Valero Energy Corp., whose renewable fuels arm is expanding, signaled Thursday that the most efficient way to reduce U.S. emissions could be via a carbon tax.

CCS

The San Antonio-based global refining giant’s management team shared a microphone to discuss first quarter performance and the outlook for the year. Valero has plenty of skin in the game as it operates 15 refineries in the United States, Canada and the UK with combined throughput capacity of 3.2 million b/d. It also operates 13 ethanol plants in the Midcontinent with total production capacity of 1.69 billion gallons/year. 

Executives were quizzed on a variety of topics during the call, including their view of implementing a carbon tax for U.S. emissions. Carbon taxes are in place around the world but have never gotten...