The production and consumption of electricity on the power grid has to balance at all times. Slow balancing, over days and weeks, is governed by the electricity market and carried out through production planning.  Fast balancing, within the operational hour, is carried out by hydropower plants operating in frequency control mode. The need of balancing power is expected to increase as more varying renewable energy production is connected to the grid, and the deregulated electricity market presents a challenge to the frequency control of the grid. The first part of this thesis suggests a method to quantify the need for balancing or energy storage induced by varying renewable energy sources. It is found that for high shares of wind and solar power in the system, the energy storage need over a two-week horizon is almost 20% of the production. The second and third part of the thesis focus on frequency control. In the second part, measurements from three Swedish hydropower plants are compared with the behaviour expected from commonly used power system analysis hydropower models. It is found that backlash in the guide vane and runner regulating mechanisms has a large impact on the frequency control performance of the plants. In the third part of the thesis, the parameters of the primary frequency control in the Nordic grid are optimised with respect to performance, robustness and actuator work. It is found that retuning of the controller parameters can improve the performance and robustness, with a reasonable increase of the actuator work. A floating deadband in the controller is also discussed as a means to improve performance without increasing the actuator work.

No description available.

<p>The project consists on the reconstruction of an old and obsolete hydropower plant situated in Ockelbo (Sweden). To carry out this goal it is done firstly a land survey on the place and a preliminary study of which kind of plant should be installed. After that it is done the management part of the project, summarized in the three documents called Business Case, Project Directive and Project Specification. These papers must be written before start running any project.</p><p> </p><p>Before start writing the real project, it is explained a short background of hydropower plants and all their components, the current situation of the site studied and also the status of this green energy in Sweden. The name of the site where it is going to be placed the hydropower plant is Wij Trädgårdar and they want to make this area as an example of sustainability with different kind of green energy production.</p><p> </p><p>Any project must have a pre-study to assure that the task is possible. The theoretical part explains this pre-study, looking at the best turbine and generator with the conditions given by the land survey. This part also gives an overview of the importance to manage a project, how to do it and people who take part on it.</p><p> </p><p>Finally, on the part of the results, the theoretical installation that should be placed with its specifications is defined and also the amount of energy that it can produce. In addition, on the management part, there is concluded how to erect the new installation with the final solution given and those suppliers that will participate on the construction. Also, an economical study is included. The three management documents are added on the appendixes.</p>

<p>This thesis is an evaluation of a new design concept for statorfeets in Gallejaur hydro power plant. Founder of the work is Vattenfall AB Vattenkraft. During the 70- and 80´s nuclear power began to be phased in to the Swedish grid, which meant that hydropower became an important source of rules. The generators began running in so called intermittent operations instead of basic operations, which meant 300-600 start/stop per year instead of one-ten numbers start/stop per year. In order to deal with the thermal forces that arise at every start and stop suppliers began to mount so called sliding joints, which is to take advantage of these forces and maintain the stator shape. This, however, led to unforeseen consequences.</p><p>The evaluation is a part of a major project, witch started in 2005 with regards to bring down the shutdown time on generators because of the sliding joints, witch are mounted on many older machines today. The sliding joints have tended to stick during operation resulting in serious consequences. Consequences such as cracks in the concrete foundations and stator core buckling causing long shutdown and providing a high level of production lost.</p><p>VG Power who delivered the concept has developed a foot, which ensures that the stator retains its shape when it expands due to the thermal forces arising from the boot and stop of the generator. Analysis and validation of design and calculations made at VG Power shows that the concept is very well dimensioned and can handle the demands that Vattenfall has in the specification. Analysis and validation of operational data from five operational cases also shows that the concept works very well. The concept shows among other things that:</p><ul><li>Movement of the new feet’s follows a clear pattern of movement when starting and stopping the unit.</li><li>The concept is well dimensioned, good margins for safety and stability are provided.</li><li>The concept is suited well for older units.</li><li>The design allows for a safer operation because of reduced maintenance that the concept requires.</li><li>High availability</li></ul><p>Further studies concerning the test of the concept strength is to start a fatigue rig to test whether the concept can handle the intense stress of the micro – movement that occurs during operation. It is important that Vattenfall is examining and doing an analysis on the micro – movement that occurs in the blocks where Vattenfall surveillance system Conwide not allow sufficiently high sampling rate. During a visit to Vattenfall Research And Development in Älvkarleby rust was discovered on the attachment, which requires further consideration of VG Power. It is and important parameter relevant to maintenance and durability.</p>

The project consists on the reconstruction of an old and obsolete hydropower plant situated in Ockelbo (Sweden). To carry out this goal it is done firstly a land survey on the place and a preliminary study of which kind of plant should be installed. After that it is done the management part of the project, summarized in the three documents called Business Case, Project Directive and Project Specification. These papers must be written before start running any project.   Before start writing the real project, it is explained a short background of hydropower plants and all their components, the current situation of the site studied and also the status of this green energy in Sweden. The name of the site where it is going to be placed the hydropower plant is Wij Trädgårdar and they want to make this area as an example of sustainability with different kind of green energy production.   Any project must have a pre-study to assure that the task is possible. The theoretical part explains this pre-study, looking at the best turbine and generator with the conditions given by the land survey. This part also gives an overview of the importance to manage a project, how to do it and people who take part on it.   Finally, on the part of the results, the theoretical installation that should be placed with its specifications is defined and also the amount of energy that it can produce. In addition, on the management part, there is concluded how to erect the new installation with the final solution given and those suppliers that will participate on the construction. Also, an economical study is included. The three management documents are added on the appendixes.

This thesis is an evaluation of a new design concept for statorfeets in Gallejaur hydro power plant. Founder of the work is Vattenfall AB Vattenkraft. During the 70- and 80´s nuclear power began to be phased in to the Swedish grid, which meant that hydropower became an important source of rules. The generators began running in so called intermittent operations instead of basic operations, which meant 300-600 start/stop per year instead of one-ten numbers start/stop per year. In order to deal with the thermal forces that arise at every start and stop suppliers began to mount so called sliding joints, which is to take advantage of these forces and maintain the stator shape. This, however, led to unforeseen consequences. The evaluation is a part of a major project, witch started in 2005 with regards to bring down the shutdown time on generators because of the sliding joints, witch are mounted on many older machines today. The sliding joints have tended to stick during operation resulting in serious consequences. Consequences such as cracks in the concrete foundations and stator core buckling causing long shutdown and providing a high level of production lost. VG Power who delivered the concept has developed a foot, which ensures that the stator retains its shape when it expands due to the thermal forces arising from the boot and stop of the generator. Analysis and validation of design and calculations made at VG Power shows that the concept is very well dimensioned and can handle the demands that Vattenfall has in the specification. Analysis and validation of operational data from five operational cases also shows that the concept works very well. The concept shows among other things that: Movement of the new feet’s follows a clear pattern of movement when starting and stopping the unit. The concept is well dimensioned, good margins for safety and stability are provided. The concept is suited well for older units. The design allows for a safer operation because of reduced maintenance that the concept requires. High availability Further studies concerning the test of the concept strength is to start a fatigue rig to test whether the concept can handle the intense stress of the micro – movement that occurs during operation. It is important that Vattenfall is examining and doing an analysis on the micro – movement that occurs in the blocks where Vattenfall surveillance system Conwide not allow sufficiently high sampling rate. During a visit to Vattenfall Research And Development in Älvkarleby rust was discovered on the attachment, which requires further consideration of VG Power. It is and important parameter relevant to maintenance and durability.

Increased renewable electricity generation is key to the reduction of carbon emissions and has the added benefit of reducing reliance on imported gas and coal while increasing diversity of the generation mix. To encourage development of renewable generation the Scottish Government has adopted an ambitious 100% renewable electricity generation target to be met by 2020. Although hydropower has generally been considered insignificant in a UK context, when forming part of a Scottish target the resource becomes much more significant as the majority of the UK’s existing capacity and potential for new capacity is located within Scotland. Scotland has a long history of hydropower development with the majority of current operational capacity installed during the mid 20th century. Recent studies have produced a range of estimates for the remaining resource from 286 to 1000 MW. The studies undertaken have tended to rely upon catchment analogue methods or the use of regression equations to produce estimates of flow at sites of interest, with simple assumptions of installation costs and energy yield. This work uses a novel method combining time series flow data produced from a distributed hydrological model with GIS techniques and a detailed parametric cost model to enable a state-of-the-art hydropower resource model to be developed. The use of time series flow data allowed investigation of the spatial and temporal characteristics of the resource to be made, both run-of-river and impoundment schemes to be investigated and a preliminary assessment of the impact of climate change to be performed. Three financial scenarios have been considered using 5%, 10% and 15% discount rates as this is the most sensitive variable when assessing the feasibility of hydropower projects, reflecting the cost of finance available and investors’ attitude to risk. The spread of discount rates will account for changes in available subsidies, electricity prices and ongoing costs. Clearly availability of low cost finance and a low risk subsidy environment will have the largest impact on hydropower development. A major limiting factor was found to be the cost of grid connection; if this were reduced the potential figure could be higher. The results of this work show that at a 10% discount rate, 440 MW of new run-of river hydropower potential capable of producing 1.7 TWh per year is available. Exploitation of this would represent an additional 4% contribution towards the Scottish Government’s 100% renewable electricity target.

The purpose of this thesis is to generate a deeper understanding of the representation of hydropower in long-term models. This is done by mapping and modelling (cascading) hydropower in Sweden with the Open Source energy MOdelling SYStem (OSeMOSYS). The first part of the thesis builds on a literature review and provides an introduction to hydropower in Sweden. The second part focuses on implementing the storage equations in OSeMOSYS. These are applied by modelling hydropower at various levels of detail to evaluate the result when the depth of detail of the storage modelling is increased. First, a model of Sweden without hydropower storage is modelled. Then, two models were set up which include storage; one with one hydropower storage for all of Sweden, one with nine rivers with storage. Finally, two models considering cascading hydropower with storage were developed; where the first is an expansion of the model with one storage for all of Sweden and the second model examine two rivers more thorough. The remain-ing power system is represented in a stylised fashion, compliant with prevailing long-term energy modelling techniques. The implications of the different levels of detail are compared and discussed. The comparisons show that it is important to consider the lev-el of detail when looking at the short-term effects of long-term energy models.

No description available.

Bhutan is a small Buddhist country nested in the cradles of the eastern Himalayas. It has rugged mountainous terrains with altitudes ranging from 500 masl in its southern plains to 4500masl in the snowy capped mountains in north. This rugged mountainous topography blessed Bhutan with huge hydropower potential. The hydropower potential of Bhutan is estimated at 30000MW with projects above 10MW capacity as per the power system master plan. This is one of the highest in the world considering its small size. In absence of other valuable natural resources, hydropower has become the main national resources in the country. Out of huge potential, Bhutan today has 1488MW of installed hydropower project under generation illuminating about 90% of all houses in the country and feeding power to its developing industries. Because of its small size and even smaller population, the internal electricity consumption of Bhutan is small roughly 30% of its present generation. The balance power is exported to India generating the most needed revenue for the economic development of the country. Bhutan plan to construct 10000MW of hydropower projects within year 2020 among which some mega projects are already under construction.Bhutan being located in the tectonically active Himalayan geological formation faces lots of geological challenges in tunneling works. The Himalayan geology intruded by numerous geological discontinuities, and frequented by the tectonic activities poses lots of challenges for tunneling works. The Himalayan geology is very complex and rock mass properties changes greatly within small distances.The engineering geological investigation for an underground work is very important. Detailed investigation is important during the prefeasibility and feasibility study stage of the project. But the availability of funds and time are the constraining factor in performing detailed engineering geological investigations. Balance need to be made to cover most important geotechnical studies within the availability time and fund to get a reliable design.Punatsangchu II hydropower project is a runoff river scheme project being constructed along this river basin in central western part of Bhutan. In this thesis, the engineering geological study of the HRT was carried out with an aim to carry out stability assessment and support requirement for HRT. The engineering properties of the rock mass along the HRT are reviewed from the stability aspect with discussion on orientation of main foliation, joints and weakness zones with the tunnel alignment. An alternate alignment is proposed, optimizing on orientation of main foliation, shear zones and main jointing with the tunnel alignment, restricting the exercise within the same limits of the start and end point of the HRT as given in designed layout.It has been found that the topography along the HRT permits very limited alternatives for the tunnel alignment layout and the location of construction adits. The main foliation and joint orientations were taken care for the tunnel alignment. However, there are some rooms for optimization within the same limits, if taken care of could bring better benefit to the project. This possible optimization was used in the proposed alternate alignment.The rock mass characteristics and possible instability problems along the HRT alignment were also reviewed in stability study. There are very less possibility of squeezing problems along the tunnel alignment but minor instability problems could not be fully ruled out due to the low rock mass strength. With the tunnel alignment crossing two nalas, some minor seepage problems were also expected at those nala crossing areas. Possible solutions for instability and seepage problems were also recommended in the relevant cases.The NGIs Q method and Bieniawskis RMR methods were used for the rock mass classification and the support design thereof. The designed rock supports are cross checked with the standards NGIs support chart and Bieniawskis RMR guide charts. It is found that a typical conservative support approach practiced in the Indian sub continent is followed for the support system. The supports designed were on much conservative side compared with support requirement from Q support charts.Finally the supports were further checked by using Phase2 numerical modeling. The result of the numerical analysis suggests lighter supports compared with the designed support for the HRT. The adoption of the conservative methods may keep the instability problems at bay, but the cost affect can be on the higher especially when the projects suffer from fund availability.