Past event - HYDRO 2008
Controlling pressure fluctuations, vibrations and dynamics stress in hydraulic machinery was the main issue in Session 13, which was chaired by Prof F. Avellan of EPFL-LMH, Switzerland.
The opening paper, presented by Masatake Maekawa of Mitsubishi Heavy Industry Ltd, Japan, covered a new approach for mitigating the pressure fluctuations experienced by a pump-turbine in the generating mode at part load. The work was motivated by the relatively high levels of pressure fluctuations and vibration experienced by the Unit 2 of the Hongawa pumped-storage plant operated by the Shikoku Electric Power Co Inc (SEPCO). This storage plant, equipped with two pump-turbines (307 MW output/320 MW input) is near the centre of Shikoku Island, Japan, and is one of the largest capacity, high- head storage plants of the country. The approach presented by the authors consisted of replacing the standard impeller cone by a new cone with helical grooves. The groove design was optimized based on model tests carried out at the Mitsubishi facilities of the Tadasago Research Center, and significantly reduced the pressure fluctuations in the discharge ring. This test result indicates that application of the developed grooved runner cone makes it possible to expand the lower operation limit of pump-turbines. This is usually restricted by the pressure fluctuation and vibration level, and also results in improvements in the equipment's reliability.
Yasir D. Siwani of Rainpower AS, Norway, presented a methodology for dynamic stress assessment in high-head Francis runners. An estimation of the dynamic stresses in the runner, with five blades and five splitter blades, had been made using finite element analysis applied to a given operating condition corresponding to a load case. The load case had been defined by carrying out transient CFD analysis on one runner blade channel, assuming a periodicity between the runner channels, and making it possible to reduce the computing time considerably. The computed periodic wall pressure field had then been input to the FEA for computing of the dynamic stresses experienced by the blades. The dynamic stresses calculated by FEA had been satisfactorily validated with dynamic stresses measured by gauge measurements carried out on the prototype runner, proving the validity of the methodology.
Guidevane actuators are very important components, which can help in optimizing the transient operation of either a hydraulic turbine or pump-turbine. Daniel Roulet of Alstom Power Hydro, Grenoble, France, gave a detailed account of his company's recent developments in actuator turbine technology, concentrating on the benefit of having a standard series of actuators. The new Alstom actuator range, based on an integrated component design, with component add-on functions, encompasses the required functions in one single device. This solution improves the reliability of the control devices and minimizes piping. This new type of component helps to increase turbine performance and reliability, and eliminates specific performance tests normally carried out for each project.
The main parts include a main distributing valve and an identical control block, regardless of the size of the main distributing valve. All pressure plugs needed for commissioning and maintenance have also been integrated. More than eight integrated functions can be added, irrespective of the main component size. These functions include proportional control, safety control, multi-slope closure, and redundancy of the feedback sensor. The design of the flanged components was standardized and it complies with specific quality standards, enabling the industrialization of the components. Component validation tests are carried out in the factory, guaranteeing their performance level and eliminating the need for testing for each specific project. Moreover, the co-author emphasized the role of these standardized components, making it possible to have individual servomotor control of every guidevane, and thus enabling to apply control strategy for by-passing unstable operating range of the machine characteristics.
Session 13 was closed by a presentation of J. Jaklin, General Manager, of Litostroj Power Group. The Slovenia-based Group specializes in the development, design, manufacture and supply of equipment for hydroelectric plants, as well as for refurbishment and upgrading schemes. A Technical Visit had been arranged for delegates, to his company and also to the Turboinstitut hydraulic laboratory, and Jaklin described production facilities for heavy duty machining, special machining and welding which were to be seen on site. He also mentioned the recent merge with CKD Blansko in Brno.
Session 14: Assessing a mitigating environmental impacts
This session included seven presentations, which covered various common issues regarding the assessment and mitigation of environmental impacts of large and small hydropower plants.
Co-Chair Gema San Bruno, Deputy Secretary-General of ESHA, pointed out the challenges that the current and future EU environmental legislation represents for the development ofthe hydro potential in the European Union.
Co-Chairman Dr. Basilio Verduzco Chávez summed up the session as follows.
The first speaker was O. Samara from Greece, who presented a methodology on how to gain public acceptance using participatory evaluation. The system he described used a points system to assess the benefits of small hydro projects.
The method is expected to be helpful in overcoming cumbersome bureaucratic procedures and to increase the likelihood of completing the projects, which were certainly needed.The second talk, by Mr. Herman Idrus, discussed the predicament of large and old hydro plants which have to be operated and maintained in completely different circumstances from those for which they were created. He identified circumstances ranging from population growth, deteriorating water quality and the enlargement of fishing facilities, which produced additional pressures on the maintenance operations. In light of these challenges, he explained that two strategic plans to minimize impacts were the reduction of pollutants and the protection of equipment. He demonstrated that while a redesign strategy was a possibility, this was less feasible if improvements in water quality were not produced.
However, the problem of making such improvements is that many stakeholders are involved.
M. Sevserko described the possibilities which could be used to solve problems of debris in hydro plants in Slovenia. She described several uses and challenges faced by operators of powerplants and her paper suggests that some changes in legislation could facilitate problem solving by opening new possibilities to handle debris and process it for various purposes.
Basilio Verduzco presented his study, which was an ideal typical model describing four possible scenarios for local sustainable development in regions impacted by large hydroelectric plants. The model had been applied in Mexico to assess the contribution to local development of six large projects and to investigate how impact assessments conducted at the beginning of the projects can be improved in light of a changing environmental, social and political situation.
Natasa Smolar-Zvanut of Slovenia presented two interesting methodologies, one for an estimation of minimum flow requirements, based on a multidisciplinary evaluation of the hydrology and the ecology of the river and producing a customized evaluation for the project. The second had been applied for an impact assessment for a pumped-storage plant. The study had concluded with recommendations for the protection of the environment and cultural heritage, and recommended a monitoring process aimed at adopting the necessary measures to prevent occurrences which could be harmful for the environment.
The papers and discussions which followed, addressed broader issues relevant for future assessment and mitigation of environmental impacts.
First, in addition to conducting proper assessments and implementing adequate monitoring processes which are required by legislation in most countries, it is still necessary to address the question of how to build up trust among stakeholders. In particular, the problem must be addressed of how to convince local communities and project opponents that the evaluations conducted are serious and committed to preventing harmful situations and identifying the best mitigation solutions; also, most importantly, that hydropower plants are among the best options available for providing the energy needed.
A second issue addressed in the debate was the question of subjectivity in impact assessments, and the advantages of using participatory approaches and multidisciplinary evaluations which might provide the best wisdom and knowledge available, and which in turn may help to overcome the world of separation between the perspectives of developers based in large cities and local communities impacted by the projects.
A third theme addressed in these presentations is the issue of preparedness for the long-term operation of hydroelectric plants. This is considered important for two major reasons. First, because the life span of projects will result in a changing social and political environment and in the emergence of different requirements which will have to be implemented to comply with new legislation. Second, because economic, demographic and environmental changes occurring at regional, and sometimes at a national level will impose different pressures and operation conditions.
A fourth theme addressed the question of how institutional arrangements shape what a developer of a hydro project can do at every stage of the project, and how this results in the need to adapt different strategies to be able to plan, construct and operate a project in an efficient way, while being able to respond to the demands of the various stakeholders.
The studies suggest that from a technical point of view, solutions exist for really complex conditions and situations, but not all the technical problems can simply be implemented without looking carefully at the social and ecological context surrounding a project.Some recommendations which emerged from the debate can be summarized as follows:
The need to show responsibility in dealing with environmental and social issues.
The benefit of planning and operating projects with sufficient flexibility to accommodate long-term changes that will certainly affect the project.
Working with regulators to find solutions which will respond to the interests of the various stakeholders.
Good practice, involving technical solutions and local wisdom, can contribute to solving some of the pressing problems that both large and small projects are facing.
Last but not least, there is the question of whether it is possible to plan and implement hydro projects seeking some form of partnership with local stakeholders, and to transform hydro plants into engines for local sustainable development, which could create opportunities for environmental protection and, as was shown in this session, to use a different philosophy combining knowledge, wisdom and art.
Future issues which could usefully be addressed are: long-term environmental management strategies and how they have evolved over time; and, comparative analyses of cases conducted in different situations (time and place), with a view to learning experiences of what works and what does not work.
Session 15: Managing sedimentation
This session was chaired by S. Alam of France, who reported that seven papers had been presented, with the following distribution of topics.
Two papers had dealt with sedimentation management in storage reservoirs by periodic or continuous dredging. One of the authors concluded that, to have precise dredging costs, it was necessary to obtain precise information on the sediment material to be dredged and the required working conditions. The other paper described the technology of deep water dredging for maintaining irrigation water supply reservoirs and transportation of dredging equipment in containers to remote places with difficult accessibility.
One paper discussed the management of hazardous substances contained in sediments deposited in a reservoir. Some of the rivers in Slovenia transport slightly chemically contaminated sediment, and the paper described some practical solutions concerning the use of these contaminated sediment materials in agricultural land filling and for construction purposes.
One paper focused on the optimization of desilting basins. The author had carried out cost analyses for various desilting basin designs, and concluded that the size of the desilting basins should be larger than that obtained by optimisation procedure.
Two papers discussed the successful use of desilting basins at hydro projects in the Himalayan regions. These projects have used hopper-shaped continuous flushing desilting facilities: open surface basins in the case of the Baspa stage II hydroelectric project and submerged chambers in case of the Vishnupryag project. After initial experience of severe abrasion problems, the project operators had defined new operating procedures and protective coatings for the turbine equipment, which is allowing the plant to obtain reasonable to good plant operation.
There was one paper on the sediment management strategy for the 775 MW Luhri hydro project located 40 km downstream of Nathpa Jhakri in India. After the incident of sediment-related damage at Nathpa Jhakri, the project owner and designer had decided not to use desilting chambers at Luhri. The concept of using a bypass tunnel to divert the flood discharge, and thus having only the power discharge in the power intake area of the reservoir, is being studied. However, the cost of the bypass tunnel might be prohibitive, and the reservoir sediment management will have to depend only on periodic flushing operations.
The author of the paper on sediment management in the Three Gorges reservoir unfortunately was not able to attend the session, but the paper is published as an article in issue 6 2008.
Session Chairman, Sultan Alam, in his contribution to the session, stressed the basic requirements for assessing the risks of sedimentation related problems in hydro reservoirs, which might consist of obtaining reliable sediment inflow related data such as:
Sediment inflow characteristics to the project site as a function of the river discharge and shape of the discharge hydrograph. Very often, he said, the bulk of the sediment load was transported by the river in the early part of the flood discharge hydrograph and very little sediment is left during the peak discharge of the flood hydrograph.
Knowing the sediment particle sizes transported by the river as a function of the river discharge is also important. This is necessary to simulate correctly the reservoir sedimentation process and its eventual flushing operations by using numerical or physical models.
The project layout may also play an important role in preventing or reducing sediment entering the power discharge. One way to achieve this is to separate the power intake area from the spillways designed for passing flood discharges significantly greater than the power discharge. For high head projects (> 100 m) this is a more efficient solution than the use of conventional desilting chambers. It has been verified that to reduce abrasion damage for very high head projects, sediment particles up to 50-60m must be removed.
The type of reservoir and the flow characteristics inside the reservoir is also of importance. For a very large reservoir, the total sediment inflow might accumulate over a long time period before sediment becomes a problem for its operation, and it thus requires practically no sediment management activities.
For smaller reservoirs with non-cohesive sand deposits, periodic dredging and/or flushing may be the procedure to be used for short-term reservoir maintenance and operation.For projects with extremely high sediment transport, like Rio Madeira in Brazil, (500 million t/year), the solution is a run-of-river upper pool where more than 95 per cent of the sediment material is transported in suspension during the normal operation of the powerplant, and the fraction of medium to coarse sand is removed during the annual flows in excess of the power discharge. The average operating head for such projects is in the order of 15 m, so there are no risks of turbine abrasion.
Session 16: Pumped storage - Role, benefits and technology
Bruno Trouille, of MWH, USA, who chaired this session, points out that there is definitely a renewed interest in pumped storage in a number of countries around the world, as demonstrated by the large attendance and number of questions raised during the two discussion periods. The number of projects being planned, designed and constructed were increasing, he said. Most important is the role that pumped storage can play in firming up the capacity and energy from other renewable energy projects.
There were two presentations on the role of pumped storage an islanded power systems with a large amount of wind power. Delegates heard that detailed computer programs were being developed to simulate better and optimise the operation of pumped storage in various wind conditions and to evaluate the resulting stability of power systems.
Other presentations described design optimization approaches for the proposed 1500 MW Lima project in South Africa, and for the new upper reservoir dam at Taum Sauk in the USA. One presentation focused on the historical development of variable speed technology and today's state of the art. Another provided insights into very detailed computer modelling of the geometry of guidevanes and turbine runners. Local project opportunities in Slovenia and the addition of pump-turbines at existing hydro plants in Austria were also discussed.The two half-hour open discussions were extremely lively, with a number of questions on the costs and benefits of variable speed, lessons learned from the dam failure at Taum Sauk, and comments made by equipment manufacturers on the latest technological advances.
Session 17: Extending the life of hydro plants
Chairman Bryan Leyland of New Zealand reported that this had been a very interesting session, with a number of valuable papers which had attracted some very good questions.
The speakers were to be congratulated, he said, on the high standard of their presentations and their papers.
Prof David Williams, Chairman of the British Hydropower Association, co-chaired the session.
The first two papers 'Difficulty of specifying rehabilitation work' presented by H. Obermoser of Switzerland, and 'Experiences gained by hydro plant refurbishment and upgrading in Slovenia', presented by I. Leban of Slovenia, complemented each other very well. The first described the problems and solutions likely to be encountered when refurbishing an old hydropower plant for a client who is very short of finance and technical support. Financing therefore needs a development bank or some similar organization which will have very specific rules about tendering, financing, cost overruns and so on. These have a major effect on the selection of a contractor, how the work can be organized, and how much refurbishment can be afforded. Very often, things that should be done will be abandoned for lack of finance.
The second paper described problems and solutions when dealing with an owner who has adequate technical expertise and sufficient finance. The problems are mainly technical and economic: for example, ensuring that the best solution is selected, and that the client gets good value for money.
Other papers dealt with refurbishment and upgrading of hydro generators, the need to develop new turbine designs as a parallel development arising from computer analysis, model testing and structural design, rather than a sequential development which often leads to an optimum hydraulic design with serious structural problems.
There were two excellent papers on upgrading existing Francis and bulb turbines, followed by a presentation on a major upgrade of an existing hydro plant. The final contribution was on problems caused by tailwater drawdown resulting from the degrading of a river bed at a power station in Croatia. During the discussion, it transpired that a similar problem at a power station in New Zealand had been solved by installing active gates at the exit to the draft tube. The speaker said that this had been considered, but had not been favoured because, they believed, no one had done it before! Incidents like this underline the value of attending international conferences such as HYDRO 2008.
Session 18: Discussion on capacity building
Session 18, focusing on capacity building in the field of hydropower and water resources management, was chaired by Adama Nombre, President of the Burkina Faso Committee on Large Dams and past Vice President of ICOLD. The question of capacity building, he said, had progressively gained interest as one of the major strategic issuea for the development of hydropower in the less developed countries and even in developed countries to maintain and upgrade existing schemes.
After introductory comments by the Chairman, to recall the main conclusions of the plenary session debate on capacity building during HYDRO 2007 in Granada, and to highlight some key issues related to capacity building, various eminent panellists were asked to make introductory comments for discussion. They were:
Johnson Kwesigabo, Secretary and General Counsel of Uganda's Electricity Regulatory Authority, representative of the Minister of Energy from Uganda; Marcel Gounot, of EIB Luxembourg; and, Sandy Tickodri-Togboa, Uganda Electricity Generation Co Ltd.
Many participants from Africa, Europe, and Asia and representing many sectors of the profession such as universities, international agencies including UNESCO-IHE and the Nile Basin Initiative, as well as the industry, contributed to enriching the discussion and created opportunities to share experience, which was the main goal of the discussions.
The mains issues highlighted in the discussions were:
the needs for capacity building in the public and private sector in both developed and less developed countries;
the value of dissemination of successful experiences in training and capacity building;
the roles of public authorities, developers, professional associations and the industry; and,the problem of how to move ahead in capacity building.
The main findings and conclusions were as follows:
Needs for capacity building
The issue of capacity building is a common one for the profession worldwide. In developed countries, with major development of the hydropower and water resources sectors, the problem is to renew the profession and preserve its experience by attracting more young people, to ensure the continuous development of the sector with new technology for renewable energy development, and to maintain the existing assets. The issue in less developed countries, particularly in the Africa zone, is to create and develop the necessary capacity to plan and implement the development of the huge hydropower and water resources potential so far remaining untapped with a view to modernizing these countries. The discussions have focused on the following aspects:
The evident need to modernize and equip the universities in Africa to train engineers and provide sufficient numbers of engineers in the disciplines related to the development of hydropower and water resources. It was evident that many African countries lack basic facilities in universities and sometimes lack the resources to train qualified and human resources for the sectors. In this kind of situation, the minimum conditions in which to advance progress in the hydropower and water resources sector is a critical issue. The situation is exacerbated by the fact that many African countries are focusing on the basic and secondary levels of education, so there are not enough resources to develop and equip universities.
The need to build capacity in the public sector, particularly ownership empowerment in project planning and development, as well as negotiating skills with others stakeholders such as the private sector and developers in the case of public private partnerships.
The need to build capacity in public entities, where the development of hydropower relies on the public sector for planning, implementation, operation and maintenance of facilities.
The need to build capacity of local investors and developers for small and medium projects as regards feasibility studies, implementation and operation and maintenance.
The need to develop capacity for the operation and maintenance of hydro stations; many assets in the less developed countries become run down as a result of a lack of efficient O&M; in some countries half of the electricity generated is lost in the network.
Successful experiences
Many on-going successful experiences in the field of capacity building were shared during the discussions. The following are a few examples:
The EIB centre of expertise for the European Union, for the development of public private partnerships, is developing capacity building in three areas:
capacity building for publics entities; government capacity building, to develop adequate frameworks for PPP development and to protect public interest; and, power sector efficiency improvement.
Also discussed was the Nile Basin Initiative capacity building plan, sponsored by UNESCO-IHE, in the area of hydrological studies, GIS and EIA, with its centre for training.
Since the creation of the centre, more than 6000 trainees had benefited from the programme, it was noted.
The role of stakeholders
Discussions focused on the development of universities and on-the-job training, and in particular the role of the industry and developers in transferring knowledge and technology during the planning and implementation processes for hydropower projects. The discussions showed that, until now, some investors, developers and consulting firms and contractors had not been considering this issue adequately, and there was also a need for improved organization of on-the-job training.
Another issue which emerged from the discussion was the lack or inadequacy of professional associations aiming to develop a suitable environment for capacity building in the profession.
It was agreed that governments and public authorities should implement good policies and incentives to attract and retain qualified and experienced professionals to improve the capacity of the sector.
How to move ahead
Many ideas were proposed on how to move ahead in the field of capacity building in the hydropower sector in both the less developed and developed countries. The main ideas expressed can be summarized as follows:
Develop and strengthen universities to train young people in the field of engineering, as in many countries the situation of human resources is very critical.
Promote on-the-job training and technology transfer during the planning, implementation and operation of hydropower projects. In this area, the industry has an important role to play.
Develop international cooperation in river basins authorities and regional organisations like the Volta, Niger, Senegal rivers basins in the same way as the Nile Basin Initiative capacity building plan.
Develop awareness on successful experiences and possibilities for training young professionals by disseminating information on these experiences.
Promote knowledge bases and networking, to disseminate knowledge and develop links within the profession.
Promote incentives to reduce the brain-drain from south to north, and to promote the involvement and commitment of local resources in the development of hydropower sector in the African countries.
Session 18 provided an opportunity to share experiences and ideas on how to move ahead in building up human and institutional capacities to sustain the progress of hydropower development in the regions where the needs are greatest, and the potential is available.
The annual hydro conferences themselves are important tools for this purpose in creating a forum for learning, and constituting a global network in the profession, along with the development of friendship among professional people.
Session 19: Dams and tunnels - Construction challenges
This session was chaired by A. Kryzanowski of Slovenia.
He noted that the authors had highlighted experience gained, as well as technical and technological procedures in dam and tunnel construction in unfavourable geological and climatic conditions. They had shown examples of interesting and innovative technical solutions to cope with the challenges caused by unfavourable natural conditions at the time of construction.
V.K. Gupta of India addressed problems which had arisen during the design and construction of the 11.6 km-long headrace tunnel for the Tapovan Vishnugad hydro plant, within a chain of hydro plants on the Dhauliganga river in India. The reasons for and against the decision on whether to select a double shielded TBM were also mentioned in the presentation. The decision on the selection of suitable technology for the tunnel construction had been based particularly on the experience gained by the contractors at similar projects in India, taking into consideration the natural conditions at the site. The extremely unfavourable conditions provided constant technological challenges to contractors during construction, and required a high level of organization and adjustments to the on-site conditions to overcome the challenges.
R. Kohler described technological problems encountered during construction of the 130.5 m-high Tsankov-Kanak arch dam on the Vacha river in Bulgaria, which is part of the Vacha-Dospat cascade hydro system. The following topics were specifically highlighted: the problems of arch dam foundation work, including sealing of the tectonic zone and weak zones in the dam foundations; and, sealing of the dam profile in pervious rocks and cooling of massive concrete blocks during construction of the dam. The presentation also included some technical solutions to overcome the problems and modifications to the technical concept during project implementation.
In the last contribution at the session, G. Petursson discussed the Kárahnjúkar hydro project in Iceland, which had involved the construction of a total of 60 km of headrace tunnels and a 200 m-high CFRD, the largest dam of this type in Europe. Characteristic of the project, which will supply energy to an aluminium smelter, are extremely unfavourable natural conditions at the site, and a short time for project completion, which presented special challenges for the designers and contractors. The author outlined the measures for tunnel construction in extremely difficult geological conditions, which had required modifications to technical solutions to enable the project to be completed within schedule. Also discussed were some very innovative solutions for shortening the testing time of mechanical equipment, by using only leakage water in partially completed tunnels, as well as a synchro-condenser to ensure suitable voltage conditions within the network before connecting the powerplant to the national grid.
From the discussion, it can be concluded that for successful project implementation under anticipated difficult natural conditions at the sites, it is absolutely necessary to ensure preliminary geotechnical research work of high quality. On the basis of this, appropriate technological measures for construction can be taken.
Session 20: New major pumped-storage schemes in Europe
This session was chaired by J. Freitas of EDP, Portugal, and focused on three new pumped-storage plants in Europe. As an introduction, the importance was highlighted of new pumped-storage plants, in view of the rising demand for peak power, and also the increase in wind power capacity throughout Europe. The connection between these two types of plants was underlined, and the fact that "one can't live without the other".The theme for the first presentation was the Limberg II pumped-storage scheme, optimized for a wide range of applications. The speaker, M. Giese of Voith Siemens Hydro, described challenges for the hydraulic design of the pump-turbine with a wide head range. Results of model tests had confirmed the accuracy of the CFD design, namely the cavitation behaviour and stability under the high head operating limit.
The second presentation, by V. Ribeiro from EDP Gestão da Produção, was about the new Venda Nova III pumped-storage scheme in Portugal.
The project consists of repowering the original, 57 year old 90 MW Venda Nova plant. The author gave a description of the various solutions studied for the scheme, including the issues which had arisen in the design of the tunnels, in relation to hydro-geological and geotechnical aspects, and in particular a comparison between existing and new underground studies.
The third and final presentation concerned a new project in Slovenia, Avce, the first pumped-storage scheme in the country. First M. Ranzinger from RGP described the excavation works which had had to be done during the construction of the plant and the problems encountered during this process. Then F. Primc of HSE Invest Ltd explained the operational advantages of the variable pump-turbine at Av?ce. He described the various characteristics of the generator, and emphasized that a pump with variable speed is not a common solution in Europe.
During the period for questions and discussion, one of the main topics was the dimensions of the unlined hydraulic tunnels at Venda Nova, and some information was given concerning the speed of flow at the scheme.
Another point discussed was the solution found for the pump at Avce, with variable speed, which although common in Japan, is difficult to find in Europe.
In conclusion, there was an agreement about the increase in pumped-storage plants throughout the world, and specially in Europe, where intermittent sources of energy were increasing.
Session 21: Refurbishment schemes
This final session was chaired by Francisco J.C. Rocha e Silva of Portugal (formerly with Hidroelectrica de Cahora Bassa, Mozambique).
He pointed out that there was an increasing number of countries where hydro equipment was approaching the end of its operating life. This, together with the current global situation of financial turbulence, and on the other hand the permanent demand for installed capacity, together put major emphasis on the benefits of, and opportunities for, powerplant refurbishment.
The presentations in the session had focused on the importance of governments being engaged in refurbishment activities, respecting the engineering approach to planning. There is always a precise time-line in launching a project and various milestones in the schedule to be respected. The success of a project often depends on this, and represents a benefit for all those involved, including the local population.Another conclusion from the discussions was the value of investing in local expertise (as technicians and engineers), but it was stressed that they must be thoroughly and appropriately trained before and during the work. This is essential to make the project, and the subsequent operation and maintenance of equipment, economic, and in effect, sustainable. Refurbishment involves, to a greater and greater extent, a range of theoretical sciences, and to support that, IT tools are extremely useful throughout all the phases. These should respect environmental and safety aspects.Finally, intensive and continuous cooperation among parties on site is essential for the progress of works and the overall success of the project, helping to avoid or at least significantly reduce surprises, delays and conflicts which can result in losses, tensions and misunderstandings. One of the cases presented in the session was an example of perfect success as a result of a cooperative relationship.