Israel, Photovoltaic technology Israel and prospects - Contribution to the Annual report 2005

Israel
Photovoltaic technology status and prospects: an update
Dr H. Avraham Arbib, Deputy chief scientist and director, Division of R&D, Ministry of National Infrastructures

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General Framework

Fig. 2 - 1 200 W off-grid system, providing electricity to a Bedouin family (photo SolarPower).

Photovoltaic activity in Israel is concentrated mainly in academic research, with limited industrial involvement. The ubiquity of the electricity grid makes most applications non-cost-effective, except in unique situations.

886 kW of peak power have been installed so far; 353 kW were installed in 2004. Nearly all the applications are off-grid remote electrification systems. Most installations were made on an economic basis, the PV system being the most economically viable alternative (because of its distance from the electric grid). At the present time, there are no promotion initiatives or subsidies for PV systems.

A resolution adopted by the Government in November 2002, mandates that at least 2 % of total electric energy be generated from renewable sources by 2007, rising to 5 % by 2016. The Israel Electric Corporation (IEC) is required to purchase electricity from private producers, according to rules set by the Ministry of National Infrastructures. The Ministry is in the process of preparing regulations regarding the purchase by the utility of electricity generated from renewable energy sources. It is expected that these regulations will also positively influence the local PV market. The IEC has general guidelines relating to the quality of the electricity it purchases.
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Industry involvement

A few firms are active in the PV field, and they deal mainly with system integration. Most companies are small, and are not exclusively dedicated to PV. Some of the local production of systems is exported.

Presently there is no local production of either PV cells or inverters. The technological infrastructure required to produce all the components needed for integration in PV systems is available; however, due to economical considerations, components such as modules are imported. In spite of this, some unique Israeli PV systems have high added value related to the balance of system (in particular, control systems), and therefore, they have international market potential.
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Research and Development

Fig. 1 - Shading by collectors in a solar field.

A relatively large number of research teams is involved in photovoltaic R&D, most of them from academe, spread over most research areas. Many of these teams cooperate with leading teams worldwide (both in academe and in industry). Among the current R&D projects, a number are highly innovative and worth noting:

The optimal design of a solar field of stationary collectors is the objective of intensive research work at Tel Aviv University. This design may be based on several criteria: maximum energy output from a given field, minimum field area for required energy production, minimum cost per unit energy, minimum plant cost, maximum energy per unit area or other objectives. The use of many rows densely deployed, in a limited field size, increases the field incident energy but also increases the shading. Therefore there is an optimal deployment of the collectors in the solar field. These design problems may be formulated as optimization problems with objective functions and sets of constraints (equality and inequality) for which mathematical optimization techniques may be applied. Field and collector parameters include field length L, field width W, number of collector rows K, distance between rows D, collector height H and collector inclination angle (Figure 1).
DiSP Ltd. is developing a Miniature Concentrating PV (MCPV) system for distributed power applications, in cooperation with Tel Aviv University. The system is designed to provide both electricity and high-grade heat, making it a true Combined Heat and Power (CHP) system. It includes a small (about 1 m diameter) concentrating dish and a high-efficiency CPV module. Preliminary calculations indicate that the power generated by the MCPV may be less expensive than grid power. The heat can be provided at temperatures suitable for steam generation, cooling, space and water heating, and process heat. A demonstration unit is currently under construction.
R&D activity at the Solar Energy Laboratory of the Jerusalem College of Technology is directed toward increasing the efficiency of silicon solar cells and photovoltaic modules without significant additional fabrication expenses. It consists of:
1. Development of improved solar cell fabrication technologies suitable for industrial application. The activity is focused mainly on back surface field (BSF) optimization and extends in two different directions:
  - BSF formation in multi-crystalline Si cells by simultaneous B and Al diffusion;
  - Research and improvement of ion implantation process as a doping method for BSF formation of the high-efficiency single-crystal solar cells (in cooperation with Italy and Russia).
2. Development and improvement of a cheap glass antireflective coating for the PV and thermal modules, allowing efficiency to increase by more than 0,5 % absolute in the PV case.
  - Long-term performance of various photovoltaic modules under desert conditions is being monitored at the National Solar Energy Center in Sde Boker.

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Demonstration and Application

Fig. 3 - 400 W grid-connected system, at a transportation museum in the Jordan Valley (photo SolarPower).

The higher fuel prices have caused increased installation of off-grid systems, replacing diesel generators (Figure 2). In addition, there is growing interest in grid-connected applications (Figure 3).

A large PV project, aimed at electrifying a Bedouin village, was started in 2005. The village of Drijat, in the Negev desert, in which about a hundred families live, is about 6 km from the nearest grid. Electricity was supplied by old and inefficient diesel generators, which only worked a few hours a day. In the first phase of the project, stand-alone PV systems were provided to 20 homes, 6 lighting poles, a school and a mosque. The home systems (Figure 4) provide about 1 000 W of peak power each, with batteries storing 14 kWh (enough for two to three days of consumption). The total cost of the first phase was 300 000 USD.

The Municipality of Tel Aviv has decided in principle that every public building undergoing restoration will incorporate a photovoltaic system. It remains to be seen how the decision will be implemented.
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Educational activities

In the Nitzana village in the Negev desert, an educational project is underway, called “Science Following the Sun.” The project brings the message of solar energy, including photovoltaics to hundreds of school children.
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Government actions

Fig. 4 - Home system at the Bedouin village of Drijat; the mosque is in the background (photo Dr. Ibrahim Yihia).

As mentioned above, it is expected that the recent Government resolution establishing a minimum quota for electricity from renewables will favourably influence the PV market. In addition, a number of actions are being taken to encourage the PV activity.

Among them:

Support of R&D excellence centers through selective funding of projects. The R&D expenditures in photovoltaics of the Ministry of National Infrastructures were only about 110 000 USD in 2005; however, additional funding is available in this area from other research foundations.
Partial funding of innovative demonstration projects.