The relatively simple concept of harnessing the offshore breeze to generate electricity entails tacking a number of diverse issues through an offshore wind farm’s development, construction, and operation. During its life, the project will require the expertise and knowledge of a large number of people with a wide range of skills. This diverse team includes specialists such as meteorologists, project managers, ornithologists, marine biologists, and ultimately lawyers and bankers, as well as the more obvious marine, structural, and electrical engineers.


How to build a wind farm

Come on a journey from the docks of Belfast to the coast of Cumbria in science correspondent David Shukman's three step guide to the challenges, costs, and construction of an offshore wind farm.

Three steps to build a wind farm - BBC

The engineering and design of Icebreaker Wind, as with any offshore wind facility, depends on site-specific conditions, particularly water depth, lakebed geology, wind conditions, waves, and ice. The turbines, foundations, and electrical systems will include technical modifications for adaptation to this marine environment. These may include foundation modifications (interface height or ice cone) to account for significant wave heights or ice flows, pressurizing nacelles to minimize corrosion due to sea spray, heated blades, cold weather packages, and brightly colored access platforms for navigational safety and maintenance access. In addition, the offshore will be equipped with extensive corrosion protection, internal climate control systems, high-grade exterior paint, and built-in service cranes.

This section provides more detail for the following items:

  • Wind Turbine Generator – The MVOW V126-3.45MW turbine is ideal for the Lake Erie wind conditions and yields the highest energy output of any turbine in the industry.

  • Foundation – Of all wind turbine foundations, the Mono Bucket is ideally suited for the lakebed conditions, and is the most economic, environmentally friendly, and easiest to install.

  • Substation Interconnect – The Cleveland Public Power Lake Road substation is the former site of a 80 MW coal plan, as well as the main transmission facility for the utility. The export cable from the wind farm will connect to a new set of switch gear located on the north end of this facility.

  • Wind Data – Icebreaker Wind has a meteorological station situated on the Cleveland Water intake Crib that has provided 12 years of continuous wind resource data.

  • Lake Erie Ice – The team has analyzed the historical characteristics of Lake Erie ice and determined the 50 and 10 year loads that can be imposed on the foundation.

Icebreaker Turbine Overview

icebreaker turbine overview

The Project will utilize six Mitsubishi Heavy Industries Vestas Offshore Wind (MVOW) Vestas V126 3.45 MW offshore wind turbine generators (WTG). Each WTG will consist of three major components: 1) the tower, 2) the nacelle, and 3) the rotor with blades. The major turbine components are illustrated in figure above.

Turbine Model Hub Height Rotor Diameter Blade Length Tip Height
V126-3.45 MWTM IEC IIB 272 ft | 83 m 413 ft | 126 m 206 ft | 62.9 m 479 ft | 146 m

For more information on this turbine, visit Vestas.

Mono Bucket (MB) Foundation

The innovative MB combines the benefits of a gravity base, a monopile, and a suction bucket. This Suction Installed Caisson is comprised of three sections: a steel bucket embedded in the lakebed, a lid/transition section between the bucket and shaft, and a shaft that resembles a standard offshore wind monopile from the mudline to the turbine interface platform above the water level. In essence, it is an “all-in-one” steel foundation system designed to support offshore wind turbines. The MB concept is depicted in the figure below.

This state-of-the-art structure has been used for decades in the offshore oil and gas industry, and deployed in the offshore wind industry (since 2002) at numerous locations in the North Sea. It has proven to be a significant material innovation over earlier foundation alternatives, simplifying installation, eliminating pile driving, reducing materials requirements, and minimizing environmental impacts. The benefits of using the MB are significant and include: 1) reduced installation time and costs; 2) reduced noise during installation (eliminates pile-driving); and 3) reduced environmental impacts (avoids drilling and dredging).

monobucket foundation arrangement

The team’s selection of the MB foundation is the result of a careful analysis of all available support structure technologies, which analysis led to the conclusion that it is the right commercially deployable solution for the Great Lakes environment. Interestingly enough, LEEDCo also performed a study of the U.S. East Coast lease areas and found that the MB was the best and lowest cost technology for sites 25 meters and less. Today, the commercial validation of this conclusion can be found at the Deutsche Bucht project in Germany, where the MB is being deployed with an 8 MW MVOW turbine in deeper waters of 38-40 m.

The MB design criteria consider factors such as 50-year weather extremes, average wind speed, wind gusts, turbulence intensity, waves, and ice loads. The first turbine erected on a MB foundation, a 3 MW Vestas V90 turbine installed in the North Sea in 2002 remains operational to this day, with dynamic and cyclic loading continuously monitored. Three MB installations in the North Sea have withstood sustained waves greater than 70 feet, far in excess of the 20 ft. waves in Lake Erie.

North Sea Mono Bucket Installation (Video)

Grid Connection

The Project substation will be located on the Cleveland Public Power (CPP) site adjacent to the existing 138 kV Lake Road Substation. The area surrounding the substation is developed, consisting almost entirely of unpaved, but previously disturbed, outdoor storage space, with no significant ecological resources. The layout plan includes a fenced area that will enclose the substation, its bus structures, switch gear, the step-up transformer (34.5 kV/138 kV), and a control building. The figure below provides an aerial view of the Icebreaker Wind substation location.

onshore substation location

Icebreaker Wind will interconnect with the CPP transmission system via grid-tie at the Lake Road 138kV substation, which connects to the American Transmission Systems (ATSI) system within PJM (Pennsylvania, New Jersey, Maryland). The Project has obtained rights to participate in the PJM wholesale market.

Project Metocean Conditions

The Icebreaker site, is an offshore site located within Lake Erie, approximately 13 km (8 mi) north-west of the Port of Cleveland, Ohio, USA. The immediate surroundings comprise the lake itself with a lake surface water level of approximately 160 m above mean sea level (AMSL). Data have been collected from a mast located on an offshore water intake structure (the “Crib”) approximately halfway between the turbine locations and the Cleveland shoreline.

Icebreaker Wind has utilized a single meteorological 50 m met mast, M1, situated between 7 km and 12 km from the proposed turbine locations. The mast is located on a structure (the Crib) approximately 30 m in diameter and 15 m tall, located 6 km offshore. The Crib extends 15 m above surface water level (ASWL) and the guyed met mast is mounted on top of a small building. The instruments are mounted on a monopole tower, with instrument heights of 30 m, 40 m, and 50 m AWSL.


The most obvious load that the wind turbine foundation experiences is waves and they are often the dominant design criterion, such as in the North Sea where offshore wind turbines experience 70 foot waves. In Lake Erie, where maximum waves are on the order of “only” 30 feet and ice is the dominant design criteria, waves are the most significant factor in foundation fatigue. Much research effort has been put into the field of wave behavior and their physical behavior is well understood.

Waves are often measured in significant height and significant period, being the average of the highest 1/3 of the waves and their corresponding period. This complies with what an experienced seaman would call the "wave height" by visual inspection. Waves are generated by winds, and hence there is a close relationship in understanding wind meteorology and wave climate. Wind energy is transmitted into wave energy through friction and waves are generally categorized as “waves” or ”swells”.

The wave parameters for Icebreaker Wind were determined by BMT Argoss using the Wave Information Studies (WIS) hindcast model at reference WIS92070 (latitude = 41.56_N, longitude = 81.76_W). WIS is sponsored by the U.S. Army Corps of Engineers and generates hindcast models for wave conditions in US waters, including the Great Lakes. The hindcast model has hourly data between 1979 and 2009 and was used to generate the Normal Sea States (NSS), Severe Sea States (SSS), Extreme Sea States (ESS) and extreme individual waves.

Using these data, Offshore Consulting Group (OCG) developed five types of sea states: Normal, Additional Normal, Severe, Extreme and BSH. The Normal Sea States are relatively benign and are typically used in the fatigue calculations. In total 3,138 simulations were undertaken to examine the effects of different sea state parameters and water level on wave loading. The maximum base shear force and overturning moment from each of the sea states were then determined and used as input into the foundation design. One of these results for Extreme Sea States are given below.

Winter Ice Loads

The foundation design is based upon the lake bed geotechnical conditions and the ability of the soil/structure to respond to the applied forces. These forces are the result of the environmental conditions, namely, wind, waves, and ice as well as other operational considerations during maintenance activities and potential vessel impacts. In Lake Erie, ice represents the second most significant force while waves only have a minor impact, whereas, in the North Sea, the opposite is true where waves may be 70 feet or greater and ice is relatively infrequent if present at all.

The objective of characterizing these ice conditions and determining the ice forces, is to ensure Icebreaker Wind applies an appropriate level of reliability with respect to personnel safety, environmental protection and structural integrity in relation to ice. Ice conditions can vary significantly from year to year and throughout the winter. Therefore, experience from other ice regions and knowledge of historical ice parameters are combined to develop “50 year” deterministic ice loads.

Pori 1 Turbine & Kemi Lighthouse, Finland

The floating lake ice that forms in Lake Erie each winter is a very important consideration for the design of the wind turbine towers and for the foundations sited in the lake and this ice cover has the potential to produce two different types of loading on the turbine tower. First, surface ice formed through heat transfer from the Lake Erie surface to the atmosphere can grow to be several feet thick. When driven by the winds and currents, this ice can cause steady and periodic loads on the wind-turbine tower. The second type of loading can come from ice ridges, which are formed when moving surface ice collides with stationary ice, causing the ice to pile up. The section of the ridge below the surface, called the keel, can extend downwards 20 m and can create ice gouges (or scours). The interstitial water between the ice pieces of the keel can freeze due to heat transfer to the atmosphere, creating a consolidated layer in the ridge.

Determining ice loads began with characterizing the historical ice cover that forms on Lake Erie. This was performed by the Cold Regions Research and Engineering Laboratory (CRREL), “Characteristics of the Lake Erie Ice Cover”, April 2016. Note, CRREL is part of the Engineering Research and Development Center (ERDC) of the US Army Corps of Engineers (USACE). Next, Ice loading methodology and calculations were provided by Esa Eranti, designer of the foundations used in Finland’s offshore wind farms, where heavy icing conditions regularly exceed Lake Erie extremes. Independently, Norman Allyn and Ken Croasdale evaluated ice loads based on recent research on first year ridges composed of fresh water ice, and measured loads on towers equipped with cones (Confederation Bridge). Cone size, angle, vertical location, and upward and downward breaking action were examined. The results from these analysis yielded a conservative set of loading and fatigue values that were applied to the foundation design to yield the design of the Mono Bucket structure

Some of the results of the ice analysis are shown below.

Examples of Sheet Ice (Left) and Ridge Ice (Right)


Ice interaction with MB Foundation - Sheet Ice (Left), Ridge Ice (Right)