By M Krishnan and P. Krishnan
The sustained double blockade of the Strait of Hormuz has resulted in bulk diesel prices stabilizing at record highs. Though retail prices registered a controlled freeze in India through April, bulk diesel prices remained high by Rs. 22-25 as serious efforts are on by oil marketing companies to make up the under recovery of Rs 18-20 per liter following regional elections. ICAR-Central Marine Fisheries Research Institute, Kochi, has estimated the motorized artisanal fleet around 75,000 to 100,000 vessels. Conventional OBMs convert only 25% of fuel energy into thrust besides scaring away precious pelagic fish stocks due to noise, vibration and heat. The OPEX for fuel and lubricants works out to 40-55% of the daily catch value for a 10m boat, keeping fishers in a working capital debt bind. With the exception of Gujarat, which succeeded in rollbacks to retail rates for fishers, other coastal states must move to solar and electric propulsion, not only to achieve a green goal but as an economic survival strategy.
Phase change material (PCM) technology for solar-powered cold storage offers a viable alternative to expensive lithium-ion batteries, which perform poorly in salty, humid coastal environments. Refrigeration units run on solar panels during the day to freeze thermal plates. Acting as a cold battery, these plates keep storage units at sub-zero temperatures throughout the night without requiring any other power source. Odisha leads this changeover, aiming for 25 solar-powered units this year. Despite high upfront costs, fishers pay a fee per crate, avoiding CAPEX. This “Cooling as a Service” model has resulted in a 20% reduction in post-harvest losses.
Deep-sea trawlers continue relying on diesel, but small-scale coastal fleets under 12 meters are moving towards electric propulsion. Navalt, the largest solar boat manufacturer in India, has introduced the Destiny series of solar-electric boats powered by highly efficient outboards and lithium iron phosphate battery packs. The economics of operating a petrol OBM boat priced around Rs. 5 lakh but running up Rs. 4 lakh in operating expenses annually—compares poorly with a solar-powered boat priced around Rs. 15-20 lakh with a breakeven of 5 years. Field trials are being conducted in Uppada harbor, Andhra Pradesh, by the National Institute of Solar Energy (NISE) to standardize the design of solar-powered boats for traditional fishers.
In a comparison of traditional diesel and kerosene (TDK) engines vis-à-vis solar-electric hybrid engines (SEH), the former pales into insignificance. The daily fuel cost of TDK engines is Rs. 1500-3500 and volatile, while SEH engines run at no cost with only Rs. 200 toward grid charges. TDK engines involve high maintenance costs since numerous moving parts result in wear and tear, plus the need for oil changes. Conversely, SEH engines involve no maintenance since the motors have solid-state architecture. TDK engines generate noise and vibration, scaring fish and causing fatigue to the crew, while SEH engines are nearly silent. The only downside, for SEH engines is the high upfront CAPEX.
The need of the hour is a “Solar at Sea” subsidy reflecting the success of rooftop solar for homes. This could be the answer for India’s 2.5 lakh small boats. The economic feasibility of an SEH engine for a standard 10-meter mechanized boat plying the Tamil Nadu and Kerala coasts works out favorably for a solar-retrofitted craft over a 9.9 HP TDK outboard motor (TDK-OBM) craft, based on March 2026 fuel prices and technical specs.
While the TDK-OBM engine involves an initial investment of Rs. 1.2–1.8 lakh, CAPEX on the Solar Electric Retrofit (SER) works out to Rs. 12-15 lakh. Daily OPEX works out to Rs. 2800-4200 (fuel and oil) for the TDK-OBM, while the SER involves just Rs. 50-150 for a grid top-up. Annual maintenance is Rs. 25,000 for the TDK-OBM, while the SER involves only Rs. 5000 for electrical checks. The TDK-OBM engine lasts 3-5 years, while the SER engine lasts 10+ years. Thus, the 9.9 HP TDK-OBM engine is becoming an economic trap for fishers in the current West Asia crisis.
Based on an assumption of 240 days at sea, switching to an SER engine enables savings of Rs. 8.5–10 lakh per year in fuel and lubricants and pays for itself in 16 to 18 months in a no-subsidy scenario, while net profit increases by 35-45% due to elimination of fuel costs. The retrofit also involves a structural makeover. Post-retrofit, a 2 to 3kW solar roof on a 10-meter boat provides enough surface area for power generation and a sunshade. Lithium Ferro-Phosphate (LFP) batteries handle deep discharge cycles for 6-hour fishing trips and are safer in high-heat environments. The instant thrust of a 6-10kW electric motor provides torque equivalent to a 15 HP petrol engine, helping navigate surf and heavy currents. SER engine-powered boats are suitable for gill netting or long lining (at 4-6 knots). However, they are currently unsuitable for chasing pelagic mackerel schools as the battery drains quickly. Support infrastructure must include high-speed chargers on cloudy days. Most harbors are currently struggling with transformer upgrades to cater to 50 boats needing simultaneous charging.
The Shipbuilding Financial Assistance Scheme (SBFAS) reduced the subsidy for small electric/hybrid boats from 20% to 15%, effectively erasing the green premium. The silver lining lies in Kerala’s approval, under the Pradhan Mantri Matsya Sampada Yojana (PMMSY), for replacing kerosene engines with electric propulsion. The Vikalpika retrofit model and a NABARD-backed credit facility to fund CAPEX are some measures taken by the Government of India to achieve energy independence for coastal economies.
Dr. M. Krishnan, is former Principal Scientist & Head, ICAR-Central Institute of Fisheries Education, Mumbai. Dr. P. Krishnan is Director, Bay of Bengal Program-Inter Governmental Organization (BoBP-IGO), Chennai.
Disclaimer: The views expressed are the author’s own and do not reflect the official policy or position of Financial Express.