Offshore Wind Energy

What makes a good offshore wind policy?

Keeping flexibility in early grid connection appraisal

What does availability really mean for your business case?

Special Edition:

EWEA Offshore Conference

Amsterdam

29 Nov. - 1 Dec. 2011

magazineOffshore Wind Energy

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sustainable energy for everyone 3

C o n t e n t s

04 The importance of HSSE competences

05 Editorial Michiel Müller

06 Evaluating the potential What makes a good offshore wind policy? Investigating offshore wind profiles

08 Developing your wind farm Keeping flexibility in early grid connection appraisal Cost benefit analysis of innovative O&M Shared offshore grid connections

11 Construction and operation An online tool to rule the waves What does availability really mean for an offshore wind business case? Performance assessments of offshore wind farms

14 Meet Our Experts

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From responsiblesources

4

I the authorities set the general legal framework and standards;

II the developer ensures HSSE is embedded in a dedicated project HSSE management system, preferably adhering to a proper management standard such as the OHSAS 18001;

III the contractor has their own HSSE management system and procedures ensuring compliance to the above legal framework and requirements of the developer.

Properly managing HSSE liabilities in offshore wind

means that these three roles must be in balance,

allocating all relevant risks and responsibilities

clearly to the most relevant parties. And of course

management commitment and the careful imple-

mentation of HSSE systems and culture is crucial.

This is the theory which Ecofys fully supports and

advises to our clients. But what we currently see

in our daily practice is that the required balance

between the above items is complex and not always

achieved yet. And this is likely to cause HSSE in-

cidents! There are various reasons for this, one of

which we want to highlight here: the competencies

of parties and thus people involved, at all levels.

Knowing what we don’t knowWith a growing number of offshore develop-

ments in the coming years, competent people will

become scarce. Also, there are many new parties,

lacking specific offshore experience. A the same

time, the wind market is still in the process of de-

veloping mutual HSSE standards and requirements

for minimal skill levels, competences, exchange of

certificates internationally, standards and guide-

lines.

If the developments go faster than the develop-

ment of framework and skills, this leads to un-

clear frameworks for insufficiently skilled people.

This is a dangerous situation in terms of HSSE and

poses potentially large liabilities for develop-

ers. Therefore, Ecofys wants to draw attention to

the importance of HSSE skills and competences of

parties and people acting in wind industry. In our

opinion a variety of measures is required to tackle

this issue, starting with a mutual awareness in

our sector! As a developer there is much you can

and should do, starting in the early phase of the

development to ensure an incident free construc-

tion and O&M phase. “Ecofys can help you to de-

velop the required skills and competences in your

team”, says HSSE expert Chris Breukink.

Minimising costs, maximising performance

During the last five years, offshore wind energy really took

out to sea. Tangible and visible large projects are proving

every day that offshore wind is delivering on its promise.

E d i t o r i a l

Michiel Müller


Meanwhile, being at the forefront of renewable energy deployment requires a lot of effort, creativity

and stamina. Margins are small, which is not necessarily bad as long as the risks are small too. The

prerequisite of any offshore project is a good reward-to-risk ratio.

For Ecofys, reducing risks is the key in all process steps for offshore wind projects, from site scouting

to financial close. Reducing risks requires a continuous innovation and improvement of harvesting the

wind, from technologies to financial engineering.

Looking in retrospective to the more than twenty years of experience of Ecofys with wind energy, I believe

innovating and improving the business case for wind energy has brought us to the top ranks of offshore

wind consultancy. Reducing the risk and the cost and maximising the performance of an offshore wind

project takes a good understanding of both the practical issues and the theoretical opportunities.

In all stages of a project, we receive positive feedback from our clients on our quality, in-depth

knowledge and reliability. We assist our clients in all aspects of offshore wind project development:

selection of the right sites, acquiring the concession, achieving the permit based on the right

Environmental Impact Assessment; analysing the wind resource, modelling the costs, conducting the

detailed design, tendering and contracting and realising financial close. And last but not least: we

analyse and maximise the yield during operation. Wherever necessary, partners leading in their field

(e.g. in construction, maintenance and financing) complement our knowledge.

We played a leading role in realising the Prinses Amaliawindpark and Belwind offshore wind farms. Our

current portfolio of projects includes the UK Round 3 Navitus Bay, Dutch Q10 and German DanTysk offshore

wind farms.

Our vision is: sustainable energy for everyone. Our business is: reducing risks by combining leading

expertise and practical knowledge. This will bring our goal within reach.

Michiel Müller,

Head of Wind Energy Unit, Ecofys.

Managing the Health, Safety, Security and Environmental (HSSE) liabilities of large offshore wind farms is a major challenge, which requires the commitment of all parties involved. At Ecofys, we strongly believe that any incident can be prevented! To achieve this, all parties have a role in safeguarding HSSE:

The importance of HSSE competencesExperts: Chris Breukink, Ed Wehnes, Rob Tegel, Jaqueline Heijnen

6

There now has been over a decade of commercial development of the offshore wind industry, with currently over 3 GW installed. Yet, the industry is still in its infancy relative to the goal of installing a capacity of up to 30 GW by 2020. In order to limit public costs, reduce risks and enable further project development it is highly relevant to look back at the lessons learnt from successful offshore wind policies and support mechanisms.

Over the course of the last 2 years, we have

carried out a series of studies and interviews that

revolved around the question ’What makes a good

offshore wind policy?’ We spoke to governments,

project developers, financial parties and industry

associations, and asked about their perceptions of

good practice and the critical factors for success or

failure.

Incentive schemesThe feedback clearly indicates that the success

of stimulation mechanisms depends largely

on design, not on the instrument itself.

Each instrument has its own advantages and

disadvantages. But, regardless of the instrument

used, long-term financial support frameworks

and stability are flagged as crucial for industry

developments and to ensure a viable business

case for developers

Spatial planning and permittingThe spatial planning and consenting framework in

the UK is mentioned frequently as a good xample.

Risks in offshore wind projects are reduced due to

a clear consenting process and high involvement

of the Crown Estate. France’s spatial planning

approach to entering the offshore wind market is

also seen as a good way. For the 2011 tender, the

government first consulted stakeholders and held

public debates to ensure proper site selection.

Grid connectionWe have found that the progressiveness of

regulations and planning regarding grid

connections are lacking behind and form a barrier

in all countries. Improving possibilities for grid

connection should be a priority.

Supply chainSupply of key components may be a bottleneck

to offshore wind targets. A massive upscaling of

offshore wind will require capacity increases and

process and product innovation. Additional

policies need to be aligned with deployment

projections. National and regional governments

could play a key role in preparing for this aspect.

Investigating offshore wind profilesExperts: Andrea Venora, Jan Coelingh, Anthony Crockford

Offshore wind measurements clearly show that the wind field is different from onshore conditions. Several parameters influence the wind offshore: the distance from the shore, the stability of the atmosphere, the waves and currents. It has been suggested that the offshore wind profile can be described with the Monin-Obukhov Similarity Theory (a model that was developed for flow above a canopy).

The theory behind the Monin-Obukhov Similarity

Theory is that the wind speed profile in the

lowest part of the Planetary Boundary Layer,

for stationary conditions, can be determined

as a function of two parameters: the roughness

length and the Obukhov length L (a measure of

atmospheric stability). There are several different

methods proposed to calculate the Obukhov

length. The research into applications of this

theory for offshore wind profiles has mainly been

conducted for shorter masts close to the coast,

and is so far inconclusive.

Andrea Venora, a wind energy consultant at Ecofys,

has analysed data from two tall offshore met

masts in the North Sea, in order to gain further

insight into the Monin-Obukhov Similarity Theory

far from shore. The research compared measured

wind conditions at the German FINO-1 and Dutch

OWEZ met masts to five different variants of the

model.

This research found that the applicability of

the model is site dependent. The model shows

different results and slightly dissimilar behavior

for the two offshore sites and these differences are

relevant for all the five variants of the model.

“The Monin-Obukhov Similarity Theory does not

contain all of the important parameters influencing

the offshore wind profile,” concludes Andrea Venora.

“The offshore wind speed profile is a difficult

phenomenon to simulate and the current metho-

dologies do not reach the desired accuracy. For this

reason, we have to improve our tools for a realistic

assessment of the offshore wind speed profile.”

Wind Profile at OWEZ Wind Profile at FINO-1


What makes a good offshore wind policy?Experts: Anna Ritzen, Frank Wiersma, Thomas Winkel

8 sustainable energy for everyone 9

Keeping flexibility in early grid connection appraisalExperts: Dirk Schoenmakers, Karsten Burges

Three onshore substations were identi-fied for the grid connection of the 900-1200 MW Navitus Bay offshore wind farm in the English Channel. There was no obvious preference for any substation, as they are all located 50-60 km from the project site. To select the optimal grid connection route, the project developer assigned an appraisal team that covered all disciplines.

After a thorough assessment of available data, all

possible data gaps were filled by carrying out soil

surveys both onshore and offshore. The constraints

along each cable route were differentiated into

hard or soft constraints with potential mitigations

including the cost and time impacts. The key to the

assessment was to maintain flexibility on the grid

connection design with alternatives for engineer-

ing, environment, consenting and land ownership

issues for the further development of the project.

This flexibility depended on the definition of the

minimum requirements for the grid connection

infrastructure and of the search area required for

finalising both the offshore and onshore cable

routes. For instance, the offshore export cable

route would need to be about 600 m wide, so a

search area width of about 2 km was used to al-

low some flexibility in the future. Onshore, the

cable route width can be as little as 30 m, but the

search area is much more constrained. Therefore a

width of 1 km was maintained.

Based on a thorough cost and risk assessment of

all three grid connection options, the appraisal

team unanimously identified Mannington as the

preferred grid connection location, based on the:

- high flexibility for cable routing both offshore

and onshore;

- lowest Cost Of Energy (COE) of all options; and

- least risks identified along the onshore and off-

shore cable route corridors

“The application of a thorough appraisal phase for

assessing the grid connection alternatives proved

to be a very powerful tool in order to make key

decisions very early in the development of the

project”, says Dirk Schoenmakers, working as grid

manager for the Navitus Bay wind farm.

Cost benefit analysis of innovative O&MExperts: Frank Wiersma, Jean Grassin

With offshore wind farms growing in scale and at increasing distances offshore, both the challenges and the potential benefits of an optimised O&M strategy are increasingly important. Reducing the cost and improving efficiency of maintenance can help lower the cost of offshore wind projects. A growing range of innovative propositions is being offered. These include advanced transfer systems, faster vessels, more reliable wind turbine drive trains, and increased redundancy in the wind farm design.

An essential barrier to implementing such

solutions in any specific project is the fact that

any innovative O&M proposition needs to be

identified as a realistic option early in the wind

farm development. Indeed, the solution needs

to be accounted for in the wind farm design

and reflected in a reliable way in CAPEX & OPEX

estimates for business cases. Moreover, it would

have to be taken into account early on in the

contracting strategy.

In practice, innovative O&M solutions are often

considered too late in the wind farm development

process. ‘Business As Usual’ solutions are favoured

because of time pressure and because the

costs, benefits and risks are better understood.

Consequently, possible cost reduction in OPEX may

not be achieved for any given wind farm, because

the suitable innovative O&M proposition was not

implemented.

In order to encourage these innovative

propositions early in the development of an

offshore wind farm, we compare the benefits

and risks against a benchmark O&M strategy for

large offshore wind farms. This allows us to focus

on those key parameters that are typically part

of business cases and service contracts, such as

warranted availability, bonus-malus payments

and weather downtime.

The structured and comprehensive perspective on

cost and benefits of these innovative O&M plans

provides a good basis for developers to evaluate

different logistical setups and advanced access

systems as part of their O&M strategies for offshore

wind projects.


Shared offshore grid connectionsExperts: Pim Rooijmans, Anthony Crockford, Dirk Schoenmakers

km from shore, the difference is even more ex-

treme. A single wind farm would require an HVDC

link bringing the cost in the range of

e 350-400 million, where the cost with a shared

connection could be as much as 40% lower.”

The reduction of Cost of Energy can be as high as

10%, bringing offshore wind energy significantly

closer to the targets for 2020.

One cost-reduction concept that is often discussed

(and about to become reality for some projects) is

a shared offshore grid connection, or “Socket-at-

Sea.” For example, if four 250 MW wind farms share

a 1GW export cable, it is feasible to construct an off-

shore converter station with a large-capacity HVDC

connection to shore. There are gains in efficiency

(lower losses) and in shared installation costs for

the single cable. But how much of an impact would

a Socket-at-Sea have on the cost of energy?

There are also potential downsides to a Socket-at-

Sea, such as higher wake losses due to many wind

farms in close proximity and reduced redundancy.

We have investigated the reductions in electrical

CAPEX for wind farms in the German Bight, and the

effect on the Cost of Energy of offshore wind. We

found that not all wind farms will see cost savings

with a Socket-at-Sea. In fact, up to about 50 km

from shore, it is often cheaper for wind farms to in-

dividually connect to shore (assuming no constraints

to landfalls).

But further from shore the costs are drastically

reduced. “For instance, at 100 km from shore, the

electrical infrastructure for a 250 MW wind farm

with a 220kV export cable would cost about

e 250 million, where a shared Socket-at-Sea

would cost only e 175 million,” says Dirk Schoen-

makers, an electrical engineer at Ecofys. “At 300

As offshore wind farms are getting larger and pushing further offshore, the costs are going up, not down. Developers, manufacturers and research bodies are all looking for concepts to reduce the costs for future offshore wind farms. Current cost of energy projections show projects costing 180 e /MWh, while targets aim for 100 e /MWh or lower by 2020.

When construction began on the 165 MW Belwind offshore wind farm, the manage-ment team wanted to improve the coordination between contractors. Bernard van Hemert, Belwind’s operations manager, had experienced the confusion in earlier offshore wind farms where coordination consisted of many phone calls and e-mails to contractors.

of emergency, a clear response chart will direct

the project manager to the appropriate actions.

“We can communicate rapidly, which is essential

when about twenty vessels are working at the site

at peak activity,” says Mr. van Hemert. “We have

saved days of work that accumulate to more than

a week. Mobilising one installation vessel already

costs more than a hundred thousand Euros, so

millions can be saved. This kind of efficiency is

needed in a sector which is still young, but that

will increase enormously in the next decade. We

cannot do without such an improvement.”

Contractors and managers alike could easily

become lost in a criss-cross of information

flows about ship movements, the local weather,

the status of the foundations or the turbines

themselves, connections, faults and smaller

accidents and incidents.

To help improve this coordination, Ecofys

developed the web-based Trident software for the

Belwind project. With Trident, project managers

and contractors all have access to relevant and

up-to-date information about the status of all

elements. The project manager can follow the

real-time status of each element, such as progress

in the construction of the foundations, cabling

or vessel movements. As a result, the project

manager can base his or her planning on the most

recent information. Likewise, all contractors have

easy access to this strategic planning process and

can have a close look at the project’s milestones

and their progress. One major advantage of the

online web-based tool is that everyone has access

to the same up-to-date data.

The online tool also makes all activities very

transparent. AIS (Automatic Identification System)

of ships makes it possible to follow all movements

in real-time and to log them as well. And, in case

An online tool to rule the wavesExperts: Nico Stolk, Pim Rooijmans


Performance assessments of offshore wind farmsExperts: Jan Coelingh, Jean Grassin, Peter Bange

Determining the actual impact of non-availability

on the business case or operations of an offshore

wind farm is complex. It includes the interaction

between a) the loss of production, b) weather and

other delays, c) the O&M costs and d) the risks that

are inherent in these.

In order to better understand these complex

interactions, we have developed an offshore O&M

contract model that describes the key processes

involved in the operations of offshore wind farms.

Through running Monte Carlo simulations of

multiple different scenarios, we are able to

investigate the relationship between loss of

production and the contractual measures of

availability.

For instance, a time-based guarantee of

availability is not directly proportional to

production loss. A long outage during windy

winter will lead to more lost production than a

similar period during a summer calm.

Some contractual definitions of availability do

not include weather delays, which would further

compound the situation, as the lost production

during the stormy winter weather would not be

covered by the guarantee.

Many service contracts for offshore wind farms

include incentive schemes that reward the

service providers for wind farm performance

above the guaranteed levels. The model provides

good understanding of how these schemes work

out in practice. Furthermore, the results provide a

basis for taking this into account in the business

case for offshore wind projects.

The pre-construction energy yield assessment is typically calculated based on the best information available, but will often rely on assumptions and hence contain significant uncertainties. This may lead to un-favourable financing conditions, and possible error in the prediction.

When contracting the wind turbine for your offshore wind farm, you may be offered ‘Type A’ with a guaranteed availability in terms of time of 92% including weather risk or a ‘Type B’ with a energy based guarantee of 90% excluding weather. Which one should you choose? Which wind turbine type will have the highest net energy yield?

What does availability really mean for an offshore wind business case?Experts: Jean Grassin, Frank Wiersma

Recalculation of the long-term expected energy

yield after one year (or more) of operation of a

wind farm will always lead to more accuracy in

the P50 calculation, with a usual tendency of

driving up the P90. The benefits are better cash

flow planning and better re-financing conditions

for offshore wind farm operators.

Ecofys performs two new independent wind

resource assessments for the operating wind farm.

The first assessment uses the same methods as in

the pre-construction calculations, with updated

wind data and current best practice methods.

The result is directly comparable to the

pre-construction energy yield assessment.

The second method is based on operational data.

This requires the correct interpretation of the

SCADA data of the wind farm to remove technical

malfunctioning to study reliable production

figures. The production figures for this limited

period are correlated to a long-term reference

data set. The results from both methods, and their

respective uncertainties, are then combined into

one best estimate for P50 and P90.

This re-calculation of the energy yield for a wind

farm does not guarantee an increase in long-term

P50. The re-evaluation may find that some losses

were under-predicted, or that wind turbines are

not performing as well as expected. However, a

better understanding of the behaviour of the wind

farm will likely lead to lower uncertainties. In our

experience, this can lead to an increase in P90,

which is often the key to re-financing on better

terms.

14 15

Meet our experts at EWEA Offshore 2011

Anthony Crockford• Specialist in Wind Resource

Assessment methods in complex

areas and wind farm layout

optimisation.

• Developed a GIS tool that

incorporates wind resource,

wake effects and a cost model,

and produces detailed Cost of

Energy maps.

• Experienced in wind farm

feasibility studies for many

onshore and offshore projects.

• Designed the layout for a test site

of twelve prototypes, optimising

the possibilities for power

performance measurements.

• Obtained his M.Sc. in Wind Energy

at the Technical University of

Denmark.

Nico Stolk• Developed Trident, the Offshore

Wind Farm Manager, a planning

tool for the construction of

offshore wind farms.

• Site manager for Test Site

Lelystad, the largest commercial

certification site for prototype

wind turbines in Europe.

• Managing a comprehensive

range of facilities for prototype

testing, infrastructure, wind

measurements and wind turbine

testing services.

• In charge of improving the

market for Wind Power Prediction

Services and responsible for

business development of wind

energy consultancy for Ecofys.

• 20+ years experience as project

manager.

Anna Ritzen• Specialised in wind energy

permitting, wind energy

cooperation, risk analysis and

feasibility studies.

• Involved with wind farm

feasibility studies and the

development of (co-ownership

of) wind farms up until financial

close.

• Completed several studies with

regards to regulations and

subsidy schemes for offshore

wind.

• Organising executive and student

offshore wind courses in China.

• Prepared requests for tenders for

onshore wind farms for several

project developers. By means

of a prefeasibility study, the

cost of energy and means of

participation are determined.

• Completed her M.Sc in Science &

Innovation Management, with an

emphasis on Renewable Energy

Supply.

Frank Wiersma• Project manager with experience

in multi-disciplinary initiatives

worldwide.

• Currently works on front-end

development of a set of offshore

wind projects around the North

Sea.

• His involvement ranges from

feasibility studies to front end

development and construction.

• Background in civil engineering

(Delft University of Technology)

and economics (London School of

Economics). 13 years of experience

in wind energy, marine

engineering and infrastructure

and met ocean information.

Dirk Schoenmakers• Responsible for grid connection

of the 165 MW Belwind offshore

wind farm off the Belgian coast.

• Working as Grid Manager for

the 900-1200 MW Navitus Bay

offshore wind farm in the UK,

and the 130 MW Q10 offshore wind

farm off the Dutch coast.

• Developed a model for

the technical / economical

optimisation of the (coupled)

grid connection of offshore wind

farms.

• Leading role in the Dutch

government: ‘Connect III – Cable

at Sea’ project of up to 6000 MW

of offshore wind power to the

Dutch onshore grid by the year

2020.

• Electrical Engineer. Master’s study

on Sustainable Energy Technology

at the Technical Universities

of Eindhoven and Delft, with

specialisation in wind energy.

Jean Grassin• Active both in the development

and the operational phase

of a number of wind farms

onshore and offshore; site

selection, preliminary design and

development planning.

• Developed the Ecofys Offshore

O&M Modelling Tool, to enable

wind farm design decision

to account for O&M costs,

and to support O&M contract

negotiations

• Performs yield estimation, layout

optimisation and preliminary

financial calculations, as well

as performance assessment of

operating wind farms.

• Completed his M.Sc. in Wind

Energy at the Technical University

of Denmark.

sustainable energy for everyone

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