How is Biomass Transported

Transporting biomass fuel to a power plant is an important aspect of any biomass energy project. Because a number of low moisture fuels can be readily collected and transported to a centralized biomass plant location or aggregated to enhance project size, this opportunity should be evaluated on a case-by-case basis.

It will be a good proposition to develop biomass energy plants at the location where the bulk of the agricultural waste stream is generated, without bearing the additional cost of transporting waste streams. Effective capture and use of thermal energy at the site for hot water, steam, and even chilled water requirements raises the energy efficiency of the project, thereby improving the value of the waste-to-energy project.

Important Factors

  • The maximum rate of biomass supply to the conversion facility.
  • The form and bulk density of biomass.
  • The hauling distance for biomass transportation to the processing plant.
  • Transportation infrastructure available between the points of biomass dispatch and processing plant

Transportation is primarily concerned with loading and unloading operation and transferring biomass from pre-processing sites to the main processing plant or biorefinery. Truck transport and for a few cases train transport may be the only modes of transport. Barge and pipeline transport and often train transport involve truck transport. Trucks interface with trains at loading and unloading facilities of a depot or processing facility. Barge and pipeline require interfacing with train and/or truck transport at major facilities either on land or at the shores.

Physical form and quality of biomass has the greatest influence on the selection of equipment for the lowest delivered cost possible. A higher bulk density will allow more mass of material to be transported per unit distance. Truck transport is generally well developed, is usually cheapest mode of transport but it becomes expensive as travel distance increases. Pipeline biomass transport is the least known technology and may prove to be the cheapest and safest mode of transport in the near future.

A biomass freight train in England

Transportation costs of low-density and high-moisture agricultural residues straw are a major constraint to their use as an energy source. As a rule of thumb, transportation distances beyond a 25–50- km radius (depending on local infrastructure) are uneconomical. For long distances, agricultural residues could be compressed as bales or briquettes in the field, rendering transport to the site of use a viable option.

Greater use of biomass and larger?scale conversion systems demand larger?scale feedstock handling and delivery infrastructure. To accommodate expansion in feedstock collection and transportation, production centres can be established where smaller quantities of biomass are consolidated, stored, and transferred to long?distance transportation systems, in much the same way that transfer stations are used in municipal waste handling. Pre?processing equipment may be used to densify biomass, increasing truck payloads and reducing transportation costs over longer haul distances.

Overview of Biomass Logistics

Biomass logistics include all the unit operations necessary to move biomass feedstocks from the land to the biomass energy plant and to ensure that the delivered feedstock meets the specifications of the conversion process. The packaged biomass can be transported directly from farm or from stacks next to the farm to the processing plant.

Biomass may be minimally processed (i.e. ground) before being shipped to the plant, as in case of biomass supply from the stacks. Generally the biomass is trucked directly from farm to biorefinery if no processing is involved.

Another option is to transfer the biomass to a central location where the material is accumulated and subsequently dispatched to the energy conversion facility. While in depot, the biomass could be pre-processed minimally (ground) or extensively (pelletized). The depot also provides an opportunity to interface with rail transport if that is an available option.

The choice of any of the options depends on the economics and cultural practices. For example in irrigated areas, there is always space on the farm (corner of the land) where quantities of biomass can be stacked. The key components to reduce costs in harvesting, collecting and transportation of biomass can be summarized as:

  • Reduce the number of passes through the field by amalgamating collection operations.
  • Increase the bulk density of biomass
  • Work with minimal moisture content.
  • Granulation/pelletization is the best option, though the existing technology is expensive.
  • Trucking seems to be the most common mode of biomass transportation option but rail and pipeline may become attractive once the capital costs for these transport modes are reduced.

The logistics of transporting, handling and storing the bulky and variable biomass material for delivery to the bioenergy processing plant is a key part of the supply chain that is often overlooked by project developers. Whether the biomass comes from forest residues on hill country, straw residues from cereal crops grown on arable land, or the non-edible components of small scale, subsistence farming systems, the relative cost of collection will be considerable. Careful development of a system to minimize machinery use, human effort and energy inputs can have a considerable impact on the cost of the biomass as delivered to the processing plant gate.

The logistics of supplying a biomass power plant with sufficient volumes of biomass from a number of sources at suitable quality specifications and possibly all year round, are complex. Agricultural residues can be stored on the farm until needed. Then they can be collected and delivered directly to the conversion plant on demand. Infact, this requires considerable logistics to ensure only a few days of supply are available on-site but that the risk of non-supply at any time is low.

Biomass Storage Methods

Sufficient storage for biomass is necessary to accommodate seasonality of production and ensure regular supply to the biomass utilization plant. The type of storage will depend on the properties of the biomass, especially moisture content. For high moisture biomass intended to be used wet, such as in fermentation and anaerobic digestion systems, wet storage systems can be used, with storage times closely controlled to avoid excessive degradation of feedstock. Storage systems typically used with dry agricultural residues should be protected against spontaneous combustion and excess decomposition, and the maximum storage moisture depends on the type of storage employed.

Moisture limits must be observed to avoid spontaneous combustion and the emission of regulated compounds. Cost of storage is important to the overall feasibility of the biomass enterprise. In some cases, the storage can be on the same site as the source of the feedstock. In others, necessary volumes can only be achieved by combining the feedstock from a number of relatively close sources. Typically, delivery within about 50 miles is economic, but longer range transport is sometimes acceptable, especially when disposal fees can be reduced.

Storage of biomass fuels is expensive and increases with capacity.

Agricultural residues such as wheat straw, rice husk, rice straw and corn stover are usually spread or windrowed behind the grain harvesters for later baling. Typically these residues are left in the field to air dry to moisture levels below about 14% preferred for bales in stacks or large piles of loose material. After collection, biomass may be stored in the open or protected from the elements by tarps or various structures. Pelletizing may be employed to increase bulk density and reduce storage and transport volume and cost.

Biomass Storage Options

  • Feedstock is hauled directly to the plant with no storage at the production site.
  • Feedstock is stored at the production site and then transported to the plant as needed.
  • Feedstock is stored at a collective storage facility and then transported to the plant from the intermediate storage location.

Biomass Storage Systems

The type of biomass storage system used at the production site, intermediate site, or plant can greatly affect the cost and the quality of the fuel. The most expensive storage systems, no doubt, are the most efficient in terms of maintaining the high fuel quality. Typical storage systems, ranked from highest cost to lowest cost, include:

  • Enclosed structure with crushed rock floor
  • Open structure with crushed rock floor
  • Reusable tarp on crushed rock
  • Outside unprotected on crushed rock
  • Outside unprotected on ground
  • Subterranean

The storage of biomass is often necessary due to its seasonal production versus the need to produce energy all year round. Therefore to provide a constant and regular supply of fuel for the plant requires either storage or multi-feedstocks to be used, both of which tend to add cost to the system.

Reducing the cost of handling and stable storage of biomass feedstocks are both critical to developing a sustainable infrastructure capable of supplying large quantities of biomass to biomass processing plants. Storage and handling of biomass fuels is expensive and increases with capacity. The most suitable type of fuel store for solid biomass fuel depends on space available and the physical characteristics of the fuel.

Issues Confronting Biomass Energy Ventures

Biomass resources can be transformed into clean energy and/or fuels by thermal and biochemical technologies. Besides recovery of substantial energy, these technologies can lead to a substantial reduction in the overall waste quantities requiring final disposal. However, biomass energy projects worldwide are often hampered by a variety of techno-commercial issues. The issues enumerated below are not geography-specific and are usually a matter of concern for project developers, entrepreneurs and technology companies:

  1. Large Project Costs: In India, a 1 MW gasification plant usually costs about USD 1-1.5 million. A combustion-based 1 MW plant would need a little more expenditure, to the tune of USD 1-2 million. An anaerobic digestion-based plant of the same capacity, on the other hand, could range anywhere upwards USD 3 million. Such high capital costs prove to be a big hurdle for any entrepreneur or cleantech enthusiast to come forward and invest into these technologies.
  2. Low Conversion Efficiencies: In general, efficiencies of combustion-based systems are in the range of 20-25% and gasification-based systems are considered even poorer, with their efficiencies being in the range of a measly 10-15%. The biomass resources themselves are low in energy density, and such poor system efficiencies could add a double blow to the entire project.
  3. Dearth of Mature Technologies: Poor efficiencies call for a larger quantum of resources needed to generate a unit amount of energy. Owing to this reason, investors and project developers find it hard to go for such plants on a larger scale. Moreover, the availability of only a few reliable technology and operation & maintenance service providers makes these technologies further undesirable. Gasification technology is still limited to scales lesser than 1 MW in most parts of the world. Combustion-based systems have although gone upwards of 1 MW, a lot many are now facing hurdles because of factors like unreliable resource chain, grid availability, and many others.
  4. Lack of Funding Options: Financing agencies usually give a tough time to biomass project developers as compared to what it takes to invest in other renewable energy technologies.
  5. Non-Transparent Trade Markets: Usually, the biomass energy resources are obtained through forests, farms, industries, animal farms etc. There is no standard pricing mechanism for such resources and these usually vary from vendor to vendor, even with the same resource in consideration.
  6. High Risks / Low Pay-Backs: Biomass energy projects are not much sought-after owing to high project risks which could entail from failed crops, natural disasters, local disturbances, etc.
  7. Resource Price Escalation: Unrealistic fuel price escalation too is a major cause of worry for the plant owners. Usually, an escalation of 3-5% is considered while carrying out the project’s financial modelling. However, it has been observed that in some cases, the rise has been as staggering as 15-20% per annum, forcing the plants to shut down.

Biomass Exchange – Key to Success in Biomass Projects

The supply chain management in any biomass project is a big management conundrum. The complexity deepens owing to the large number of stages which encompass the entire biomass value chain. It starts right from biomass resource harvesting and goes on to include biomass collection, processing, storage and eventually its transportation to the point of ultimate utilization.

Owing to the voluminous nature of the resource, its handling becomes a major issue since it requires bigger modes of logistics, employment of a larger number of work-force and a better storage infrastructure, as compared to any other fuel or feedstock. Not only this their lower energy density characteristic, makes it inevitable for the resource to be first processed and then utilized for power generation to make for better economics.

All these problems call for a mechanism to strengthen the value chain. This can be done by considering the following:

  • Assuring a readily available market for the resource providers or the producers
  • Assuring the project developers of a reliable chain and consistent feedstock availability
  • Awareness to the project developer of the resources in closest proximity to the plant site
  • Assurance to the project developer of the resource quality
  • Timely pick-up and drop of resource
  • Proper fuel preparation as per technology requirements
  • Removal of intermediaries involved in the process – to increase value for both, the producers as well as the buyers
  • No need for long term contracts (Not an obligation)
  • Competitive fuel prices
  • Assistance to producers in crop management

The figure below gives a general understanding of how such a model could work, especially in the context of developing nations where the size of land holdings is usually small and the location of resources is scattered, making their procurement a highly uneconomic affair. This model is commonly known as Biomass Exchange

In such a model, the seed, fertilizer shops and other local village level commercial enterprises could be utilized as an outreach or marketing platform for such a service.  Once the producer approves off the initial price estimate, as provided by these agencies, he could send a sample of the feedstock to the pre-deputed warehouses for a quality check.

These warehouses need to be organized at different levels according to the village hierarchy and depending on the size, cultivated area and local logistic options available in that region. On assessing the feedstock sample’s quality, these centers would release a plausible quote to the farmer after approving which, he would be asked to supply the feedstock.

On the other hand, an entity in need of the feedstock would approach the biomass exchange, where it would be appraised of the feedstock available in the region near its utilization point and made aware of the quantity and quality of the feedstock. The entity would then quote a price according to its suitability which would be relayed to the primary producer.

An agreement from both the sides would entail the placement of order and the feedstock’s subsequent processing and transportation to the buyer’s gate. The pricing mechanisms could be numerous ranging from, fixed (according to quality), bid-based or even market-driven.

Roadblocks

The hurdles could be in the form of the initial resource assessment which could in itself be a tedious and time consuming exercise. Another roadblock could be in the form of engaging the resource producers with such a mechanism. Since these would usually involve rural landscapes, things could prove to be a little difficult in terms of implementation of initial capacity building measures and concept marketing.

Benefits

The benefits of  a biomass exchange are enumerated below:

  • Support to the ever increasing power needs of the country
  • Promotion of biomass energy technologies
  • Development of rural infrastructure
  • Increaed opportunities for social and micro-ntrepreneurship
  • Creation of direct and indirect job opportunities
  • Efficient utilization of biomass wastes
  • Potential of averting millions of tonnes of GHGs emissions

Conclusions

In India alone, there has been several cases where biomass power projects of the scale greater than 5 MW are on sale already, even with their power purchase agreements still in place. Such events necessitate the need to have a mechanism in place which would further seek the promotion of such technologies.

Biomass Exchange is an attractive solution to different problems afflicting biomass project, at the same time providing the investors and entrepreneurs with a multi-million dollar opportunity. Although such a concept has been in existence in the developed world for a long time now, it has not witnessed many entrepreneurial ventures in developing nations where the need to strengthen the biomass supply chain becomes even more necessary.

However, one needs to be really careful while initiating such a model since it cannot be blindly copied from Western countries owing to entirely different land-ownership patterns, regional socio-political conditions and economic framework. With a strong backup and government support, such an idea could go a long way in strengthening the biomass supply chain, promotion of associated clean energy technologies and in making a significant dent in the present power scenario in the developing world.

Overview of Biomass Handling Equipment

The physical handling of biomass fuels during collection or at a processing plant can be challenging to conveying equipment designers, particularly for solid biomass. Biomass fuels tend to vary with density, moisture content and particle size (some even being stringy in nature) and can also be corrosive. Therefore biomass fuel handling equipment is often a difficult part of a plant to adequately design, maintain and operate.

The design and equipment choice for the fuel handling system, including preparation and refinement systems is carried out in accordance with the plant configuration. This is of special importance when the biomass is not homogeneous and contains impurities, typically for forest and agro residues. Some of the common problems encountered have been the unpopular design and undersized fuel handling, preparation and feeding systems. The fuel handling core systems and equipment are dependent on both the raw fuel type and condition as well as on the conversion/combustion technology employed. The core equipments in a biomass power plant include the following:

  1. Fuel reception
  2. Fuel weighing systems
  3. Receiving bunkers
  4. Bunker discharge systems (stoker, screw, grab bucket)
  5. Fuel preparation
  6. Fuel drying systems
  7. Crushers
  8. Chippers
  9. Screening systems
  10. Shredding systems
  11. Grinding systems (for pulverised fuel burners)
  12. Safety systems (explosion relieve, emergency discharge, fire detections etc)
  13. Fuel transport and feeding
  14. Push floors
  15. Belt feeders
  16. Conveyers, Elevators
  17. Tube feeders
  18. Fuel hoppers and silos (refined fuel)
  19. Hopper, bunker and silo discharge
  20. Feeding stokers
  21. Feeding screws
  22. Rotary valves

To enable any available biomass resource to be matched with the end use energy carrier required (heat, electricity or transport fuels) the correct selection of conversion technologies is required. Since the forms in which biomass can be used for energy are diverse, optimal resources, technologies and entire systems will be shaped by local conditions, both physical and socio-economic in nature. Since the majority of people in developing countries will continue using biomass as their primary energy source well into the next century, it is of critical importance that biomass-based energy truly can be modernized to yield multiple socioeconomic and environmental benefits.

Logistics of a Biopower Plant

Biomass feedstock logistics encompasses all of the unit operations necessary to move biomass feedstock from the land to the energy plant and to ensure that the delivered feedstock meets the specifications of the conversion process. The packaged biomass can be transported directly from farm or from stacks next to the farm to the processing plant. Biomass may be minimally processed before being shipped to the plant, as in case of biomass supply from the stacks. Generally the biomass is trucked directly from farm to biorefinery if no processing is involved.

Another option is to transfer the biomass to a central location where the material is accumulated and subsequently dispatched to the energy conversion facility. While in depot, the biomass could be pre-processed minimally (ground) or extensively (pelletized). The depot also provides an opportunity to interface with rail transport if that is an available option. The choice of any of the options depends on the economics and cultural practices. For example in irrigated areas, there is always space on the farm (corner of the land) where quantities of biomass can be stacked.  The key components to reduce costs in harvesting, collecting and transportation of biomass can be summarized as:

  • Reduce the number of passes through the field by amalgamating collection operations.
  • Increase the bulk density of biomass
  • Work with minimal moisture content.
  • Granulation/pelletization is the best option, though the existing technology is expensive.
  • Trucking seems to be the most common mode of biomass transportation option but rail and pipeline may become attractive once the capital costs for these transport modes are reduced.

The logistics of transporting, handling and storing the bulky and variable biomass material for delivery to the biopower plant is a key part of the supply chain that is often overlooked by project developers. Whether the biomass comes from forest residues on hill country, straw residues from cereal crops grown on arable land, or the non-edible components of small scale, subsistence farming systems, the relative cost of collection will be considerable. Careful development of a system to minimize machinery use, human effort and energy inputs can have a considerable impact on the cost of the biomass as delivered to the processing plant gate.

The logistics of supplying a biomass power plant with consistent and regular volumes of biomass are complex.

Most of the agricultural biomass resources tend to have a relatively low energy density compared with fossil fuels. This often makes handling, storage and transportation more costly per unit of energy carried. Some crop residues are often not competitive because the biomass resource is dispersed over large areas leading to high collection and transport costs. The costs for long distance haulage of bulky biomass will be minimized if the biomass can be sourced from a location where it is already concentrated, such as sugar mill. It can then be converted in the nearby biomass energy plant to more transportable forms of energy carrier if not to be utilized on-site.

The logistics of supplying a biomass power plant with sufficient volumes of biomass from a number of sources at suitable quality specifications and possibly all year round, are complex. Agricultural residues can be stored on the farm until needed. Then they can be collected and delivered directly to the conversion plant on demand. At times this requires considerable logistics to ensure only a few days of supply are available on-site but that the risk of non-supply at any time is low.

Losses of dry matter, and hence of energy content, commonly occur during the harvest transport and storage process. This can either be from physical losses of the biomass material in the field during the harvest operation or dropping off a truck, or by the reduction of dry matter of biomass material which occurs in storage over time as a result of respiration processes and as the product deteriorates. Dry matter loss is normally reduced over time if the moisture content of the biomass can be lowered or oxygen can be excluded in order to constrain pathological action.

To ensure sufficient and consistent biomass supplies, all agents involved with the production, collection, storage, and transportation of biomass require compensation for their share of costs incurred. In addition, a viable biomass production and distribution system must include producer incentives, encouraging them to sell their post-harvest plant residue.