Reuters: Suez (LYOE.PA: Quote, Profile, Research) Chief Executive Gerard Mestrallet called on Friday for a common energy policy and a single regulator in Europe, but said this would probably take time. Mestrallet also reiterated his opposition to plans by the European Commission to separate energy production and transport networks. "We need to go further in the creation of a big European energy market. I am in favour of a single regulator. This would be gradual with a common …