Ireland is trying to withdraw from an international treaty for energy investment disputes but as it makes for the exit, it must contend with a $100 million (€88 million) claim. Lansdowne Resources, the oil and gas exploration firm, has formally filed its case at the International Centre for Settlement of Investment Disputes over a claim that the company was wronged by Ireland refusing approval for an oil and gas field in the Celtic Sea. The grounds for the claim are the Energy Charter Treaty (ECT), a mechanism for resolving disputes between states and corporations over energy investments. This comes just…