Marco Beccali, Maurizio Cellura, Christian Bartolomeo*

Dipartimento di Ricerche Energetiche ed Ambientali (DREAM),

Universita degli Studi di Palermo
Viale delle Scienze, edif. 9 — 90128 Palermo, ITALY
Tel.+39+091236141; Fax. +39+091484425; marco. beccali@dream. unipa. it

Abstract

In the last years Sicily has benefited, together with other Objective 1 areas, of relevant funding coming from UE — Agenda 2000 programme in order to improve the economic framework strengthening its infrastructures, its enterprises and exploiting its resources. Many of these resources have been directed also to improve energy and environmental policies of the region.

At the same time National and Regional Government are today involved to grant the fulfilment of about Greenhouse gas reduction and Renewable Energies diffusion objectives shared with other UE countries. By this way, some of the actions implemented by the Regional Government have been addressed to the upgrade of the energy system also focussing to the role played by local enterprises into the market of energy efficiency and renewable energy technologies.

In particular, in the framework of the Energy Master Plan a survey of the state of diffusion of solar energy technologies in Sicily has been conducted. The study, conduced by the DREAM department, has also investigated, using innovatory methodologies, the global technical and economic potential of solar energy (PV and thermal application) in residential and industrial sectors taking into account both opportunities and barriers to its diffusion.

The main results of the study have emphasized how to improve energy policies in Sicily in the field of Renewable Sources integrating National and European policies with local specific actions.

This report summarises the work carried out by the Department of Energy and Environmental Research of the University of Palermo on the behalf of Regional Government of Sicily for the development of the new Regional Energy Master Plan. An Action Plan for the diffusion of renewable energies and the promotion of rational use of energy has been proposed to decision makers in order to start a negotiation activities among political, enterprises, users, technicians, research actors.

In order to suggest the most effective actions, the first step of the work focussed on the monitoring of the on-going policies for RET support, mainly based on UE funding for agenda 2000 programme and structured into the framework of the Regional Operative Plan (P. O.R.). Solar Energy support policies today are addressed to low and high temperature solar thermal technologies and also PV grid connected systems.

Funding are allowed either to private and public investors and are provided as unsecured funding. The amount of the specific funding and the eligibility criteria have been expressed in several “sectorial” calls for tender that are described in the following pages.

Furthermore, is necessary to highlight that new energy regulations have created,
after a “green” renewable energy market, a brand new “white” one based on the
trading of “energy efficiency” or “white” certificates. Minimum targets of energy

efficiency have been in fact stated for energy utilities in addition to the ones referred to minimum share of renewable energy production.

Dr. Michael Haerig, Marsh GmbH, MIP Power, Duesseldorf, Germany

Terms as Basle II, Rating, Risk Management present for medium and small-scale enterprises a challenge and a barrier which can lead to the breakdown of these companies. Without a good rating performance it is nearly impossible to obtain a credit with good conditions and it is quite possible that credits are not allowed or frozen. Coverage of business risks influences strongly the rating, because it means security for the bank loans.

Marsh is the world’s leading risk and insurance services firm and provides advice and transactional capabilities to clients in over 100 countries. A specialized branch team working in the power and utility business has taken an active role in the risk and insurance management of renewable energies from the beginning.

This lecture will point out risk and risk management. An insurance program developed particularly for photovoltaic systems is introduced.

Definition of Risk and Risk Management

The term risk is linked to several ideas like Uncertainty about what and when, Uncertainty about impact, undesirable consequences and other. A pure risk presents the possibility of a loss, but not a profit. A speculative risk may produce a profit or a loss. Like the term chance is risk doubt about a future outcome. In one case the outcome is more favorable than in the other case.

Taking this into consideration, risk can be best described using objectives what is also according to several International Standards.

"Risk is the chance of something happening which will have an impact on objectives” or another definition coming from business:

"Factors, events or circumstances relevant to the organization’s activities that may prevent or detract from the achievement of its aims, including failure to maximize opportunities”.

Figure 1 shows the Risk Management Process which consists of identification, analysis and economic control of those risks which threaten assets or earning capability.

Georgia has been a net energy-importing republic in the former USSR. Almost four fifths of the country’s energy supply was imported from other republics. In 1985-1990, energy consumption in Georgia was stable and constituted approximately 18 million TCE (Tons of Coke Equivalent) per year. The collapse of the former USSR had a devastating effect on the energy supply of Georgia. Between 1990 and 2000, the energy consumption was reduced more than twofold.

As most accurate data is available on electricity generation and demand in Georgia, the below figures (Table 3 and Figure 1) are provided from the last seven years and compared to those from 1990.

From the above data one can easily see how dramatically energy consumption (generation) was reduced in Georgia. This is due to political instabilities, civil wars and significant destruction of industrial base, followed by rapid decline of the country’s economy. Most generating plants are undermaintained and at the verge of breakdown, generating only a small fraction of their design capacity. A serious problem is a very low collection rate for delivered electricity (in 2003 average countrywide payments were below 25-30% and approximately 65-75% in Tbilisi[39] [40]) and a widespread corruption in the energy system. Blackouts and electricity restrictions are frequent; many parts of Georgia do not receive electricity for hours or even days at a time. The generation system operates almost without a spinning reserve. The retail tariff for electricity (in Tbilisi) has grown from 2.5 Tetri/kWh (1.9 US cents/kWh) in 1998 to 12.4 Tetri/kWh (5.8 US cents/kWh) in 2003.[41] All this contributes to and stimulates population’s creative thinking regarding attractiveness of micro-hydro and small solar home systems. Small-size renewable energy installations supply them with power to satisfy at least a family’s minimal energy needs when not available from the national grid.

Since frameless modules are used, secondary support structure was designed in order to withstand with winds levels required by normative. Besides an special adhesive replaced metallic contacts between parts of structure of different metallic compounds. These two facts and the height of the main structure motivated a test of a prototype according to standard E 1830-01 "Standard Test Methods for Determining Mechanical Integrity of Photovoltaic Modules”, chapter 5.5 "Cyclic Load Test Apparatus” and chapter 5.5.1 "Air Bag Scheme”. The aim of this test was to check if the set of structure and frameless module could deal with:

o A static load test to 2400 Pa to simulate wind loads on both module surfaces corresponding to a wind speed of 58 m/s (209 km/h). This test was satisfactorily fulfilled after 100 cycles of 2400 Pa static load. o A cyclic load test of 10 000 cycles duration and peak loading to 1440 Pa to simulate dynamic wind. This test was satisfactorily fulfilled.

Final result of the test can be observed in next photograph. After 87 cycles of 3200 Pa static load (278 km/h), part of the secondary structure was broken and then the module too. Before these 87 cycles, three sets of 100 cycles with 2400, 2800 and 3000 Pa were applied successfully.

II. Inverter

The consortium decided to choose the inverter equipment through a call for tender. Three important European manufacturer were invited to participate. Finally the ACEF model from Enertron was selected. This model has next characteristics: o Self commuted with IGBT o AC Current by hysteresis bands. o Nominal Power: 125 kW (three units) o Input: 450 — 756 Vdc (MPP: 450 — 620 Vdc) o THD (Current, 100% load) < 5% o Power Factor: >98% for output above 25% o Maximum Efficiency (including LF transformer): 96% o European Efficiency (including LF transformer): 94% o Noise level: <65 dB.

Three main features must be highlighted:

o A Master-Slave-Slave control technology is used. Global efficiency will be improved, especially during morning and afternoon and with low irradiance levels. Control equipment is independent from inverters, so any of them can be selected as Master or Slave.

o An additional inverter will be installed in parallel as stand-by. This way availability of energy can be improved providing a fast response when an inverter is damaged. o As a condition included in the contract, values of efficiency and availability of equipments are guaranteed by the manufacturer. Penalty can be applied in case of deviation.

Starting from the year 2006 electrical and electronic devices sold in Europe may not contain any lead [EU02]. For the replacement of lead containing solder two procedures can be taken: First of all soldering with lead free solder at an increased temperature and secondly gluing with conductive adhesives. In the following section we focus on conductive adhesives since the exchange of lead containing by lead free solder seems to be unproblematic because the solder temperature has only to be increases by 40°C.

In the literature some publications can be found which deal with the contacting of solar cells by adhesives. Mainly with very thin solar cells ([Frisson01], [Eikelboom02]), with solar cells which for manufacture-technological reasons have no bus bar and thus can not be soldered ([Beier01], [MAU02], [Mau03]) and with back contact solar cells [Eikelboom01].

Fig. 2 shows the measured values for different pairs of materials connected with four different contacting materials.

120

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on silver

Fig. 2: Transition resistance of different material pairs. The error bars indicate the standard deviation. Meaning of the letters: a) soldering paste, b) one component silver filled acrylate adhesive, c) two component silver filled acrylate adhesive, d) one component silver filled polyimide adhesive.

it has to be recognised that the contacting on aluminium leads to insufficient transition resistance, which is due to the oxide existing on the aluminium. Furthermore one can see that adhesives are hardly suitable for the contacting of tinned copper ([Hennemann91], [Verbundprojekt99]).

The material combination silver/copper results in a very good transition resistance compared to soldered contacts. it was shown that this resistance remains extremely stable after aging by temperature changes ([Beier01], [Eikelboom01]).

Connecting the solar cells

For interconnecting high efficient solar cells in shingle technology the two material combinations silver/Ti, Pd, AG or silver/aluminium had to be contacted with each another. Regarding a process simplification during the solar cell production it would make sense to contact an aluminium layer, since the back metal of the solar cells is aluminium. Today on this aluminium a layer consisting of titanium, palladium and silver is vapour-deposited, to ensure a good electrical and mechanical contact. However if one regards the measured
values in Fig. 2 the material combination silver/aluminium has a very bad transition resistance no matter which contacting material is used. With solder this material combination could not be contacted. If good electrical module characteristics should be achieved, it’s necessary, to evaporate a titanium, palladium and silver layer on the aluminium back side of the solar cells. This back side can be glued or soldered with the silver front side of the next solar cell.

In the following part of this work the contacting of solar cells by conductive adhesives is examined. It turned out that adhesives have the advantage of the higher flexibility opposite solder. They are used if mechanical stress is feared by thermal expansion and no other element (e. g. tabs) can take up the tension. In addition adhesives are used where contacting is not possible by solder (unsolderable materials) or it appears technologically advantageous (back contact cells).

In summary adhesives for special applications are definitely an alternative to solder. They won’t achieve for the manufacturing of high efficient solar modules, since the curing time is too long.

Juras Ulbikas, Daiva Ulbikiene, Vida Janusoniene

Institute of Lithuanian Scientific Society, A. Gostauto 11-466, 01108, Lithuania Karolis Pozela

Semiconductor Physics Institute, A. Gostauto 11, 01108, Lithuania

To find methods for reduction of the PV Cells production costs per Watt while in the same time keeping optimized or even reaching higher performance of Solar Cells is the main challenge for PV Cells manufacturing technology. For the majority of commercially produced solar cells the dominant material up to now is still crystalline silicon (c-Si). A lot of efforts has been undertaken to increase the electrical efficiency of Si based solar cells, nevertheless commercially available products still have performance in the range 15-17%. One of the promising trends to achieve higher performance of the monocristaline Si based Solar Cells is development of complicated spatial structure on absorbing surface of PV Cell (so called Spatial Solar Cells). Reports indicate efficiencies as high as 24% in laboratory samples, but with significant raise in costs for Spatial SC production.

Increase in production costs is caused by introduction of additional costly processing steps and due to this, low possibility to use such improvements in commercial industrial products. Application of self-formation methods in Solar Cell technology (www. self-formation. lt) is expected to reduce technological processing steps leading to significant simplification of SSC processing. In our paper we will present recent experimental results of SSC development using Self-formation methods. First estimations demonstrate significant reduction of the production costs for SSC produced by Self-formation technology.

On the other hand with introduction of Spatial structure for Solar Cells, optimization of performance characteristics in dependence of developed spatial structure is becoming of primary importance. Simulation results on physical characteristics of SSC with different spatial structure will be presented as well. We expect that proposed method for optimization of SSC performance can become useful tool in the hands of technologists predicting and optimizing SSC properties.

Background

The use of conventional microtechnology patterning processes in Solar Cells manufacturing is one of the main obstacles for wide spreading of the commercial use of photovoltaic. Self-formation with its possibilities to reduce number of required patterning processes is one of the promising ways to reduce significantly SC production costs with parallel increase in SC efficiency. Self-formation as a concept for irreversible evolution of the artificial object with complexity increase was introduced for understanding of the processes existing in microelectronics technology [1]. Recently developed tools for simulation of technological processes for Solar Cells manufacturing [2] clearly indicate that self-formation is becoming interesting tool for technologists trying to create and optimize microelectronic devices.

Higher efficiency in monocristalline Si based Solar Cells typically is achieved by introduction of complicated spatial structure on absorbing surface of SC. Reports indicates efficiencies up to 24% in laboratory samples. This trend is still limited to laboratory stage due to significant production costs.

The mono-crystalline silicon solar cells with record performance characteristics requires 5-6 [3] patterning processes which are the high-priced manufacturing process part. In order to have cheaper product the number of patterning processes in mass manufacturing solar cells
are minimised to one or two, but cell efficiency falls to considerably smaller value. As it was shown in [4] the structure of PERL type solar cell can be realised by two photo-masks if self­formation elements are included into manufacturing process.

PERL solar cell [3] is realised by typical external formation which is normally used in planar technology. All needed patterns are brought from outside as photo-masks, which converts chaotic media (UV light) to structured one. Pattern in photo-mask is aligned with object pattern. All the other processes: development, etching and even doping, forms recurrent sequence after each patterning process and reproduces photo-mask pattern to the technological layers on the wafer or to the wafer.

Following the survey conducted, in order to assess quantitative and distribution of biomass residues, an economic potential of their exploitation was calculated. The main goal was to asses the price of biomass. The cost of biomass has resulted by the sum of harvesting operations, gathering, pellets production and the most influent was result the transportations cost. These last costs were calculated from centres that should been made in proximity of the ones planned from the Regional Waste Master Plan for the gathering of the dry substances present in waste. By mean of the slope map, the street network map and the climatic type is possible to calculate the areas easily accessible and with a good technical potential. Distances, that are very significant for the cost’s calculation were
calculated from the collection centres. The next step was to evidence how and with which cost the biomass might be transported to collection centres.

By the knowing the distances and a cost of transportation for km, has been possible to create the economical supply curves for each type of biomass. The curves were built considering that as the price rise it becomes possible to gather more biomass due to the possibility to gather the biomass at increasing distances. In the following figure is shown the regional supply curves for agricultural biomass, for SRF and for the forestry biomass of Parco dei Nebrodi. The supply curves were done for every type of biomass and for the nine provinces of the Region.

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200 150

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Figure 3. Supply curves

The potentials of wind power and solar electricity production from PV and concentrating solar power stations are discussed in the following. Except where otherwise indicated, the calculations are based on meteorological data of the European Centre for Medium-Range Weather Forecasts (ECMWF) and, in the case of solar energy, also on data of the National Center for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) [ERA-15] [NCEP 99].

• 3.1 Potentials of Wind Energy

The potentials of national wind energy are dependent not only on prevailing wind conditions but also on factors such as population density or nature preserves and other restrictions. According to [Qua 00], for instance, the realizable wind power capacity on land sites in Germany can correspondingly be estimated at 53.5 GW. A total annual wind power production of about 85 TWh is assumed to be achievable as a result. This figure represents about 17% of total consumption (approx. 490 TWh) and is equivalent to 1600 full-load hours (FLH) of wind power per year. The additional offshore wind potential is taken to be about 79 TWh at nearly 3400 FLH [Qua 00]. In another study, the German offshore wind potential is given as approx. 240 TWh [GMN 95], even though a maximum distance of 30 km has been assumed between the offshore wind turbines and the coastline. This limitation has been rendered superfluous by more recent planning (s. e. g. [BSH 04]), so that a far greater potential may be assumed. If only locations are considered where the water is not deeper than 40 meters, with offshore turbines erected entirely at locations not previously declared nature preserves, military zones, or otherwise unavailable, a "conflict-free” potential of about 67 TWh results according to [IGW 01]. These assumptions may be considered particularly conservative. Permit applications have already been made for water depths of 45 meters [BSH 04], opening the way to a high multiple of "conflict-free” sites compared with the above considerations. Nature preserves and areas used by the military have also come under consideration [BSH 04]. Consequently, the yearly production of several hundred TWh is easily imaginable. In addition, the German portion of potential wind power sites in the North Sea makes up only about one-eighth of the total area with a depth of less than 50 meters (s. also [Czi 00]). Considering the use of the southern North Sea with Denmark’s northern tip as the northernmost point, an area of roughly 200’000 square kilometers with sea floor depths less than 45 meters can be found [Czi 00]. Here theoretically, neglecting all restrictions, an area sufficient for 1600 GW of rated offshore wind power would be available for generating up to 6000 TWh of electricity. This is roughly three times EU consumption, thus demonstrating that even after taking major restrictions into account a huge North Sea potential might still be realisable. Furthermore, shallow areas in other European seas with abundant wind resources would cover more than two times the area of the southern North Sea [Czi 00]. Greenpeace has recently published a scenario in which a capacity of 237 GW offshore wind power would be installed in EU coastal regions by 2020 to produce more than 720 TWh, while covering only 3.4% of the area available after all constraints

had been have been taken into account [Gre 04]. Notwithstanding differing estimates of potential, a significant contribution to electricity production is harnessable. The full use of offshore wind energy necessitates a wide spectrum of cooperative measures among European countries for arriving at the most favourable scheme of implementation.

According to conservative estimates of the Danish company BTM Consult, the technical wind power potential of land sites within the EU and Norway is 630 TWh, corresponding to 315 GW of installable wind capacity [EWEA 99]. The very simplified assumption has been made in this case that all turbines would be delivering 2000 FLH a year, meaning they would operate at an effective average capacity of roughly 23% at each site. In relation to the total electricity consumption within the EU of about 2350 TWh (with Norway, 2450 TWh), this technical potential could thus be harnessed to fulfil about one-fourth of electrical energy demand [DOE 02]. Another particularly detailed analysis of the wind conditions at a relatively narrow strip of land along the Norwegian coastline determined a technical potential of 1165 TWh at an average turbine load of 2900 FLH, not considering any possible restrictions, with the most favourable sites producing 156 TWh from turbines delivering an average of 4100 FLH [Win 03]. According to our own conservative estimates based on meteorological data of the ECMWF [ERA-15], a selection of wind sites within the European Union could generate about 400 TWh of wind energy with an average turbine performance of 2670 FLH using about 150 GW of total installed capacity, taking into account restrictions due to densely populated areas. Under the particularly favourable meteorological conditions prevailing in Ireland and Great Britain, far more electricity from wind power could be produced than estimated here. Due to the conservative assumptions adopted, however, their contribution has been limited to 25% of the total capacity installed in the EU and Norway. The respective electricity generation under these conditions would equal 32% of the electricity consumed in Ireland and Great Britain. In other countries, by contrast, the corresponding figure lies below 10% of domestic consumption. As previously mentioned, an annual average turbine operation of roughly 2700 FLH can thereby be achieved, whereas an even distribution of wind generators within the EU would only allow approx. 2000 FLH to be realized [Gie 00]. If in fact the total achievable potential for Great Britain and Ireland could be exploited, the generated electricity would slightly exceed their current demand. To insure that these possibilities may be realized, the transmission grid to neighbouring countries should be expanded in response to the growing use of wind energy to anticipate and stimulate the multilateral integration of wind power capacities.

The land-based wind power potentials in the EU are limited to the estimated levels identified above, due less to technical and meteorological restrictions than to the population densities of particular regions. If it were possible to use land areas freely, electrical energy requirements could be fulfilled many times over with wind power alone (s. Fig. 1). Restrictions due to the high population density are of secondary importance in many distant windy regions surrounding Europe. The population densities of northern Russia and western Siberia, northwestern Africa, and Kazakhstan lie between 0 — 2 inhabitants/km2 and are thus at least two orders of magnitude below those of Germany with its 230 inhabitants/km2 (s. e. g. [Enc 97]). In addition, these areas are steppes, deserts, semi-arid regions, or tundra of practically no inherent economic value, so that wind electricity generation may be instituted as a beneficial means of "farming in the desert”. The potential electricity production from wind power is shown in Fig. 1. Even considering only land sites at which more than 1500 FLH can be achieved (within the rectangle roughly 40% of the land area), and without further restrictions, the area shown within the rectangle comprising Europe and its neighbours could deliver 120’000 — 240’000 TWh of electricity from wind power at a installation density of 4 — 8 MW/km2. This result constitutes a maximum of about one hundred times the current electricity demand of the

EU or fifty times the electricity consumption of all countries within the selected area. If only the best wind sites with the highest production at an installation density of 8 MW/km2 were employed, just 4.3%o of the land area would be required to provide the equivalent of the annual electricity consumption of the entire area within the rectangle shown on the map. About 2.5% of the area would be adequate for covering the equivalent of the electricity demands of the EU. Furthermore, the area covered by the turbines and accompanying infrastructure themselves is typically only about 2% of any land dedicated to wind farming. (The figure of 2% applies generally to wind farms consisting of individual turbines of 600 kw rated capacity. The area is reduced if larger single units are employed.) Therefore, the land space required for generating the equivalent of total EU electricity consumption is actually less than 0.05% of the entire marked geographical area. By comparison, the roughly 6% of total land area in Germany currently sealed by streets, buildings, and other infrastructure covers a thousand times bigger fraction of space.

The three regions previously mentioned — northern Russia with northwestern Siberia, northwestern Africa, and Kazakhstan — each offer a greater wind energy potential alone than required for meeting EU consumption requirements in their entirely. In the following treatment, therefore, only the areas within these regions with the highest yields have been considered. In Tab. 1, the size of the areas selected for the analysis, the installable turbine capacity for a conservative assumption at a moderate installation density of 2.4 MW/km2, the expectable average production of the turbines assuming wide-range turbine placement over the selected area, and the expectable yearly output are given. Because of the data used, the estimates tend to be conservative. In the case of southern Morocco, for instance, measurements have shown that load factors of far more than 4500 FLH may be assumed directly on the coast at favourable locations [ER 99]. In Kazakhstan, measurements and other investigations likewise indicate that yields significantly over 4000 FLH may be expected [BMW 87] [Nik 99]. The higher the topographical complexity of the terrain, the more significant the underestimation tends to be. Wind potentials in [CGM 03] calculated from Rise for the region at the Gulf of Suez in Egypt represent the most extreme underestimation of wind conditions in any complex terrain known thus far to the author. A comparison of this map and the date with the data depicted in Fig. 1 indicates a maximal average production of roughly 2200 FLH at low spatial resolution (like the data derived from ECMWF data, which build the basis of the scenarios), while the high-resolution Rise

data corresponds to 6000 FLH (for better comparison, see also [Czi 01]). Even if this example is particularly extreme, such underestimation is rather typical for complex terrains, making clear that the scenarios represent a very conservative approximation of actual possibilities and thus provide compelling reasons for further argumentation, since — as the example shows — there must be substantially better wind potentials worldwide at many places than can be inferred from the data bases used for the scenarios. It appears certain that high-yield locations would be exploited first if they were known, whereby high potentials could be expected at high quality sites. [31]

at about 190 GW (150 TWh), some 120 GW (95 TWh) of which would be on rooftops [Qua 00]. This figure corresponds to an average yearly full-load capacity of 770 FLH or 780 FLH on roofs. Our own calculations have shown that good modules employed on rooftops with optimum angular position and unaffected by shadows could produce about 950 FLH. The difference to the values given in [Qua 00] is due primarily to the inclusion of shadow and disorientation factors. Fig. 2 shows the potential yearly electricity production from PV.

Table 2 contains the potentials and FLH for a number of countries.

Tab. 2 Potential power (P) and electricity generation (EG) from PV (Module = 14%) on roofs as well as simplified assumptions on the expectable average equipment duty factor (L0) under consideration of the losses due to shadows and roof disorientation, or under optimum conditions (Lopt). It has been assumed that the same roof area per inhabitant is available in all countries as in Germany an that it is distributed in th countries according to the population. [32]

Africa could satisfy 500 times the electricity demand of all EU countries. Since domestic consumption is comparatively low, however, this high solar energy potential could only be realized to a significant extent if solar power were exported outside the northern African region. The output of this solar thermal power plants with parabolic arrays depends crucially on their design. Therefore, the performance characteristics can be stated only with reference to the design parameters. The use of thermal storage units is of major importance in this respect. The quality of the site can be determined by the heat production of the mirror array, independent of the specific parameters of the power plants, as shown in Fig. 3.

The heat may be employed in a conventional thermal power plant to generate electricity at an efficiency of about 35%. If heat storage is included in the overall design, a larger linear mirror array is employed to charge the storage medium during the day. In this way, electricity may be produced throughout the night while supplanting the fossil fuels otherwise necessary for continuous operation of the plant. The storage facility therefore provides greater flexibility and reduces the cost of the solar electricity produced, since the conventional part of the power plant utilizes more solar heat, which during the night is delivered from storage. Therefore, the specific costs of the conventional part are lower, while not entirely compensating for the investment in storage capacities. In order to estimate the achievable electricity generation at certain locations, it is assumed that the storage has been generously dimensioned for 14 FLH, so that the solar heat produced in the mirror field will never be partially wasted due to the limited influx capacity of the conventional section. Such a parabolic trough power plant could attain nearly 5600 FLH in southern Morocco (western Sahara). Farther south in Mauritania, more than 5800 FLH would be possible, while 3000 FLH could be expected at a good location on the Iberian Peninsula.

Marcel Gutschner and Stefan Nowak
NET Nowak Energy & Technology Ltd
Waldweg 8, CH-1717 St. Ursen, Switzerland
Tel. +41 264940030, Fax: +41 264940034
marcel. gutschner@netenergy. ch, stefan. nowak@netenergy. ch

Oliver Ouzilou and Jacobus van der Maas
ScanE, DIAE, Department for Environment and Energy
Canton of Geneva, Switzerland
PO 3918, 1211 Geneva 3
Tel +41 223272092, Fax +41 223272094
olivier. ouzilou@etat. ge. ch, jacobus. vandermaas@etat. ge. ch

The Canton of Geneva (Switzerland) is renowned for a strong energy policy promoting both renewable and local energy and a sustainable development. Besides tangible quantitative targets, the policy also aims at optimising the interfaces and interactions between the relevant stakeholders (authorities in energy issues, building / urban design and land planning, multi-utility, customers, etc.) in order to facilitate and promote solar energy. This paper focusses on two issues in the wider context of the energy policy and activities supporting the implementation of renewable energies: 1) Assessment of the solar energy resources and 2) Setting­up of a public multi-stakeholder strategy for the promotion of solar energy.

Purpose

The objective of the "Assessment of the solar energy resources and Setting-up of a Public Multi-Stakeholder Strategy for the Promotion of Solar Energy” covers two interrelated issues.

Within the energy policy, the Canton of Geneva (Switzerland) aims at optimising the interfaces and interactions between the relevant stakeholders (multi-stakeholder strategy with authorities in energy issues, building / urban design and land planning, multi-utility, customers, etc.) in order to facilitate and promote solar energy.

The assessment of the solar energy resources is part of the process and provides information to strengthen strategies in order to exploit the solar energy resources and potential available on its own territory, particularly in its building stock.

A number of barriers must clearly exist be overcome before the construction sector can become deeply involved in carbon trading markets. These include

the availability of suitable technologies and awareness of them on the part of building and property professionals, owners and occupants. There is also an important need for access to financial expertise, means of coping with uncertainty in the process and level of transaction costs relative to benefits. As one construction professional expressed it, “The key to green office buildings lies not so much in developing the technical side but in adjusting the ecoomic arguments in favour of more sustainable solutions” (McKee 2003).

The following three case studies, taken from US examples in Northern California indicate some of the technologies and design approaches available to implement energy efficiency in practice, and how these might relate to carbon trading.

Case study 1: Hewlett Foundation, Menlo Park

Fig 4: Hewlett Foundation, Menlo Park, California.

Architects (shell): B. H. Bocook; (interiors): HPS Architects

The William and Flora Hewlett Foundation is a philanthropic organization created by one of the founders of Hewlett Packard. Its purpose built accommodation, completed in 2002, is located next to the Stanford campus. The 48000 sq. ft. building is designed to provide office and meeting space for the Foundation.

It also provides facilities for staff, including a gym and refreshment area.

The plan is a shallow U-shape around a central courtyard: due to the shallow plan, most office areas have windows. The interior zones on the upper floor have either rooflights or clerestory lanterns. The side windows are openable.

The building is fully air-conditioned: however, the system uses displacement ventilation supplied from the 18” raised floor, with local controls. On the upper floor, the ceilings are open — increasing potential for natural ventilation and well-controlled lighting.

Large roof overhangs shade the upper floor windows; some lower windows are also shaded by roof overhangs, while others are sheltered by the colonnade which adjoins the courtyard. Lighting controls are sensitive to room utilization, and switch off after 10 mins when not required.

The building has a roof mounted PV system sufficient to power exit signs and emergency lighting in the event of a power cut.

This building provides a field study base for the educational activities of the Jasper Ridge Biological Preserve (JRBP), attached to Stanford University. It is located a few miles from the Stanford campus, about 30 miles south of San Francisco.

The 9 800 sq. ft. building, completed in 2002, is a linear, single story form housing 2 classrooms, a herbarium and administrative offices, a research lab and ancillary spaces including a cold room. Toilets and showers are accessed from outside, and are not within the conditioned envelope of the building. The building’s main axis runs east — west: most eye-level glazing is oriented almost due south. North-facing glazing at high level lights the ancillary spaces; north-facing monitors and rooflights bring daylight to the center of the plan.

The building is naturally ventilated: high ceilings in the main areas provide a plenum and clerestories can be opened manually to give stack ventilation in summer.

Clerestory windows are opened in the evening for night purging: thermal mass is provided by the floor. To minimize heat gain — and heat loss in winter — the building is highly insulated, with walls and roof meeting R-30 standard. High performance glazing is used: double glazed low-e panes with thermally-broken aluminum frames. These are not standard items in California, and were shipped in from out of state.

This building has both PV and solar thermal panels. The PV installation is almost invisible from ground level: the amorphous silicate panels are mounted on the south­facing internal slope of the roof. The solar thermal installation dominates the building’s southern fagade. Six panels sit on the south side of the roof monitors, while the rest are mounted between the eye-level and clerestory glazing of the main spaces. These panels have a secondary function in providing extensive summertime shading to the main south facing windows; the roof overhang gives some shade to clerestories. The primary, glycol-filled loop heats a massive water tank located in an ancillary space: this supplies low-level radiator panels in the lab and offices and ceiling mounted forced convective heaters in the classrooms. A small propane furnace provides a back-up system for cool, dull spells in winter.