An area of sea where devices for harnessing energy from renewable marine sources will be set up for testing and demonstration.
These Wave Energy Converter facilities have been set up for technology demonstration purposes: in other words, to assess the viability of the technology involved and to study and improve other aspects in relation to their maintenance, behaviour in different sea conditions, mooring, etc.
In line with the description above, those who wish to install their ocean energy converters in bimep will be able to do so on a temporary basis. The converters will be moored over a series of months but never on an indefinite basis. Likewise, their primary purpose will not be to generate electricity, as these technologies are not sufficiently mature to be exploited on a commercial basis. A typical case scenario will be for a new technology to be moored in bimep over the summer months and withdrawn during the winter months. As technology develops in line with the findings from bimep, mooring periods may reach as long as 24 consecutive months.
The ocean energy converters moored in the bimep will be prototypes, sometimes even scaled-down versions of the final devices. To date, state-of-the-art equipment has 1 MW (megawatt) of total installed power. This means that at the moment, the best of these ocean energy converters is capable of generating the same amount of electricity as that required for domestic consumption in the town of Lemoiz. bimep is designed to house more than one of these devices at the same time, so if the platform were fully occupied it would be capable of generating almost the same amount of electricity as that required for domestic consumption in the Uribe Kosta association of municipalities. As these ocean energy converters are prototypes, their capacity for power generation will be relatively low compared to what can be expected when the associated technology is at a more mature stage. In any case, the mission of the bimep is not to generate electricity but R&D of technologies for harnessing ocean energy.
Each one may cost as much as several million euros as many of their component parts do not currently exist in the market or may never even have been manufactured before. This cost also includes the time spent by scientists and technicians researching into these devices, as well as the trials conducted to date to reach the prototype stage. As these prototypes are set up in bimep and progressively become commercially viable devices, their cost is expected to fall considerably.
It’s very difficult to establish a cost per kWh of electricity generated by this type of device, as maintenance needs and costs for this type of prototype technology are still largely unknown.
Further research and learning from the prototype devices installed in bimep is essential to reach a technology readiness level which will bring about a considerable reduction in the cost of the energy produced by these devices and enable them to be exploited on a commercial basis. It will be another 20 years or more before we see the first commercial ocean energy converter plants feeding the grid at a cost seen as competitive with other power generation sources. In this respect, the contribution made by the bimep will be fundamental worldwide.
The only platform similar to the bimep and which is up-and-running can be found in the UK. Even so, the bimep has a greater power capacity than the UK plant.
First and foremost, it’s a renewable source of energy, i.e. it’s non-contaminant, it doesn’t produce any greenhouse gas emissions and it’s inexhaustible. Operating at full power, the bimep would avoid the emission of 40,000 tonnes/ year of CO₂ to the atmosphere: in other words, in terms of carbon sequestration, the equivalent of 5,300 hectares of woodland. Secondly, the devices are powered by a renewable ocean resource which is free, clean, inexhaustible and available in large quantities along our coastline.
We don’t yet know the exact size of the “future users” of the platform as what will be moored to the seabed initially are prototypes. However, on the basis of current research activities, these WECs range in size from 5m in diameter (in the case of buoy-type devices) to snake-like devices around 100m long and 4m in diameter. In the freeboard (the part of the device outside of the water) is minimal in all cases, so their visual impact will be less than that of a small boat.
Various technologies are currently under development with respect to offshore wave energy conversion devices, all of which basically transform the energy generated by the movement of waves into electricity.
All technologies installed in bimep will be designed for converting ocean energy. None of the devices used on the platform will be fitted with conventional sources for generating electricity such as diesel engines, gas or steam turbines, etc. It is strictly prohibited for any of the technology-types moored to bimep seabed to be equipped with hazardous substances such as harmful chemical products, radioactive elements, explosives, etc. The devices will, in some cases, be equipped with products considered as standard on sea vessels such as hydraulic oil or batteries. However, there will be no fuel on board. Some WECs may be equipped with small wind turbines or photovoltaic panels as a back-up power supply for measurement and control equipment.
The WECs will not cause the water temperature to rise. Even if some of them are fitted with a cooling system for their machinery, it would be similar to the system used by normal boats to cool their engines.
These devices can only capture a small amount of the energy generated by a wave, around 2% of it at most, so the braking effect they have on a wave before it reaches the coast is minimal. In comparative terms, like that of a small boat anchored at the same distance from the coast.
This sea zone, or concession of public domain, is sited just off the coast of Armintza. At its nearest point, the platform is almost one mile away (1,700m) from the coast, and covers a total surface area of 5.3 km².
The area where these devices are to be moored is perfectly marked out by seven marking buoys, in compliance with all applicable national and international regulations on maritime signposting and, in any case, in accordance with the provisions of the State Ports Authority.
The proposed space to be occupied by the platform has been reduced from 8 km² to 5.3 km² to minimise any possible interference with other users of the sea. Another measure taken has been to increase the space between the concession and the coast from 700 m to 1,700 m. Furthermore, the corners of the platform have been cut back to ensure free passage to the port of Armintza, and a bigger sailing area has been provided to the north of the concession.
Though the application for the concession of public domain covers an area of 5.3 km², the surface area actually occupied will not be more than a few dozen square meters. It will, in effect, look like an area where several medium-size boats have anchored. It will, however, be necessary to prohibit all vessels and fishing gear from entering the marked out area to avoid interference with the mooring lines, which may be up to 350 m long either side of the WECs.
A series of subsea power cables transport the electricity to the onshore grid, with the landing point in the town of Lemoiz. Within the area delimited by the marking buoys, these 13.2 kV cables run along the seabed or are partially submerged.Outside of the marked-off area, the subsea cables are buried 1m under the seabed. The fact that the cables are buried should provide them with sufficient protection. However, to avoid any possible damage to the subsea cables and mooring equipment, the aim is to prohibit vessels from anchoring anywhere within 250 m of where the buried cables run outside of the bimep area itself.
The high voltage cables will not interfere in any way with the navigation or communication equipment of adjacent vessels. There have never been any reports of cables like these or of a higher voltage (such as the one connecting the peninsula with the Balearic Islands, or the one crossing the Strait of Gibraltar) having any effect on vessels.
As outlined in the examples above, the cables have no adverse effect on marine flora and fauna or on birds.
The WECs will be moored within the area marked off by the marking buoys. As a rule, devices will be moored to concrete deadmen similar to those used for mussel rafts, or using anchors similar to those used by merchant vessels. No plans are in place to use chemical anchors or any type of complicated system since the prototype devices, as mentioned previously, will only be moored at the bimep for a question of months.
bimep is expected to create around 200 jobs either directly or indirectly. Though there will be few people working full-time on the platform, the project is likely to have a considerable impact on the local shipbuilding and industrial sector, research centres and on marine-related services such as small boat repair workshops, the diving sector, etc.
For several reasons.
• The energy potential of the waves along the coastline of the Basque Country is rated as medium to high (24 kW/m), ideal for mooring prototypes. There are areas of greater energy potential (for example, along the coast of Galicia, with 55 kW/m), but in those locations, the prototype technology in question would be subject to excessively aggressive conditions for the purpose under consideration: testing. Other coastal areas have also been identified (for example, the Mediterranean, with 8 kW/m) where the energy potential is too low to make the testing worthwhile.
• The typology of the seabed is ideal for mooring and for burying the subsea cables.
• The existence of a currently unused and highly suitable point for power transmission to the grid: the substation built for the Lemoiz nuclear power station that never became operational.
• No interference with the local marine fauna or flora.
On the basis of the data and lessons learnt from the experiments undertaken, to improve and develop this technology to a point where the price of electricity generated by these WECs is similar to that of other renewable energy sources. However, researchers and scientists need to be able to put their technologies to the test if they are going to improve them and bring this objective closer to reality. In this sense, the bimep project and the Basque Country will be the focal point of world attention.
The WECs will be moored in such a way that some of them, depending on their particular characteristics, may require mid-water or even surface anchor ropes. Furthermore, any power generated will be transmitted through a cable floating in mid-waters (an umbilical cable). These circumstances make it necessary to prohibit the entry of any vessels into the area to avoid potential damage to the WECs, the mooring system, the power cables and the intruding vessels themselves. As has been mentioned above, and despite the fact that burying the cables outside of the bimep zone should ensure their protection, anchoring within a defined area of where the buried cables run will be prohibited.