Economic and financial optimization of a wind park revamping: a case study

Introduction

We present an economic and financial optimization on a wind park revamping in Italy.
Wind park revamping refers to designing in the same site and with the same boundaries a new wind park that typically contains less turbines of greater power and/or bigger size and delivers approximately the same maximal power with possibly higher capacity factor. Further purpose of the revamping is to produce more energy, possibly with less environmental impact.


Approach

The optimization considers as inputs the evaluation of existing infrastructures, the wind data from the site in terms of IEC class and of productivity, and the evaluation of some different alternatives of design for the new layout. The costs associated with these alternatives are then used in a business and financial model to evaluate economic outcomes.

Main body of abstract

Some of the costs necessary to build the park have already been sustained in the old project. For this reason the plant cost and the production in a revamping can be significantly more convenient than in the old park. If we add the fact that old turbines and some infrastructure can be sold and therefore represent a value we see how evaluating a revamping is a pretty complicated matter. The optimization considers that some equipment can be preserved from the original park, as for example electric lines, roads, electric stations, even if they are old and therefore subject to higher maintenance costs. The existence of some infrastructures influences the choice of max power and therefore of turbines.
This analysis is typically performed in wind parks that were built 10 or more years ago, and for this reason are frequently windier than sites that are under development from greenfield. For this reason in the wind assessment we analyze different layouts and turbines in order to achieve the best economic result and understand what differs from the case of a new park.


Conclusion

Final scope of the work is calculate a new internal rate of return (IRR) and a cost for the energy. It will be shown that a revamping can lead to costs of energy that are significantly lower that in the previous plant.


Learning objectives
As a secondary result of this work, in order to take advantage of general rules that emerged from the analysis we present guidelines for the evaluation and calculation of wind park revamping.