Energy consumption is the most significant variable in the cost of our production processes. We carefully track and manager energy purchases, and our conservation programs are focused on continually improving energy efficiency across our plants, particularly larger facilities.
Our energy consumption in 2018 was 50.8 million MWh, representing a 7% increase from 2017. The increase was a result of our growth that was driven by rising customer demands, particularly in Asia and India.
Of our electricity purchases in 2018, 23% was from renewable sources. This is an increase of 5% from 2017 due to our higher use of renewable energy in Europe, as well as increasing the amount of renewable energy we use that is available on the girds in certain regions where we operate.
In 2018, our ASUs realized a 2% reduction in energy intensity from a baseline year of 2015. Our HyCO units improved energy efficiency by 0.9%. These successes were realized through higher plant utilization; increased production at new, larger and more efficient facilities; and hundreds of facility improvement projects involving changes to equipment and manufacturing processes. For example, equipment replacements at one ASU in the western U.S. saved over 2,000 MWh of electricity and over $500,000 in costs.