Sharing best practice as offshore scales up

EUROPE: It covers an area more than three times the size of Luxembourg, it is in the middle of the North Sea and it is very windy. This is Dogger Bank, or even "Dogger" as the area is perhaps best known to the millions who listen to shipping industry weather forecasts for the British Isles.

Google Translate

But ten years ahead, much of this sandbank off the east coast of England could be covered with wind turbines, vying for the title of the world’s largest wind farm.

Over 32 GW of site concessions in nine zones around Great Britain were granted by seabed owner the Crown Estate in the UK’s third round of offshore wind development.

It is expected to deliver up to 25 GW of wind power capacity to help meet the UK’s renewables targets.

All nine Round 3 developers selected for concessions are currently embarking on appraisals of their allotted seabed zones to identify the key issues, including undertaking environmental and geophysical surveys and consulting stakeholders.

The site development licence for the Dogger Bank zone was awarded to the Forewind Consortium comprising German utility RWE, Scottish utility SSE and Norway’s Statkraft and Statoil.

At 9 GW and covering 8660 square kilometres (3344 square miles), Dogger Bank is the biggest of the nine zones. It is large enough to house 13 GW of wind power generating capacity—enough to supply 10% of the UK’s electricity needs.

As well as the challenges that would usually be associated with building wind turbines in up to 63 metres of water and between 125 and 290 kilometres (78 and 180 miles) from shore, the developers have to take into account the rich history that lies beneath the waves—as well as unknown environmental implications.

Dogger Bank has been proposed as a special area of conservation for its shallow sandbanks.

This would make it a strictly protected area under the EU’s habitats directive.

"Over the past few months we have been trying to better understand what impact this might have," says Gareth Lewis, head of development at Forewind.

He says that an initial assessment shows that the project would at worst have a very small impact of less than 1% of the total area.

Since January the consortium has been undertaking environment and geophysical surveys, he says. These include the biggest boat based and aerial bird surveys that have ever taken place.

But potential problems could arise with the seismic surveys of the site.

"Now that we are moving deeper into oil and gas territory, we have become aware of the impact that their exploration seismic surveys could have on our own seismic surveys," Lewis says.

Oil and gas seismic sources are louder and penetrate deeper under the seabed—down to three kilometres compared with just 50 metres for wind.

This means they can impact wind surveys from up to 50 nautical miles away, he says. And with the latest round of licensing blocks for oil and gas exploration which will be awarded this month, more surveys could be coming to the area next year.

For the fishing industry Dogger Bank has been important for centuries.

"We are working with UK and international fishermen to understand the key areas of interest on the site," says Lewis.

But it is the archaeological significance of the area that particularly captures the imagination. Two famous sea battles took place at Dogger Bank: the first was between the English and Dutch fleets in 1781 and the second was in the First World War where the German vessel, the Blücher, was sunk with the loss of over 700 lives.

There are also further wrecks from WWI on the site, Lewis says. "Understanding the whereabouts of these battles will not only be important for understanding the maritime heritage but also for determining any ordnance or underwater hazards within the zone during the construction phase."

He says, going back a further 6000 years, in Mesolithic times Doggerland was a large inhabited island—one of the last parts of the land bridge that connected Great Britain with mainland Europe before it was inundated due to sea level rise after the ice age.

"Dutch fishermen have for years been recovering archaeological artefacts from the site. Our geophysics surveys will add to that knowledge base."

The Forewind consortium plans to develop the Dogger Bank zone in four tranches. Following consultations with stakeholders, it has identified the location of the first tranche.

Two years of stakeholder engagement, surveys and studies are in progress, leading up to a consent application at the end of 2012—with hopes for a decision a year later.

Next year, Lewis says that Forewind hopes to identify tranche B, with C and D to follow at further yearly intervals.

The project has already secured an offer from Britain’s transmission operator National Grid for connection of 1 GW of output into the onshore network.

But Lewis warns of grid challenges ahead. "Far offshore has been made technically possible by new HVDC technology, however this has never been built for greater than 400 MW."

There is a way to go yet before developers will be comfortable enough to place contracts, he says.

In addition, plans for the new regime of independent offshore transmission owners (OFTOs) are a cause for concern.

"There could be a risk of timelines stretching because the OFTO would not be prepared to take on some of the early commitment risk that the developer would," Lewis says.

Furthest North

Facing a similar set of site constraints is the Moray Firth zone off the north-east coast of Scotland.

It is the furthest north of all the proposed UK offshore wind developments. The 1300 MW project is being developed by Moray Offshore Renewables (MOR), a joint venture of Portuguese utility EDP Renováveis (EDPR) and Britain’s Sea Energy Renewables as the minority partner.

As well as the usual environmental and seabed conflicts, development is also constrained by cumulative and "in-combination" impacts, says Enrique Alvarez-Uria of EDPR.

The zone is next to the 920 MW Beatrice project that in 2009 was awarded a site development licence in the Scottish Territorial Waters round.

"It’s obvious that there are impacts between the two projects and we are engaging in close discussions to look at the mutual benefits," he says.

The two sets of developers are collaborating to identify potential cumulative effects and to standardise their approach to site assessments.

In addition to the wind project under development next door, there are also two existing wind turbines and several oil platforms located on the edge of the zone.

MOR has split the zone into two areas and intends to develop first the eastern area where there are fewer constraints. MOR claims it is outside any conservation-designated areas, and outside the helicopter safety zone or shipping access routes around the oil platforms.

The area is located an average 26 kilometres from shore with water depths of 35–60 metres. Wind speeds average 9.75 metres a second at 90 metre hub height.

MOR plans to install some 200 turbines, generating between 1 GW and 1.14 GW.

The project is expected to generate its first electricity in 2016, with further capacity coming on line up to 2020. Alvarez-Uria says the programme is challenging but "doable".

Like the Forewind consortium, MOR sees a significant challenge in getting the wind farm’s generation to customers.

As the northernmost project, the zone is far from load centres, with the result that it is penalised by high transmission charges in spite of its "tremendous" wind resource.

"We are also facing very high financial securities," he says, referring to the large sums of money that need to be paid upfront to secure a grid connection.

"On top of this we have the OFTO regime which is bringing uncertainty that can impact our programme."

Alvarez-Uria warns of the potential downsides to the joint ventures and strategic alliances that are being formed to take forward the next generation of huge offshore wind projects.

"We cannot disregard the inherent risks they bring. Challenges are everywhere and are going to be coming for many years so we have to ensure that our goals are compatible," he says.

With offshore wind being a very long cycle industry, there will be misalignments over time of goals, risk profiles and of diverse corporate cultures from countries such as Spain, Denmark or the UK. The players will have different incentives and resources, and evolutions in technology may disrupt some relationships, he says.
"I don’t have a silver bullet for this, but having project-focused organisations is helpful," he says. Project oriented teams with clear roles that bring accountability and complementary skills and resources will help avoid redundancies.

"This will ensure the consistency that the supply chain is demanding to standardise and move away from designing on a project by project basis," he says.

As an example of the need to standardise, he points out that the substations deployed at every single wind farm so far have been of a completely different design.

"Industrialising is key. Offshore companies should leverage on scale—and utilities have scale in procurement, financing and IT systems."

Design one, then build many

Agreeing with the need to standardise is Steve Clarke, UK content manager at Mainstream Renewable Power. Mainstream is half of SMart Wind, a 50:50 consortium with Siemens Project Ventures, which bagged the 4 GW Hornsea zone.

The consortium makes much of its vertical integration with tier one suppliers. Siemens is expected to supply the turbines and substations while Mainstream will provide the development expertise.

The two main players are supported by Hochtief Construction and Beluga Shipping. "The intention is to design out as much risk as possible and place the remaining risk with the right experts best able to manage it," says Clarke.

"The overall objective being a reduction in capital cost and lifecycle cost."

The zone covers 4735 square kilometres and extends between 34 and 190 kilometres from the Yorkshire coast—equivalent to the width of England from Liverpool to Hull.

Water depths are mostly 30–40 metres but with maximum depths up to 70 metres. SMart Wind intends to develop the zone in eight smaller 500 MW blocks.

"Such modular development and construction gives a far higher degree of predictability to the supply chain and to the investment community as well. The idea being to design one and then build many," says Clarke.

Both Clarke and Alvarez-Uria stress the need to bring the costs of offshore wind down. "It is key that we deliver clean energy at competitive prices," says Alvarez-Uria. "We cannot rely on subsidies for more than a decade. It has to be in our mindset from day one."

Clarke adds: "Having seen the price of wind energy double, thankfully the curve is now going in the right direction." He points out that the industry is about to see greater competition in turbine supply with around a dozen new turbines being developed or already on the market.

Round 3 offers the economies of scale and opportunities for innovation to deliver less expensive solutions.

"Future gigawatts offshore will be delivered using new turbine foundations and grid system solutions and new install vessels too, all bringing significant reductions in capex and opex," he says, referring to capital expenditure and operating expenditure.

Have you registered with us yet?

Register now to enjoy more articles
and free email bulletins.

Sign up now
Already registered?
Sign in