Ontario’s first cap-and-trade auction has sold out all current allowances. The system aimed at lowering greenhouse gas emissions requires certain electricity importers, natural gas distributors and fuel suppliers to take part. They have caps on the amount of pollution they can emit and if they exceed those limits, they must buy an equal number credits or allowances at auction or from other companies that come in under their limits. Results released Monday from the March 22 auction show that all current allowances were sold.The government says the auction brought in $472 million. The Liberals hope to the auctions bring in 1.9 billion a year, to be invested in programs that reduce emissions.