Client: Energy, Ecology, Engineering LLP (3E)
Application: Bankable energy yield assessment and layout optimisation
Sector: Renewable – Onshore Wind
Since 2010, 3E has been involved in the engineering and design of renewable energy projects. The company is currently supporting four wind power projects from 5MW to 50MW in various stages of development; from wind survey through planning to construction and operation.
Background to the project:
Shevchenko is a 50MW onshore wind project planned on the coast of the Caspian Sea, near the town of Aktau in Kazakhstan.
Turbine choice and layout were critical considerations facing 3E in order to optimise the site; the wrong turbine choice and poorly planned positioning would result in the wind farm not achieving the best possible returns. This could also lead to problems during the operational phase of the project due to high levels of turbulence induced fatigue, causing mechanical failures in the turbines.
A bankable energy yield assessment was also required. The assessment calculates energy production across the project's lifetime and an accompanying confidence level for that prediction.
Such an assessment is critical during the development stage of a project as it informs the investment decisions being made.
How Lloyd's Register helped:
LR analysed the wind data measured on site and performed a long-term adjustment of the wind statistics using a Measure-Correlate-Predict (MCP) technique. A wind flow model using WindPRO and WAsP was created to generate a wind resource map for layout optimisation.
The best turbine type was determined based on site conditions, such as wind speed and turbulence intensity.
The turbine wakes were also modelled in order to calculate the energy yield of the site. This was followed by a loss and uncertainty analysis from which the energy yields at various confidence levels (P50, P75 and P90) were derived.
LR used two approaches to optimise the layout:
- using the automatic optimising tool within WindPRO based on the wind resource map
- manual optimisation of a grid layout with the intention of minimising the turbine wake losses.
The second approach was proposed because of the flat and simple terrain features, the cold climate and the fact that the prevailing wind direction is parallel to the largely rectangular site area.
Outcome for the client:
Our work gave 3E the optimum solution for the Shevchenko site, ensuring energy yield was maximised through turbine selection and layout.
As a result of our expertise, the manually optimised layout (figure 2) was chosen, producing approximately 2.5% more energy than the alternative WindPRO approach (figure 1) - enough energy to provide electricity for 1000 homes. The selected layout will also reduce electrical cable and road length requirements on the site, helping to maximise the project's profitability.
Furthermore, the bankable energy yield assessment gave certainty and confidence where project financing decisions needed to be made.