An environmental permit has been issued to the firm behind plans for an £800m waste incinerator in Flintshire.
Natural Resources Wales (NRW) said it was satisfied energy from the waste plant on Deeside Industrial Estate could "operate without harming the environment".
Once in operation, it will burn 200,000 tonnes of non-recyclable waste a year, sending enough electricity for about 30,000 homes to the National Grid.
Planning permission was granted in May.
The councils looking to process non-recyclable waste via the incinerator are Flintshire, Denbighshire, Conwy, Gwynedd and Anglesey.
Wrexham council is the only local authority in north Wales pushing forward with its own plans to tackle black bag rubbish which goes into landfill each year.
Wheelabrator Technologies Inc said it aims to start building the incinerator, Parc Adfer, in 2016.
The project is expected to take three years.
As part of its consultation process, NRW consulted with Betsi Cadwaladr University Health Board and Public Health Wales to consider whether the facility could affect people's health.
Sian Williams, NRW north Wales head of operations, said: "We studied the application in great detail and are satisfied that the facility can operate without harming the environment or the health of people nearby.
"We are therefore issuing a permit to allow it to operate and will monitor its operation to ensure that it complies with its permit conditions."
Combined heat and power technology will incinerate the waste. It will generate steam which will produce the electricity through a turbine and generator.
Ash produced through the process will be treated on-site to produce materials for the construction industry.