https://www.um.edu.mt/library/oar/handle/123456789/1438 2026-04-26T08:20:15Z 2026-04-26T08:20:15Z Aquilina, Matteo Sant, Tonio Farrugia, Robert N. https://www.um.edu.mt/library/oar/handle/123456789/23006 2017-12-11T12:18:17Z 2014-01-01T00:00:00Z

Title: Cost modelling of floating wind farms with upscaled rotors in Maltese waters Authors: Aquilina, Matteo; Sant, Tonio; Farrugia, Robert N. Abstract: The technical viability of offshore wind projects depends upon a number of factors such as the site-specific wind resource, sea depth, seabed composition, distance to the shore and climatic conditions amongst others. The Mediterranean is characterised by deep seas relatively close to the shore and only a reasonable wind climate if compared to conditions in countries that are forerunners in the offshore wind sector. The development of floating wind turbine support structures will allow wind farms in deeper waters and will be a catalyst for the wider diffusion and larger-scale implementation of offshore wind farms on a global level. This study investigates the prospects for a hypothetical 100 MW floating offshore wind farm well to the west of the island of Malta. The study models three upscaled turbines having rotor diameters of 126, 145 and 170 m. The study shows that the rotor upscaling process can improve the economic viability of offshore wind turbines with the improved energy yield counterbalancing the higher investment costs required for such a project and thus resulting in a lower cost of energy. The levelised cost of electricity is estimated to be in the 21.0 to 23.6 €cent/kWh range which, although still well above the current market prices of electricity generated by conventional means, is expected to drop considerably over the coming years as new international players enter the offshore wind market. Increasing levels of competition, new concepts coming to fruition and wider and larger-scale diffusion of new technologies will help bring down costs of energy for the offshore wind farms of the future.

2014-01-01T00:00:00Z Vassallo, Emanuel Mule’ Stagno, Luciano https://www.um.edu.mt/library/oar/handle/123456789/23005 2023-02-13T08:49:43Z 2014-01-01T00:00:00Z

Title: Assessing the design options for the optimisation of a 2MWp ground mounted PV system in Malta Authors: Vassallo, Emanuel; Mule’ Stagno, Luciano Abstract: The objective of large scale PV installations in space constrained countries has gradually shifted from production maximisation to that of reaching an optimised economic performance. The main reason for this is the ever decreasing price of the modules. This has resulted in systems with lower tilt angles, increased mutual shading and overloading of inverters by design, in the continuous quest of balancing reduced yield with development costs over the entire lifespan of the project. This approach has shifted the traditional view of evaluating a PV installation from a Euro/watt approach to the use of optimisation metrics such the Levelised Cost Of Electricity (LCOE) or Internal Rate of Return (IRR). Optimisation can be simply described as a balancing act, evaluating tradeoffs to assess which combination gives the best economic performance. By its very nature, optimisation is an iterative process. This paper evaluates a number of design parameters which, together with production modelling within the context of the Maltese solar climate, aims at identifying an optimum design for the building of a 2MWp ground mounted PV installation. Among the issues considered are; layout optimisation with issues of tilt, cross shading and cabling options, and inverter architecture whether string or central including dc-to-ac rating.

2014-01-01T00:00:00Z Muenchrath, Janis Weissenbacher, Manfred https://www.um.edu.mt/library/oar/handle/123456789/23004 2017-10-26T01:34:15Z 2014-01-01T00:00:00Z

Title: From oil to gas : an analysis of Malta’s power sector transition with regard to CO2 emissions, the integration of renewables, and the role of energy storage Authors: Muenchrath, Janis; Weissenbacher, Manfred Abstract: Malta’s electricity generation is based on heavy fuel oil and gas oil. However, profound changes are underway as the power sector is being shifted to natural gas and an HVAC interconnector to Sicily will connect the hitherto isolated Maltese electricity grid to Europe. Within this study projections for supply and demand have been compared, and the power sector transition has been reviewed with respect to carbon dioxide emissions and economic impact. The latter included a review of Sicilian electricity prices to investigate opportunities of electricity trade through the interconnector. A model has been built to compare various scenarios of electricity generation and import/export levels for different years. While the Maltese power sector transition will reduce overall national carbon dioxide emissions below 1990 levels, achieving high renewable energy shares will be challenging. Though Malta has managed to reach the two percent intermediate renewables share target for 2012, the national renewable energy action plan needs to be revised, in part due to the impact of the new fossil fuel setup. In turn, energy storage options might facility the way towards the further rise and integration of renewable energy integration. The modelling results indicated that investment into storage rather than generation capacity might be the better option once the older generation capacity at Delimara power station will retire. Seawater pumped hydro storage and ocean compressed air energy storage have been identified as two of the options that would fit Maltese settings.

2014-01-01T00:00:00Z Caruana, Caroline Yousif, Charles https://www.um.edu.mt/library/oar/handle/123456789/23003 2017-10-26T01:34:17Z 2014-01-01T00:00:00Z

Title: Heat transfer characteristics of locally manufactured hollow concrete blocks Authors: Caruana, Caroline; Yousif, Charles Abstract: The paper is focused on the investigation of the thermal properties of traditional local building blocks with the aim of understanding its resistance to the transfer of heat. The building blocks under test shall be hollow concrete blocks (HCBs) manufactured by a local company. The hot box method technique shall be applied to obtain values of the thermal conductivity of the respective HCBs being tested. Dimensions and weight of these blocks shall be recorded and compression testing carried out. The correlation between thermal conductivities and compression strength shall provide useful information on the thermo-physical behaviour of these building elements. The first part of this paper reports on the actual setup of the hot box. It is then followed by the description of the testing methodology adopted and calculations applied to obtain values for comparisons between the different HCBs tested. The final part of the paper is then focused on the discussion of results and the ultimate conclusions. The aim is to succeed in obtaining a correlation between U-values of existing local HCBs, their density and compressive strength, which will enable future extrapolation of results, based on simple measurements such as density.

2014-01-01T00:00:00Z