How will the energy produced on-site be connected to the National Grid? What will be used to transfer it, and how is it safe?

A new connection to the local electricity network would be required to export electricity off site.  The substation will be located within the Installation boundary, from where cabling will run underground to the base of the quarry void (circa 104m in length), prior to overhead cable (circa 74m in length) to the existing electricity pylon as shown on the drawing below.  The substation is shown as the purple block.  Underground cabling is the dashed purple line, above ground is solid purple.  The nominal voltage is 33kV.

Substations are part of the electricity supply network that enables the widespread use of electricity in homes, work places, schools etc.  As shown below, the substation will be located within the quarry void, and there will be no public access.  Anyone working on the apparatus will be authorised and competent.  The means of connection and disconnection will be a single 33kV metered circuit breaker within the substation.  There will also be an emergency trip facility that will open the circuit breaker and disconnect the connection.