while the hs can capture most renewables the ubiquitous nature of some goods and their component parts means that the dual use problem will remain over and above what could be sorted out by introducing greater specificity in the hs tariff codes as for ghgefficient goods or goods produced in a ghgefficient way there are simply no hs codes to match moreover climate or energy efficiency include fast evolving technologies hence the identification of such goods in a closed list is a moving target the inclusion of goods derived from ghgefficient process and production methods ppms is especially problematic as it may dramatically increase the scope for protectionist measures