However, this tax credit is due to expire in 2012. Wemau (2011a) estimates that up to one-fifth of the state’s power generation capacity could decide to exit the market rather than invest in the necessary upgrades, potentially driving up the price of coal by 65% and offering opportunities for renewable energy sources. It saves approximately 47 000 tons of CO2 per year and replaces annually over eight million private vehicle trips in the city of Calgary.