Issue 077 Cover

Wind Turbines

By Khaled Abou Alfa • 31 of May, 2020

I can trace back my first encounter with the turbines back to my childhood. On spring weekends my dad would take us for long drives in the countryside. I distinctly remember one such trip, coming across wind turbines on the top of a hill. They waved us hello, and then goodbye, as my dad’s tank’ (a navy blue American spec Volvo) barreled down the single lane road somewhere in the south of Greece.

I would have to wait a long while to see them again. In what now seems like a completely different time (though only 6 months ago), I am on a flight heading towards Copenhagen. Sitting next to me, a young mother and her daughter. As it turns out, we had both decided to move our families to build a new future in a place neither of us had ever visited before. As the airplane made its decent into Kastrup airport we both gave a vocal gasp at seeing the wind turbines which flank the Danish coastline. Although we were heading to an old European city, the turbines transformed this perception; it felt of the future.

Persia. Sometime between 500 and 900AD, work began on one of the most significant buildings of the twenty first century. It was a long and linear structure made of mud, wood and stone. The structure was completely unassuming, save for one unique design element never seen or used anywhere in the world. Installed on top of the building, were 36 vertical windmills with a grindstone at the bottom of each. A complicated, but ingenious, manner to grind the wheat harvested from across the province.

Built on the top of a large flat plain, the position of the building was not by accident. To extract the most from the wind they positioned the building at the very centre of the storm. At the storms sting’ — Nish Toofan. Time has a way of softening the edges of everything it touches, including language. Nish Toofan became Nashtifan. A small town built around the windmills that have not stopped turning for over a thousand years.

Ali Mohammad Etebari wakes up every morning and does his rounds. Ali is part of the long lineage of caretakers that have tended to each of the 36 windmills across the centuries. It is tough, backbreaking work to preserve a tradition. Ali may be the last of his kind as he has not found takers to continue this tradition. While there is a sadness at the loss of an ancient tradition, there is also solace. Solace in the fact that the work carried out by the windmill caretakers of Nashtifan provided the necessary inspiration to the rest of the world. Inspiration to harness the power of wind.

A Modern History of Wind

While wind energy has taken slow steps forward, these steps have been purposeful. The history of modern wind energy starts in the 1890s in Denmark. Poul La Cour, began laying the foundations that would allow the small nation to establish itself as one of the world leaders in this field. In typical Scandinavian fashion he discovered that less is more; using fewer rotor blades generated more electricity.

The shape of what we understand to be a modern wind turbine came in 1956. Johannes Juul, a student of La Cour, introduced the Gedser turbine. A three bladed turbine that had emergency aerodynamic tip breaks and are still in use today.

Sadly the world lost interested in wind energy until the 1970s. The energy crisis forced nations to consider fossil fuel alternatives and become energy independent. This period saw several initiatives launched, notably NASAs Glenn Research Center in Cleveland. This led the U.S. Wind Energy Program for large horizontal-axis wind turbines. During this period, NASA worked on developing a model that took into account three-dimensional effects. This predicted stall behavior with far greater accuracy than previous methods, thus improving wind turbine performance.1.

This spirit of collaboration, to develop a 1000 year old nascent technology, spurred the first offshore wind farm in 1991. 29 years later there are over 1890 offshore wind farms worldwide and the number is set to explode over the coming years.

Current State

Incredibly, wind generation currently accounts for a mere 0.3% of all global power generation. This is a laughable amount compared to the incredible underutilised potential. A special report by the IEA, published in late 2019, commissioned a new geospatial analysis. Typically offshore wind farms are located within depths between 50-60m in depth - moving to deeper waters increases costs. This criteria is the current economical and technical limits of offshore wind turbine installations. Even with this constrained criteria, the report detailed a global capacity capable of providing twice the global energy usage today. Expanding this criteria would unlock incredible amounts of wind resources.

No other technology, available on the market today, has the soaring potential that wind has to break us free of our dependence on fossil fuels. Countries the world over have the opportunity to benefit from this technology as it is clear that the vast amount of wind resource has not been tapped. Most telling is the amount that countries depend on wind energy. According to REN21s 2019 annual report:

At least 12 countries around the world met 10% or more of their annual electricity consumption with wind energy in 2018.

The split between onshore and offshore wind farms provides some context to the sluggish uptake. While onshore wind farms are more prevalent, these are typically less efficient compared to their offshore counterparts. This is attributed to changes in wind direction and inconsistencies in wind speed (too fast or too slow). The main barriers to entry into the offshore wind market is the large capital costs necessary — a 250MW project typically costs $1 billion. It is expected that these costs will continue to fall as ever larger turbines are brought to market2.

Another factor is the expensive (and technically challenging) aspects of offshore wind turbines are the transmission assets. In the UK, these transmission assets are being required as part of the tender, which ultimately puts competitive pressure and in turn drives the overall costs down.

Innovations and the Future

Issue 027 Cover

Photo by Nicholas Doherty

Floating Foundation

In order to move further within the ocean, past the current 50-60m depth limit, new’ floating foundation technologies are being considered. These technologies are proven in the oil and gas sector, and would enable vast untapped wind resources. There are currently three main concepts:

  1. Spar-buoy
  2. Semi-submersible
  3. Tension Leg platforms

Hydrogen Production

There is still much work to be done to extract the what we need from the available wind resource that we have. To look at what we would do if we had excess energy (having covered all our needs) is a progressive move. Yet that is exactly what some nations are considering as the conversation begins to shift towards building hydrogen production facilities.

The hydrogen economy has been waiting silently on the fringes for years. Currently the purview of specialised applications, combing energy created from wind would allow cities and economies to be transformed. This would allow countries to take complete ownership of their energy needs, not beholden to geopolitics in far of lands. The exciting prospect of this combination is that technology does not need to be invented or for increased efficiencies to be achieved.

We are certainly not there yet but we could be at the start of this process around the world within a decade.

Environmental Impact & Challenges

Proving that no technology is complete, the wind generation industry does have its own dirty little secret. The existence of wind turbine blade graveyards brings into sharp question whether we are on the precipice of solving our biggest global problem while creating a whole new one. The blades are made out of resistant materials (composite carbon and glass fibres) that can withstand the harshest of elements. This means that they are extremely difficult to recycle or repurpose. So they end up in landfills (in the US) or incineration plants (in Europe).

This has been common knowledge for a long while. This research paper, published in 2009, assesses the available methods of disposal and predicts the impact (based on a 20 year life cycle) from Europe and the rest of the world. Clearly as the number of wind turbines is set to quadruple over the next 10 years, the material science needs to evolve enough to have reasonable and viable solutions to this very issue.

Wind energy is an existing technology with incredible potential that has not even begun to be realised. Targets set for 2030 and 2050 are only possible if wind technology is fully embraced by nations the world over. We have the tools at our disposal. What is missing is the political will and urgency to use them.

  1. This is captured by the Viterna Method.↩︎

  2. Capital Expenditure (CAPEX) will increase because larger turbines have construction challenges and larger foundations, however the Operational Expenditure (OPEX) will decrease (as fewer turbines need to be maintained).↩︎

The Stet newsletter explores the ideas, projects and technologies that define our built environment.