Wave energy: "There is a progression but with steps back from here and there"
20 Mar, 2009 09:13 am
With 830 km of coastline bording the country on the west and south, Portugal bets on wave power, which uses the energy in waves to produce electricity. The director of the Wave Energy Center, evaluates for us the situation of the most emblematic technology: the sea snake.
|Pelamis - Pelamis Wave Power
Prof. António Sarmento, you are the director of the Wave Energy Center in Lisboa. Portugal is ahead in the field of wave energy. What is its potential?
We estimate that it could be up to 5 000 Megawatts and that it would produce something like 20 % of our electrical energy consumption, assuming that everything goes well: that the energy is cheap and safe and that there is no significant environmental impact. All this has yet to be proven. It is in a way an optimistic scenario and results from what we estimate that can be deployed along each kilometer of Portuguese coast that can be used in the future. The benefits of this energy potential are very high but if the environmental impact turns to be higher, the cost of energy will also be higher. At this stage, it is very difficult to say what it could be. 5 000 Megawatts could be possibly the maximum.
Precisely, the first commercial wave farm opened in september 2008 off the western coast of Portugal with three Pelamis units. What is it about?
The Pelamis is one of the technologies that are being deployed. It is a floating device composed of four horizontal cylinders linked by three joints. These joints have hydraulic rams which pump high-pressure fluid through hydraulic motors. The hydraulic motors drive an electrical generator and energy is transported to land through submerged electrical cables.
The Pelamis farm opened six months ago. Today, would you say that it meets your expectations?
I do no think I can because the technology is experiencing some problems. The three machines are not offshore but are waiting in the yard to be repaired. It seems that it is not critical but nevertheless Pelamis Wave Power which produces the Pelamis estimated that it could not be safe to leave the machine offshore during the winter. At the present time, as far as I kown, the machines are not working. It might not produce as much energy as we expected. It is a technology which is for the first time in the water and it is complex. We must accept that there are some difficulties and that things do not turn well from the early phase of development. We also experienced this in the plant we had in Pico. There is a progression but with steps backs from here and there.
Finally, what is the next project to be implemented in Portugal?
I do not expect to see any wave farm in the next one or two years. My feeling is that, due to these difficulties, the deployment of other Pelamis farms will be somewhat delayed. It is not official of course. Yet, three or four technologies will be tested in the near future in Portugal at the level of prototype.
António Sarmento is an associate professor at the Department of Mechanical Engineering of the Instituto Superior Técnico (Technical University of Lisbon) and he is the director of the Wave Energy Centre since its foundation in 2003.