Category Archives: SonSolar

Information material

With the help of my father, I also succeeded to get the literature I needed for my work. In general, the search for adequate literature as well as the getting of it is not very easy for students.

First we have to know where and how to seek. Second we have to come to know which literature is understandable for us as students with relatively poor knowledge, and this, often without haven’t yet seen the literature. Third we have to choose out of this a sample that gives us all information we need for our work. And fourth we have to find out if the information given in this material is reliable. For all this, help from experts is needed, and teachers are often overtaxed with this task.

I myself have begun my work with an internet search. You can find much in the internet about future energy issues, especially also very actual information. But it is not good structured, and out of the waste information only a small part is usable for a Facharbeit.

A big problem, especially in future energy issues, is that you haven’t got the guarantee that the facts presented are objective true. Even if you get your information out of serious books (we luckily have a lot of them at home) you cannot be sure if the information given is reliable. Special people who work for the industry or want to sell something may have interest to falsify information. Thus you can find many contradictory reports or fact presentations and you do not know which one you can really trust.

My teacher could not help me in this question. He is not an expert in this field (how could he be?). The only thing I could do, was to collect first all information I could get and compare the single presentations in order to find similar information given by different authorities. But even then you cannot be satisfied because you still do not know if this information is right.

Another point is, that you have to collect much different information in order to get this way just a little security that the information you use in your work is reliable, and also in order to get all the needed information for the work. The internet sources are not enough. So it is necessary to have the possibility to use good libraries which have books about your working theme. But you cannot find such libraries everywhere. Normally only libraries of universities with nature or engineering sciences or have sufficient technical literature. With respect to future energy issues there exists a special financial problem: Actually university libraries in Germany have not got enough financial resources to be all up to date in fields developing as fast as that one of renewable energies.

But even if the desired literature is available in an university library in the surrounding area of your home, there exists a further organizational problem. In Birkenfeld for example the next university library with sufficient literature is about 60 km away, if you travel by car (but the most school students cannot travel by car!).

The library of the Umwelt-Campus Birkenfeld is up to now not completely built up and comparably small. With trains and busses the way is even longer and costs a lot of time. I myself have every day at least until half past three in the afternoon lessons at school, and thus it is nearly impossible to visit a university library.

Course structure

The 12-months programme is divided in three parts, getting progressively more and more practical:

The “core” provides a firm comprehensive background in the key renewable energy technologies (wind, sun, biomass, water). It concentrates on energy production and use and addresses the socio-economic context. Mostly theoretical courses are completed with laboratory workshops.

The “specialisation” focuses on the specific technology and implementation aspects of one renewable energy discipline of the student’s choice: Wind energy, biomass, photovoltaics, hybrid systems, or solar energy in the built environment. In-depth theory classes alternate with extensive practical work in laboratories and testing facilities, while study excursions illustrate real-life implementation.

The project is the opportunity for students to apply and further develop the skills acquired in the technology of their specialisation during a placement in a renewable energy company or a research centre. A tutor from the host company supervises and guides the student during project work, while a second supervisor from the university at which the student will undertake his or her specialisation helps the student with his/her project work.

Industry relevant education

The balanced mix of theoretical and practical courses optimally prepares graduating engineers for jobs in the growing renewable energy industry. Both core and chosen specialisation include laboratory assignments since practical and experimental skills are regarded as important for the potential employers. An extensive 4-months company placement for hands-on project work is an integral part of the programme. It provides students with valuable working experience, while allowing companies to fill their short-term human resources needs and to “try out” potential future employees. Companies are encouraged to contact EUREC Agency with a project proposal they would like to have a trainee for. EUREC Agency then finds trainees for them. All trainees already hold an engineering or other relevant degree and have followed the European Master in RE core and specialisation by the time they enter a company; they are already junior RE experts.

Green energy fraction (GREF) equations

In terms of fuel quantities, the general equation for the green energy fraction (GREF) of a solar power plant system is, by definition,


GREF = (gr baseline — gr input)/ gr baseline

GREF = 1 — (gr input)/(gr baseline)


gr input — — total fuel consumption in the hybrid system

in grams per 1kWhe net electrical plant-output (gr/kWhe)

gr baseline — — 160 gr/kWhe, the specific fuel consumption of the chosen reference system (baseline standard), (for visualization, a CC using fuel of around 9000 kcal/kg)

For simplicity, both the hybrid system and the reference power system here use the same fuel. It should be realized that the grams-ratio expressions signify the inverse efficiencies ratio. The use of grams emphasizes the requirement that any fuel used in the plant should be counted and included in the equation.

The concept of fuel avoidance requires to compare the fuel-blended, renewable hybrid system to a baseline standard, which is a real, competing, efficient, non-renewable system, set as reference. On circumstances where CC systems cannot be considered as a useful alternative fuel fired electricity generator, thence the 60% baseline becomes impractical. Then, another a locally competing, fuel-fired, efficient system is to be selected for reference standard. Thus, the 40% Rankine-cycle system may serve as a secondary standard against which solar systems will have to compete. In such a case, because by definition the green energy is a functionally reference-dependent parameter, the resulting value for the green energy fraction will be different.

Transformation of a green energy fraction from one reference standard to another can be performed by


GREF1/GREFF2 = (B2/B1) (B1-gr)/ (B2-gr))


GREF1 — — green energy fraction 1 GREF2 — — green energy fraction 2

B1 — — baseline 1- — in gr/kWhe, (reference standard 1)

B2 — — baseline 2- — in gr/kWhe, (reference standard 2)

gr — — the total fuel consumption in grams by the hybrid system, per 1kWhe net

plant electricity output

This equation converts a GREF 1 of baseline 1 to GREF 2 of baseline 2. It is significant for enabling comparison between technologies and systems.

The Pyrheliophoro

II.1- The first steps: the metallic lens

Father Himalaya, from his early days, saw solar energy as means to provide energy not just for the production of hot water or steam, but as a direct means to provide energy for industrial processes, in particular to those associated with materials production or processing, if high enough temperatures could be achieved. Among other objectives, he wanted to produce nitrogen based agricultural fertilizers by extracting the nitrogen directly from the air! He could never achieve that with his devices, as we can today well understand, but he managed to achieve perhaps the highest controlled temperatures of the day, about 3800°C, in the solar furnace of his pyheliophoro, a truly remarkable achievement.

If not before, at least in Paris, at the end of the turn of century, he became quite likely familiar with the works of A. Mouchot [2], Louis de Royaumont [3], Charles Metelier [4]. Also, mainly from his corresponcence and from documents found among his belongings, it is fair to assume that he must have had some degree of familiarity with the works of John Ericson [1,8] W. Adams [1,8], Calver [1,8,5], Aubrey Eneas [1,6,7,8], among others.

He was critical of the devices produced by Mouchot-Piffre, and soon understood that he needed to modify them in order to obtain higher temperatures and also in order to break the mechanical coupling between the solar furnace ( placed in the "focal zone") from the structure supporting the mirrors. If possible he also wanted a stationary solar furnace, while only the optics would do the necessary tracking of the sun’s apparent motion in the sky.

In Fig1.(a) the device developed by Mouchot-Piffre is shown, a paraboloid like shaped structure with reflecting inner walls, and a furnace place along its optical axis.

(a) (b)

Fig.1.- (a) Solar device of Mouchot-Piffre (b) parabolic trough of Ericson

Truncated cone like shaped mirrors (Eneas Fig.1. (c)[6,7], Pasadena, California, 1901) and large flat ones (Calver, [5]Tucson, 1901) were among some of the solar optics of the day. John Ericson [1,8] proposed a parabolic shaped mirror in 1880 (Fig. 1(b)), but Himalaya’s ideas went in rather different directions.

References [5,6,7] are explicit instances of Portuguese magazines dedicating space, in those days, to those and other inventions and F. Himalaya likely read them. It was not possible to consult the referred magazines and therefore their level of technical detail is not known to the author. However these were publications for a general audience and little should be expected beyond some photos or drawings and a reference to the purpose of the inventions. .

To the interested reader the author recommends the first section of a modern book [8] containing an interesting introductory chapter on the history of solar energy. This book makes an explicit mention of Father Himalaya and his crown solar achievement — the Pyrheliophoro — at the St. Louis Fair of 1904.


Fig.1. (c) — solar experimental apparatus of Eneas

He soon understood that the very high concentration factor he needed required two axis type tracking. With materials processing in mind, he needed solutions that would not have, in his own words, "the furnace between the reflector and the sun”. He thus first thought of lenses to do the job, since these could send the concentrated light down and out, towards the target. However the required dielectric (glass!) lenses were not a practical idea in those days and his first remarkable attempt can be seen in Fig.2 and 3. It is a metallic Fresnel lens type, done with flat-strip — mirrors, ring shaped, the whole ingeniously tracking the sun in elevation and compensating for the earth’s rotation, by moving together on circular rails.

Fig2.- Figures from Patent [10]

Fig.3(a)- the device and Himalaya standing in front of it, in Paris

His experiments were carried out in the French Pyrenees, (Castel d’Ultrera) not far from Odeillo and Font-Romeu (of later day fame, for very similar solar reasons!)

The results he obtained were not as good as he expected, but it seems that he was able to achieve temperatures in excess of 1500°C (melting iron), a remarkable achievement, given the choice he had of materials for the mirrors, and a good measure of the mechanical precision with which he was able to produce his device. It should be noted that the solar furnace itself was object of careful developments, to be able to contain the materials he was melting/processing with it. His temperature measurements were crucially dependent on what he was able to melt.


Fig.3(b) — the device at Castel d’Ultrera

In fact the furnace itself was the object of patents, perhaps the most important of which being Patent [9].

Fig.4 is taken from that patent, showing a radiative type furnace, where the side walls c, c’ were to be heated with the burning of fuel and the heat radiated into the triangular shaped cavity was to be concentrated (focussed) down onto the hot cavity F, by a paraboloid shaped upper wall d. This furnace was later very easily (and much better) adapted to the solar focussing optics to be described next, with solar radiation coming trough an aperture placed in d and the side walls c, c’ now serving as a second stage concentrator.

In the process of these developments he invented also a radiometer — to measure solar radiation intensity using his metallic lens concept.

Solar Cell Structures in the Near and Distant Future

Many specialists share our opinion that in the near future a change of paradigma will occur in the solar cell production. It means that instead of elemental semiconductors, compound semiconductors will be used as solar cell materials [3]. The indirect energy band transition of silicon is not really suitable for optoelectronic devices. The reasons for using it in the fabrication of solar cells are: it has a stable technology and the relaively low price. The amorphous silicon is a more suitable material, because there is no longdistance orderlines of atoms, so the fine energy structures are undefined. The technology of amorphous silicon is made with chemical vapour deposition or sputtering. Its band gap is strongly technology dependent. High efficiency solar cells can be produced from direct band structure materials e. g. from galliumarsenide. For the selection of suitable semiconductor materials their electronic band structure has to be known. It is also important to know the absorption coefficients of these semiconductor materials. The most efficient solar cells are made from galliumarsenide, their efficiency is over forty percent. In the case of latter materials instead of the pn-junction one can use the built-in electronic field generated by different layers (so-called heterostructures) which are grown above each other, by metal-semiconductor interface (so-called Schottky junction) or by electrolyte junction. These materials are e. g. cadmiuntellurid, cooper-indium-diselenide and the above mentioned amorpous silicon or silicon- germanium. Because of the high absorption coefficience of the above materials thinner absorption layer can be used, too. These structures can be produced with different thin layer technics. Some of these materials have bad transport properties, therefore on these materials there are grown wide band gap, transparent and well conducting materials. They are e. g. zincoxid, tindioxid. These so-called windows materials serve not only as a transparent electrode but as antireflection coating and heat mirror, energy efficient window, as well. The window layers can be produced by thin layer technics, too.

Activities for the change

A great deal needs to be done to overcome the main problems in the development of renewable energy sector. The national RES strategy places specific obligations on the Government, while specifying tasks for the Ministers of several sectors.

The government strategy is to be evaluated every three years and recommendations concerning necessary changes and solutions will be proposed. A detailed inventory of renewable energy installations in Poland will be carried out and the results published in Statistics Yearly. A database of available renewable technologies should be created.

Tasks to implement the strategy include not only organisational activities within the Government, but legal actions such as executive regulations, assistance provided to the local and regional authorities in the preparation of energy plans, simplification of licensing procedures for electricity generation from RES etc.

As instruments enhancing economic viability of RES in the initial phase of the implementation of investments, specific funds are allocated from national and foreign institutions. Financial support for beneficiares and investors in the form of grants or preferential loans is available, though with some difficulty. National institutions such as: National Fund for Environmental Protection and Water Economy (NFOSiGW), Regional Funds for Environmental Protection (WFOS), Bank of Environmental Protection (BOS), EcoFund Foundation (EKOFUNDUSZ), Thermo-modernisation Foundation, Foundation for Support Programs for Agriculture (FaPa) and Techniques and Technology Agency (ATT) are engaged in allocation funds to RES purposes. In the framework of international co­operation EU pre-accession funds (ISPA, SAPARD) and PHARE have been launched. Participation of Polish partners in research and demonstration projects of European Union (FP5, FP6, ALTENER II, SYNERGY) is a support and good possibility to implement new techniques and technologies. Bilateral funds and others could be of assistance to Polish investors. These instruments should be resorted to until renewable energy sector is fully competitive on the market.

It must be emphasised that the development of the green sector would be of great benefit to the environment and to the regional and local communities in creating new jobs. And above all, diversification and decentralisation of the Polish Energy sector would contribute to security of energy supply.

Closing the experience gap in the field of PV energy. with training of social, technical, financial and business management skills

Georg Bopp, Sebastian Golz, Felix Holz, Werner Roth, Gisela Vogt
Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr.2, 79110 Freiburg, Germany
Tel +49 (0)761/4588-5228; Fax: +49(0)761/4588-9283; sebastian. goelz@ise. fraunhofer. de


Education, training and awareness raising is recognised to be a main task for the development of markets and technologies. One reason for the failure of many projects and programs of rural electrification attributes to the lack of knowledge, training and competence of participating people at all levels. (International Energy Agency IEA, 2003).

All these alerting experiences advise that different accompanying measures have to be considered in line with designing and implementing solar power systems. Both in grid coupled and off-grid markets cultural, social, economical, organisational, and financial aspects have to be incorporated (Will & Vogt, 2003). Various competencies and skills are required to plan, implement, commission, and promote solar power systems. Therefore the substantial objective of this article is to illustrate the spectrum of relevant training topics, to report from current state of knowledge in two exemplary markets and to describe the profit of customised training programs.

1. Training and further education for comprehensive market support

At all levels of off-grid and rural electrification projects an extensive demand for training can be identified (Vogt, Will, & Sauer, 2003). Investors, politicians, planners, installers, suppliers, users, and service personnel frame the target groups of different training programs. During the last years, the Fraunhofer Institute for Solar Energy Systems ISE has conducted various projects (SUNRISE, SOPRA-RE; SOLTRAIN) to design and to accomplish training concepts for these target groups. Starting from these experiences Fraunhofer ISE offers a broad assortment of programs for further education. The various job training, designed and applied by an interdisciplinary team, cover the following target groups and topics as listed in chart 1:

Study profile

The University of Applied Sciences Nordhausen pursues a fundamental system — oriented education in the domain of development, planning and operation of renewable energy systems. In addition to solid engineering basics the energy — and process-related principles of solar thermal, photovoltaic or wind energy systems and their integration into existing — and here in particular electrical — supply systems takes the centre of the training. Special attentions will be put to renewable energies in the vehicle technology — keyword fuel cell — and to bio energy systems.

Fig.1: System expertise is more than feeding electric energy into the public power supply

Graduates of this study program are to acquire expertise of renewable energy systems. This means for the example of a wind power plant knowledge of the fluid mechanics at the rotor, of the shaft bearing, of the conversion of mechanical into

electrical energy and of the feed of the electric energy into the public power supply system. In order to open the graduates a broad spectrum of vocational possibilities, the training also involves classical power engineering and additional subjects. Latter are for example information and diagnostic systems, management in the energy industry, energy law or the use of recycling materials for power generation.


To meet these requirements, a three-level model (Fig. 2) was developed which clarifies the study contents for the curriculum.

level I: energy sytem

level II: sytem Integration

level III: Implications

Level I: Energy system. The first level deals with basics of power engineering, power converters and energy transport. This covers work and power machines, cooling and heating up to photovoltaic and bio energy systems.

Level II: System inte­gration. The second level concerns with system engineering. This includes technical diagnosis as well as technical management of energy or buildings. Level III: Implications. for example energy law

The ongoing working process

Other organizational problems result by the prevailing conditions given in every day school life. During the working period on the Facharbeit students have to meet their supervising teacher several times to give a report about their work and discuss how to proceed further. But it is hard to find a date when both, teacher and student, have the needed time. That is why you get into a big pressure of time. This is unsatisfactory as well for the student as also for the supervising teacher. I myself had problems of this kind.

Additionally, the missing experience of teachers in guiding a Facharbeit results in many misunderstandings between teachers and students, and in ineffective work.

Sometimes the students have bad luck with their supervising teachers. At the very beginning some teachers say that they will guide a student’s work and afterwards they show no interest at all in this work, or they say that they have no time for the next few months to do anything to help the student, or they let the student work and do not even read during the working period the single text parts the student has written. This all happened to several friends of mine in my grade. In this point I was more lucky.

Successes and insights I won

In spite of all the difficulties I do not regret to have worked on a Facharbeit. Contrarily, I have won a lot of valuable insights. First, I have learnt a lot about a topic of my interest. Second, I performed a research work that requires another way of working, thinking, organizing and structuring as usual school work. Especially the kind of presentation and to work out a paper in scientific manner are valuable experiences far beyond of the skills usually learnt at school.

A special highlight was the participation at the competition “Jugend forscht” where I presented together with my sister Inge a part of my work. We received a lot of acknowledgements: the first price in the field of technique, the special price for environmental technique and the price for innovative work done by females. In the higher level we were proud to win a practicum at the department of inorganic chemistry at the university in Mainz.

A European Master run by renewables-experienced universities

The EUREC member network of renewable energy research centres covering all EU member states, the European Master in Renewable Energy has been designed in cooperation with nine universities in five EU countries, with each institution adding its specialised technological knowledge to the programme.

The core is taught by universities having a strong record in general renewable energy technology teaching: Students can follow the core alternatively at the following universities:

■ Loughborough University, UK (language: English)

■ Carl von Ossietzky University at Oldenburg University, Germany (language: English)

■ Universidad de Zaragoza, Spain (language: Spanish)

■ Ecole des Mines de Paris at Sophia Antipolis (Nice), France (language: French) The core lasts from October to December and ends with a series of exams.

The specialisations take place at universities with a specific focus on one renewables technology: As specialisations, all taught in English, are available :

■ Wind energy — at the National Technical University of Athens, Greece

■ Biomass — at Universidad de Zaragoza, Spain

■ Photovoltaics — at University of Northumbria at Newcastle, UK

■ Hybrid systems — at Kassel University, Germany

■ Solar buildings — at University of Athens, Greece

The specialisation lasts from January to April and ends with a series of theory and practical exams.

In later years, it is expected that the list of specialisations available will grow. A specialisation in water power (to include micro-hydro, wave and tidal power) would be especially welcome and relevant as this technology is expected to soon reach a commercial stage.

A truly European course

Different to the few other existing Master-level RE courses, the European RE Master plays the European card: students are required to study in at least two different European countries. This feature reflects the fact that there is at present a tendency to cross national borders and set up foreign representations or carry out project work abroad, even for small and medium RE companies. Clearly, intercultural awareness and foreign languages are assets that present a plus for any employer today.