Powertrains Replace Diesel Engines on Existing Freightliner Trucks DALLAS, TX / ACCESSWIRE / June 24, 2024 / Principal Solar, Inc. (OTC Pink:PSWW) ("Principal" or "the Company"), a strategic investor in and acquirer of technologies that support next-generation opportunities in traditional, renewable, and clean energy sectors as well as an investor in and operator of undervalued petroleum-producing properties, today announced that its Royalty Agreement Partner, eTruck Transportation, expects to begin producing powertrains that turn Class 8 diesel trucks into hybrid battery-electric vehicles by the end of 2024. Used Freightliner trucks.