Rampion windfam could be extended if it proves a success

That is the view of a renewable energy expert as workers continue to construct the 27 square mile site off the Sussex coast.

Dr Gordon Edge, director of policy at Renewable UK, said it would be a number of years before a new windfarm is build in the English Channel but said Rampion could be extended.

He said: "It is difficult building in the Channel. The wind speed is OK but there are better locations and it is a relatively constrained area in terms of sealife and shipping.

"But with Rampion, all the infrastructure will already be there and there are good links here to link up to the system.

"If it proves a success, E.ON could request to extend the Rampion site.

The German-based energy provider is behind the £1.3 billion windfarm which when built in 2018 will power 300,000 homes and reduce C02 emissions by up to 600,000 tonnes.

Rampion workers are currently in the early stages of construction and are hammering the foundations of the turbines into the seabed.

However, work has been temporarily held up after the discovery of Second World War bombs on the sea bed near to the site.

E.ON has brought in demolition experts and controlled explosions took place yesterday and will continue today.

Last month the work of hammering the foundations into the seabed caused disruption with residents reporting noise and vibrations from their homes.

An E.ON spokeswoman said tests had been carried out and under most circumstances work will not be audible from the shore.

However, she said a number of factors combined - such as weather, wind direction, other background noise and the nature of the seabed - could result in some noise being heard.

Wildlife groups have also raised concerns for marine life, particularly mammals such as dolphins and porpoises which communicate by vibrations through the water.

The spokeswoman for E.ON explained the company employees scouts who keep watch for marine mammals.

If they are spotted swimming nearby then work is delayed.

She added: "We also employ a soft-start piling mitigation, whereby we slowly build up the energy and frequency of the piling to allow marine life to move away from the piling location."

Chris Tomlinson, Rampion's development manager, said progress on the site has been promising.

He said: “Over the last few months, our highly skilled team has continued to prepare the site for foundation installation, progressing with boulder relocation and unexploded ordnance surveys.

"We are now pleased to be entering the next stage of piling and we’ll now work towards installing the remainder of the foundations by the end of this year, in preparation for turbine installation to begin in 2017.”

Rampion is expected to be completed in 2018.

SOMETIMES IT IS SIMPLY A LOT OF HARD HAMMERING

IT HAS led to sleepless nights for those along the coast and left marine mammals confused.

But what exactly are the Rampion workers doing eight miles off the Sussex coast?

In short, they are midway through one of the engineering wonders of Sussex.

Because whatever you think of offshore wind farms, there is no denying that their construction is quite incredible.

It is hard enough building a turbine on terra firma.

But to securely place 450ft windmills – all 116 of them – in the middle of one the busiest stretches of water in the world is nothing short of remarkable.

So how on earth do you build an off-shore wind farm and how will those spinning rotors eight miles out at sea power our laptops, TVs and heating?

Dr Gordon Edge, director of policy at Renewable UK, explained that location is key.

He said: “You obviously need an area with good wind speed. Factors such as shipping traffic and marine life also come into play.

“Perhaps most important is the seabed. It can’t be too deep and ideally it should be sandy so you can hammer the foundations down.”

There are a number of different turbine designs.

Some are bolted on top of a sort of tripod with multiple connections into the seabed. Others have a wide suction base holding them down while experts are currently developing floating turbines.

But Rampion’s turbines are securely held into the seabed with what is called a monopile.

This is basically a single huge tube of steel which is hammered up to 40 metres into the seabed.

This is the work currently being done on site which has resulted in sleepless nights for some.

Workers have two special jack-up ships which come with huge metal legs.

Once in position the legs are lowered to the seabed and the ship is lifted out of the water.

This creates a stable platform not affected by the movement of the sea from which workers can install the monopiles.

A 1,000 tonne crane on deck hoists each 500 to 800 tonne monopile vertically before a special gripper perfectly positions it to the inch.

A huge hydraulic hammer then whacks the pile into the seabed by as much as 40 metres.

This depth is required to ensure the wind turbine will be secure and able to operate in winds of more than 100mph.

Dr Edge said: “It is basically a huge hammer that comes down on the pile until it is in. It sounds almost medieval but that is the way they do it.”

Once in the ground the cranes then lift and place what is called the transition piece which will make the turbine visible above the water for the first time.

This yellow metal casing is bolted in place and forms the connection between the foundation and the shaft – which is to come.

Rampion workers have fitted the transition piece on about two dozens of the turbines so far and hope to have completed all the foundations in the next six months.

Early next year, work will begin on lifting and placing the huge towers onto the transition pieces.

These towers will make up the majority of the structure that can be seen from shore.

This work will again be carried out by the cranes onboard the jack-up vessels.

The towers house the cables to transmit the power along with a staircase for workers to access the moving parts at the top.

Once the towers are in place workers will then use the crane to lift and bolt on what is known as the nacelle and hub.

The blades will then be individually fitted to the hub.

The nacelle houses all the important pieces of machinery to ensure the turbine works safely and efficiently, including the control system, gearbox and generator.

Dr Edge explained: “As the wind turns the blades, the blades turn the shaft and the gear box ensures the turbine is doing the appropriate revolutions per minute.

“That electricity being generated then travels down a cable inside the tower and through what is called the J tube.”

But instead of going straight back to the land-based substation in Mid Sussex, the 116 cables transfer to a nearby offshore substation, which looks like an oil rig.

The substation transforms the energy created by the turbines to a higher voltage which ensures energy is not lost on its eight mile journey via a cable back to land.

But this is not the end of the journey.

The electricity generated then travels from Brooklands Pleasure Park in Worthing – where the cable reaches land – across the South Downs to a huge substation at Bolney where it is transferred to the National Grid to power our homes.

Dr Edge added: “It is all quite impressive really and wind power is going to be increasingly important to our energy make-up in the future.

“We are already at five per cent of our total and by 2020 that will have doubled.

“The government is talking of doubling that again by 2030 to 20 per cent.

“At the end of the day we are an island nation and we need to make good use of the wind.”

ON-SHORE WORK STILL UNDER WAY

WORK is continuing apace on the land-based part of the Rampion wind farm project with a 16-mile cable route taking the power generated by turbines to the National Grid.

The cables reach land at Brooklands Pleasure Park, Worthing, and then snake through the South Downs until they reach the substation at Twineham, near Bolney.

The onshore work has been split into 12 stages.

For each stage, access points are first constructed to allow vehicles to lay the cable route.

Trenching work then takes place to lay the ducting for the cable.

The cables are put in and finally the ground is reinstated.

E.ON bosses have said that around 60 per cent of the route has now been complete. But some parts of the route are proving more troublesome than others.

Workers have had to employ a method known as trenchless drilling to install cables underneath the railway just north of Brooklands, the River Adur and the A283 and A27.

This is to minimise the impact on the environment and to avoid disruption to roads.

Similar work is planned when the cables cross the A259.

When complete, Rampion will provide enough electricity to supply the equivalent of around 300,000 homes and reduce C02 emissions by up to 600,000 tonnes a year.

The project is due to be completed in 2018.