Turbines, placed on breakwaters equipped with an oscillating water column system, combine coastal and port defense with the production of electricity by exploiting the wave motion. In the last few days of last December, two solutions configured in this way were tested by the Enermedsea company, together with Fimeco, on the pier of Marina Corta di Lipari, powering the street lamps.
The so-called 'oscillating water column' (Owc) systems are devices for the production of energy from wave motion consisting of a partially submerged concrete or steel structure, with an open chamber below the surface of the water in which the air above the water remains trapped. The oscillatory motion of the water inside the apparatus, produced by the wave motion, creates a flow of air that drives a turbine coupled to an electric generator. A simple and effective solution. The two turbines, placed on the same number of anti-bag cells on the pier, activated nine light points. The system, made specifically for the waves of the Mediterranean Sea, also triggers with low waves, guaranteeing a high efficiency of the system, which therefore results in activity for most of the day.
“We installed two turbines in Marina Corta, one 150 Watt and one 1,3 kiloWatt - explains Enermedsea project manager, Francesco La Spada - to demonstrate concretely that these turbines can start producing electricity with minimal wave motion. We currently have 5 and 7 kW turbines under construction and 10 kW turbines to be tested, for example, in one of the large OWC chambers in the port of Civitavecchia.
It is a technology that is the result of years of study and still today the object of further promising innovative developments ". The system "we called it Wels," explains the engineer, "Wave energy light system, a name that recalls that of the historic Wells air turbine for wave motion, from which it was inspired by the type of fin of this application".
La Spada underlines the importance of the agreement with the CNR and of the collaboration with Fimeco, a Messina plant engineering company, thanks to which "an important bidirectional test bench was created, unique in Italy for its characteristics - explains La Spada - in which the variation of the pressure of the oscillating flow leaving the Owc chamber can be reproduced for each site to test the turbines on the specific dynamics of the place of installation ".
In Lipari, the turbines were placed, for demonstration purposes and then dismantled, on two of the 18 small anti-tear cells of the cellular caissons of the port quay, “by using all available cells in the future, it will be possible to illuminate the entire square of Marina Corta with a only 9 kW - continues the engineer - turbines can also be applied on particular breakwaters, thus combining the need to protect the coast from storm surges with the opportunity to produce electricity from waves. We intend to present to the Municipality of Lipari a partnership proposal for the protection of the inhabited area of the Acquacalda fraction from the storms, with the construction of a 300 kW power plant ".
This coastal protection system with the production of energy from wave motion can be applied to all coastal stretches at risk of erosion, and in particular also for the protection of roads and railways. Enermedsea and Fimeco propose themselves as suppliers of engineering services, system builders and co-managers together with the customer, to offer maximum guarantees on the final result, they explain.
"We promoted an 'all-green' initiative - said Sebastiano D'Andrea, sole director of Enermedsea - to demonstrate concretely how corporate know-how can be a point of reference for all those administrations and entities that want to undertake an energy transition path, with particular attention to the smaller islands: Lipari's experience has laid the foundations for a green, or rather blue, path that we believe will be a winner for the environment and sustainable development ".
For his part, the Mayor of Lipari Marco Giorgianni says he is "happy and proud that our island has been chosen for the start, albeit still experimental, of a project as fascinating as it is innovative. My administration can only share the assumption that it is the one for which the sea is a precious resource not only from an environmental or tourist point of view, but also from an economic point of view ". Being able to exploit the potential of marine energy to illuminate the pier of Marina Corta "and, in a future that we hope is near, also all our port areas would lead to an incredible saving in costs and consumption, for a decisive improvement in the quality of life ”, Concludes the mayor.