F. Minissale, G. Viglianesi, M. Catena
ENEL, Passo Martino Zona Industriale 95121 Catania, Italy
Tel +39.095.7481273, Fax +39.095.291246, E-mail francesco. minissale@enel. it,
giovanni. viglianesi@enel. it, mario. catena@enel. it

Summary

ENEL, the Italian Electric facility, carried-out the realisation of a Hybrid plant in Ginostra, an isolated village of Stromboli Island, to comply with the specific needs of the residents, taking into account the available energy resources and the prescription of the Sicilian Environmental Department for the Aeolian Islands. The plant consists in a stand-alone system feeding an isolated electric mini-grid that is developed for about 2 km to reach all the village houses even the most remote ones. The specific peculiarity of Ginostra village is a high variability in the residents’ number: about 50 people in winter and approximately 600 during July and August. So as to reach a best exploitation of the production capacity of the plant, a desalination system will be realised in a second time and it will constitute a periodical load to store water during the low occupation period (winter) and cover the demand in the summer. The plant realisation, financed by the Sicilian Regional Administration with 2,8 Million EUR, has started on July 2003 and its completion was on February 2004. Also the works for the mini grid realisation were completed for that period. The plant is already in operation.

ENEL performed the design and the realisation of the PV-diesel Plant, putting it in running condition and for the following seven years will supply the plant normal operation, assuming the burdens of the system ordinary maintenance.

The visual impact of the plant and of its support infrastructures are rather reduced, thanks to the selected position, visible only from mainland and from few areas. To such aim the typical plants of the Mediterranean bush, present in the PV-plant area, have been preserved in a nearby land, so as to be able to be put back again around to the PV-plant area in order to reduce its visual impact.

Akos Nemcsics, College of Engineering Budapest, Tavaszmezo str. 17, H-1084 Budapest, e-mail: nemcsics. akos@kvk. bmf. hu

In this work we will present a novel household waste management which involves traditional composting, special compost toilet and special sewage management with solar energy utilization.

The Basics of the Ecological Waste Management

The appropriate waste management is one of the most important enviromental problems. One kind of these problems is managing water-pollution and sewage. It is well known that the cleaning of diluted sewage is more difficult than that of the concentrated one. The further problem is the mixing of different dirts in water. The different sewage with different origins and with different dirts needs different cleaning mechanism, too. In spite of this fact canalization is not performed according to this idea. Instead of the large size waste management the effective solution should be small-size local management. The solution is partly the economical treatment of water and partly the selective sewage similar to the selective litter collection.

In this work we will present a new household waste management which involves traditional composting [1], special compost toilet [2] and special sewage management. One of the most important problems of the compost toilet is the size which is a very huge barrier of its wide-spreading. We introduced a small, simple and portable thing just two years ago. During this time we have not had negative experiences with the use of these things. This year an action has been started to collect further experiences concerning this toilet [2]. The basic part of this toilet is a commercial plastic tank. The complete equipment can be home-made very easily. So, in our case the household sewage contains only water from the kitchen and from the bath only. This water is collected into a large tank and cleaned biologically. The wasted water is circulated and aired with the help of electrical pumps. Solar cells supply the electrical energy for these pumps.

The monasteries of the Serbian Orthodox Church were, as a rule, built at hidden, sunny locations — at foothills, in ravines and alike. As the jewels of our cultural heritage, monasteries are the places of pilgrimage of a large number of well-off people (possible sponsors) from all over the world.

Although majority of the monasteries is connected to power grid, within monastery buildings there is a wide space for application of PV modules (for lighting of monk and set — aside cells, pump drive and alike). For example, in Serbian monastery Hilandar ar the Atos peninsula (Greece), during 1995, and 1996, two PV systems (360 W and 433 W) were installed with 500 and 1,470-Ah accu-batteries, respectively. [13]

Wise utilization of solar energy in monastery objects, due to emulation affect, should be soon implemented in town and village churches, too. Solar lighting of church yards as the place of spiritual gathering of people may, same as at schools, serve an impressive example of demonstration of application of solar cells.

Without more detailed analysis of this unusual market for solar cells, we assume moderate increase of implementation from 20 kW in 2006, to 130 kW in 2010. (Table 9.).

In order to overcome these existing market barriers an expert working group was set up with participants from major german housing associations (GdW, BfW and Haus&Grund), decisions makers from experienced housing companies and

the initiators Federal Environmental Agency, the German Solar Industry Association (BSI) and Berlin Energy Agency to discuss promising instruments.

As a first step a clearly focussed information campaign was designed to inform decision makers within housing companies about the current state of solar collective technology by means of successful projects from housing companies.

In order to get information on a more regular way to the target group, professional articles were prepared in cooperation with different experts for association-linked magazines like "Die Wohnungswirtschaft” and “Freie Wohnungswirtschaft”. The articles were ment to inform actors about situation and prospects of solar collective systems for multi-family buildings as a more general overview. Furthermore the conference “Solarthermal for Multifamily Houses” organised in the frame of the trade fair Solarenergy in May 2003 in Berlin, was announced in these articles as well as the launch of the internet plattform www. soltherm. info.

The internet platform is addressed to attract building owners and building caretakers who are considering the use of solar thermal systems. Besides general technical and framework condition information the site contains different best-practice examples, which are presented in a consolidated way and give direct contact information to involved employees of the different housing companies. The selected examples in Berlin, Gelsenkirchen, Hennigsdorf, Kassel, Munchen and Linz are spread across the country in order to give potential buyers a chance to contact companies in their region.

The internet plattform and the published brochure invite the readers to contact the Berlin Energy Agency for further assistance in case they would like to develop an own solar collective system project. In the frame of the initiative the experts of the Berlin Energy Agency can provide manufacturer independent advice.

The mentioned brochure was developed in close cooperation with members of the expert group, and is sent to interested persons on demand. Furthermore the brochure was distributed to all 5000 members of the 2 main housing associations GdW and BfW, financed by the Federal Environmental Agency and the two associations. A second print run was done to cover the needs of several BSI member companies.

Additionally, presentations are being held during real estate events to attract decision makers for solar thermal projects.

While these growth trends are only suggestive, it appears that this finance mechanism is emerging as a viable method for deploying PV in multiple sectors. However, the practice faces several barriers to continued growth:

1. Absence of performance contracting authority: In some states, no legal authority for performance contracting exists.

2. Low maximum contract terms: In the states where performance contracting authority is in place, maximum contract terms can vary by state. Term ceilings of 10 years or less, for example, may not allow enough flexibility to bundle PV into performance contracting. This is also true to some extent at the Federal level. While 25 years is the maximum term government-wide, some agencies have established their own, lower term ceilings (Strajnic, 2003).

3. Over-dependence on rebates: Almost all of the projects in the survey relied on rebates to drive the contract economics. A change in the policy environment could suddenly limit or eliminate available rebates. This could result in the scaling back or outright cancellation of PV performance contracts. In light of this vulnerability, PV performance contracts may have difficulty penetrating both rebate and non-rebate state markets.

4. Limiting life-cycle analysis criteria: While the Federal government encourages its facility managers to evaluate projects based on their overall life-cycle cost — effectiveness, there is no such directive in place for state and local government. Negotiations for a potential PV performance contract in New York almost collapsed, for example, because each component was evaluated separately for life-cycle cost- effectiveness (Simpson, 2004).

5. PV’s lengthy payback term: Government officials, ESCO representatives, or both may refuse to incorporate PV in performance contracts because of its lengthy payback time. Many ESCO industry representatives and clients view PV as a niche technology whose value does not offset its impact on overall contract term (Hall, 2003). As a result, other technologies with shorter-term payback technologies are often prioritized over PV (MacIntosh, 2003).

6. Decision maker reluctance: As Hughes et al. (2003) report, some institutional decision makers are fundamentally wary of performance contracting and prefer to rely on direct appropriations. Others are hesitant to enter into lengthy financing terms because existing debt may affect a facility’s ability to borrow new funds (Anderson et al. 1999).

7. Lack of inter-industry collaboration: For PV industry stakeholders, performance contracting represents a potential vehicle for their products and services. For some ESCOs, however, PV represents a technology that increases contract transaction costs without providing much perceived value to the company. When such perceptions are prevalent, the inter-industry partnerships necessary for PV performance contracts can be difficult to establish (Dominick, 2003).

While these barriers may not easily be resolved, there are a number of policy options that could mitigate their effects. The first four barriers, for example, could be lowered through regulatory directives or legislation. The remaining three barriers could be targeted by a combination of training, information dissemination, and incentives. To encourage facilities, ESCOs, and PV firms to proactively develop projects, for example, government could establish a low-interest loan fund that specifically targets PV in performance contracts (Stronberg & Singh, 1998).

In April 2001 LABSOLAR installed the first hybrid Diesel / PV system without storage in the Amazon. This 20.4kWp PV installation was added to an existing Diesel mini-grid to demonstrate the economic and technical potential of designing medium to large systems without battery banks for the supply of villages in the Brazilian Amazon region, where hundreds of mini-grids fed by Diesel thermal units exist [4,5]. In this particular case, the daily load to be covered amounted to some 700kWh, with two 56kVA Diesel gen sets providing constant power to the mini-grid, with the line-commutated sinewave inverters connecting the PV system to this grid whenever there is photogenerated power available to be fed to this mini-grid. For small PV penetration levels like the one proposed in this project, it was demonstrated that the absence of battery storage can be an advantageous strategy, with economic and environmental benefits in terms of reducing Diesel

The system described in the paper consists of three elements: supply system, water ozonizer and water circulation system. Schematic diagram of the system has been presented in Fig. 3.

1.1. Supply system

Photovoltaic test stand to conduct the research on using solar energy has been situated on the roof of the four-storey building in which the Institute of Electrical Engineering and Electrotechnologies is located.

The following elements constitute the system:

— photovoltaic panels BPS 275 BP Solar; total power 6x75W=450W,

— accumulator battery BP Solar 12V, capacity 640 Ah,

— control system BP Solar,

— Trace DR1512 inverter,

— PCL 818 HG Advantech measuring card,

— PC Pentium,

— CM 3 pyranometer,

— voltage divider system with 12V measuring card,

— analogue meters with current and voltage shunts in meter circuit.

In order to improve the usage of solar energy reaching photovoltaic panel buffer sources are usually applied which accumulate the surplus energy that is not used by the receiver. Accumulators are most commonly used especially because of the fact that photovoltaic panels generate direct current suitable for charging batteries. Electric energy is supplied from the charged accumulator to the receiver in case of the lack of the solar radiation or if it is insufficient. The system for swimming pool water treatment described in the paper will be used during summer season i. e. in the period of higher insolation. The investigations of real object will show whether it is necessary to apply accumulator batteries in the system. Our earlier considerations brought us to the application of the inverter with the controllable frequency at the output of the photovoltaic panel. This solution will allow for the selection of optimal frequency of the voltage supplying the ozonizer. The operation of the test stand has been presented below.

Photovoltaic system described in the paper enables continuous measurement of the insolation which allow for the estimation of solar conditions in Lublin. As the system for water ozonization is intended to be applied in summer season, only selected results of the measurements taken in June are presented in the paper. The measurements were taken between 1-3 June 2002. Solar battery was set at the angle of 30° (the whole year).

The investigations were carried out with the application of the computer equipped with the measuring card. Professional software Genie was applied to develop suitable measuring method. Essential parameters of the system such as solar battery voltage, current intensity, accumulator voltage, current flowing from and to the accumulator, current of the receiver and insolation have been measured with the application of PCL-818 measuring card.

Average insolation results have been presented in the chart (Fig. 5).

The insolation in June reached its maximal value of about 1100 W/m2 at 1 p. m.

Yiping Wang*, Wei Tian, Yonghui Liu

(School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072,China) Tel.:+86-22-27404674,Fax:+86-22-27404771,E-mail:xinxing@tju. edu. cn Abstract: Solar cells immersed in a dielectric liquid under certain conditions have an increased operating efficiency, and the liquid can provide an effective cooling to the solar cells. This kind of immersion operation of solar cells is also suitable for photovoltaic concentrator and photovoltaic/thermal systems. In the paper, a theoretical analysis has been presented to study thermal performance of solar cells immersed in silicon oil. The system has two different cooling types, which are free convection and forced convection respectively. Steady state heat transfer equations are derived and the average temperature of solar cells for these two different cooling types is calculated. The effects of various factors on the solar cell performance are analyzed. Further, the temperature distribution of solar cells was achieved by using aNsYS Finite Element Analysis (FEA) program. It is indicated that the experimental data fit well with the estimated values according to our models.

1. Introduction

Solar cells have been studied by various authors on efficiency improvement through different ways. An effective method that solar cells are immersed in liquids can increase conversion efficiencies and decrease the temperature of solar cells. The photocurrent and electrical characteristics are investigated for solar cells operated in liquids by Tadaki et al.

[1] . They found that photocurrent increases with the increase of the permanent electric moment of molecules in liquid and this effect is considered to be due to adsorption of polarizable molecules which reduce carrier recombination at the surface of solar cells. Russell [2] invented an optical concentrator and cooling system for photovoltaic cells which system is effective in concentrating the sunlight and in cooling the cells economically. The new system consists of an elongated tube with a curved transparent area for admitting sunlight. This elongated tube is filled with a clear nonconductive liquid having a refractive index suitable for concentrating the sunlight onto the solar cells mounted inside the tube and immersed in the liquid. Solar cells have been demonstrated to function satisfactorily when immersed in a clear nonconductive liquid. Abrahamyan et al. [3] also describe the effect of an increase in the efficiency of solar cells (in particular, common silicon solar cells) by their immersion in an isotropic liquid dielectric. The presence of a dielectric thin film results in an increase in the solar cells efficiency by 40-60% from the reference value. Authors think that the increase effect is caused by several reasons which include an increase in the barrier height of n/p junction, a decrease in the velocity of the surface recombination followed by an increase in the factor of the separation of charge carriers generated by light as well as a decrease in a part of the reflected radiation and the last two factors are main ones. Tanaka [4] thinks that solar cells operating in liquid have an increased operating efficiency resulting from two independent physical phenomena, an increase in output current from the solar cells from simply wetting the solar cells, and enhanced collection of light through refraction and inner reflection of light in the liquid. There are different explanations of increase effect in solar cell efficiency immersed in liquid.

The PV module cell temperature is a function of the physical variable of the solar cell material, the module configuration and the surrounding environment. Temperature is a key factor because the efficiency of solar cell decreases significantly with increasing temperature. The studies of thermal model of solar cells have been mostly concentrated on photovoltaic system and hybrid photovoltaic thermal system. Radziemska [5] summarizes the recent progress obtained in the field of the temperature performance of
crystalline and amorphous silicon solar cells and modules. Various authors have modelled the temperature of a PV module by evaluation of energy inputs and outputs thought radiation, convection, conduction and power generated. The energy balance of photovoltaic cells is modelled based on climate variables by Jones et al. [6]. Module temperature change is shown to be in a non-steady state with respect to time. A one­dimensional heat transfer model was derived by Davis et al [7] to improve upon the NOCT model. Garg et al [8, 9] have developed a computer simulation model for predicting the steady state and transient performance of a conventional photovoltaic/thermal (PV/T) air heating collector with single — and double-glass configurations. Lee et al. [10] concerns the development of a thermal model to predict the temperature profile of a typical building — integrated PV roof and comparison of the performance of this model to that of the simplified model for flat-plate PV arrays presented by Fuentes.

The aim of the thermal model presented here is to predict the average temperature and temperature distribution of solar cells immersed in silicone oil. Silicone oil is very suitable for immersion operation of solar cells mainly because of its low electrical conductivity and thermal stability. The liquid of the immersion operation system is usually chosen to be high electrical resistivity, optical filtering with suitable spectral response, low freezing point, high boiling point and high refraction index et al.

As a next step, RES calculation procedures currently being used in energy performance regulations for new dwellings and energy performance methods for existing buildings have been collected and analysed. The main choices that Member States have to make when starting up the development of an energy performance method or the development of RES calculation modules in an existing energy performance method are based on the complexity of calculation. The complexity of a calculation can be expressed in a number of items such as the time frame, detail of input and calculation principle. Figure 5 presents an overview of characteristics of RES calculation methods used in energy performance methods for new housing in which the calculation period, limitations, input, calculation procedure and explicit RES calculation are described (Buscarlet, C., 2004). It appears to be very difficult to give an objective judgement about the preferred level of complexity, since this is very much dependent on the present ideas about such policy instruments in a member state. While some will state that the calculation procedure should be as detailed as possible, as long as this would be covered by an easy-to-use user interface, others say
that since this considers a policy instrument it doesn’t need to be very detailed, as long as it is possible to compare buildings and to set a regulation level. Another thing is that some member states already use certain (energy performance) methods and may tend to look for additional calculation procedures, such as RES procedures, that suit their current calculation principles.

Figure 5 Overview of characteristics of solar thermal calculation procedures in energy performance methods used for building regulations for new dwellings4

Figure 6 Overview of characteristics of solar thermal calculation procedures in energy performance methods used for building regulations for existing dwellings5 [22] 2 [23] [24] [25] [26] [27]

Figure 6 presents an overview of characteristics of RES calculation methods used in energy performance methods for existing housing mainly used for certification purposes. The calculation period, limitations, input, calculation procedure and explicit RES calculation (Cruchten, G. van, 2004) are described. In fact the calculation of RES techniques in existing dwellings doesn’t need to differ from the calculation in new housing. Considerations as regards the complexity of calculation are similar to new housing.

Insured is a loss which is caused by an unforeseen event while not being excluded by a specific named peril. Examples for insured perils are high voltage, short circuit, natural hazards and other forces majeure. Errors in operating are insured too and it is important to know that the insurer will not seek recourse at the employees who performed the faulty operation.

Not insured perils are among other nuclear energy or loss caused deliberately by or due to gross negligence of the insured or its representative. As already mentioned concerning insured interest, loss for which the supplier or the repair workshop are responsible or liable is not insured (supplier’s guarantee). Direct consequence of permanent influence from operation, e. g. wear and tear, is not insured because it is not unforeseen.

Indemnification and Business Interruption

After having mentioned all the conditions which have to be fulfilled, now it is of interest how indemnification is made up. In case of a damage the insurer will compensate the reinstatement cost to the pre-loss condition. This is repair work and related cost. The Insurer will compensate repair work and replacement of parts as well as freight.

Additional cost for overtime, work on Sundays and public holidays and work over night will also be compensated. As the insurance policy includes indemnification for loss through business interruption, the insurer is interested to minimize this period and will compensate for this additional cost through acceleration measurements.

If the damage causes a loss to other items which are not insured, these cost may be insured too. Examples are clean-up cost and cost for earth-works as well as debris removal and disposal cost. Here is to observe that there exist indemnification limits per event. If own personal is deployed for repairing the damage, the cost will be compensated, too.

Alterations and improvements of the installation will not be compensated.

In case of a damage, the reinstatement of the system is arranged and is no further risk for the operator. Now, there is the problem that the financing is running on, but it is not possible to earn money with the installation. For this reason, the Policy includes an insurance for business interruption.

Compensated will be lost in charge according to “Zweites Gesetz zur Anderung des Erneuerbare-Energien-Gesetzes vom 22. Dezember 2003” which is the German Renewable Energies Law. Now it is obvious why the insurer pays additional cost to accelerate the repair works. The insurer is interested that the installation comes back to an operating condition as soon as possible.

Important is to observe that there is only an indemnification if the business interruption is a consequence of an insured property damage and all conditions mentioned above are fulfilled. Other reasons for business interruption as revision works will not lead to indemnification.

In particular cases it might be possible to insure decrease of receipts due to lessened solar radiation. For this additional insurance two independent certificates about the solar radiation at the location of the photovoltaic system are required what is worthwhile for bigger systems (or plants of systems) only. If this insurance is taken out, the insurer participates when there is loss in earning due to unfavorable weather.

There are limits in indemnification: In case of a total loss, the insurer will pay the current list price but maximum EUR 5.000 to EUR 6.000 per kW peak (depending on size of installation). The Duration of liability in the business interruption insurance is 6 months, beginning at the date of the property damage.

The best is, if there is no claim. To assure that the operator does his utmost to avoid claims there exist deductibles which differ according to the size of the installation and which have to be borne by the owner or operator.

Obligations

For insurance coverage there are several obligations which have to be fulfilled as meeting the maintenance instructions or the immediate notification of a claim. Damaged parts which are replaced have to be kept in stock until the Insurer has settled the claim. If parts are damaged they must not be used further on without the consent of the insurer.

If there is a change in operation or application of the system, the Insurer has to be informed in advance because the change can result in a change of the risk which is borne by the Insurer.

Best is, if insured act as if they had no insurance, meaning the loss is minimized wherever possible.

Conclusions

Marsh has developed a highly efficient policy for controlling the main risks of photovoltaic systems. It is not required to take out different fire, machinery breakdown or business interruption insurances but you receive all from one source and it is tailored to the requirements of owners and operators of photovoltaic systems.

From the coverage of property damage as well of pure financial loss due to business interruption results a planning and financial balance security.

The reduced risk for the owner and operator means also a reduced risk for the company financing the project. Just in recent years it appeared that banks consider very strong before they deal in credits. When the risk is clear and manageable as for example through a comprehensive risk management, it is easier to find a financing partner.

Disclaimer

This presentation is for introduction of the insurance program developed by Marsh for owners and operators of photovoltaic systems. It is a summary with informative translation and it is not describing completely the German policies which are written in German language and negotiated with insurers. Without further explanation it can lead to misunderstanding.

SHAPE * MERGEFORMAT