2-stage digester

The process is based on the anaerobic digestion of biomass. The proposed digester technology for the project is a so-called High Performance Temperature Controlled (HPTC) biogas plant. The HPTC, in contrast to the conventional one-stage digester, is a 2-staged digester in which the process of hydrolysis/acidification and methanisation is taking place in separate tanks. Main advantages include a substantially higher (20-30%) biogas yield and more importantly the HPTC allows the efficient use of different, mixed organic substrates that are difficult or impossible to digest in conventional plants.

The following diagram is a simplified presentation of the two-stage HPTC digester:



1. HiPo-S

   - small sized plants from 10 to 60 kWel or to provide cooking gas

   - robust, simple components with low degree of automation

   - generated for rural areas in developing countries which are not connected to the electrical grid

novis small biogas plant (HiPo-S) in Benin, novis GmbH 2010


2. HiPo-M

   - medium sized plants from 100kWel to 1MW

   - typically used in the agricultural field

   - fully automated, reliable biogas plant for feeding into the electrical grid

   - including a heat recovery concept

   - particularly suitable for substrates heavy to use like manure, grass silage, or often changing substrates

250 kWel biogas plant in Zarchlin, northern Germany, novis GmbH 2012


 3. HiPo-XL

   - extra large plants bigger than 1MWel

   - used in the agricultural field, for food products, or for bio-waste

   - operational safety is ensured by the redundancy of the technical system

   - feeding in the electricity- or natural gas-grid

2 MWel biogas plant in Simbach, southern Germany, novis GmbH 2002


Electricity distribution grid

The produced electricity is distributed to the villages via 10 kV lines. In the villages a 400 V underground grid is used to supply the households with 240 V AC.

Every household has a measure-and-control unit which is activated with a pre-paid card. These cards can be charged at the local bank.

All installations are according to German standards; there are no cut backs when it comes to safety.


The following diagram shows a rough outline of the grid: