ITALY
TECHNOLOGY DEMONSTRATION
OPERATIONAL PROJECTS
GEM project
GEM, the Ocean’s kite, has been patented and the concept consists of a submerged floating body linked to the seabed by means of a tether. The main hull houses electrical equipment and auxiliary systems. Two turbines are installed outside the floating body and are exposed to the external currents. Due to a relatively safe and easy self-orienting behaviour, GEM, The Ocean’s Kite, is a good candidate to solve some problems involved with oscillating and reversing streams, typical of tidal current. An additional advantage of its configuration is related to the possibility of avoiding the use of expensive submarine foundations on the seabed, because these are replaced with a flexible cable connected to a single mooring point. Releasing the anchorage cable allows the system to pop-up for easy maintenance. A special diffuser (shroud) has been designed to double the output power keeping the blade length small.
After several numerical investigations, a series of experimental tests on two different scaled models has been carried out in the towing tank of the Department of Industrial Engineering at the University of Naples. The models tested were completely instrumented so that a dynamic behaviour and the off-nominal working conditions were investigated. The real scale prototype system of 100 kW, with 5 knots of water current speed, has been built and has been deployed nearby Venice in a very slow speed current of about 3 knots downscaling the power to 20 kW. This prototype has been built by a consortium of Venetian companies thanks also to a financial contribution of Veneto Regional Authority. The real field tests have demonstrated the fully correspondence of the system behaviour with respect to what had already been measured on the 1:5 model during the test campaign in the naval towing tank. A full scale prototype of 200 kW at 2.5 m/s water current speed is being designed and will be deployed in the Strait of Messina to definitively assess all the performances of the system.
THE KOBOLD TURBINE
The “Kobold Turbine” has been developed since 1998 by ADAG Group of the Department of Industrial Engineering, University of Naples “Federico II”, in collaboration with “Ponte di Archimede international Spa”, a company that works in the field of research and development into alternative and renewable energy sources, specialising in the environmental aspects of this work. The Kobold consists of a submerged vertical-axis turbine for exploitation of marine currents, installed in the Strait of Messina, 150 metres off the coast of Ganzirri since 2002. The realization of the Enermar prototype has been financed by Ponte di Archimede Company, together with a 50% fund paid by the Sicilian Region Administration (Regione Siciliana), in the framework of European Union Structural Funds. This project has been disseminated among the developing countries in which the United Nations Industrial Development Organization (UNIDO) operates and the first three countries that expressed interest were the People’s Republic of China, the Philippines, and Indonesia.
A joint-venture was created, under the auspices of UNIDO, between “Ponte di Archimede” and the Indonesian Walinusa Energy Corporation.
A prototype is being built and will placed on the Lomboc Island (the island immediately at east of Bali), where it could feed energy to a small village. The Indonesian plant will have blades length 7 m (chord 0,4 m), and diameter 5 m (intercepted area 35 m2). The power could be about 120-150 kW. The Ponte di Archimede company has now transferred its assets to the Horcynus Orca Foundation with the aim to leverage on the experiences gained with Kobold and the local workforce in the area to create a centre of excellence in the marine energy space.
40SOUTH PROJECT
Enel Green Power (EGP) has bought the H24 wave energy device from the Italian company 40South Energy. H24 represents the first EGP’s wave energy harvesting device as the company lays the groundwork for the development of a new technological line with ‘huge potential’. The 50 kW H24 machine was deployed as part of Marina di Pisa project off Tuscany, Italy. It consists of a guiding part located on the sea floor, or on a support structure, and of a moving part above it, which moves according to waves. H24 device can behave as both a tidal and wave energy generating unit, but for this particular project it will harness the energy of the waves to produce electricity.
ISWEC PROJECT
Sea waves are one of the most interesting and well distributed renewable energy sources in the world. At the current state of the art, all the existing sea wave energy conversion systems are designed to operate offshore, mainly in the oceans where the waves’ height is definitely high. In the Mediterranean Sea, waves are generally low, except under particular meteorological conditions. Thus, it is necessary to develop devices that can exploit other properties of the waves instead of their height, like wave slopes. The mechanical conversion system, called ISWEC, that will be used for the development of the project has been analysed by Politecnico di Torino and results show that the system possesses good potential for energy conversion. ISWEC device is composed mainly of a floating body with a slack mooring to the
seabed. The waves tilt the buoy with a rocking motion that is transmitted to the gyroscopic system inside the buoy. The gyroscopic system is composed of a spinning flywheel carried on a platform.
Trials at various levels have been carried out: in the first phase, a set of “dry tests” has been done on a controlled position mobile platform; in the second phase, a series of tests have been performed in the INSEAN wave tank, with suitably generated and controlled waves. Finally, the system has been placed and tested on Pantelleria Island for the real sea tests. Further tests will be carried out in order to develop and tune optimized control algorithms. In August 2015, the first ISWEC 1:1 scale device has been moored 800 m from the coast of Pantelleria Island in a water depth of 35 m.
REWEC PROJECT
Among the wave energy converters, the Oscillating Water Column (OWC) system is the most widespread: such system consists of an air chamber with a seawater inlet and an air discharger. If seawater moves as a result of the vertical motion of external waves, then the seawater within the OWC moves as well. This movement within the system generates air pressure, which produces power to turn the turbine in the air discharge port. In this light, EGP is evaluating a particular onshore OWC system to test together with a Reggio Calabria University Spin-off, Wavenergy in Central Italy; the system is called REWEC (Resonant Wave Energy Converter), already built in Civitavecchia Port.
PLANNED DEPLOYMENTS
Umbra aims to deploy two temporary installations of a point-pivoted WEC buoy within two R&D projects: in 2017, the components will be prepared and 2018 will see the deployment in the Mediterranean sea of a 60 kW unit and of a 90 kW device on Orkney Islands. In early 2016, Umbra has started collaboration with the French start-up EEL Energy (http://www.eel-energy.fr/en). This company has been developing an original tidal energy device that consists in a flexible membrane which, actuated by tidal currents, oscillates longitudinally with respect to the current direction. The oscillations are damped by several EMGs placed on the membrane backbone.
A small scale device prototype, featuring six 2 kW EMGs, has already undertaken two laboratory test campaigns at IFREMER (http://wwz.ifremer.fr/institut_eng/) that have shown very promising results; further test campaigns are scheduled for 2017. Umbra and EEL Energy are now preparing a second prototype version that will undergo sea trials in 2017- 2018. A first test in real environment is planned for October at SEENEOH (http://seeneoh.com/), in Bordeaux. The final goal is to deploy a 1 MW prototype by 2019-2020, thanks to the support of 3.7 million received from the French Programme d’Investissement d’Avenir (PIA - Future Investment Programme) and future European Union (EU) funding.
After the deployment of the first ISWEC device, W4E is planning to install a second Gyro, doubling the amount of energy from the sea.
