dee karen/Shutterstock While green hydrogen is expensive to make, prices could drop due to falling renewable energy costs and rising carbon prices.China's three national oil companies (NOCs) are investing in green hydrogen as part of their decarbonization efforts.Sinopec operates the world’s largest green hydrogen project; PetroChina is also making strides in the sector, but China National Offshore Oil Corp. (CNOOC) lags both. Save for later Print Download Share LinkedIn Twitter The Issue