FReePA (Fixed Reference Point Absorber) - SPOWC (Solar Photovoltaic Oscillating Water Column)

Blue energy is meant to be an important industry to support decarbonization and to reach the sustainable development goals of Agenda 2030. The MOREnergy Lab (http://www.morenergylab.polito.it/) and W4E (https://www.waveforenergy.com/) team have a keen interest in sustainability and are endowed with long experience in the blue energy field. In particular, through oceanographic, mechanical, and economic analyses, several innovative devices able to obtain energy from the wave and offshore wind have been successfully developed. The pilot version of one of these devices, called ISWEC (Inertial Sea Wave Energy Converter), was deployed for the first time off the North coast of Pantelleria in 2015 and has been continuously operating near Ravenna in the Adriatic Sea since 2019. Another device, called WEPA (Water & energy Point Absorber) is going to be installed near Porto Conte, in Sardinia. The achievement of these goals has been possible thanks to the team's twenty years of experience and to the collaboration with ENI and FINCANTIERI. The team also has an interest in all aspects of sustainability and can provide support in implementing decarbonization strategies. Indeed, the MOREnergy Lab has contributed to the drafting of the transition agenda for the island of Pantelleria and is currently providing a similar support to the islands of Carloforte and Favignana. Finally, the team believes that community involvement is crucial and plays a key role in the future roadmap for reducing environmental impact. Therefore, the MOREnergy Lab has begun an outreach campaign to spread awareness of environmental and energy issues in all their aspects.

The team has developed a keen eye for the transition and decarbonization through the utilization of offshore renewable energy sources. From the first full-scale prototype developed in Pantelleria to decarbonize the island, the team has started a collaboration with ENI in order to decarbonize and power the offshore platforms from natural gas to wave power and solar photovoltaic. Every location has its own energy resource therefore the team is always proactive to find a solution that suits the need of the specific energy demand and the availability of power.

The team proposes to analyze the availability of renewable energy sources with modeling techniques and an on-field measurement instrument (weather station, floating or fixed mast, etc.).

Based on these activities, it is important to elaborate preliminary techno-economic feasibility analysis that takes into consideration renewable energy systems plants and storage plants.

In parallel, it is important to involve in an open discussion all the main stakeholders, like local administration, protected areas administration, touristic operators, economic operators, citizens, and so on, to have a comprehensive understanding of the context in which blue energy projects are planned.

The objective is to define a strategic plan for:

-         Defining future energy scenarios

-         Design development and definition of the optimal Wave Energy Converters (WEC) device

-         Evaluating risks and vulnerabilities

-         Defining mitigation actions.

In particular, the team has all the knowledge and skills necessary to go from preliminary design to installation, that is:

-         Seabed characteristics evaluation to choose the most suitable mooring type

-         Bathymetric trend analysis to identify the mostly flat area

-         Intervisibility analysis to assess the possible visual impact of the device

-         Wave and wind detailed assessment through numerical models able to reproduce the propagation of the waves and the wind

-         Wave and wind statistical analysis to identify the main project parameters

-        Choice of the most appropriate WEC and then optimization of the chosen device, to adapt its shape and its operation to the wave characteristics

At the same time, the aspect related to the choice of material is taken into consideration, in particular materials with the following characteristics are preferred:

-         Short supply chain

-         Low environmental impact

-         Possibility of disassembly, reuse, and recycling

-         Resistance to aggressive materials

Two main ideas have been identified to be appropriate to address the challenge:

-         Fixed Reference (FreePA)

-         Solar photovoltaic and Oscillating Water Column (SPOWC)

The Fix-Referenced Point Absorber (FReePa) is a point absorber directly installed on infrastructure already available in harbors areas.

The device extracts energy from the wave power using floaters that moves up and down accordingly with the wave motion. The floaters are equally spaced and oriented with the dominant wave direction, they are connected to the infrastructures through rigid arms which transmit the mechanical power to the power take-off (PTO) system, converting the mechanical energy into electricity.

Compared with other analogous devices, we propose a solution with the following innovations and competitive advantages:

-         Optimized superstructure: the device needs to be installed on a pre-existing structure. However, to reduce costs and maximize repeatability, it is convenient to design the superstructure to be easily installed on a diverse range of supports. This is also mostly realized with off-the-shelf components and standard installation routines

-         Adaptability: waves are, by nature, irregular and variable on different time scales (seconds, hours, days, seasons, and years). Therefore, to extract the highest amount of energy, the system must be adaptable to the operating conditions, throughout the whole useful life. This is achieved by including ad-hoc adapting elements in the superstructure and a variable ballast system in the floaters, as well as an advanced energy-maximization control strategy for the power take-off control, to vary at will the dynamic properties of the system to best match the resource

Wave energy is abundant, especially offshore, but major difficulties come from large water depths and distance from shore, which make, mooring and electric cable costs increase significantly. Similarly, offshore installations have low accessibility, increasing maintenance costs and reducing availability (number of working days per year). A convenient solution is to install wave energy converters directly onshore, which leads to the following main advantages:

-         Cost-sharing: the device can be installed directly on existing structures, significantly reducing the investment amount required

-         Highly accessible for maintenance

-         Survivability mode: when harsh conditions are foreseen, the floater can be readily removed from the water, avoiding critical damages

Solar Photovoltaic and Oscillating Water Column (SPOWC) is conceived as a floater consisting of a deck with an equilateral triangular shape connected to three partly submerged cylinders. The large deck surface provides the space for PV panels and wind turbine installation, while the submerged cylinders are oscillating water column devices.

The oscillating water column devices are allocated in the three cylinders are characterized by the presence of an air chamber. In particular, when the air in the chamber is compressed by the rising level of the water, due to the waves, the swelling of the water forces the air through an air turbine in order to create electricity.

Wave energy is abundant, especially offshore, and a combination with other renewable energy sources has the advantage of capturing also wind energy as well as solar energy. In addition, the energy mix reduces the problems of renewable energy variability. The SPOWC solution is based on the integration of different existing technologies in a single device capable of operating independently.

The innovation of SPOWC lies in the coupling and optimization of the individual components to maximize productivity and reduce costs and impacts. In particular:

-         Adaptability: devices capable of converting energy from both sea, wind, and sun allows to acquire energy in a multitude of situations. In particular, such a device is able to adapt to external conditions by providing energy in the absence of waves but in the presence of wind and/or sun

-         Negligible environmental impact: They present low environmental impact considering the careful selection of the materials and their possible recycling. Moreover, the mooring of the devices does not alter the seabed condition and fish activities

Cost-sharing: the WEC, PV, and wind turbine are coupled in the same device, and this significantly reduces the investment amount required

The team's expertise also concerns the optimization of devices. This activity is important since the optimal device shape can be defined according to the specific site of interest to obtain the maximum return. Therefore, the shape and properties of the device are optimized through advanced genetic algorithms based on evolutionary theory, achieving the best compromise between cost and performance. In particular, operating on the device sizes according to the most occurrences waves, it is possible to increase the extraction potential.

A preliminary analysis of the wind and wave resources has already been performed, as shown in the following wind rose plot and wave occurrence scatter diagram, respectively, taking into account 6 years of data, from 2015 to 2020. The site characteristics will be used for the optimal design of the wave energy converter.

Overall, each designed device has the following characteristics:

-         Low or near-zero environmental impact

-         Scalability, so that the power extracted can be varied as needed

-         Modularity, so it can progressively become an array according to the electrical demand

-         Versatility and adaptability according to different contexts and sea states

-         Easiness and practicality access to the mechanical part, to facilitate the maintenance phases

-         Safety towards ships, through appropriate radar and light signals

-         Power immediately provided to the grid, also including power conditioning directly onshore without bulk constraints

These direct benefits lead, moreover, to a series of indirect benefits, but very attractive:

-         Lower energy costs

-         Energy independence, especially for small islands

-         Strong media impact for the local community, gaining in terms of image and tourism promotion

-         Development and increase in employment, using local companies and workers

MOREnergy Lab @Polito

The Marine Offshore Renewable Energy Lab (MORE) research center is based at Politecnico di Torino and represents the result of the experience gained by Politecnico in the marine energy field. The Team is highly multidisciplinary and enumerates more than 50 members between permanent and temporary researchers, PhD students and research fellows that constitute the propulsive core of the Centre. The MOREnergy Lab main activities focus on the developments of analysis methods, design, and test of marine energy powerplants technologies with activities focused on design, numerical modeling, control systems development, tests both in Tanks and in Open Sea.

http://www.morenergylab.polito.it/ 

 

Wave for Energy (W4E) 

W4E is a dynamic young spinoff company (from MOREnergy Lab), born upon several years of research and studies on mechanics and waves interactions. The company has completed the technology transfer of a wave energy converter, named ISWEC, moving from the laboratory of the Politecnico di Torino (TRL 3) to designing, constructing, installing, and operating two full-scale devices in the open sea (TRL 6) and up to licensing the technology to the global energy player, Eni Spa. The team includes 11 people of staff with expertise in mechanical, electrical, mooring and control design, project management, and offshore operations. On top of the technical know-how, W4E can bring to the table also market and technology transfer capabilities, as also demonstrated by a current collaboration with the European Space Agency, for the completion of a feasibility study of the application of space-based assets to the ocean energy industry, and with the public administration of the Parco Speciale di Porto Conte, for the development of an ad-hoc wave energy converter for desalination and electricity generation needs. 

https://www.waveforenergy.com/

 

The two groups have collaborated since 2010 in several projects, both at local, regional, national, European, and international levels. The activities carried over at Pantelleria where the integrated team has developed a test site where the first ISWEC wave energy converter has been installed is a key example of the capability of the group in a relevant context for the activities hereby proposed.