Supplying small islands with a stable and affordable energy is always a challenge. Malta, a densely populated island nation with high energy demand and limited land area, may need to turn to the sea for alternatives.
The sea off northwest Gozo shows good potential for generating energy from waves
Space as a marine resource is almost unlimited offshore and the potential for generating energy by far exceeds our demand.
At this year’s Institute for Sustainable Energy annual conference there was much interest in the potential of energy generation from the natural resources of wind and waves.
Just as fine-tuning research on land-based photovoltaic panels continues and energy-saving devices to regulate voltage are on the increase, attention is turning seaward.
Anthony Rizzo, a former Water Services Corporation CEO, said this was the last time that the Malta Resources Authority (MRA) would be reviewing the island’s energy policy and its role as regulator would be strengthened now that there was a clear demarcation between the policy arm and the ministry.
Regarding the energy market, which was liberalised in 2007, but which is still awaiting legal notices to be amended to allow full regulation, the authority has some work to do, especially in relation to the collection of gas cylinders. Another issue is that of petrol stations that do not source their fuel supplies from Enemalta but opt for a different supplier with possible variation in standards, although nearly all are now compliant.
The emergence of vertical solar heating systems for apartment blocks designed to operate at angles from vertical to 60 degrees is an encouraging step forward.
The institute’s courses are now also being offered by video conferencing at the University Gozo Centre. ISE training courses include single- and three-phase photovoltaic (PV) installation, in line with an EU directive.
The institute also offers a techical service to the public. Inspections of installed equipment allows owners to address calls for improvements in performance to suppliers. It also holds information sessions for potential buyers of solar heating systems.
A Malta Council for Science and Technology (MCST) project looked at energy use in vineyards, with the local project partner researching the use of solar energy for cooling systems at the Buskett wine research centre.
An action plan is about to be published following a five-year project on renewable energy scenarios in islands between Italy and Malta. Students on a visit to the Marsascala biogas plant identified further potential to generate hydropower at the site.
A project out of the European Awareness Scenario workshop has linked the University and MRA with partners in Sicily. A renewable energy atlas is being created for each of the two islands, showing how much clean energy has been generated, with contact details to allow experiences to be shared. Ten installation sites demonstrating best practice will be featured in the Malta atlas and 20 renewable energy sites in Agrigento and Ragusa.
Variety within the PV category (roof-based, ground-based, solar parks) is also being studied. The province of Ragusa has come up with an interesting new carbon capture technique capturing used gas from the oil industry.
With seawater confirmed by studies as a valid working fluid, the use of water from the sea as a coolant for air conditioners is also being looked at.
EU funding for a floating wind farm project by a Swedish company in waters off Malta ran aground last year over technical issues. The NER 300 project was financially unclear. A floating deep water installation promoted during the previous administration, it had the disadvantage of being an unproven technology lacking wind tests or prototypes. Next month another call for applications on floating wind farms will be issued.
At this point, the main barrier to offshore wind energy development in Malta is the supporting structure. New designs for a deep water supporting structure for offshore wind turbines at 70 metres depth, optimised for Mediterranean weather conditions, is the aim of an ongoing project between MCST and the University. The southeastern area off Malta was found to be a more favourable environment even if wind speeds are less.
A 350-megawatt wind farm in the southeast offshore zone would contribute around 16 per cent of total energy consumption in 2020. This is greater than the total PV potential offered by rooftops of buildings.
The sea off northwest Gozo, with maximum wave height exceeding seven metres, shows good potential for generating energy from waves. Wave studies first appeared in a pre-accession report by Scott Wilson at a time when Malta’s energy options were being weighed up.
Since then, the University’s Physical Oceanography Unit has been working on computer-based wave models and recently collected field data on waves as part of the MCST-funded Blue Ocean Energy project funded. This study has set the basis for understanding the sea wave conditions around Malta and estimating the wave energy resource, providing the baseline information to potential projects for feasibility assessments and the identification of the best sites for energy extraction.
According to study coordinator Aldo Drago, with the right energy extraction technology, wave energy can be considered as a supplementary source of renewable energy. Even though there is strong seasonal and inter-annual variability, the average annual wave power is still useful and comparable to the resource in the North Sea, where wave extraction projects are already in action.
Possibly the most useful and efficient application of wave energy could be using it directly to generate pressure (rather than convert wave power to electricity) to pump water at reverse osmosis plants. A search for funding to investigate this simple but practical concept is under way.
Finding space on land for a one-megawatt installation the size of three football fields would be a huge obstacle – but not at sea. Another interesting project investigates floating PV panels.
Regarding the development of a hollow concrete block with improved insulation in the light of building energy directive requirements, engineer Charles Yousif concluded: “We know there is really no way out except to change our traditional building methods.”
To make for the smoothest transition, the new bricks are identical in size and shape to normal building bricks and no added training is needed for builders.
Other presentations at the conference covered a study on increasing output of PV modules by reflectors, and a hydraulic offshore wind turbine combined with a pumped water storage facility. In situations where demand and supply are mismatched, this technology is already being used to increase wind energy penetration, especially in small grids.
Closing the conference, ISE chairman Tonio Sant said that deep water technology is developing rapidly and was expected to be more cost competitive.
“It is crucial that Malta starts working seriously on a marine spatial plan, identify the most suitable site, taking into account planning and technical issues and constraints,” he said, calling for a full review of the national energy plan. The path to a climate-resilient economy needs to reflect present realities.