 Mini-grid systems that use biomass resources are generally based on modular technologies for either combustion or gasification. For the best performance, the technology specifications and the system design need to be tailored to the characteristics of the biomass feedstock. Because large quantities of solid materials are involved, the system design must accommodate the collection, storage, preparation and processing of the feedstock as well as removal, processing and disposal of ash residues.
Feedstock characteristics that can influence the design and selection of technology and equipment include particle size distribution, moisture content, organic and non-organic (ash) content, chemical composition and energy content. Feedstock preparation steps can often include size reduction and drying, and one of the common design choices how much automation to build into the feedstock handling steps. Industrialized countries with high labor costs tend to build highly automated systems, whereas in developing countries where labor is cheaper, much of the feedstock handling is manual or mechanized, but not automated.
 Biomass combustion
Direct combustion systems burn biomass fuel in a boiler to produce steam that is expanded in a turbine to produce power. Nearly all current biomass power generation is based on direct combustion in small, biomass-only plants with relatively low electric efficiency (20%). For mini-grid systems, modular technology is preferred, because it offers relatively less expensive systems with higher reliability, because the modules can be pre-assembled in a factory and tested before shipping to a remote village site. The main drawback of steam-turbine based systems is the relatively high operating pressures and the level of technical skills required for plant operation. Thus, they tend to be used only for applications greater than a few MWs. Where heat is a need, either in northern climates for winter heating or for small industry use, combined heat and power (CHP) applications can be cost-effective. Total system efficiencies for CHP can approach 90%. 
Biomass gasification
Modular biomass gasification systems produce a synthesis gas (syngas), which can be burned in a gas or diesel engine to provide electricity and motive power and burned in a boiler or furnace to provide heat. Modular biomass gasification systems are an emerging commercial technology that is available in sizes ranging from 3kW to 5MW. Hundreds of commercial applications exist in India alone that include village power, industrial process heat and electricity, and grid electricity supply. In China, hundreds of crop straw gasification systems were installed primarily for cooking gas applications. While technically successful, the utilization of the high-cost capital equipment for cooking only (4 to 6 hrs operation per day) was too low for most systems to be financially viable. The addition of electricity generation to improve the utilization of the gasification equipment and add another revenue stream makes technical and financial sense, but implementation of such system beyond the demonstration stage will require promotional policies.
Many of the early commercial systems have not always been reliable and clean, but recently, biomass gasification systems for village-power applications have been developed that are efficient, reliable, and clean.
One of these advanced biomass gasification based systems has been developed by US-based Community Power Corporation (CPC) for markets worldwide. The system, which is illustrated in the figure below, produces thermal energy, shaft power, and electricity, and a commercial prototype of this system is operating in the Philippines at a coconut cooperative, providing energy and power for production of commercial products from coconuts.
The heart of the system is the Gas Production Module (GPM) that converts coconut shells (and other dry woody biomass) to a product gas for delivery to a spark-ignited engine mounted on a power distribution platform. The platform can allocate shaft power as needed to various mechanical and electrical loads. The peak electrical output is 15 kWe in the commercial prototype, and about 20 kW of thermal energy) is available in the form of clean, hot air for drying crops and fish. This size system is well suited for many rural enterprises and small mini-grid systems. Larger size systems are suitable for larger mini-grid systems. 
Additional examples of leading biomass service and equipment supply companies that focus on small-scale systems appropriate for mini-grid applications and have rural electrification experience include:
- BTG Biomass Technology Group BV (BTG), is Netherlands firm which for the past 20 years has specialized in the process of conversion of biomass into useful fuels and energy. BTG has as its mission the world-wide development and implementation of economic and environmentally sound bio-energy systems.
- Ankur Scientific Energy Technologies Pvt. Ltd., an Indian company providing two types of biomass gasifier systems: one for wood waste or wood-like materials and another for fine biomass materials like rice husk, crop stalks and other agricultural residues.
Resource Assessment Assessment of biomass resources is an essential project development step that requires very local inputs. National and even regional level assessments of biomass resources exist that are useful in identifying particular feedstocks that should be pursued in certain areas. However, when evaluating specific project opportunities, it is critical that the biomass supply chain be investigated in detail. Whether the biomass is forest residues, agricultural residues, mill wastes or energy crops, specific sources must be identified and along with any competing uses for the resource. Long-term project viability requires the development of supply agreements with specific suppliers for amounts, prices and set time-frames. Furthermore, the requirements and cost sensitivity of competing users of the resource must be understood to avoid shocks to the resource availability and price once a plant starts operating and increasing demand on the resource. The costs for collection and transportation must also be correctly assessed. These costs can be significant and often are equal to the base cost of the resource. Biomass storage and handling must also be considered, especially if the resource is generated seasonally.
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