The United States produces about $200 of GDP for every million Btus (British Thermal Unit – measure of energy used) of primary energy consumed. This is half of what the UK produces and a third of what Switzerland produces. So, according to Sean Casten, Congressman, Illinois’ 6th District of the U.S. House of Representatives, investing in efficiency could double or triple the U.S. economy without additional energy consumption and CO2 emissions. And how does CHP fit into all this? Let’s find out in this interview.