Herbert Leopold GABRYŚ
Electric power industry in Poland. How was it? The preliminary assessment of the last year. How will it be? The prognosis for the year 2013
Discussed are the basic problems of the Polish electric power industry in 2012 against the past dynamics of the electric energy production development in our country and external factors alike - especially the EU energy policy. The attention is called to the growing differentiation of energy production by power plants basing on hard and brown coal and the increasing share of those last mentioned ones in the energy production, caused by lower prices of the brown coal. Emphasized is unreality of the being carried out by the EU policy of „decarbonization” resulting in decreasing effectiveness and uncompetitiveness of the economy of the Union countries in the global market. Indicated is that, in comparison with the previous years, the share of electric energy producers in the total financial outcome of the whole power sector is decreasing - for the year 2011 it equalled 65% while for the first half of 2012 only 57,5%. Increasing is the share of DSOs - from 17,5% in 2011 to 25,9 after the first half of 2012. Discussed are financial results of the power sector - the total result after the first half of 2012 reached 7,39 billion zloty and it was (without inflation rate indexation) 5% more than the result after the first half of 2011, where the share belonging to transmission operators equalled 0,42 billion zloty (and it was 15,1% more) while the energy trading showed 0,63 billion zloty (and it decreased by more than 1/3). But the most important in all these comparisons are the changes in financial outcome in the part concerning producers and Distribution System Operators. The producers showed the result on the level of 4,25 billion zloty which is comparable with the first half of the year 2011, but the DSOs showed almost 50% more and it equalled 1,91 billion zloty. The DSOs financial performance improvement becomes permanent, what is really promising taking into account their investment needs resulting not only from necessity of reconstruction and modernization, but also from more thorough rebuilding of the whole infrastructure in the direction of „intelligent networks”. And if such performance dynamics remained for several years, the distribution would become able to take over not only the profoundly distributed generation, but first of all it will create a chance for a prosumer power industry which, if the distribution is not able to open up for this kind of industry philosophy, will stay in category of a vision rather than reality. And, in the end, a somewhat rhetorical question - when will the domestic electric energy consumption and the producers’ financial results increase to the level of the production amount from before the economic slowdown and whether it will not happen when there occur generation deficiencies caused by „outages” of the oldest and least effective power units as well as by exacerbated regulations of the EU Directive which come into force with the beginning of the year 2016.
Keywords: Polish electric power industry, assessment of the year 2012, prognosis for the power industry in the year 2013
Stanisław TOKARSKI
Realization of biomass projects in Grupa TAURON Wytwarzanie - a way to reduce CO2 emission
Presented is a polemical opinion concerning reduction of the support of biomass co-combustion programs in power and CHP plants. There is proved, on the example of producers gathered in Grupa TAURON Wytwarzanie, that biomass co-combustion is - apart from the developed in TAURON Wytwarzanie 100% biomass combustion technology - the most effective way to fulfil requirements related to increasing the share of energy coming from renewable energy sources (RES). Indicated is that this method, in contradiction to other alternative ones, does not deteriorate the work of an electrical power system. Propositions to reduce the support of biomass co-combustion should be regarded as destructive for our domestic power industry, Polish biomass producers as well as the Polish tax-payer and the client which will unnecessarily pay so much for the electric energy. We may also expect a temporary breakdown in the biomass market until new units, dedicated to combust 100% of biomass, are put into service. With regard to the assumed bill of RES concerning the system resignation from co-combustion, an attention is called to the fact that authors of these proposals cannot perceive the unquestionable advantages which result from this technology. It should be noticed that it is not only a cheap investment solution where to the already exisiting boiler installation there are added storing, feeding and biomass settlement installations but it also has indisputable values like a high power generating capacity coefficient, availability, possibility of power control as well as high efficiency, especially when co-combustion takes place in big units, which place this kind of RES definitely in front of other methods. Attention is called to the fact that, it is true, there is an indisputable necessity to diversify the support level for various technologies of RES energy generation but it is postulated not to determine the value of coefficients allowing such diversification only on the basis of the capital expenditure level but also to take into consideration the current operational costs relating to energy production from different RES types.
Keywords: renewable energy sources (RES), biomass co-combustion, advantages of a biomass co-combustion process
Andrzej ZIĘBIK
Systems analysis in energy engineering
System analysis – in spite of the fact that the notion “system” goes back to Aristotle’s times – was developed only in the second half of the 20th century. System approach bases on Aristotle’s statement that “the whole is more than the sum of its parts”. This means that a power plant is not only a set of the boiler, the turbine, the condenser and the pump but also their mutual interconnections. Large energy systems are characterized by a hierarchical structure. The domestic energy system, the supersystem in this hierarchy, is divided into subsystems, viz. fuel systems (e.g. the gas-energy system), electro-energy system and thermal- energy systems. On the lower level of the hierarchy there are industrial energy systems, energy systems of complex buildings, as well as modern integrated power or CHP plants. The latter ones are the subject matter of the investigations dealt with in this paper. A characteristic feature of such systems is the inseparable inclusion of the consumers of fuels and energy within the structure of these systems. In the system investigations presented in this paper first of all the input-output analysis was applied. A general notation of the mathematical model of energy management has been presented, later on applied to analyze industrial energy systems (on the example of ironworks), the energy system of complex buildings and integrated oxy-fuel combustion power plant. The application of the model of the energy management of ironworks has been provided in order to investigate the energy rationalization (replacement of the traditional water cooling of the furnace by evaporative cooling) which influences the entire energy management of ironworks. In the case of the mathematical model of energy systems of complex buildings its application in the assessment of cumulative energy consumption has been shown. When the system approach is applied for the purpose of investigating an integrated oxy-fuel combustion power plant, the results of the influence of the purity of oxygen on the direct and cumulative energy efficiency of an integrated power station has been analyzed. The paper includes also an algorithm and example of system approach to the preliminary design of energy systems. The structural analysis concerning the input-output analysis was presented in order to transform it to a matrix with diagonally-arranged blocks containing the least number of non-zero elements below the main diagonal. Lagrange’s multipliers method of decomposition of the global optimization task has been applied. It has been proved that the matrix method of calculating the unit costs of energy carriers is a coordinating procedure in the applied Lagrange method. The example concerns an industrial-urban complex.
Keywords: system, system approach, input-output analysis, industrial energy systems, energy systems of complex buildings, integrated power plant, preliminary design, decomposition
Sylwester KALISZ, Szymon CIUKAJ, Mateusz TYMOSZUK, Szczepan WARCHOŁ
Investigations on co-firing of various kinds of biomass in the hybrid satellite furnace of a pulverized fuel boiler
Presented are results of diagnostic investigations carried on in a hybrid biomass co-combustion installation consisting of a rotary furnace, stationary fluidized bed and a dust boiler. During the investigations the measurement of the gas composition and its temperature at the cross-ssection of the fluidized bed were made with the help of aspiration probe, deposit samples were taken and the process of deposit building-up was monitored with the help of a deposit probe in conditions of forest and agricultural biomass co-combustion. Presented are conditions in which the investigation took place, the results from both probes and the influence of biomass on the installation working conditions. The measurements of temperature and gas composition in the fluidized bed plane lying in the rotary furnace axis showed that the furnace works mainly as the biomass dryer while the actual combustion of dry mass and carbonizate takes place in the fluidized bed. This combustion entails occurring of high temperatures in fluidized bed creating conditions for deposit agglomeration and defluidization. Measurements made by deposit probe allow the precise determination of deposition speed. The measurement principle consists in projection of the investigated exchanger work - the probe metal temperature is equal to the exchanger metal one and the probe is washed by flue gases of the same temperature and composition as the investigated heated surface. The fuel chemical composition and the ash forming in the process of combustion has significant influence on the properties of the deposition process on the boiler heated surfaces. The carried out oxide analyses of ash obtained from the direct biomass incineration showed an increase in the amount of alkali elements (especially K and Na) and also Cl in the forest and agricultural biomass mixture ash as compared to the ash coming from the pure forest biomass. The tendency is inversed if it comes to results obtained from analyses of ash samples collected by deposit probe. It may give evidence of tendency to sticking of the sand to deposit accumulating on the probe (increased content of SiO2). This phenomenon confirms, from one side, the low temperature of ash sintering (the bed material capture) and from the other demands caution in the analysis of chemical constitution of samples collected by the probe placed directly in the fluidized bed material stream.
Keywords: pulverized fuel boilers, biomass, biomass co-combustion
Wojciech JÓŹWIK, Szymon ZACHARSKI, Andrzej ZBROWSKI
Diagnostics of installations and technical processes with the application of fast visual technologies
Presented are results of a research based on observation of high-speed phenomena with the help of a rapid shot digital camera. The research instrumentary was applied in examination of the bearing rollers forging process. Moreover, there are presented results of the research of high-energy processes occurring in missiles jet propulsions and in pneumatic hurling systems. Described is also the application of fast visual technologies to determine the speed of a piston rod in a pneumatic percussive actuator. Application of the fast visual technologies enables simultaneous examination of many parameters of fast-changing processes which are hard to diagnose by other methods. An example of such multidimensional examination is recording of an explosion of spectacle pyrotechnic charges. Thanks to the visual method it is possible to simultaneously determine a pyrotechnic charge combustion time as well as the fireball size and the radius of a charge fragments scatter. Application of fast digital cameras allows simultaneous contactless determination of fast moving objects momentary speed and the object observation during the moving time. Methods involving application of laser or mechanical gates - as opposed to the visual method - enable only speed determination in a certain measurement range.
Keywords: rapid shot camera, cold forging, combustion processes, percussive actuator, pneumatic cannon
Stanisław KOZIOŁ, Eugeniusz MATRAS, Andrzej ZBROWSKI
Diagnostic system for determination of the safety state of fire ladders and lifts
Presented is a modular diagnostic system for testing stability, rigidity and safety of fire engines, ladders, lifts, cranes and other special vehicles with devices intended for height works. The system is intended for testing of the impact of the roll angle on stability of vehicles and for testing rigidity and endurance of automated rotary ladders and lifts used during the fire-fighting actions. The structure of the system consists of the distributed actuation, control and measurement modules adapted for performing simple and complex test sets. The applied communication protocols, control algorithms, specialised computer software and the RF communication system between the individual modules allow the set-up of a flexible, configurable, modular diagnostic system with a free functional and spatial arrangement. The set of test procedures realized with the use of the system has been implemented for the assessment of stability and determination of operating parameters of the rescue and special vehicles. The aim of this research is determination of the optimal use of its technical potential in various terrain, urban and industrial conditions as well as assessment of the risk and identification of the operational hazards. The developed methods and test procedures together with the measurement modules of the system allow performing diagnostic qualification tests in accordance with relevant regulations compatible with the standards obligatory in the EU. The results of the tests performed with the developed solutions will constitute the basis for issuing approvals of the tested equipment for the use by fire departments.
Keywords: safety diagnostics, height rescue, vehicle stability
Andrzej ZBROWSKI
X-ray tomography in diagnostics of synthetic roller bearing cages
Presented is the application of X-ray tomography in diagnostics of the synthetic construction elements of roller bearings. This method was applied for detection of inner material faults of bearing cages made of a synthetic. Presented are examples of faults occurring in objects made of two different construction materials. Documented was the impact of a forming tool construction on occurrence, size and location of internal faults in the form of voids and air bubbles. The carried out research confirms the great usefulness of the computer X-ray tomography method in diagnostics of the internal macrostructure of objects made of synthetics. The applied research instrumentarium enabled precise quantity and quality assessment of material structure faults in the form of air bubbles and voids occurring in synthetic bearing cages made of PA and POM. The computer tomography allowed testing of the material in relation to its geometric structure. Detected were material discontinuities and porosity assessment was made. The made tests showed important influence of the forming system construction solutions on the quality of a ready product internal structure. The received results document the direct dependence of internal structure faults from the effectiveness of mould cavity venting.
Keywords: roller bearings, internal faults, synthetics, tomography, bearing cages, tomograph
Grzegorz MOSKAL, Radosław SWADŹBA, Bartosz WITALA
Application of non-destructive 3D optical testing in assessment of the thickness and destruction of TBC layers
Presented is a possibility to apply the method of 3D laser topometry for the assessment of the thickness of plasma sprayed ceramic layers. For the measurements, the ATOS system developed by GOM has been applied what enabled performing of fast high-resolution measurements of objects. Analysed were TBC layers made on the basis of gadolinium zirconate and obtained on a real object which was a gas turbine rotor blade. The first stage of the research contained the assessment of the blade ceramic layer thickness obtained immediately after the process of thermal spraying. The ceramic layer thickness was measured in randomly selected locations and on the blade cross-sections. The obtained results are presented in the form of numerical values corresponding with specific locations on the blade, in the form of coloured maps reflecting the ceramic layer thickness distribution on a randomly selected cross-section and in the form of 3D maps. The variety of measurement results presentation forms allows localization of places on the blade surface which are characterized by non-uniform distribution of the measured layer thickness. Taking the advantage of the high measurement resolution of this method, the measurements of the blade surface after cyclic oxidation tests were made and the blade with an already sprayed layer was used as a standard. Such method enables localization of damage initiation sites occurring in the form of „puff-ups” and falling off of the ceramic layer in the early stages of a destruction process what is practically imperceptible when using a visual assessment only. The results obtained on the basis of such measurements, and especially the ones concerning the non-uniform layer thickness, become an important for technologists source of informations on thermal spraying process parameters. High resolution achieved in this method allows also observation and more precise localization of early stage layer destruction sites appearing in the invisible for a human eye form of the layer „puffing up”.
Keywords: TBC layers, 3D optical testing, evaluation of the TBC layer destruction level
Grzegorz GOLAŃSKI, Tomasz GARSTKA
Microstructure and analysis of Barkhausen noise in the area of the 7CrMoVTiB10-10 (T24) steel welded joint
Discussed are features of the new type of low-alloy steel 7CrMoVTiB10-10 (T24). Tested is its weldability without thermal treatment. Presented are preliminary results of tests including microstructure analysis and Barkhausen noise properties in the area of a welded joint. The tested fragment of the installation was collected from the steam superheater coil pipe working in a circulating fluidized bed (CFB) boiler. During the testing analysed was the influence of intensity and frequence of the magnetizing current on such Barkhausen noise parameters like rms value or a shape and location of characteristic envelope peaks connected with the microstructure. Magnetic research was preceded by tests and microstructure analysis carried out with the help of light and scanning microscopy of all areas of the welded joint. The tested pipeline section was operated in a 460 MW CFB boiler for about 12 000 hours, in the temperature of 5400C and with the pressure of 5,48 MPa. The analysed T24 steel uniform welded joint was characterized by the proper structure with no weld inconsistency. Observed in the weld was a lower bainite (or martenzitic-bainitic) microstructure characterized by high hardness. This high hardness of the weld after the operating time serves as a sign of a lack of the heat treatment - stress relief annealing after welding - and indicates the occurrence of the secondary hardness effect during the joint operating time. There is a strong connection between the measured Barkhausen noise parameters and the tested object microstructure. Observed is a great diversity in the envelope shape (amplitude and an envelope peak location) of the Barkhausen noise in the weld and in the native material. The profile of changes in the joint area correlates well with material hardness changes in the area.
Keywords: power thermal installations, low-alloy stel, steel welding without heat treatment
Janusz JURASZEK, Andrzej KACZMARCZYK
Identification of cracks in multilayer ropes by the steel ropes magnetic testing method
Presented are magnetic testing results of multilayer ropes with introduced damages and used in mine shafts. Complex structure of these ropes causes difficulties in identification of wire craks in their inner layers. The applied magnetic method enables quality and quantity assessment of a rope technical condition by obtaining diagnostic signals coming from cracks, abrasions and corrosion of a rope wires both visible (external) and invisible (internal) ones. Described are results of multilayer ropes magnetic testing in industrial conditions. Proposed is implementation of false damages consisting in cutting the wires in several places of a rope’s cross-section and a special test stand is built. Magnetic testing of multilayer ropes sections were carried out enabling the evaluation of possibility to detect the faults of inner layer wires. Assessment of technical condition of multilayer ropes working in a heavy loaded shaft in case when no clear signals from magnetic testing (coming from wire cracks) are ascertained, should be complemented with the analysis of the rope unit elongation. If this parameter is close to the one determined by the producer as the maximum allowable, we can expect wire cracks in the rope inner layers.
Keywords: steel ropes operation, measurements of a rope wear-out degree, magnetic methods of measuring a rope wear-out
Andrzej CICHOŃ, Sebastian BORUCKI
Practical example of power switch contacts wear-out level diagnostics with the application of an acoustic emission method
Presented is a practical example of an under-load tap changer (ULTC) diagnostics with the use of an acoustic emission method (AE). The research was carried out on the switch VEL 110-24 made by ELTA, installed in a 25 MVA distiribution transformer working in a power substation. The analysis of the obtained results was carried out in time and time-frequency domains. The description of AE signals generated by ULTC in a time domain was realized with the help of time patterns, Hilbert transform module and characteristic times. In a time-frequency domain the measured signals are described with the help of power spectral density spectrograms using the short-time Fourier transform. The determined descriptors of AE signals generated by the investigated ULTC are compared with results obtained in laboratory conditions and on this basis the attempt to assess the investigated ULTC technical condition is made. With the aim to verify the obtained results, measurements of the investigated ULTC, using an oscillographic method, were made and the internal revision of a power switch and a selector was carried out.
Keywords: power transformers, under-load tap changers, acoustic emission method
Sebastian BORUCKI, Andrzej CICHOŃ
The assessment of vibroacoustic parameters of a power transformer depending on changes in its load
Discussed is research on the development of vibroacoustic methods applied for diagnostics and technical condition assessment of power transformer cores. Presented are results of measurements and mechanical vibrations analysis of a 270 MVA unit transformer tank depending on its load change. The aim of this study was an attempt to determine the minimum power load level of the monitored power object which would enable the effective transformer magnetic circuit diagnostics based on the applied in our country criteria values.
Keywords: power transformer, vibrations, core, vibroacoustic method, diagnostics
Cecilia WETTERHOLM, Bruce PAHLAVANPOUR
Oxidation resistance of insulating mineral oil and its influence on the oil operating time
The insulating oil in a transformer has got three basic functions: insulation, cooling and maintaining of its functions for a longer period of time, and with the aim to secure these functions the adequate standards were implemented. The leading in the world two specifications of transformer oils are IEC 60296 (2012 ed) and ASTM D 3487 which enclose many specific requirements and limitations concerning both the physical and chemical properties alike. Many of these properties and their limitations result from chemistry of mineral oils in conjunction with specific requirements concerning electrical insulation. In the times when alternatives for mineral oils are being elaborated, it is very important to know what we really need and what is possible to achieve from the technical point of view. But for the present, when some transformer oil brands can merely fulfill their specifications, the other outdo them. In the end, it is a user who must make a decision which properties are the most important for a specific application. Technical specifications have also an influence on such questions like capital management, maintenance plans and investment budgets and, in order to facilitate making decisions in these fields, one must have some basic knowledge about specific requirements and limitations. An intension of this article is to supply some material worth consideration and helpful to understand the problem. However, there is too little valuable and even basic information concerning insulation materials and providing some knowledge about their behaviour in transformers after a long operating time. Such information would be very valuable from the point of view of a transformer operation protection (capital management) as well as for making the conscious choice what kind of insulating liquid should be applied in a new installation.
Keywords: transformers, insulating mineral oils, oil oxidation
Jacek TKACZYK
Selected aspects of electricity supply security in underground mining plants
Discussed are selected aspects of electric energy supply security in underground mines on the example of the group 2 transformers operated in distribution substations that are a component of internal HV and MV installations and distribution networks, as well as supplying objects, machines and appliances according to competences of the Specialized Mining Office. Reliability of electrical energy supply in the aspect of securing the maintenance management of basic installations, machines and appliances working in underground mines is particularly important because of the fact that the maintenance disturbances in most cases generate, or are able to generate, the instantaneous threat to people, property and environment as well as to the mining enterprise. Supply reliability is an indispensable element to secure output continuity and achieve the assumed economic effects. Transformers mounted in distribution transformer substations are the last link in the domestic power system supplying basic objects, machines, installations and distribution networks of underground mining plants. The necessity to maintain the electrical energy supply reliability brings about a situation in which one of the most important problems is a properly carried out transformer operation and especially the early detection of important changes in the transformers technical condition. The present measuring methods of electrical oil chemical constitution, winding insulation condition, functioning of under-load tap changers etc. enable proper diagnostics and taking up the planned overhaul activities ensuring lifetime elongation of the transformers in operation and also avoiding their failures, creating direct threat to running the underground mining plants.
Keywords: underground mining plants, electrical energy supply, transformer investigations
Jan SUBOCZ, Marek SZROT, Janusz PŁOWUCHA, Andrzej MROZIK
New assessment methods of transformer bushing insulation
A survey of basic mechanisms of bushing insulation thermal ageing, relaxation processes and the applied standard diagnostic methods was conducted. Ascertained is that these methods are mainly based on measurements of dielectric loss coefficient at the frequency of 50 Hz. However, the problem analysis shows that interpretation of these measurements leads often to wrong conclusions, that results in non-adequate diagnosis with relation to the actual condition of the insulation. The most important problems of tgδ 50 Hz value interpretation are connected with the measurement carrying out methodology and especially with applying a lower measurement voltage in comparison to the operating one, measurement temperature differing from the internal one and the measurement little dependence of insulation structure changes. Presented are investigation results of the influence of various bushing OIP and RIP insulation failures on the dielectric response. In particular, measured was the influence of the moisture, gases contents and products of paper and oil decomposition in OIP insulation on tgδ values in a wide frequency spectrum as well as the polarization index obtained by the step voltage method (SVM). Presented are also investigation results of the influence of thermal ageing, partial discharges (PD) decomposition products and the presence of moisture in RIP insulation on relaxation processes measured in time and frequency domains. They show that the insulation dielectric response depends on the type of the failure and on the bushing construction (OIP or RIP). Ascertained is that, from the practical application point of view, very promising methods with a higher OIP and RIP insulation technical condition assessment reliability can be the measurements made with the use of a step voltage method (SVM) or the analysis of PD characteristics. Presented are also operational measurements carried out on 110-400 kV OIP and RIP bushings that generally confirmed the observations taken during the model investigations.
Keywords: power transformers, transformer bushings, bushing insulation
Marek SZROT, Janusz PŁOWUCHA
Elongation of the life-time of power transformers
Maintenance management service, in both industrial and power engineering, and also the persons responsible for development and investment planning are under the constant pressure of increasing the reliability with simultaneous reduction of outlays on the current operation. Transformers are one of the key-links of the supply chain from either technical or economic point of view. At the same moment the statistic data show that their average age exceeds the assumed by designing engineers 30 years of a life-time. Taking the above into consideration it is obvious that their replacement with the new ones is impossible. So, in this situation, the elongation of transformers life-time becomes a must, and then the bearing of necessary costs and a risk connected with such operation are the most substantial problems that the operational services must face. Maintaining reliability on an acceptable level creates the need of detailed and reliable technical assessment of the units destined to the life-time elongation that, in turn, is connected with carrying out their complex diagnostics. Modern approach to transformer diagnostics is based on a multiparameter assessment of their technical condition and determination of operational perspectives. Making use of diagnostic tools and a many years’ experience, Energo-Complex company elaborated and implemented TrafoGrade System which is very helpful in management of big power transformers populations. Presented are in short the system TrafoGrade principles and an example of application of this system in an underground mining plant as a basis for making decisions concerning elongation of transformers life-time.
Keywords: power transformers, diagnostics and elongation of life-time, information system for transformer management
Elżbieta MORYŃ-KUCHARCZYK
The place of solid fuel gas-steam power plants in the „energy mix” of the future
Described is the present condition and development prospects of integrated gas-steam systems of IGCC and PFBC type used in electric power industry. The carried out SWOT analysis confirmed a great potential of these solutions both from the power industry and environmental protection point of view.
Keywords: gas-steam system, IGCC, PFBC, environmental protection, SWOT analysis
Jarosław OSIAK, Adam KUPCZYK, Adam STĘPIEŃ, Ewa GOLISZ
Present condition and future prospects of bioethanol sector in Poland against the international background
Discusssed is the history of ethanol production in Poland. Attention is called to the fact that the fuel produced from ethanol was for the first time used in Poland in the year 1928. Domestic production abilities of the first generation (produced from edible plants) ethanol used for fuel purposes amount to about 750 million litres per year. Disadvantageous global surrounding and its competitiveness have unfavourable influence on the domestic bioethanol sector. Transport biofuels, used at present throughout the world, are the first generation bioethanol and biodiesel produced mainly from agricultural raw materials which are at the same time used for consumption purposes. Bioethanol makes 75% of the world production in volume while the remaining part is biodiesel. The European Union is the biggest biodiesel producer in the world (for many years Germany is in the lead) whereas bioethanol production on the old continent seems to be very minimal in comparison with the production scale of global leaders in this field i.e. the United States and Brasil. Only less than 30% of the domestic demand for bioethanol comes from our market. Substantial influence on the present recession in this field can have promotion of second generation fuels produced from inedible plants. Domestic bioethanol sector is in the second generation bioethanol production far away behind the world and European leaders. On the stage of deregulation of the alcohol products domestic sector (years 1996-2000) nobody was thinking about creating the development strategy of distillery and bioethanol sector which is, after all, technologically connected with alcohol industry. It seems that such necessity is just arising and should comprise both biofuel sectors: of the first generation and the just originating sector of the second generation transport biofuels.
Keywords: renewable energy sources, transport biofuels, bioethanol
Marek MOKWIŃSKI, Zdzisław PAWLAK, Jerzy PRYWER
Who will invest into the Polish wave energy converter? (debate article)
Presented is Mr Zdzisław Pawlak's invention allowing effectively make use of sea waves for production of electric energy by means of the so-called energy converter i.e. transverse axis type two-stage turbine called "the Pawlak turbine". The solution was patented but no production has been taken up so far. Prototype investigations carried out at Politechnika Łódzka confirmed advantageous features and results obtained by Pawlak's Converter. The well-known abroad installations like Pelamis-2, serving the energy convertion of sea currents and waves, are complex and very expensive as well as hardly effective and uncomfortable to use. They are not resistant to swinging motion and resonance phenomenon connected with magnitude and frequency of sea waving. The proposed Pawlak Compact Turbine converts all sea wave lengths with the same efficiency. Situated among the Pelamises, and even coupled with them, will increase wave energy converted from the same sea area. The compact turbine is a construction around 9 times lighter than a Pelamis, so 9 times smaller amount of materials will have to be used. Assuming that these materials will be of a better quality (stainless steel) so more expensive respectively, the Pawlak turbine of the same output power will be about 5 times cheaper than a Pelamis converter. When choosing the adequate generators for that new turbine it is advisable to use asynchronous generators with possibility to overload them for another 50%. It will enable working with double power in winter months as - e.g. in Ireland - the wave power then is at least doubled in comparison with the normal generated power mean value. Such solution can be justified by the fact that the cost of asynchronous generators is very low and will not have much influence on rising of the project costs - the Pelamis converter in such situations is limiting the power capacity. And yet another fact - commercial price of a ready-to-work Pelamis converter amounts to 1 000 000 USD while the one of the comparable Pawlak converter is less than 100 000 USD.
Keywords: sea wave energy converter, two-stage transverse axis type turbine, utilization of sea waves for energy production