A biomass-solar combination for cold storage of farm produce

09 May 2019

A novel way of utlising biomass and solar power to create cold storage facility in rural areas

Farm produce
In 2018, farmers across the country could not sell approximately 40% of their farm produce (specifically fruits and vegetables) due to poor transport and storage facilities.

India ranks second globally in the production of fruits and vegetables and is expecting an increase in demand of fruits by 228% and vegetables by 95% by the year 2050. Thus, there will be a need to adopt mechanisms to prevent post-harvest losses which have been estimated to be as high as Rs. 92,651 crores per annum. Out of this, losses due to poor storage facilities amount to nearly Rs. 63,000 crore per annum.

As per the available statistics, in 2018, farmers across the country could not sell approximately 40% of their farm produce (specifically fruits and vegetables) due to poor transport and storage facilities[1]. Provision of reliable electricity is a must in establishubg storage facilities. However power supply in rural areas is erratic and disrupted by periodic power cuts[2].

In light of this, The Energy and Resources Institute (TERI), the Indian Institute of Technology (IIT) Delhi, and the Delhi Technical University (DTU), have been working together to design and develop a holistic solution to address the dual challenge of electricity access in remote and rural areas and preventing post-harvest losses. The project involves design and development of Biomass-Solar PV electricity and cooling solution for rural India, and is a part of the Off Grid Mission Innovation Challenge funded by Department of Science and Technology of the Government of India. The project will be piloted in two remote villages in Odisha.

As part of the exercise, a micro-grid will be installed in selected villages. The micro-grid will comprise:

  • A 20kWe capacity two-stage biomass gasifier developed by TERI
  • A 25kW solar PV installation along with a battery-bank
  • A cold storage solution with 10 tonnes of storage capacity

The hybrid system comprising of a two-stage gasifier and solar PV system, along with a battery bank, will provide continuous electricity supply. The cold storage system will run using the waste heat rejected from the gasifier for its operation as a cold room to store perishable fruit and vegetable produce. The electricity produced by the gasifier and solar PV system will be utilised by consumers in the village for lighting application and productive usage/s.

The advantage of employing the cold storage unit with biomass gasifier is to effectively utilise the waste heat coming from the exhaust of biomass gasifier that is otherwise lost into the air. This arrangement will operate the cold storage unit and minimise thermal wastage. The cold storage unit is called Green Chill and is an ammonia-based system that runs on a vapour adsorption cycle. Ammonia in vaporised form, running through an evaporator, is used to cool a 'cold room' with 10 tonnes of storage capacity. The entire system will operate in a micro grid model and will be utilised to increase the post-harvest life of the farm produce as well as strengthening livelihood activities such as cashew processing.

As part of the project, TERI also organised a workshop with the objective of bringing together the project team to discuss future action plan and establish short-term goals and propagate the advancements in the project to researchers working in the sector.

During the workshop, the design and planned operation of the integrated system was also demonstrated. The event registered participation from professors and researchers of IIT Delhi and DTU, participants from the international project partners ENEA (Italian National Agency for New Technology, Energy and Sustainable Economic Development, Italy) and Energigarden (Norway) were also present. The team from IIT Delhi discussed the Alternating Current (AC) and Direct Current (DC) synchronisation mechanism of the micro-grids that will be installed. The team explained that the solar PV system and the biomass gasifier together will counteract each other's intermittency resulting in a continuous electricity supply. TERI's presentation deliberated over the integration of the chilling solution with the gasifier, which is being tested at TERI's campus in Gurugram, Haryana, along with the design of heat exchanger of the chilling solution.

The international partners presented their areas of research during the workshop. ENEA discussed several advancements that they are researching upon in the field of solar (PV and thermal) and biomass energy whereas Energigarden, a premier centre for bioenergy in Norway, talked about the different gasifier systems it is working on along with 'Energy Farm', an entirely sustainable farm that makes use of renewable energy for electricity and fuel.

The key lesson to emerge from the workshop was that solutions such as the biomass-solar PV-'Green Chill' hybrid system can effectively meet the electricity requirements of a rural community along with provision of a much needed cold storage system. In the long run this could be a potential solution towards the problem of stubble burning caused by the underutilisation of surplus agricultural produce, accompanied by a cold storage to help increase the life of farm produce.

[1] https://www.downtoearth.org.in/news/agriculture/poor-post-harvest-storage-transportation-facilities-to-cost-farmers-dearly-61047
[2] https://factchecker.in/a-villages-journey-to-electrification-and-why-100-claim-rings-hollow/