Some PV industry observers believe the next frontier in solar will be building-integrated photovoltaics (BIPV), where PV cells are integrated into roofing, walls and other building materials. Konarka Technologies Inc., Lowell, Mass., the developer of Konarka Power Plastic, a lightweight, flexible material that converts light to electricity, recently announced the company is working with the Color/Construction Unit of ThyssenKrupp Steel Europe, a supplier of steel construction elements in Germany, to develop steel roof and other construction elements for building-integrated photovoltaics (BIPV). The joint solar solution will be based on Konarka's Power Plastic, which replaces conventional building materials in roofs, skylights and facades.