Shipping ethanol from farm states to the East and West coasts by pipeline could open up markets and help clear a bottleneck that has kept the fuel additive from getting to the pumps. Association of Oil Pipe Lines, a Washington-based trade group that represents about 50 pipeline companies, already is studying whether gasoline blends containing up to 20% ethanol can be transported safely in existing pipelines to break the current rail car, barge and trucking log jam.