Energy Secretary Rick Perry (right) and NRG Energy CEO Mauricio Gutierrez toured the newly opened Petra Nova carbon capture and enhanced oil recovery system on April 13, 2017. This joint venture by NRG Energy and JX Nippon Oil & Gas Exploration Corp. is located near Houston and started operations at the end of 2016. The project has delivered more than 300,000 tons of carbon dioxide to the West Ranch oil field, owned by Petra Nova and Hilcorp Energy. The CO2 is injected into the oil reservoir to increase oil production in a process called Enhanced Oil Recovery. Image courtesy of NRG Energy/AP.