Copenhagen Energy is now promoting PV and the Solar Stock Exchange in Copenhagen (see also www. ke. de for details in Danish). Private customers can here buy 250 DKK (33,- EuRO) PV-electricity or more in relation to their total electricity bill for 2004 at a market price. Based on this Copenhagen Energy guaranties to install a similar PV area based on a 20 year contract.

It is aimed yearly to have installed around 200-300 kWp of PV-modules based on a feed-in tariff of approximately 0.55 EURO/kWh which will be financed by green electricity sales to environmentally concerned citizens. Installation of the PV projects for the Solar Stock Exchange will be made by private companies based on a 20 year contract with Copenhagen Energy. In connection to this a Copenhagen PV-Coop has been established based on the idea to secure investments in shares of PV installations from private people along the same lines as the “Middelgrunden” windmill park which has been erected in The Copenhagen Habour.

Solar City Copenhagen and the need for an overall sustainable building approach

In November 2003 a two-day-seminar was arranged in Copenhagen concerning the establishment of a "Solar City Copenhagen” organisation which shall promote use of PV and energy efficient building in connection to foreseen urban development projects in Copenhagen not only focussing on Valby but on Copenhagen as a whole, and in June 2004 the Solar City of Copenhagen organisation is officially launched as a partnership organisation — see also www. solarcitycopenhagen. dk.

In relation to the PV activities in Valby and Copenhagen a new R&D development project, "PV and Architecture”, have been supported by the Danish Energy Agency to ensure the realisation of important development work concerning how to integrate PV in new and more architectural acceptable but also more economic ways, in cooperation with leading architect companies and building component producers.

Examples are : new PV-shutters, new and more efficient PV designs for flat roofs and new PV/T solutions.

The establishment of the Solar City Copenhagen organisation is working with a combined strategy of promoting the use of renewable energy and PV electricity in the city and at the same time focus on a general approach on sustainable and energy efficient building.

In the following there is a short extract from the new EU thematic strategy for city areas (KOM(2004)6039 to illustrate the relevance of this:

"In the EU countries only very few buildings are build or renovated in a sustainable way, even through there exist documented solutions for this. The main barrier is a lack of interest from the contractors and investors, which believes that sustainable buildings is expensive and which are suspicious concerning new technologies. The long term benefits from sustainable building, as lower maintenance and operation costs, improved durability and a higher value for the building is not visible in the short term and in relation to the original purchase. Due to this it is needed to make a special effort to focus on such benefits, so investors, banks and mortgage banks will be able to spot the difference between buildings realised by normal solutions and sustainable buildings”

As mentioned above the situation is that there exist a lot of experience, technologies and tools to ensure an approach with sustainable and energy efficient building, so what is mainly needed now is to ensure organisation of activities so such a policy can be implemented in practice. Here the EU energy performance directive for building can be seen as an important step in the right direction. In figure 5 is shown an example of a suggested Green Quality Building Process which has been developed in connection to the European Green Cities Network Cooperation (see also www. europeangreencities. com).

In the EU SAVE project, Green catalogue which Cenergia is coordinator for, there is at present being developed performance requirements and check systems for best available technologies which can support the needed qualities of RUE and RES technologies (see also www. greencatalogue. com). And in connection to the "Builders for sustainability” cooperation in Denmark a special A and B quality labelling system which promotes sustainable and energy efficient housing has been developed, see figure 6 on this.

In Cenergia we have developed the tools Optibuild and Ascot which can be used to make calculations for energy optimised housing projects. Both can be downloaded from Cenergia’s homepage, www. cenergia. dk, and especially Ascot is very easy to optimise for your situation because it is made in a spred sheet.

The Solar City Copenhagen initiative is mainly a local initiative in Copenhagen, but at the same time it is also linked to a European initiative coordinated by ISES. This is the European Solar Cities Iniatives, ESCI (see www. eu-solarcities. org) and the international solar cities initiative (see http//sc. ises. org and http//solarcities. ises. org).

CHP based electricity plants 2001

300.000 m2 PV = 30 MWp = 7.5 m2 I 0.75 kWp per person

Expected GEO thermal heating

RUE and RES Optimised in relation tei " Solar City Copenhagen Partner Organisation

Fig 1. ILLUSTRATION OF THE SIZE OF THE FORESEEN 30 MWp OR 300.000 m2 PV MODULES IN THE CITY AREA VALBY IN COPENHAGEN WITH 45.000 INHABITANTS. BESIDES IS SHOWN HOW THIS FITS INTO AN OVERALL GREEN ACCOUNTING FOR VALBY.

FiGURE 2. HERE IS SHOWN THE PEAK SHAWING EFFECT OVER THE DAY OF 15 MWp PV MODULES IN THE VALBY ELECTRICITY CONSUMPTION IN THE MONTH OF JUNE. ESPECIALLY IN AN ENERGY SYSTEM BASED ON CHP THE PV INSTALLATION WILL HAVE A VERY POSITIVE EFFECT.

FIGURE 3. EXAMPLES OF BUILDING INTEGRATED PV SOLUTIONS IN VALBY AND COPENHAGEN.

The four systems have been simulated for a one year period and the results were summed up to monthly and yearly values. The total flue gas losses are also calculated during off periods of the burner and thus contain the leakage losses.

The simulation results from figure 3 show that the flue gas losses are in a range between 9% and 16% of primary energy for all systems. For system 2 and 4 the highest flue gas losses are observed, also when considering the absolute values in figure 4. When looking at the leakage losses the influence of the hot water volume in the boiler of system 4 and the combistore of systems 3 becomes visible. System 1 has almost no leakage losses and system 2 can be found somewhere in between.

Fig. 4. Monthly heat losses of four combined solar and pellet heating systems simulated for house with annual space heat demand of 87 kWh/m2 located in Stockholm. The store, boiler and burner heat losses do not contribute to the space heating.

From figure 4 it can be also seen that the boiler and burner of system 3 and 4 respectively operate also in the summer months when only domestic hot water is required that can be covered by the solar system and an electrical heater as a backup. Consequently the question was how much energy can be saved by a seasonal operation of the pellet heating units. Moreover it was interesting to investigate to what extent the heat losses contribute to the space heating when the store and boiler are placed in the heated area. For this reason two more variants of the systems have been simulated: variant 2 where the system is placed in the heated area; and variant 3, which is the same as variant 2 but with a seasonal operation of the pellet heating units. This means the burner is turned off from the middle of May until the beginning of September.

In figure 5 the total auxiliary energy demand and the effective store heat losses are illustrated for the simulation variants, where variant 1 is the previous simulation variant with the heating system located outside the heated area of the building. The total auxiliary energy consumption consists of the used pellet fuel energy (lower heating value) and the auxiliary electricity. It can be seen that system 1 is the most energy efficient system for variant 1 under the premise that the heat losses from the DHW-store do not contribute to the space heating, the building has only one zone and that each kWh electricity has the same worth as one kWh pellet fuel. Under these conditions system 4 with the pellet boiler is the worst solution, mainly due to the poor boiler efficiency. Nevertheless the differences could be even higher if the higher solar gains of the combisystems did not balance it out to a certain extent and the average room temperature during the heating season would be exactly the same and not 0.3 °C to 0.8 °C lower than for the two systems with pellet stoves. System 2 needs slightly more auxiliary energy than the similar system 1. The analysis of the simulation results showed that this is mainly due to the higher total flue gas loseses in system 2.

Figure 5 shows that the total auxiliary energy and the effective store, boiler and burner losses can be reduced drastically when placing the heating system in the heated area. The effective storage losses are defined as the storage losses occurring when the room temperature exceeds 24 °С. Again, this assumes that the heat losses can be distributed effectively to the whole building. Significant are the energy savings for system 3 when operating the burner only in the heating season. In the other systems almost no effect could be seen since the stoves/ boiler have anyhow not been operated in the summer months. The effective losses in variants 2 and 3 are an indicator for the overheating problem that will occur in the summer months.

Fig. 5 Total auxiliary energy demand (left) and effective store, boiler and burner heat losses (right) of the four systems for the three variants. The dashed area represents the electrical auxiliary energy.

The auxiliary electricity consumed has been taken into account with a conversion efficiency of 100%. More realistic for a global consideration would be to use a primary conversion efficiency of about 70% for Swedish electricity production. However, the auxiliary electricity consumption of the system is not including any parasitic electricity for pumps, controller, pellet conveyor etc. Neither are the electricity demand of the pellet heating units in included.

The evaluation of the solar gains for such different systems is not an easy task. A very interesting method was proposed by Letz (2002) using a reference system to calculate fractional solar savings. Due to the lack of a suitable reference system and the rather

different studied system designs a simpler method was used expressed by the obtained solar fraction.

3. Conclusions

Four commercial combined solar and pellet heating systems have been investigated and evaluated according to their thermal performance particularly with regard to the heat losses of the system. The total auxiliary energy demand for heating (bought energy) is about 17800 kWh for the best system that is also the simplest system (system 1). The other systems require between 2 and 11 % more energy for heating. If the house has an open design with no obstructions for the heat transfer to ambient air system 1 is the best solution. For houses with more than one zone system 2 and 3 is a better solutions. If the whole heating system is placed within the heated area system 3 and 4 have a smaller energy demand as system 1 and 2 provided that all the losses from store and boiler/burner can unresisted be distributed in the building. For this solution the overheating problems have to be studied more closely.

All systems offer potential for improvements. An intelligent controlling of the pellet heaters would reduce the number of starts and stops. System 1 with a power modulating stove proved that although the stove was not operating on maximum power the efficiency was still better than all other systems. Further investigations are necessary to evaluate the potential of emission reductions. Moreover the interaction between boiler/burner and storage need to be improved to prevent unnecessary electricity consumption and to keep the temperature in the store as low as possible with a good stratification. The poor performance of system 4 can to a large extent be attributed to the low average boiler efficiency, which in turn is due to relatively high total flue gas losses (including leakage) and the very high boiler losses to ambient.

Flue gas and leakage losses also can be reduced by optimizing the combustion air settings or using an automatic combustion air control (lambda sensor). Leakage losses can be reduced by 6% to 25% when closing the chimney during the summer months when the burner/boiler is turned off. From 134 to 485 kWh primary energy can then be saved for system 2 to 4 per year if all leakage losses can be reduced to zero.

The solar savings for all systems are very low. With relatively simple modifications it would be possible to achieve higher solar fractions.

Acknowledgement

We are grateful to the Nordic Energy Research for their financial support for this wok within the REBUS project.

Solarisation of the existing small and medium-capacity hydroelectric power plants includes their equipping with more powerful PV pumps that would make river flow back to accumulation during sunny periods. In this way, without reduction of consumption of all the more precious (and expensive) mountain water larger quantities of electric power would be produced.

According to Todorovic Z., combined hydro-electric power plant of 50 MW and solar power plant of 1 MW, operate at peak rating 3 hours a day, providing conditions for an average daily production of 4,060 kWh (1,000 kWh more than if only hydro-electric power plant would operate). [10]

There are about 50 small hydroelectric power plants in operation in Serbia and Montenegro (Srbija i Crna Gora — SCG) today, producing about 250 GWh a year, which is only 11% of technically usable hydro potential of small hydroelectric power plants. According to domestic estimates, on small mountain water currents, new small-capacity hydroelectric power plants of a few kW to 10 MW, would be built that would produce more than 2,000 GWh per year.

Their selective equipping with solar pumps, production of electric power in summer period may be increased by almost one quarter. Estimate of dynamics of solarisation of small hydroelectric power plants in SCG for the observed period is given in Table 7.

After positive experiences with experimental plant with of 40 kW solar pumps in 2006, it is assumed that power rating in 2007, will be for times higher and later on increased on selected, already existing small hydro-electric power plants.

With announced privatization of SCG energetic sector, conditions will be created for installation of new reversible solar mini hydroelectric power plants that would actually be able to engage another 380 and 400 kW of solar cells in 2009, and 2010, respectively.

The German housing market is the largest national market in Europe with more than 38 million appartments in nearly 17 million buildings. About 54% of the dwellings are located in multifamily houses (MFH).

Unlike in many other European countries about 60% (or 21 million) of the total stock are rental dwellings and about 30% are owned by professional housing companies.

This specific ownership structure with professional companies managing a large share of buildings is a potentially good starting point for installation of solar collective systems avoiding usually tremendous problems in case of condominium buildings with complex decision making procedures. Gathering acceptance of all owners is a very difficult task.

Based on the average annual refurbishment and construction activities in the MFH sector (480.000 dwellings refurbished, 150.000 dwellings constructed annually) and assuming a share of 50% of buildings that are technically feasible for an implementation of solar collective systems, there is a resulting market potential of about 500.000 m2 annually installed collector area.

Given these very general figures it should be considered, that the housing market is heterogenuous — with a lack of available flats in some areas and prospering cities and up to 15 or even 20% unoccupied dwellings mainly in the eastern parts of Germany — thus housing companies facing completely different economic situations and needs.

In addition to promoting project-based life-cycle cost analysis, the Federal government also encourages the incorporation of PV in its facilities’ performance contracts. Since 1988, performance contracts of various types have been used to attract more than $1 billion in private-sector investments for Federal efficiency upgrades (FEMP, 2002 and 2004c), with $259 million in investments in 2003 alone (FEMP, 2004c). As a result, the US Federal government has emerged as the country’s largest customer for performance contracts (Rufo, 2001) and has a potential need for an additional $5.2 billion in energy service investments (Brown et al., 2000).

The Super Energy Savings Performance Contract (ESPC) program is the most current iteration of the Federal government’s performance contracting authority (FEMP, 2004a). Managed by the Federal Energy Management Program (FEMP), Super ESPCs are umbrella contracts designed to streamline the performance contracting procurement process. Under Super ESPCs, ESCOs are awarded Indefinite Delivery, Indefinite Quantity (IDIQ) contracts that allow them to bypass the cumbersome Federal Acquisition Regulations. As a result, agencies and ESCOs are able to design and implement projects in a shorter period of time.

In the late 1990s, the Super ESPC model was expanded by the creation of a ’’technology — specific ESPC” that targets the inclusion of PV in performance contracts (FEMP, 2003b).

The release of Executive Order (E. O.) 13123, "Greening the Government through Efficient Energy,” in 1999 more thoroughly outlined the case for Federal PV performance contracting. E. O. 13123 sets goals for a 35% decrease in energy costs compared to 1985, a 2.5% renewable energy goal for Federal facilities, and 20,000 solar energy systems on Federal buildings by 2010 (Clinton, 1999). To achieve these targets, EO 13123 recommends that facilities maximize their use of ESPCs (Sec. 403.a), bundle energy efficiency projects with renewable energy projects (Sec. 401), and "use savings from energy efficiency projects to pay additional incremental costs of electricity from renewable energy sources (Sec. 404.c.1).”

In response to this emphasis on renewable energies, several agencies have incorporated PV into their performance contracts. Of particular note are two large-scale PV installations on military facilities in California. The first is a 750 kilowatt (kW) PV system installed at Naval Base Coronado as part of a $22 million Super ESPC. The PV panels were deployed to shade a large section of the base parking lot as a carport and thus provided value through electricity savings and as a construction material (FEMP, 2003a). The PV system, which had a 38-year simple payback as a supply technology, was advantageously bundled with other energy conservation measures, including lighting and air compressor upgrades, for an overall simple
payback of 9.8 years. State rebates and Federal prepayments further reduced the project payback to 6 years and a 10-year financing term (Neeley, 2003).

The second large-scale PV performance contract was a 1.1 megawatt (MW) PV installation incorporated into the $56 million contract for the Marine Air Ground Task Force Training Command (MAGTFTC) in the Mojave Desert. The PV system was selected to help maintain combat readiness by providing emergency power, and to help shave the base’s 20-MW summer peak (DOE/EERE, 2003). As with Naval Base Coronado project, the MAGTFTC PV system was advantageously bundled with other technologies, and the overall simple payback was blended to 7.4 years (Johnson Controls, 2003).

Taken together, these two projects demonstrate that PV can be deployed as an energy services technology in a performance contract: PV was effectively bundled with other technologies in both projects for an acceptable blended payback term; both projects sought to capitalize on PV’s distinct service values; and both projects incorporated large-scale PV systems that rank among the biggest in the nation. In the past 4 years, the Federal government has completed eight PV performance contracts with a combined total of over 2 MW of PV. Unfortunately, the Federal ESPC authority expired in October 2003, and has yet to be renewed (FEMP, 2004b). While there is broad support for ESPC renewal, the expiration has nevertheless stalled momentum of the Federal energy services market and put a halt to new PV performance contract development.

In 1998 LABSOLAR was working on a 4.7kWp stand-alone project for a hybrid PV-Diesel system to be installed on an island close to Florianopolis, where the University operates a historic site with a 18th century Portuguese fortress shown in the following section. The PV modules, batteries, charge regulators and inverters were already at the University warehouse ready to be installed, but clearance to install the system was delayed due to discussions with authorities concerned on whether the 50m2 PV array would represent a considerable visual impact on the historic site. LABSOLAR was therefore with an idle stand-alone 4.7kWp system available, plus the 2kWp building-integrated, grid-connected system described in the previous section. The idea was born, to promote a PV-powered rock concert to showcase PV. GREENPEACE was considered the ideal partner to involve in such an event, and after being contacted, immediately agreed to take part, taking care of all the media coverage and seeking sponsorship to make the event possible. A pop band enjoying great popularity, especially among teenagers, volunteered to fully sponsor the event, and so BRASIL SOLAR was made possible. The concert took place on the University’s main campus, and attracted an estimated 25 thousand people (entrance was free). The idea was to demonstrate the concept of both grid-connected and stand-alone PV systems to an audience largely unaware of the potential of PV power. The 2kWp grid-tied PV system operating at LABSOLAR’s building and injecting energy in the public grid since September 1997, and the 4.7kWp stand-alone PV system installed next to the stage guaranteed a 100% solar-powered show. The concert started at 6PM while the sun was still high in the sky, and finished at 10PM at night, also to demonstrate that solar energy works even when the sun is not shining. Three bands played one hour each, and the closing event at night received national TV coverage. During each of the 15 minutes intervals, a large screen showed videos prepared by the LABSOLAR team, explaining the wonders of PV technology to the audience. Figure 6 shows some images of the concert, and more are available at the laboratory’s web site (www. labsolar. ufsc. br). The event attracted considerable media coverage and was national news on television and newspapers, which suited well the dissemination objectives of LABSOLAR.

11 helio-power regions have been distinguished across Poland:

— Nadmorski

— Podlasko-Lubelski

— Slqsko-Mazowiecki

— Swi^tokrzysko-Sandomierski

— Mazursko-Siedlecki

— Wielkopolski

— Pomorski

— Podgorski

— Suwalski

— Warszawski

— Gornoslqski Industrial Area

The most favorable solar conditions are at the seaside region where since April to September the highest sums of total radiation and the highest number of insolation hours have been observed. Due to the accumulation of over 70% of average sum of annual solar radiation during this period in such region like like in Kofobrzeg is more than 3800 MJ/m2 and this region is regarded as privileged one. Another region of great importance is Podlasko-Lubelskie because of frequent flow of dry air from the Ukraine.

Presented data on the intensity of solar radiation, irradiation and insolation in Poland reveal, that annual solar power potential in Lublin region is quite high. However, in practice its usage is limited by technical possibilities and investment resources of potential users. Real barriers in the development of solar energy usage are connected not with the supply but rather with the demand for this sort of energy.

The research on the usage of solar energy that have been carried out at the Institute of Electrical Engineering and Electrotechnologies for several years are focused on the assessment of the possibility to apply solar systems in Lublin region [1,2]. The solution presented in the paper describes the usage of photovoltaic panels to supply the ozonizer.

For the measurement of the internal series resistance (which desribes internal losses and losses due to bad contacts as well) two IV-curves of different irradiance but of the same spectrum and at the same temperature are necessary according to IEC 60891 [6].

From the two characteristics two working points V1 and V2 have to be obtained of which the series resistance can be calculated.

The two working points are determined as follows: Definition of a current interval AI. Here:

AI = 0.5 — Isc2

Determination of the working points V1 and V2 with (2)

Vi=V(Isci-AI, Rpvi, Vti, I01, Iphi) V2=V(Isc2-AI, Rpv2, Vt2, I02, Iph2) Calculation of the series resistance

Isc1 Isc2

For single cells and single modules the second IV-curve can be obtained by covering the cell or module with an insect-screen.

For large PV-generators (several kW) this method could not be applied. A new method is here necessary which allows to determine the internal series resistance out of only one IV — curve under illumination.

M. Beerepoot, OTB Research Institute for Housing, Urban and Mobility Studies / Delft University of Technology — P. O. Box 5030 — 2600 GA Delft — The Netherlands — m. beerepoot@otb. tudelft. nl

K. Engelund Thomsen, Danish Building and Urban Research — Dr. Neergaards Vej 15 — DK-2970 Horsholm — Denmark — ket@bv-og-bva. dk

The recent EC Directive on the Energy Performance of Buildings (Directive 2002/91/EC, in short: EPBD) will urge member states to develop and design energy performance regulations before 2006. The international EC Fifth Framework Altener research project Build-On-RES[19] was formulated with this objective in mind. The Build-On-RES project aims to develop the methodological and contextual framework to maximise the incorporation of renewable energy sources (RES) in an Energy Performance Method for both new and for existing residential buildings. Build-On-RES started by benchmarking energy regulations in five of the EU member states that have experience of energy performance regulations and scrutinised the extent to which they encourage the use of RES in buildings. In addition to energy regulations, other policy schemes that encourage use of RES techniques like financial incentives and schemes based on communication have been collected and described. On the basis of this collection of existing information, the project is designing a framework to maximise the incorporation of RES in an Energy Performance Method for use by member states that are in the process of (re)designing their (new) energy performance building regulations. This paper describes the results of the Build-on-RES research and presents in short the methodological and contextual framework to maximise the incorporation of RES in an Energy Performance Method.

In Risk Management the questions summarized in figure 3 have to be considered.

What can be damaged? It is not only the photovoltaic cell or the module which can be affected. Injury of persons by accident or through illness is normally covered by the Employer’s Liability Insurance Association or by the sick-fund. Buildings and equipment can be damaged. Property and fortune can be wounded too. Credits must also be repaid when due to a damage no electricity is produced. When as a consequence the financing collapses the personal reputation is affected too.

When occur the risks? During planning, erection and construction or during operation.

Which defensive measurements are possible? These are for example regular revisions. An easy way reducing risk of damage to the electronic power inverter is to place it not in a cellar room which is Figure 3: Risk Management overflowed regularly after heavy rain.

Who bears the risk? The risk of force majeure e. g. natural hazards is borne from the employer. A damage during the warranty phase will be claimed against the contractor. Of course it is an advantage if the producer bears the warranty risk. But this is not really helpful if shortly after putting into operation the producer goes into liquidation. During operation the operator is responsible for failures.

Which insurances should be taken out? In the concept from Marsh it is property, business interruption and as an option, reduced receipts.

Who should take out insurance and which conditions (e. g. which sum insured, which deductibles, which perils)? The erection and construction of a big power plant but also of a photovoltaic system is carried out by several companies. Each party could insure its own risk, but a better solution is to take out collective insurances which include all involved parties. The most important point to observe is the fact that the party with the main interest should take out insurance. During erection this is not the contractor but the initiator of the building project and during service this is the operator who has to make profit with the system.