Copenhagen ranks highly in the European Green City Index for its overall environmental performance. It scores first in CO2 emissions from energy and buildings. The city aims to be carbon neutral by 2025 with initiatives like district heating systems and renewable energy targets. Copenhagen also ranks highly for its waste management, with over 50% of waste recycled. Its new waste-to-energy plant will treat 400,000 tons of waste annually and provide heat and electricity to many homes when completed in 2017. Copenhagen has strong bicycle infrastructure with over 40% of residents biking to work, and its metro system provides reliable public transportation.