The European Union should share the cost of filling Ukraine’s natural-gas storage if it wants to prepare for worst-case scenarios next winter, the country’s energy minister said in an interview, highlighting a potential clash in coming negotiations between the EU, Kiev and Moscow. An EU-mediated deal that helped maintain gas supplies to Ukraine and the rest of Europe during the winter expires at the end of March. The comments by Volodymyr Demchyshyn, a former investment banker who took office in December, underline how difficult it will be to reach a follow-up agreement that ensures deliveries over the summer and beyond. About half of the EU’s gas imports from Russia pass through Ukraine. Mr. Demchyshyn also warned that the government in Kiev might decide to cut off shipments to regions controlled by pro-Russian separatists because of a failure by local energy distributors to pay for […]