Energy in farming: Engineering methods

Tractors, livestock, three kinds of pump and fertiliser compared

What this tab covers The engineering methods that can do this conversion, compared on efficiency, scale, economics, limitations and reliability.

Four ways energy enters food production: field operations for crops, livestock care, irrigation pumping and fertiliser.

Comparison

Method	Efficiency	Scale	Economics	Limitations	Reliability
Crop farming (field operations)²⁸	Photosynthesis at most 4.6-6% of sunlight	Agriculture as a whole uses 2.5% of world final energy	Diesel and fertiliser are the largest energy costs	Few practical alternatives yet to diesel for heavy field machines	Mature machinery; timing is critical at harvest
Livestock³¹²	About 7% of feed calories become food on average (beef about 3%, poultry 13%)	Livestock processes dominate agricultural methane and nitrous oxide emissions	Feed is the dominant cost, far ahead of direct energy	Methane from digestion and manure	Milk cooling and ventilation need reliable power
Electric irrigation pumps⁵⁶	Existing sets 25-30%; star-rated 50-60%	About 20 million in India, using about 18% of national electricity	Cheap to run for farmers on subsidised tariffs, costly for utilities	Poor-quality supply (low voltage, few hours a day) damages motors; free power encourages over-pumping of groundwater	Motors burn out under poor voltage and are often rewound rather than replaced
Diesel irrigation pumps²¹¹	About 25% for a new, well-matched plant; often 12-15% for small worn sets (assumption)	74% of the energy used for irrigation pumping worldwide	Low capital cost, high fuel cost per cubic metre	Fuel price exposure, emissions, noise	Simple and repairable locally
Solar irrigation pumps²⁹¹⁵	About 11% sunlight to water energy (calculated)	1.1 GW worldwide in 2023, 94% in India; 574,324 standalone pumps under PM-KUSUM by November 2024	High upfront cost, close to zero running cost; heavily subsidised in India	Output only in daylight and lower in monsoon cloud; risk of theft	Few moving parts; panels last 25 years or more
Fertiliser use⁴	Fertiliser ammonia averages about 50 MJ per kg of nitrogen (calculated)	Just under 70% of 185 Mt of ammonia (2020)	Fertiliser price tracks natural gas prices	Much applied nitrogen is lost to air and water, wasting its embedded energy	Supply shocks when gas prices spike

On-farm energy is a small share of world energy, but its efficiency is often poor: Indian pump sets lose about three-quarters of their electricity, and diesel sets lose more. Replacing pump sets roughly halves pumping electricity, while solar pumps remove fuel cost entirely at the price of upfront capital. The biggest energy input to most cereal crops, though, is the natural gas embedded in nitrogen fertiliser, so using fertiliser more precisely saves more energy than anything done to tractors.

How each method works

Crop farming (field operations)

Tractors and harvesters burn diesel to plough, sow, spray and harvest; dryers use fuel or electricity to dry grain. The crop itself provides the main energy conversion through photosynthesis.

Livestock

Animals turn feed into milk, meat and eggs. Farms use electricity for milking, cooling milk, ventilation and lighting, and fuel for feed handling and heating.

Electric irrigation pumps

A grid-powered induction motor drives a submersible or surface centrifugal pump that lifts water from a borewell or canal.

Diesel irrigation pumps

A small diesel engine drives a pump, often moved between fields.

Solar irrigation pumps

Solar panels feed a controller that drives a DC or AC motor and pump directly during daylight, usually without batteries; water storage in tanks or the field replaces electricity storage.

Fertiliser use

Nitrogen fertiliser made from ammonia is spread on fields to raise yields; its energy is spent in the factory, not on the farm.

Sources

Renewables 2025 Global Status Report: Agriculture REN21, 2025
Emissions of greenhouse gases from energy use in agriculture, forestry and fisheries: 1970-2019 (Flammini et al., Earth System Science Data 14, 811) Copernicus Publications (FAO authors), 2022
Ammonia Technology Roadmap IEA, 2021
Agricultural Demand Side Management (Ag-DSM) Program in India: Adopting technologies to boost efficiencies (white paper) (2016 data) ICF International, 2016
Adding value: improving the cost economics and energy efficiency of pumps Indian Infrastructure, 2021
What is the maximum efficiency with which photosynthesis can convert solar energy into biomass? (Zhu, Long and Ort, Current Opinion in Biotechnology 19) University of Illinois / Elsevier, 2008
Photovoltaics Report Fraunhofer Institute for Solar Energy Systems ISE, 2026
Basics of on-site pumping plant evaluations (Pub. 3241-F) LSU AgCenter, 2014
Energy and protein feed-to-food conversion efficiencies in the US and potential food security gains from dietary changes (Shepon et al., Environmental Research Letters 11, 105002) IOP Publishing, 2016
Lok Sabha starred question 234 (PM-KUSUM progress, answered 11 December 2024, Annexure I) Ministry of New and Renewable Energy, Government of India, 2024