For over a hundred years coal has been the primary source for electricity in the US, but new green technologies are increasingly gaining market share. According to Doug Vine, with the Center for Climate and Energy Solutions, ''Ten years ago, coal was producing around 50 percent of U.S. electricity and today that’s down to around a third''. Vine explains that the main player responsible for this shift is natural gas, which now has reached a level of electric power generation close to that of coal. Yet natural gas remains for many a controversial topic as its extraction and consumption still leave a mark on the environment making it a greener resource but not one comparable to renewable energy sources. But at the same time, the combustion of natural gas emits about half the carbon dioxide of coal, explains Vine adding that ''Natural gas is a technology that can be brought on very quickly so it can be back-up or support for renewable electricity sources''. The support of natural gas has therefore become essential from the growing renewable energy sector in the US. Wind energy is currently generating roughly 5% of all electricity in the US, but in certain states, that figure is much higher and far more relevant. Kansas and South Dakota each get more than 20% of their electricity from wind, while in Iowa, it’s more than 35%. The natural gas industry is therefore clearly evolving in the US and in greater need of resources and infrastructure. In Pennsylvania for example - one of the states expected to see an important development in the sector - during a recent event at Lehigh Career & Technical Institute di Schnecksville, Bill desRosier di Cabot Oil & Gas Corp., announced that his company is working with career and trade schools and regional high schools to help students consider programs related to the natural gas industry. ''We’ve invested in a number of career and technology centers, we have to make sure that we have properly educated people to fill these jobs as the older generation retires and more jobs becomes available''. Event participants also faced the issue of the need for new infrastructure for the production and distribution of gas. ''Being afraid of pipeline is like being afraid of railroad or highways. Investing in natural gas and building new infrastructure using highly trained and skilled professionals with the most advanced technologies assures the safest means of transmission for natural gas'', said David Taylor, President of the Pennsylvania Manufacturers Association, adding that those involved in the sector "need to come together and say we want the growth, we want the investment and prosperity that’s going to come from this sector."