e Wi isles

New Opportunity for UK’s Wind Industry?

D espite being one of the world’s

windiest nations, UK is only

eighth in terms of installed

wind turbine capacity, with 400MW on

stream (by the year 2000). In compari-

son Germany (6000), USA (2500), Spain

(2000) and Denmark (2200) all had

installed capacities well in excess of the

UK total. UK has had a particular prob-

lem with public acceptance and

approvals for onshore sites, but now that

attention throughout much of densely-

populated north western Europe is tum-

ing offshore, British enterprise may have

another chance to achieve global scale

and enhance the country’s international

position in exploiting this sustainable

resource. Is, however, its industry in a

position to seize the moment? There may

be some doubt since there are few indige-

nous companies producing the turbines

and blades that are key, though a number

of lead overseas players have established a

presence here. George Marsh, Refocus

magazme, takes a closer look

British wind turbine manufacturing? As far as turbines are concerned, there have

been virtually no British manufacturers out-

side the small wind sector. That may, how-

ever, be about to change as St Albans-based

Renewable Energy Systems Ltd has running

in Ireland a prototype of a 1MW system for

which it has major hopes. RES, collaborat-

ing with Peterborough based company

Brotherhood Machtech over both design

and manufacture, has applied lessons it has

learned in carrying out wind energy projects

around the world over the last two decades.

Developed with the help of Department of

Trade and Industry and European funding,

the RS 52/1000 system is a three-bladed,

pitch regulated horizontal axis wind turbine

that utilises variable speed (8 to 26 rpm) to

optimise energy capture and reduce noise

emissions at low wind speeds. Variable

speed also permits effkient generation of

power at unity or leading power factor.

The system’s 52m diameter rotor has

three 3.3 tonne blades built by LM

Glasfiber, attached to a spherical cast SGI

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FEATURE - THE WINDY ISLES

hub through four-point contact rolling ele-

ment bearings. A Morley induction genera-

tor is driven at 1500 rpm via a Flender

PEAC 4355 stepup gearbox. Output, from

the Alstom inverter, is 690V at 50 Hz.

Control algorithms developed by RES to

achieve optimum power at low wind speeds

and blade pitching for speed control are

applied via Mita Teknik control system

hardware. The turbine system in its nacelle

is mounted on a 45m high tapered tubular

steel tower with a 3.6m diameter base.

UK has a number of small-wind turbine

producers and at the upper end of these

North Energy Associates, though not yet in

the ‘big wind’ league, does sell a system

that, at 2OkW, is viable for powering small

industrial units.

Rotors In terms of the rotors that drive wind tur-

bine generators, some of the largest are

being built in Britain, though by companies

that have overseas ownership. The two

manufacturers of large turbine blades are

Aerolaminates, a subsidiary of Danish man-

ufacturer NEG Micon, and Aerpak UK in

Scotland. Aerolaminates recently moved to

a purpose-built riverside factory at

Newport, Isle of Wight, so that it can man-

ufacture and ship the largest onshore rotors,

typically up to 33m in diameter, plus future

rotors of 6Om and above needed for off-

shore wind exploitation. The factory is not

only an answer to the challenge of produc-

ing these immense structures in hundreds as

demand builds up, but is also a primary

NEC Micon centre of technical excellence.

In Scotland, KircaIdy-based Aerpac UK

has been renamed NO1 Scotland since the

company was acquired by NO1

Rotortechnik of Germany this year. The

company was set up in the mid 1990s by

Dutch blade maker Aerpac BV but was

pushed into receivership as a result of a dis-

pute between the Dutch branch and a major

client, allegedly over the quality of blades

delivered under a large order. NO1 is a rela-

tively new company, having been founded in

Thuringia, Germany, in 1999. In its five-year

life, Aerpac UK produced over 600 blades,

nearly all of which were exported. Now suc-

cessor NO1 Scotland is targeting the British

market with 24m blades suitable for 600 to

75OkW turbines. It also has its eyes on the

emerging offshore market, for which blade

size would more than double to some 56m.

The company starts life with contracts,

enough fresh work having been secured

under receivership to re-employ some 85 of

I40 workers who had previously been laid

off, and hopes to be back up to around 120

workers by the end of this year.

There are differences in emphasis between

these two companies in the way they produce

their blades. NO1 Scotland uses vacuum

infusion of glass reinforced epoxy (GRE) to

produce two half shells, which are subse-

quently bonded together to form the com-

plete blade. Its blades are therefore all-plastic

based on glass reinforcement.

Aerolaminates, on the other hand, is one of

the few remaining producers that still champi-

ons the use of wood composite. Blade design-

er for the company Mark Hancock says that

the material occupies a place between ‘heavy’

glass/polyester and light but expensive aero-

space materials. Over 5000 wood composite

blades produced during the 1980s in USA

gained a reputation for strength and reliability

and Aerolaminates has since exploited this

technology in Europe. Hancock says that the

microstructure of wood gives it outstanding

properties including superior fatigue resis-

tance, low density and high specific stiffness.

Using wood results, says the company, in thick

shell structures that are light, strong and stiff.

Wood composite is used for the main blade

strength member, or spar, while the trailing

edge is a light fairing of foam sandwich con-

struction.

Nevertheless, Aerolaminates is also cur-

rently developing prototype blades which

are fully reinforced plastic and can be pro-

duced by a closed-mould resin infusion

process. This may indicate a move towards

all-composite blades for future very large

offshore rotors where automated produc-

tion will be needed to ensure repeatability

and control costs. Both NO1 Scotland and

Aerolaminates are looking into the inclu-

sion of carbon fibres for the larger blades

now being developed for the offshore sector.

Hybrid reinforcements containing carbon

will be necessary to stiffen up really long

blades so that they cannot deflect under

high loads and strike the support tower.

Bigger turbines and rotors are one of the

major means by which the price of wind

energy has been brought down over the last

two decades from around US40 cents per

kilowatt hour to less than 4 cents today,

explaining why in many western countries

much new wind energy capacity is being

achieved by replacing existing turbines with

larger ones. The large blades which are a

leading enabler for this process represent an

important market for materials. UK has one

of the world’s most significant suppliers of

materials to this sector. Over the last decade,

SP Composites has developed integrated

materials packages to meet the unique

requirements of the wind energy market and

has seen that market overtake marine, aero-

space, automotive and all other sectors to

become its leading outlet. It is no accident

that SP is located on a site immediately next

to that of Aerolaminates, who are one of its

main clients, and likewise has a purpose-built

factory at Newport, Isle of Wight. The com-

pany supplies materials to most of the lead-

ing blade manufacturers, the majority of

whom are in Europe.

A new product/process showing great

promise for blade producers is SP Resin

Infusion Technology. SPRINT material

comprises dry fibre reinforcement layers

sandwiching a pre-catalysed resin film.

The material is laid up into the mould, in

as many layers as are required to make up

the laminate, the lay-up then being vacu-

um bagged and heat cured. During the

cure cycle, resin drawn from the film per-

meates into the reinforcement, helped by

vacuum. An advantage over other closed-

mould processes such as resin transfer

moulding (RTM) and resin infusion

moulding (RIM) is that the resin has vir-

tually no distance to travel, having simply

to penetrate the thickness of the adjacent

reinforcement. Wet-out is therefore even

and thorough, resulting in a high-quality

component with low void content. SP also

provides a material combination for blade

manufacturers who use pre-impregnated

(prepreg) materials in a quest for aerospace

levels of quality. PRIME 20 is a readily

infusing epoxy having characteristics

matched to those of its SE 90 prepregs,

now being produced in widths of up to

two metres at the Newport factory. For tra-

ditional wet lay-up moulders, the Ampreg

22 epoxy laminating system is matched

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Qs /u‘i FEATURE - THE WINDY ISLES A -

RES 52/l 000 wind turbine, Northern Ireland.

with SP multiaxial and unidirectional rein-

forcement fabrics.

Offshore and big Although British Wind Energy Association

and others believe that potential for onshore

wind farm sites in the UK could become

brighter as the planning process is made

more rational and local communities become

more directly involved, there seems little

doubt that the main prospects for big wind

lie offshore. This is the potential market that

is attracting overseas companies like Vestas

Wind Turbines to the UK. But Britain, with

its acknowledged offshore expertise and

industrial base, could be in there too. Many

of the components used by UK-based over-

seas turbine manufacturing operations are

sourced here already. Denmark’s NEG

Micon, for example, has now installed nine

2MW turbines that were assembled at its

Thorpe, Surrey, facility using mostly UK-

produced components. A logical develop-

ment would be for a UK company or con-

sortium to carry out integration at this level

to produce an indigenous turbine system.

RES, as we have outlined, is showing the

way, but 2 to 5MW systems will be the

future in the offshore sector if the required

economies of scale are to be delivered.

One of the 2MW turbines assembled at

Thorpe is now up and running in the Orkney

Isles off northern Scotland. Noted for winds

that are so strong that trees do not grow, the

Orkneys are considered a realistic testing

ground for future offshore systems.

Hurricane-force winds of 140 mph, for

which offshore installations will have to be

designed, have been recorded there.

Designed, built and tested with the help of

funding from the DTI’s Sustainable Energy

Programme, the Burgar Hill, Orkney, turbine

is on a 215ft tower and has a 236ft diameter

rotor. Along with a second turbine, rated at

1.5m the new system will be operated by

Orkney Sustainable Energy and will generate

about a quarter of the islands’ power.

Just under 4MW of the UK’s current

400MW plus total installed wind energy

capacity comes from the country’s first off-

shore wind farm, a twin-turbine installation

Ikm off Blyth Harbour, Northumberland.

These Vestas wind turbines, providing

enough power for 3000 households and

claimed to have been the worlds first multi-

magawatt offshore turbines, are open to the

full forces of the ocean winds. Their opera-

tor, Border Wind, collaborated with

PowerGen Renewables (itself a joint venture

between PowerGen and Abbot Group),

Nuon UK and Shell Renewables in imple-

menting the project, which complements

an existing wind farm on the harbour walls

comprising nine 300kW generators. The f4

million project, supported under the

European Commission’s Thermie

Programme, is being monitored as part of

the DTI’s Wind Energy Programme which

aims to support UK industry in developing

offshore wind power resources.

If academia were any indicator, UK’s wind

energy sector would be thriving. Courses

seen as ‘green’ are popular and student

demand has driven the creation of courses on

aspects of renewable energy at a range of uni-

versities and other learning centres. Official

science is engaged too. Of note are the

Centre for Economic Renewable Power

Delivery at the University of Strathclyde, the

Centre for Sustainable Energy in Bristol, the

Rutherford Appleton Laboratory at Didcot,

Crest at Loughborough University, the

National Energy Foundation at Milton

Keynes, the Energy and Environment

Research Unit at the Open University, the

Department of Electrical Engineering at the

University of Manchester Institute of Science

and Technology, the Electrical Power and

Control Group at Durham University, the

Department of Aerospace Engineering at the

University of Glasgow, and the Department

of Engineering and the University of the

West of England at Bristol.

Boost Recent national and EU pronouncements

might constitute a boost for Britain’s wind

energy prospects. The government has said it

wants 10% of the country’s electricity to be

derived from non-fossil renewable resources

by 2010. Under the Renewables Obligation,

that replaces the previous British government

Non Fossil Fuel Obligation, electricity com-

panies will be required to source 10% of their

supply from renewables by that year. This will

concentrate the minds of those companies,

and since renewable-generated electricity will

be exempt from the Climate Change Levy,

equivalent to 0.3p per unit, we can expect

substantial power consumers to follow the

recent example of Sainsburys in investing in a

6OOkW wind turbine to supply a major

Scottish facility. Further hope is seen in the

announcement that Renewable Obligation

developments can now be relocated from one

site to another, apparently removing an

inflexibilility under which a development

agreed for one site could not be redesignated

to another if local planning permission is not

granted for the first. Moves like this have

cheered the British Wind Energy Association,

which suggests that UK wind turbines could

be generating 5.7 billion units of electricity

per year by the end of 2005.

UK remains a densely populated island

and, even given some upsurge onshore,

much of the extra 1500MW of new generat-

ing base needed to meet the target will have

to come from offshore. The Crown Estate

has approved I8 firms to go forward with

applications to build up to 500 offshore

wind farms around the coast. Potential devel-

opers, including Shell, Powergen, British

Energy, NEG Micon, RES and Amec Border

Wind, now have to apply for specific project

consents from several government depart-

ments, but all being well (for instance if the

Ministry of Defence does not put a spanner

in the works by seeking a blanket ban on off-

shore wind farm development for reasons

related to low flying and radar) construction

could begin by 2003. UK’s wind energy

industry, dismayed by the failure of wind

energy to take off at home, could at last be

facing a more rewarding future. That being

the case, companies like Renewable Energy

Systems - which last year developed or built

237MW of new capacity across five different

countries - might be able to turn more of its

attention back to securing a future in this

promising sector for Britain’s own indige-

nous industry.

Ed note: Ironica& it Iooks as though

more of the global wind energy turbiie sec-

tor might be UK ControlIed after all since it

was recently reported that City and inter-

national private equity company Doughty

Hanson had acquired Danish company

LM Glasfiber, the world’s largest bIade

manu&turer, for an undiscIosed sum.

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