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In the Renewable Energy Sector, BIG SOLAR is expanding its activities in the Waste to Energy production from biogas, as Investor, Technology provider, Equipment supplier but also as EPC Contractor.

Having installed around 30 MW of Solar and Biogas projects, BIG SOLAR is mastering high technological expertise and construction experience and is able to undertake projects as EPC Contractor, providing complete solutions starting with the development and design of a project, until the equipment delivery, the construction and the start-up of the plant.

The undisputable added value  BIG SOLAR offers to a Biogas Investor, is originated from the fact that after thorough research in the sector and the available technologies, the company proceeded in the implementation of its first owned Biogas plant of 1 MW, in the area of Pella, Greece, which is operational already.

Specifically, BIG SOLAR offers the following services:

  • Feasibility Studies
  • Optimal Solution Design
  • Construction and Supervision
  • Commissioning and Start-up
  • Monitoring of biogas plant during the first months of the operation
  • Online process monitoring and consultancy

BIG SOLAR has established a strategic partnership with FARMATIC Anlagenbau GmbH (FFE SOLUTIONS) a German company with more than 50 years experience in metallic tank construction, silo, biogas plants and waste water treatment.

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Κάθετος Αντιδραστήρας

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Κεντρικός Αναδευτήρας

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Εναλλάκτης εξωτερικός

The Foundation of Technology Excellence BIG SOLAR implements is consisted of

Vertically Continuously Stirred High Performance Digesters

The Vertical Tall Metallic Digester is the signature component of the Technology BIG SOLAR is implementing, and is proposed for every biogas plant ≥ 500 kW. Each Biogas plant design is custom-tailored to the customer specifications and to the feedstocks available locally.

The Digesters are designed by FARMATIC and are delivered as a complete functional unit for integration into an EPC project, offering a hands-free turn-key product of high quality. They operate as Main Digesters CSTR in a 2-stages anaerobic digestion process, which enables a higher biogas production. The design and the construction material of the digesters ensure a superb cost/performance ratio to the client.

Constructed with assembled glass-coated steel  panels, for high resistance to corrosion and bolted with special silo bolts with elastic sealant for absolute tightness of the tank, these Digesters ensure high efficiency and durability.

The Digester can be built in record time diminishing the plant’s construction period dramatically. The special jack system for the assembly of the tank does not require extensive scaffoldings or crane works.

Central Vertical Stirrers
The Stirrers are custom-fitted for each vertical stirred digester and depending on the mixture of substrate they have two or three sets of rotor blades. The vertical agitator mounted on top of a self-supporting roof keeps the substrate in constant downward motion. Central agitators are installed with an external transmission on the roof of the digester, which ensures continuous operation with low maintenance. The central agitator can be removed from the digester through an inspection or repair, through the roof without the necessity to empty the digester content.

External Heat Exchanger


  • Minimized risk of clogging and settlement on the various heating pipes installed internally in the digester.
  • High surface area for heat transmission
  • Very high heat exchange rates
  • Easy replacement of individual modules
  • No parts subject to wear and tear- no maintenance
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Automation and process Control

The operation of the biogas plant is controlled and supervised through a SCADA system. The visualization of the whole biogas process including all tanks, drives, ancillary machinery and sensors, as well as substrate paths, is shown in graphical form on the screen of the plant’s PC. The settings of automatic control routines can be adapted by the operator of the plant. Additionally, operating parameters are logged and previous values are stored and can be visualized as individual trends. Remote access to the complete system is possible and alarms may be sent automatically in text form in mobiles or tablets.

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  • High Biogas Efficiency due to continuous and better stir and homogenization of the substrate in the main digester.
  • Manage a wide variety of substate (organic waste from restaurant leftover, food industries, slaughterhouses, fat and oils) in contract with the simple agricultural biogas plants which manage mainly manure and maize silage.
  • Continuous stirring in the digester prevents from clogging, settlements and floating layers.
  • Foam creation from digestion of complex substrates is significantly reduced, thanks to superior process design.
  • The biogas plant concept is optimized for easy accessibility and allows maintenance and repair during operation.
  • Each biogas plant is taken as a specific project and the design focuses on the optimal combination of the individual specifications and the highest satisfaction of customer’s needs.
  • Very short construction time and fast start-up using pre-constructed equipment.
  • Highly efficient plants due to the highest quality of construction materials and design, with minimal maintenance and operational costs in combination with low parasitic energy consumption.