National Grid is considering whether it can fast-track two controversial power cable projects to help the government meet its pledge to create a clean electricity system by 2030.

The FTSE 100 energy company is reviewing plans to build a 114-mile (184km) power line from Tilbury in Essex to Norwich, which is expected to begin construction in 2027 and carry electricity from offshore windfarms by 2031.

It is also considering speeding up plans for the Sea Link project, 90 miles (145kms) of undersea cable that would come ashore at two points – near Sandwich in Kent and between Thorpeness and Aldeburgh in Suffolk.

National Grid is hoping to receive government approval for the projects by 2026, despite strong local opposition from campaigners who fear the 50 metre-high (164ft) pylons on the Norwich-Tilbury line would “destroy historic landscapes” and require a “huge loss of trees”. Green groups have also raised concerns that the Sea Link project would damage coastal ecosystems.

John Pettigrew, National Grid’s chief executive, told the Guardian that it was considering whether it could deliver the projects about a year earlier than planned after a report by the system operator described the power line as “critical” to meeting the government’s clean energy goals.

“Reassuringly, the report found that the projects we are working on are the right projects to progress. We are now looking at our supply chains and contractors to see whether they can be delivered a year earlier,” he said.

The recently formed National Energy System Operator (Neso), which was once part of National Grid, called for the project to be fast-tracked as part of its official advice to new ministers on how to reach Labour’s election pledge to “decarbonise” the power system by 2030.

Neso said the projects were “critical to delivering a network which supports the clean power pathways, but at present have delivery dates after 2030”. The system operator added that without these projects the clean power target would fall short by about 1.6% in 2030 and would mean that consumers could face £4.2bn in extra costs.

National Grid, which builds and runs power grids and cables in Great Britain and the US, reported a better-than-expected 26% rise in its underlying pre-tax profit to £1.44bn for the six months ended 30 September.

Pettigrew said the company was “looking forward to working with the new [Trump] administration”, and added that the incoming president’s policies would have “no significant impact” on its plans to build new power grids in the north-east of the US.