The costs of wind turbines is dropping. But that means all the other capital costs – site preparation, foundations, infrastructure, tower construction – will become a bigger part of the total. In the U.S. they currently account for around 30% of the capital expenditures needed to install a land-based wind plant. To keep those costs under control the National Renewable Energy Laboratory (NREL) has created a comprehensive open-source modelling tool, called LandBOSSE, that allows users – researchers, analysts, developers, government agencies – to input their numbers (or use industry data and trends) and estimate costs. Want to try a different mix of inputs, designs, locations and strategies? What’s the trade-off between different labour rates, foundation designs, and turbine installation methods? You can change the numbers. Each module breaks down all the costs you can put a name to. The main four modules are: foundations, site preparation, erection, electrical collection system. Other modules include: development, management, grid connection, substation construction, weather delay. Optimisation means more efficiency means better decisions.
The contiguous United States has the technical resource potential to generate up to 32,700 terawatt-hours of electricity per year—more than eight times the amount of electricity consumed in the United States in 2018.
However, significant cost and performance improvements in wind power technology are needed for the wind industry to reach this potential.
That’s where NREL’s Land-based Balance of System Systems Engineering (LandBOSSE) tool can help. This open-source model, now publicly available, will provide researchers, analysts, wind power developers, government agencies, and the public with a flexible tool that can be used to estimate the balance-of-system (BOS) costs associated with onsite wind power plant construction at land-based wind plants.
Balance of System (BOS) costs
BOS costs—the costs to perform site preparation, construct foundations, install electrical infrastructure, and construct the tower—currently account for approximately 30% of the capital expenditures needed to install a land-based wind plant. And the relative importance of BOS costs is expected to increase as the cost of wind turbine hardware decreases.
“Because BOS costs for wind plants can vary widely by site and installation strategy, it’s important for wind energy developers to understand and explore how factors such as labour rates, foundation designs, and turbine installation methods might impact a project’s total investment costs,” said Annika Eberle, NREL Principal Investigator for the LandBOSSE tool. “LandBOSSE can help by allowing users to estimate how BOS costs might differ when aspects of a plant’s design or construction rates change.”
Modelling all the costs
Eberle and a team of NREL researchers developed LandBOSSE in response to the need for a mid-fidelity model that can provide flexibility for assessing wind plant BOS costs at a system level. Formulated using market research, industry data, pricing trends, and insights from experienced land-based wind plant developers, LandBOSSE helps users explore tradeoffs between innovative design scenarios while balancing the level of detail and speed required for model execution.
As described in more detail in a recent National Renewable Energy Laboratory (NREL) report, the model is based on a bottom-up, process-based assessment of inputs and outputs associated with each BOS operation and, where needed, is supplemented by top-down estimates of costs from industry.
The current version of LandBOSSE features process-based capabilities for four modules: foundations, site preparation, erection, and collection system. This modular approach allows for future expansion that could enable the exploration of a variety of plant sizes, locations, and site-specific parameters, along with different types of tower technologies, turbines, and foundation designs.
Researchers developed the LandBOSSE tool with funding provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy’s Wind Energy Technologies Office. The research team also partnered with several industry leaders, including Mortenson, RES, Wind Tower Technologies, and Apex, who reviewed the model and supported its validation efforts. The LandBOSSE model is also currently being integrated into NREL’s Wind-Plant Integrated System Design and Engineering Model (WISDEM) and NREL’s System Advisor Model (SAM) to improve accessibility and connectivity of the model with other NREL tools.