Revamped PEWEC wave device shaping up as ‘the clean power solution’ for small Mediterranean islands

The new and improved version of PEWEC (Pendulum Wave Energy Converter), being developed by Italy’s national agency ENEA and Polytechnic University of Turin, could prove to be an ideal solution for small and medium-sized islands across the Mediterranean as they transition to net-zero future.

Italy’s National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) and Polytechnic University of Turin (PoliTO) have developed PEWEC 2.0 device, designed for the Mediterranean Sea with small height and high frequency waves.

The low-cost system of energy production from the sea is particularly interesting for many small Italian islands that are not self-sufficient in terms of energy, and where the supply of electricity is secured by expensive and polluting diesel-fueled power stations, according to ENEA.

The new floating system, similar to a semicircular hull positioned in the open sea, is capable of producing electricity by exploiting the oscillation of the device in accordance with the waves.

“PEWEC 2.0 has some technological improvements over the previous version. A 1:25 scale prototype was tested at the Naval Tank of the Federico II at the University of Naples to study the response of the hull and moorings to extreme waves.

“We exposed the hi-tech device to a series of particularly high waves, both regular and irregular, artificially generated within the test basin, to highlight an excellent holding capacity and electrical production of the system even in extreme conditions.

“These types of tests are essential to evaluate the performance and resistance of the converters even in critical situations like in storm waves,” explained Gianmaria Sannino, head of the ENEA’s laboratory for climate modeling and impacts.

ENEA and PoliTO are now working on the development of the preliminary project, where the full-scale PEWEC device will be installed along the ‘most energetic’ coasts of the Mediterranean, such as the west coast of Sardinia and the Strait of Sicily.

The 525kW device will be 15 meters long, 23 meters wide and 7.5 meters high, including the ballast weight of over 1,000 tons.

The team of researchers is also studying the cost reduction pathways for the device and optimization of energy conversion efficiency through the adoption of low-cost materials and the integration of photovoltaic panels.

This will ensure a reduction in the cost of energy, making the device competitive with other more mature renewable technologies, the developers claim.

“The PoliTO Lab team has developed advanced numerical codes for the development of the technology and the prediction of the manufacturability of the PEWEC device.

“Genetic optimization codes, based on the Darwinian concept of natural selection, were adopted to reduce the energy cost of the device. The experimental tests carried out at the Naples Naval Basin were fundamental to demonstrate and validate the promising numerical results,” said Giuliana Mattiazzo, head of the Marine Offshore Renewable Energy Lab (MORE) research center at PoliTO.

The installation of the PEWEC can completely satisfy the energy needs of small and medium-sized islands that base their energy supply on fossil fuel sources, according to ENEA.

These technologies can be implemented not only in the supply of electricity for domestic or civil uses, but also for industrial uses as well, starting with aquaculture, the agency notes.

“To estimate the potential market in the Mediterranean basin, we start from these data: in our country there are more than 50 smaller islands with an average population of about 2,500 inhabitants, an average per capita consumption of 6 kWh/g and an energy cost very high.

“A dozen of these devices could produce electricity for a country of 3,000 inhabitants, significantly contributing to counteracting pollution and erosion by reducing the energy of the waves that break on the coast, without significantly impacting flora and marine fauna,” concluded Sannino.