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Off-Grid Power Supply

Energy is here

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Affordable Energy for Rural Areas Around 1.6 billion people in the world have no electricity. The majority live in remote regions, where long distances and high connection costs make it impossible to connect to the public grid. As an example, Sub-Saharan Africa has a rural electrification rate of below 10% with approximately 70% of its population living in rural areas. Local development is directly connected to energy which represents a decisive argument for the establishment of local industries or small companies.

What is off-grid? Off -grid systems are energy systems that are not connected to the public power grid. They could be either fossil fuel based (conventional energy) or renewable energy based. They produce elec-

Decentralised autonomous power supplies will be a major contributor to the energy production of the sun-belt region in the future, even more so for rural communities.

tricity for autonomous energy consumers (e.g. health centers, hotels, etc.)

The price for off-grid power Solar off -grid power systems already represent an attractive economic alternative to conventional generators. Fossil energy systems require a relatively low initial investment, but high operational costs, while renewable energies require relatively high initial investment and very low operational costs. Thanks to the global market growth of renewable energies, the costs for off -grid solar systems have been steadily decreasing. Whilst at the same time, the oil-price has risen continuously and will continue to do so into the coming decades. The economical parity of solar off -grid systems compared with diesel applications in high solar irradition regions like Africa lays between 3 to 4 years. Reflecting the fact that the diesel price will rise in the coming few years, this breakeven time will constantly decrease.

Solar System versus Diesel Generator Assumptions: PV: 140 kWp, Battery: 36.000 Ah, System: AC coupled, Fuel costs: 1.2 €/L, Solar fraction: 75 %, Replacement of batteries every 7 years, incl. installation, maintenance and operation costs

Project costs in mio. € 2.5 2 1.5 1 0.5


Solar Hybrid






Our Motivation juwi Solar is convinced that solar energy is one of the best solutions to assist sunbelt countries in their economic development. With our energy solutions, we provide a basic power supply for buildings, schools, small businesses or health centers. We are convinced that the developing countries can only progress by implementing a strong local industry. This is the reason why we plan and implement our energy solutions in close co-operation with our local partner network. juwi Solar is linked to the fields of education, employment, health and water supply due to its co-operation with governmental organizations and NGOs.

Training for local installers and operators in Mushubi, Rwanda.

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juwi’s Services juwi Solar plans and builds off -grid solar power systems throughout the world. With years of experience in projecting and implementing we can adapt the systems to your local conditions, deliver worldwide and establish the solar system on-site. We work with local partners to guarantee operations and maintenance. juwi supports you and your project from the very beginning. With our advanced sizing software and our experience we are able to off er the optimal solution for your energy requirements. In co-operation with our logistic partners we are able to deliver worldwide and support the installation or commissioning at site with our local representatives. For further information, please visit our homepage ( To help us to comprehend your individual requirements, please complete the downloadable off -grid questionnaire you can find on the homepage and return it to us. We will then design a bespoke technical layout and non-binding quotation for you.

juwi’s product portfolio. You can find more information on the following pages. Page 5

Solar System DC-coupled Solar System AC-coupled

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Hybrid Solar Systems

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Village Electrification

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Energy Containers

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Backup System

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Small Wind & Hydro Power

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Solar Pumping





kilowatt peak

Solar Systems Solar power systems provide the basic electrical power for households in rural areas. This allows you to use environmentally friendly power for lights, refrigerators and communications devices – even when you are far away from the power grid. There are two main technologies for a solar power system, the AC-coupled and DC-coupled system. Both have their inherent advantages and disadvantages. Based on your specific requirements, we will help you make the right decision.

Reference AC-coupled solar System for primary school complex, Rwanda

PV Power: 3.69 kWp polycrystalline modules Surface: 40 m², roof mounted Battery bank: 750 Ah Commissioning: 2010

Technical Overview DC Coupling Modules

AC Coupling Modules

PV Inverter

Charge Controller



Battery Inverter


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Hybrid Solar Systems By combining di erent energy sources (e.g. solar energy, small wind turbines or diesel generators) it is possible to increase system availability and/or lower the initial investment costs. Such combination of energy sources is particularly beneficial for larger consumers such as local commercial centers, hotels, schools and hospitals. A hybrid system is capable to operate autonomously and we can retrofi t existing pure diesel generator sites with solar modules in order to achieve less fuel consumption. These systems can be monitored locally and remotely (via GSM and web-based solutions).

Reference Hybrid solar system for a winery, Germany

PV Power: 4.1 kWp polycrystalline modules Surface: 42 m², roof top installation Battery: 550 Ah / 48 V, lead gel Commissioning: 2010

Technical Overview Modules

DC Coupling



AC Coupling PV Inverter

Charge Controller

Inverter Battery Inverter Generator Batteries


Village Electrification Rural electrification based on solar power often represents the most economic solution for settlements in sparsely populated rural areas. A centralised solar power plant supplies the village via single or three phase mini-grid with electrical power. Each household is connected to this mini-grid. These connections can be equipped with energy meters or similar products (as energy limiter, prepaid counters etc.) to achieve a specific business and operation model. Village electrification systems typically include a mix of energy sources such as solar photovoltaic plants, wind turbines, micro-hydro turbines as well as diesel generators. In settlements where the consumers are sparsely distributed, the power can be transferred via higher voltages lines. Standard juwi Solar solutions range from 200 to 300 kW systems. Individual adaptations can be made in order to meet power demands up to 1,000 kW and more.

Reference Village electrification, Namibia

PV Power: 201 kWp polycrystalline modules Surface: 3420 m², free field installation Batteries: 21.840 Ah / 48 V, lead acid Diesel power: 2 x 140 kVA, 1 x 350 kVA Commissioning: 2011

Technical Overview Modules

PV Inverter

11 kV Mini-grid Battery Inverter

Batteries Generator

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Energy Containers Containerised power solutions have many advantages, amongst them are quick deployment, standardisation of equipment and cost savings in terms of in-situ construction. Due to its modular nature, the energy containers could be combined to increase system capacity, and could be replicated across a region to ensure a harmonized deployment that simplifies maintenance. Our energy containers use primarily solar energy and can be equipped with other energy sources. The systems are available either completly installed and tested or to be assembled at site.

Reference Desalination Plant, Namibia PV Power: 20 kWp polycrystalline modules Surface: 180 m², free-field Batteries: 1000 Ah, 48 V Commissioning: 2010

Backup System Regions with weak public grids often suff er from electricity black-outs, which can lead to fi nancial losses in small businesses or to critical situations in hospitals. Backup systems are a suitable solution to deliver a sustainable power supply even during grid failures. If such systems are combined with solar power, the energy in the battery storage is supplemented, thus extending the bridging time of the back-up system. This also represents a desirable alternative to diesel generators as they require regular testing and maintenance. 

Reference Backup power solution for IT equipment, fire protection system, lights in office building, Germany

PV Power: 120 kWp Battery: 4500 Ah / 48 V Commissioning: 2008

Technical Overview Modules

PV Inverter Public grid

Backup Inverter


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Small Wind & Hydro Power When feasible, combination of solar with wind turbines and/or micro hydro turbines represents an optimal solution, resulting in either lower investment costs or the increase in energy available to the system. The energy output of wind or hydro power generators is dependent on local site conditions. Having experiences in all renewable energy sources, juwi can support you in the design and implementation of the optimum system for your needs.

Reference Hybrid system with wind turbine, Morocco

PV Power: 5 kWp Wind turbine power: 3 kW Battery: 1000 Ah, 48 V Commissioning: 2010

Technical Overview AC Coupling

DC Coupling

Inverter Inverter



Solar Pumping for Water Supply Energy and water supply often belong together in Africa and other sunbelt countries. Solar pumps for village water supply, water purification or desalination plants represent an important base for the development of rural communities. As solar pumps are not dependent on batteries these pumping systems work very efficiently and are extremely robust.

Reference Solar Water Supply, Nambia

PV Power: 5 kWp Depth: 50 m Commissioning: 2010

Technical Overview Modules



Submersible Pump



juwi Off-Grid Activities Worldwide

Last updated: 06/ 2011

juwi Solar GmbH

Energie-Allee 1

Tel +49 (0) 6732 96 57-3351

55286 Wörrstadt, Germany

Fax +49 (0) 6732 96 57-7001

juwi_solar_de_Off-grid_Energie fernab vom Stromnetz  

juwi Solar: Off Grid Power Supply

juwi_solar_de_Off-grid_Energie fernab vom Stromnetz  

juwi Solar: Off Grid Power Supply