Wind Energy in Chile

After my trip to Uruguay I’ve had the pleasure of visiting Chile, another promising destination in South America. The country enjoys a high GDP growth, with controlled inflation and a stable regulatory framework, and it’s a place where several big players are betting.

We are ending the construction of Talinay, a 90 MW EPC wind farm I’ve worked at together with my team. Initially developed with Vestas money it has recently been acquired by ENEL Green Power, a Utility that is active in the local market with several other projects such as Valle de Los Vientos. The money comes from the Denmark's Export Credit Agency and (at least as far as I know) no PPA has been signed.

This is a peculiarity of the Chilean energy market: several developers are working on projects without power purchase agreement, selling on a merchant basis at the spot price of energy (right now around 80 $/MWh).

Other financial solutions do exist: Irish developer Mainstream Renewable Power, with many active projects, is using Chinese financing and Chinese turbines (Goldwind, of course). Pattern Energy has signed a long-term power-purchase agreement (PPA) with Antofagasta Minerals (a mining company). They are not alone: copper, the commodity that is moving the whole economy, has energy intensive extraction, and this model will be probably replicated in the future.

The strong economic growth justify this approach, as the energy demand is increasing while several mega-project have been stopped due to environmental problem and lack of popular support, like the HidroAysén dam developed by ENEDSA/ENEL  in the Patagonia region.

From a construction point of view, local prices are sky high (concrete and steel sells at around 1.5 to 2 times the European price) and salaries of skilled laborers are growing unstoppably. The good news is that you don’t have to build hundreds of kilometers of high voltage lines, because due to the peculiar geography of the country the main electrical line is always nearby.

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Wind farm internal roads bends additional widening

One of the problems frequently found in wind farm project and construction is that road bends with a reduced radius often needs an additional widening to allow the passage of the trucks with the WTGs components.

Normally the biggest problems come with the blades. I suggest using a commercial software such as AutoTURN to estimate the actual additional road widening needed, because the tables provided by wind turbine manufacturers are almost invariably inaccurate and often based on wrong hypothesis.

The point is that there are too many variables to simplify the problem and give a single "one size fits all" value:

  • Angle between entry and exit tangent of the bend: the lesser the angle, the bigger the widening.
  • Bend radius:  smaller radii means greater widening.
  • Type of vehicle (number of wheels, center of turning circle, dimensions).
  • Different possible trajectories chosen by the driver.
  • Use of real wheels independent control.

Simulating software are great because they use real word data: the trucks are equipped with GPS equipment and the movements of the vehicle is registered and transformed in an algorithm that allow to replicate it in your AutoCAD project, with realistic results and cost effective solutions.

In the next image the trajectory of the different components of the truck in a bend with reduced radius are detailed. If the tractor unit follows a path in the center of the road, the rear wheels (orange lines in the drawings) will need an additional road widening both before the beginning of the bend and inside the bend.

It will also be necessary to clear an area appropriate for the transit of the blade tip (outside the bend, cyan line in the drawing) and for the truck body (inside the bend, green line in the drawing).


Figure 1: Standard wind farm internal road bend

It is also noteworthy that most of the trailers for WTGs components transportation allow orientating rear wheels independently from guiding front wheels.

For this reason, the road widening can be completely internal to the bend (using the steering control of the rear wheels) or external, sweeping the area outside the bend.

These solutions are normally more demanding in term of additional required area. They are used in situation where, due to existing constraints (buildings, structures, property boundaries, etc.) the standard widening cannot be used and a solution only inside or outside the bend must be found.

Here you have an example of a widening only in the interior side of the bend:

Figure 2: Wind farm internal road bend. Widening only in the interior.

This is a non standard solution, and as you can see it needs more space.

The third possibility is to use only the area outside the bend:

Figure 3: Wind farm internal road bend. Widening only in the exterior side.


This solution needs an enormous amount of space, and we use it only in exceptional situations.

Wind farm civil works projects: typical errors

Here you have my collection of errors I frequently see when I check wind farm project developed by external companies.

Being a quite peculiar sector is no surprise that I normally found several mistakes: here you have the most commons.


Error #1: two levels crane pad / foundation area designed without considering the slopes of the foundation pit.

Here the problem, as you can see in the transversal section, is that the slope of the foundation pit “enters” inside the crane pad and the road nearby, reducing the available space.

The only way to build something similar is with a "2 steps" constructive approach, i.e. to build the foundation, to close the hole and after to build the crane pad.

An example of this 2 steps approach can be seen in the following drawings, taken from a real wind farm. The ground was very steep, so first of all we calculated the elevation of the bottom of the foundation pit to ensure the necessary soil covering that help balancing the overturning moment. In several cases the result was that the center of the foundation was too far away from the border of the crane pad (around 16 meters), making difficult the work of the main crane (a standard distance is around 10 meters).

So we had to approximate the border of the platform to the foundation filling the area in between until the required distance is reached:


Error #2: crane pad and foundation on an embankment.

The problem here is that the foundation must be realized below the natural ground for stability reasons. Normally the depth of the bottom of the foundation pit is around 3 meters, calculated from the lowest point of the terrain around the circumference of the foundation.

But if in the project the WTG is shown on an embankment, probably the stair or even the tower door will be below ground. In the transversal section you will see clearly the problem.



Error #3: road and crane pad at different levels

Here you have a top view of a platform and the access road. Everything looks fine:

But then, when we check the longitudinal profile, we discover that the road is going down (while obviously the platform stays at the same level, 646 meters). The only way to build something like that is to use a wall to retain the earth inside the crane pad, but this is obviously not the case.

At the end of the platform, the height difference is almost 5 meters:

In the longitudinal profile above you can see the platform in yellow and the road in dark blue.


Error #4: insufficient vertical transition curve

Sometimes the Kv parameter for the vertical transition curve, defined as  is not adequate.

This happens when it’s lower than 400 – 500: in these cases, the truck can remain “stuck” because it touches below.