An energy expert has warned Northern Ireland consumers could face a hike in bills after Brexit.
Richard Murphy of law firm Pinsent Masons said if negotiations were to leave the UK outside European energy networks, it could push up prices.
"The direction of travel for energy markets has long been towards further integration. This facilitates the efficient transfer of energy from generation points to demand, flattening out peaks and troughs on the system and allowing for smarter trading," he said.
"If Brexit meant that we were to find ourselves moving away from this pan-continental network, we couldn't benefit from those efficiencies and costs would rise. The levels of investment in the infrastructure that has delivered these integrated networks makes it a practical non-starter to divest ourselves from the European system.
"Brexit presents undoubted challenges and uncertainties for the Irish energy market, as recognised by its inclusion the NI Executive's letter to the Prime Minister.
"However, for the sake of businesses and consumers, we must remain focused on the introduction of I-SEM and the necessary supporting infrastructure such as the proposed North-South Interconnector. Brexit cannot disrupt this work."