2024 FINANCIAL RESULTS AUSTIN, Texas, April 30, 2024 – Hyliion Holdings Corp. (NYSE: HYLN) (“Hyliion”), a developer of sustainable electricity-producing technology, today reported its first-quarter 2024 financial results. Key Business Highlights • Announced that H2 Energy Group has executed a letter of intent to purchase up to 10 KARNO generator units that will operate on hydrogen rich ...