Operation with continuous R&D and product optimizing

BARD Offshore 1 is Germany’s first commercial windfarm, a pioneering deep-water project comprising 80 5MW turbines located in the German North Sea at approximately 100 kilometres north of Borkum Island.

Owner and operator Ocean Breeze Energy in its long-term upkeep strategy combines continuous product and process improvement through sustained ongoing R&D effort, which is considered a unique approach in an offshore windfarm operating-phase. Today, BARD Offshore 1 is claimed Germany’s most productive offshore wind farm.

Founded in 2004, wind industry newcomer and pioneer BARD Offshore only three years later installed two 5MW BARD 5.0 prototypes at the windy Rysumer Nacken wasteland site west of the German port Emden. The near-shore prototype at Hooksiel near Wilhelmshaven followed in 2008, this time atop an in-house Tri-Pile in again a next step towards full industrialization and ‘real’ deep-water offshore wind power deployment. BARD was initially viewed with suspicion, because of the Russian born founder/investor Arngolt Bekker behind the ambitious venture, and admiration for the bold plans, unprecedented fast development pace and all milestones they met.

In April 2007 BARD received building permission for the 400MW BARD Offshore 1 project, to be built during 2009 and 2010 in 39 – 41 metre water depths and with commissioning planned that same year. However, construction start was delayed until 2010 when also the first power was fed into the grid, but again a year later BARD had gone even further behind schedule. According to wind industry insiders this was due to inexperience, BARD’s determined strategy to do everything themselves, and technical issues with turbines and foundations. Furthermore, the offshore conditions, with mean wind speeds above 10m/s, were excellent for energy production but highly challenging for windfarm construction.By September 2013 all 80 turbines were grid connected, but too late for the financially troubled BARD group – also in-house producer of turbines, blades, and foundations – that discontinued operations at the end of 2013. 

The company collapse immediately created a unique situation for especially the project’s main financial party UniCredit group, of which Ocean Breeze Energy (OBE) is a full subsidiary. According to managing director Jean Huby, who joined Ocean Breeze shortly after BARD delivered the project, in his introduction: “The immediate challenge was that 80 turbines capable of generating electricity required regular O&M services. Part of BARD’s expertise had gone into OWS, a newly-founded structure, which took over activities from the former BARD group for ensuring continuity of all services. Furthermore, we quickly concluded that reconstruct an engineering department was crucial because BARD had ceased operations and OWS was focussing on operations.”

He added that being the windfarm operator, OBE had to fill that gap. Furthermore, building an in-house engineering team, currently comprising 17 different experts, enabled OBE to tackle pending challenges from the windfarm construction period successfully. They could in parallel take advantage of design improvements and fresh experiences from the rest of industry.

Many components of the BARD turbine, especially in the mechanical drive train, were similar to the ones applied in other early 5MW turbine designs. Huby: “Examples are the single rotor bearing, identical to the bearing in 5MW Multibrid-type (AREVA/Adwen) turbines, or the gearbox, which has a lot in common with the units deployed in 5MW REpower (Senvion) turbines. However, the two designs are also characterized by different specifications, technology principles and system dynamics behaviour compared to the BARD 5.0.”

In parallel, OBE started looking for an experienced industry partner for supporting the OWS team, for which Bremen-based EDF Renewables subsidiary REETEC was selected. They were according Huby already familiar with BARD 5.0 technology through their installation of the first BARD prototype. OBE attracted also expertise from Deutsche Offshore Consult (DOC) to reorganize the sea logistics set-up.

“Technical issues with turbines and foundations”

OWS, REETEC and its partner Wind Multiplikator, together with OBE’s engineering team succeeded in gradually improving turbine reliability and windfarm output in parallel. During 2013 and 2014, BARD Offshore 1 electricity generation was still just under 0.5 TWh, and from 2015 significantly increased to over one TWh. Huby: “BARD Offshore 1 thus continuously increased output and in 2017 reached around 1.5 TWh. Our pioneering project also paved the way for the offshore wind industry in Germany. This journey is not over yet. With all experience gained at OBE together with our industry partners, we still have lots of potential left for further optimizing.”

BARD Offshore 1 is serviced from an onshore service hub in Emden. It is largely operated by OWS / REETEC, who want to further develop it into an independent service infrastructure for offshore windfarms. Most of OBE’s engineering activities also take place at this site. It invested in the Rysumer Nacken test site too, by refitting it with BARD 5.0 turbines for operating as a testing and training site.

Renamed REETEC EDF Renewables acquired all OWS’ service-related activities and 170 staff in 2017, and it signed a new 10-year service agreement with OBE for BARD Offshore 1. This specialized company is responsible for a comprehensive package of windfarm monitoring, maritime surveillance, turbine troubleshooting and core O&M, major component replacement and overhauls, blade repairs, and spare parts storage and management.

“Further developed for addressing future needs”

Besides ‘third-level’ engineering support, OBE delivers the sea logistics set-up.  The company deploys the self-propelled Wind Lift 1 jack-up, fitted with a 500-tonne crane, currently for retrofitting critical components, especially main bearings and gearboxes. It added from this May a new walk-to-work support vessel, the Acta Auriga. This new service and logistics concept aims at boosting offshore personnel productivity by up to 25 per cent through a combination of higher flexibility and reduced waiting time, with positive impact at windfarm availability too.

For the near future, OBE also plans a comprehensive revamp of the wind farm’s SCADA and data storage systems, as well as the introduction of a new turbine controller developed by Fraunhofer IEE. This project, dubbed ‘OceanControl’, is according Huby a key performance enhancement lever: “The initial set up was not well integrated and hard to be further developed for addressing future needs. Our new expandable Ocean Control has a focus at optimizing wind farm performance, offers a decrease in turbine operating loads while boosting output, is easy to use and minimizes training costs.”

Since the challenging starting situation five years ago OBE step by step improved BARD Offshore 1 performance, said Huby confidently. Last year 94 – 95 per cent availability was achieved and the windfarm generated more electricity than any other German offshore project. “We intend to further boost availability to 95 – 96 per cent within three to four years. While it has already been a fantastic journey with the BARD Offshore 1 wind farm, there is still a lot potential for further optimizations. A main lesson we could already draw at this stage, and valid too for the entire offshore wind industry, is that R&D effort should not stop once a wind farm is commissioned. Building technological know-how and experience is the key to success, across the whole project life-cycle.”

The conventional high-speed geared three-bladed BARD 5.0 features 122-metre rotor diameter. The 29-tonne 60-metre in-house produced rotor blades feature a wide 5.94-metre maximum depth (chord), and incorporate aluminium tip winglets. The unusual blade structural design features a central section incorporating two main webs (structural reinforcements) and separate leading edge and trailing edge sections each made in one piece. This eliminates the erosion-critical leading edge seam, and the structurally-critical trailing edge seam. Development of the turbine commenced in November 2005, for which German engineering consultancy aerodyn Energiesysteme was contracted. For the required short time-to-market from prototype development to testing and certification, BARD went for proven wind technology only. This includes the gearbox, DFIG plus converter, single main bearing, and pitch system. Because of huge time pressure, there was only a two-year timespan between design process start and prototype installation, which according the company left substantial potential for later-stage (mass) optimizing. These design reserves would be re-used in steps through stepwise scaling process to a final ‘(7 + X) MW’ rating with matching rotor diameter.

Another novel BARD product development and outcome of a Benchmark study was the Tri-Pile deep-water foundation, consisting of a central transition piece and three cylindrical piles. Each pile has a standardized 3.35-metre outer diameter and variable pile wall thickness between 40 – 120 millimetre in dependence of soil and wind conditions and water depth. The grouted connection between transition piece and piles is reinforced by welding shear keys. BARD company Cuxhaven Steel Construction produced the first Tri-Pile’s in 2008.

BARD’s in-house hardware supply chain together with in-house installation, and service companies aimed at building a series of North Sea projects. Each standardized windfarm was to be equipped with the annual factory output of about 80 turbines and Tri-Piles. This in turn was integral part of a fast growth strategy, and a wider ambition of becoming the world’s largest offshore windfarm developer. BARD’s first windfarm construction delays did not stop them refitting the two onshore prototypes at Rysumer Nacken in early 2011 with 6.5MW Winergy Multi-Duored high-speed gearboxes, each with two output shafts and two PMG’s. One of BARD’s main demands was that the new gearbox should be made to fit into the existing cast main chassis, while rotor diameter, rotor bearing, with additional nacelle structures remaining unchanged. An overall product development objective was to utilise the substantial built-in design reserves of the 5MW concept, while simultaneously minimizing scaling time and costs.

A main drive technology achievement was that Multi Duored gearbox mass could be kept almost unchanged, while power rating increased by one-third. The renamed BARD 6.5 turbines were envisaged for a new German windfarm in 2013 but never certified. A similar faith applied for the longer BARD XX rotor blade in 2010 presented as the following product development step towards the final (7 + X)MW turbine size as envisaged in 2007 by company founder late Arngolt Bekker.

Sources: BARD article “Heading offshore – fast” (Renewable Energy World, September – October 2007); additional BARD and external references.

This article was previously published in the Offshore WIND magazine, issue 4, 2018.