The Indo-German cooperation project “Solar Payback” for accelerating Solar Heat for Industrial Process (SHIP) has identified Dairy processing as topmost potential sector as per the study undertaken by Solar Thermal Federation of India (STFI). Figure 1 below lists the potential industrial sectors that should adopt Solar Heat for Industrial Process (SHIP) in their various production processes.

At 176.4 million tonnes annually, India is the global milk and milk products producer as per 2017-18 data released by National Dairy Development Board (NDDB). There are over 1,200 large, medium & small dairy industries.

Ministry of New and Renewable Energy (MNRE), government of India currently has a financial assistance extended for concentrator solar thermal systems for Cooking, Process Heat, Space Heating and Cooling, Dairy processing falls under Process Heat. Table 1 below shows the break-up of installations application-wise until March 2019. Process Heat has a share of 36% of the total installed system and dairy processing has the lions share 40% amongst Process Heat. This places India amongst top five countries in the world on use of SHIP in dairy processing industries and perhaps the only in Asia.

 

Figure 1: Potential industrial sectors best suited to adopt Solar Heat for Industrial Process

 

Table 1: Concentrator solar thermal systems installed under MNRE programme and share of dairy processing

Application Installed Area (m2)
Cooking 31,756 (49%)
Process Heat 23,885 (36%)
Cooling 9,819 (15%)
TOTAL 65,460
Dairying 9,538 (40% of Process Heat)

 

A sample survey done by STFI amongst the NDDB dairy processing units and few private units shows milk processing in India constitutes around 35% of total milk production. The organised dairy industry accounts for 13% of the milk produced while the rest of the milk is either consumed at farm level or sold as fresh. Energy plays a major role in processing milk and milk products. In a dairy processing, primary energy sources such as furnace oil, etc. are used in boiler for generating steam which in turn is used for heating applications like pasteurization, evaporation, drying of milk. Table 2 shows the energy mapping of a typical dairy processing.

 

Figure 2: Installation at Ludhiana Dairy

 

Table 2 shows the mapping of various diary processes

Process Energy/Fuel being used Application media Temperature required OC
Washing and Cleaning Electricity, furnace oil, gas and agriculture waste Hot water 40-60
Chilling/Cold Storage Electricity, gas and diesel – < 5
Pasteurisation Fuels like furnace oil, coal, gas and agriculture waste Process heat 70 – 80
Ultra- Pasteurisation Fuels like furnace oil, coal, gas and agriculture waste Process heat 125 – 140
Sterilization/ Evaporation Fuels like furnace oil, coal, gas and agriculture waste Process heat 100-120
Spray drying Fuels like electricity and gas Hot air 100 – 140
Butter making- drying/ evaporation Fuels like furnace oil, coal and gas Hot air 70 -110

 

Going by the potential National Dairy Development Board (NDDB), a national Institution to support policies for growth of farmers have launched an initiative by implementing 15 pilot SHIP projects in the country and are showing promising results. There have also been several learnings on the grey areas. Mandatory heat demand supported with higher subsidies for renewable energy technologies will positively attract dairy processing units to adopt solar thermal heating. A Case Study of solar thermal heating plant in Ludhiana is given below in Table 3.

 

Table 3: Case study of the solar thermal process heating plant installed at Verka Dairy, Ludhiana

Industry example Dairy Industry
Used collector type CPC( Compound Parabolic Concentrator) type collectors
Average operation temperature 75°C
Supplied processes Hot Water for CIP, crate washing and boiler feed
Estimated annual energy consumption

Total FO Consumed in 2017-18: 1,948,995 ltr

Calorific Value : 9600 Kcal/kg
Active collector area 1,040 m2
Necessary space for mounting the collector field 1,040 m2 for 2,500,000 kcal per day
Specific thermal storage volume 36,000 litres hot water storage capacity
Production profile in the factory The dairy processes milk-based products like skim milk, buttermilk, cheese, milk powder, yoghurt, ice cream, etc.
Moderate thermal conversion efficiency of existing heat supply system ~ 80% using Furnace Oil Boiler
Net end consumer price per gross flat plate collector area including hydraulics and installation INR 23,200,000/- for an area of 1040 m2, generating 2,500,000 kcal per day including storage tank costs
Net end consumer prices for water storage tank (above 3 m³) No specific cost available for storage
Annual medium irradiation potential at site DNI between 1100 – 1200 kWh/m2
Energy source for current heat supply system Furnace Oil
Average price for current energy source Current Furnace Oil @ INR 49.17/- Litre.
Daily production profile in the factory 24 Hour Industry and production is related to milk and milk products
Weekly production profile in the factory 24 x 7 production related to milk and milk products
Average collector operation temperature 80°C
Energy inflation rate Rate of Furnace oil fluctuated between INR 18 to INR 42 per litre in the last 12 months
Investment / technology lifetime 23,200,000/- life expectancy of 15 years
Annual O&M costs Appx. INR 500,000

 

Recommendations

  • Constitute working committee from NDDB, MNRE, NITI Aayog, STFI and IIT Mumbai
  • Committee to identify the grey areas in the existing installations and identify solutions to overcome them.
  • Analyse heat demand of sample small, medium and large-scale dairy processing units and identify best solar thermal system to supplement.
  • Perform real time financial feasibility over 12 months and estimate the payback period.
  • Analyse heat output at different geographic locations taking into account the site Direct Normal Irradiance (DNI)
  • Being an emerging technology and an agriculture sector, subsidy be linked to performance and upfront be avoided so that best performing technologies are considered.
  • Formulate policy paper for Solar Heat Obligation that will drive industries to
  • Explore Energy Service Company (ESCO) overcoming capital investment
  • Approach multilateral agencies under Climate Change programmes for funding support owing to high capital investment.
  • Mass awareness workshops on advantages of solar thermal be conducted by MNRE and Department of Animal Husbandry.
  • Involve Department of Animal Husbandry, Dairying & Fisheries and Ministry of Food Processing Industries in workshops

 

References:

www.solar-payback.com

www.stfi.org.in

https://www.nddb.coop/sites/default/files/NDDB-solar-initiative.pdf