Andreas Makris is a research engineer working for CRES, Greece’s national Centre for Renewable Energy Sources and Saving. The country is considered to be ideal for the exploitation and use of renewable sources of energy due to its climate and weather. Many analysts say that these sources could be an answer to the economic crisis.
To what extent can renewables be a way out of the Greek crisis?
It is true that Greece has a high wind and solar potential. However the installation of power plants is not enough on its own. A more attractive tax system and an energy policy that favours renewable energy installation and production could be of interest for potential investors.
Investing in local production units could help reduce the unemployment rate and encourage economic growth.
One of your research areas focuses on new technologies in the wind energy sector. You’re collaborating with the international project Windtrust, which aims to reduce the cost of wind energy generation. What are your main findings?
We are analysing technologies that deliver solutions with a high level of technological readiness. The aim is to further improve the reliability of key turbine components. These include a new erosion protection system for the blades and a more reliable power module which will reduce operational and maintenance costs. It is these costs that make energy more expensive, especially for offshore wind farms.
The project is also investigating the use of new hybrid blades, which are essential if they are to have increased rotor diameters, as required by offshore multi-megawatt turbines.
Our main contribution involves assessing how cost effective the innovations are, and we use the Levelised Cost of Electricity (LCOE) as a key performance indicator. The total reduction of the wind energy LCOE at the studied wind turbine scale, such as 2MW wind turbines and 60MW wind farm, could theoretically range between 14% and 22%.
From the first results, these innovations are expected to have a much greater effect on wind turbines of larger capacity, and even greater still on offshore developments.
Offshore (the book) installation is considered to be expensive. In the U.S. the Department of Energy (DOE) is even financing the design of gigantic blades longer than two football fields, in a bid to make wind energy affordable…
The general approach to reducing the price of offshore wind energy is to make bigger machines; the U.S. Department of Energy’s goal is 50MW. And another current offshore technology project – Innwind.EU – is assessing the feasibility of producing 20MW devices.
However, the cost of constructing and operating such enormous machines remains unknown, as does the level of reliability.
Can you describe the different scenarios and locations that you have studied and tested, which are representative of the variety of climatic conditions?
The solutions developed in our project have been implemented in a wide range of terrains across Europe and proved profitable in various climatic conditions.
Our studies consider complex terrains, which often occur in Southern Europe, Mexico, China, India. We study wind farms with total rated power of 30 to 60MW. The rated unitary power of the installed wind turbines is also a parameter and can vary from 1.5 to 3 MW.
These machines often face a wide range of temperatures, from freezing during winter to 40° during summer. We expect LCOE to be greatly reduced thanks to a new control system, using new algorithms which will optimise the performance of the wind turbine. We are also studying 100MW offshore wind farms, comprising turbines with a rated power of 5 to 10MW.
The offshore farms face additional erosion problems due to the salt water. Here we expect LCOE to be reduced mainly by the lower maintenance costs, thanks to the improved blade erosion protection and the better, more weather-resistant, power converter modules.
The cost benefits of the innovations for offshore developments in the North Sea are also being examined.
Finally, we are analysing flat terrains such as in Netherlands, Germany or Belgium. The example is a 30MW wind farm using 3MW rated power turbines, very close to an urban area.
By bringing the noise level under the authorised limit more machines can be installed or the authorised blade tip speeds can be increased.
Replication of these innovations is still being studied but we expect to be able to come to some solid conclusions.
How close to production are these new technologies?
Before the end of the project, in September 2016, final testing and validation will take place, with the designs being incorporated into a 2MW onshore turbine at a facility in Spain. Following successful validation of the proposals, the industrial partners will be ready to implement the solutions in mass production.
By Elias Aggelopoulos
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