Winter energy prices are likely to rise, but not because of this week’s decision by OPEC. Instead, energy traders say, look to China. Earlier this week, OPEC—14 nations representing just under half of the world’s oil production—reached a gentlemen’s agreement of sorts to trim crude oil production by 700,000 barrels a day from more than 33 million barrels a day sometime later this year. That announcement briefly nudged oil prices back up toward $50, but prices have eased again on concerns that OPEC, notorious for not sticking to its agreements, won’t stick to this one either. What’s more likely to keep winter energy prices propped up, energy traders say, is the secretive stockpiling of crude oil by China, the world’s second-largest consumer of oil next to the U.S. New data released on Thursday by geospatial analytics firm Orbital Insight shows that China has been under-reporting its oil stockpile—and continues gobbling up supplies on the global market.