The budding biodiesel industry is mostly fueled by vegetable seeds such as soybeans and canola. But, according to David Kargbo, an instructor in Temple's College of Engineering, green experts are looking for alternatives to food-based fuels. "You know, energy is everywhere. And sometimes where we get the energy from can be very expensive, and also not good for the environment. Therefore, we have to look for other means, and one of them is right in front of us, which is using sewage sludge," he said. Biodiesel from sludge doesn't burn any cleaner, but, Kargbo says, extracting more biodiesel from sludge means relying less on food crops for fuel.