Windoor, the sustainable wind tunnel

April 23, 2019 08:08



Our core business, providing our customers and users with a unique flying experience, involves a considerable amount of electrical energy. On first sight this may seem to be inconsistent with the environmental awareness of the group’s staff, managers and investors, those of whom, to a large extent, are great fans of outdoor sports and, therefore, have a great respect for nature.

Our tunnel consumes between 500 and 1,200 kW per hour, depending on the speed at which users fly at any point in time. Our hourly occupancy is very high so, as you can imagine, annual consumption figures in terms of MWh are considerable. To give you an idea, the monthly consumption of facilities such as Barcelona’s Camp Nou is small in comparison.

So, what can we do to make our activity more sustainable?

Firstly, to opt for an efficient design, which has already been done at both our Empuriabrava tunnel and the one soon to be opened in Barcelona. The choice of tunnel technology (a closed-loop tunnel to take advantage of the inertia of the already accelerated air) and its characteristics (size, construction, cooling system) already puts us in an advantageous position in terms of electricity consumption compared to other European tunnels.

But now that we're consuming, what alternatives do we have?

Well, the first thing to do is to consider what impact we want to have on the environment, asking ourselves how much we want to contribute to global warming. Our answer is, of course, not at all.

The only way to achieve this is to buy all our energy from a company that can guarantee that it only sells energy from renewable sources. At present we are with Bassols Energía.

And what are renewable sources? How do they contribute to Windoor being a zero-emissions company? If the current circulates through the same high-voltage power cables, how can we know that we are exclusively consuming green energy

To answer these questions – and here begins the densest and most technical part of the article – we must first
understand how electricity generation and distribution works in Spain (and the rest of Europe).

In the case of Spain, electricity generation is private. Many companies produce electricity and supply the electrical
grid, but transmission is performed by REE (Red Eléctrica de España), which boasts a website with very
interesting real-time statistics.

To fully understand this, any company with means to generate electricity can sell it by supplying the high-voltage grid. Once on the grid, the energy is distributed to the final consumers. The amount of energy produced must be in line with demand. IIf too much energy is produced, problems are generated. If too little is produced to meet demand, yet more problems are generated. Analysing said problems could take up its own separate article, so let's stick to the main idea: supply and demand must be balanced, or else there are big issues at stake.

It should also be noted that there are two types of electrical energy:

  • That which comes from renewable sources; in other words, energy that can be naturally replenished, such as wind, sun, waves or river waterfalls.
  • That which comes from non-renewable sources; in other words, energy from sources that have a limited amount of resources: chiefly oil and its derivatives and coal, as well as nuclear energy obtained by the fission of radioactive elements.

In environmental terms, energy sources can also be classified in one other way, which is very similar to the previous distinction but with certain differences, distinguishing between:

  • Energy that releases CO2 emissions into the atmosphere (and therefore causes climate change).
  • Energy that does NOT release emissions and is therefore climate-neutral.

Both classifications almost readily coincide, as renewable energy sources do not generate CO2 (except in some rare circumstances, which you can read about at the end of the article in this note) and non-renewable energy sources, as in the case of burning fossil fuels, do generate CO2, in turn, contributing towards the greenhouse effect. However, the one exception is nuclear power, which does not produce CO2. However, it does represent other types of environmental problems that may not be so pressing but are serious nonetheless, which is why, from an environmental perspective, it should be eradicated.

On any given normal day, such as Monday 1 April for example, an energy generation graph for the Iberian Peninsula would take on the following form:

On the y-axis (left) is the amount of megawatts (MW) generated, and on the X-axis (bottom) is a time line of the chosen day. Notice the coloured stripes and the kind of energy they represent. 1 April was a stable day in terms of climatology, so the green band (wind) is not excessively significant. The nuclear purple band predominates, delivering 7,080 MW continuously, and at the time at which the values are frozen, at 12.50 p.m., the yellow combined cycle stands at 8,676 MW.

If we remove all non-renewable sources from the chart, we're left with this:

Notice how disheartening it is that, on a sunny and stable spring day, the amount of renewable energy supplied to the grid to meet programmed demand is very insignificant. And if we observe the orange and red bands, which represent solar energy, the potential of the sun can also be put into context compared to other renewable  sources.

So, what do we achieve by buying our energy from companies such as BASSOLS, which only sell energy from renewable sources? (that is, the type of energy seen in the last graph). Well, the answer is simple. As environmentally-conscious consumers we have the power to decide what we do and don’t consume. If everyone were to buy green energy, we would force producers to generate more green energy. It's that simple. If the consumer demands clean energy, producers will have no choice but to research, build and generate energy  using renewable-energy power plants.

Is renewable energy more expensive? At present, yes. For big consumers such as Windoor it is a sacrifice that is only justified by a social and ecological conscience, which is part of our DNA. At Windoor we believe that pushing in the right direction is always worthwhile. Will you lend a helping hand?

Jordi Meseguer

Jordi Meseguer

Chief Technical Officer


  1. Link to the REE website. Monitoring of electricity demand (Iberian Peninsula)
  2. Note on the impact of renewable sources on CO2 levels: The burning of plants that have been planted in order to obtain energy is considered CO2 neutral. It is believed that a level of CO2 is released into the atmosphere that we have previously helped to address, so the final result is zero increase in CO2. This applies to renewable thermal energy.
  3. Just to lift your spirits a little, here you can see the same graph from 2 February 2019, the day on which the typical Tramuntana winds of the Empordà region were about to spoil the closing ceremony of The Wind Games 2019. It was a cold winter day with a lot of wind and atmospheric instability, which meant that wind energy  covered almost half of the Iberian peninsula’s electricity demand. This is the way to go!