Pigs – Generate renewable energy

Generate renewable energy

System: Pigs

Mainly applicable for: Intensively rearered indoor herds where there is a high demand for electricity.

Not applicable or effective for: Outdoor herds.

Description

Generating electricity from solar panels, wind turbines or anaerobic digestion of biomass (such as manure) on the farm, and using the electricity for farm processes. Electricity from solar panels and wind turbines on the farm can be used for farm processes on the same farm, or sold to the grid. The anaerobic digestion process produces biogas, which can be used in various ways: combusted to produce heat; converted to green electricity using a CHP (Combined Heat and Power generator); or separated and the biomethane upgraded to replace natural gas. The factsheet on anaerobic digestion can be found under ‘Manure storage and treatment’.

Mechanism of effect

By using electricity from renewable energy sources such as sun, wind and biomass, farms can avoid carbon dioxide emissions from fossil fuel combustion for electricity generation. Some CO₂ emissions are generated upfront during the manufacturing and transport of renewable energy equipment, but once operational the system emits no or little CO₂, and the initial ‘carbon debt’ is offset within a few months or years of operation. In effects shown below, only renewable energy used on the same farm is counted toward emission reductions, not the electricity sold to the grid. Additional reduction in CO₂ emission can be realized in case of electrification of vehicles and machinary (effect not shown in this factsheet).

Reference situation

Average European grid mix. Farm with no battery storage or electrification of vehicles.

Legend

● – Small effect (<5%)	o – No effect	o – no effect
●● – Medium effect (5-20%)	● – Unfavourable effect	? – unknown effect
●●● – Large effect (>20%)	● – ● – Variable effect (depending on farm characteristics or way/level of implementation)

Effect on total greenhouse gas (GHG) emissions (kg CO2-eq)

	per kg product		per farm (absolute)		Level of evidence
	Mean	(min-max)	Mean	(min-max)
Use home-produced solar energy	●	●–●	●	●–●	High
Use home-produced wind energy	●	●–●●	●	●–●●	High

Effect per emission source

	Source	Manure storage		Animals	Feed and forage production			Barn
	Gas	CH₄	N₂O	CH₄	CO₂	N₂O	LUC	CO₂
Use home-produced solar energy								●●●
Use home-produced wind energy								●●●

*risk of an adverse effect (see ’cause of variable or unfavourable effect’)

Explanation of variable effect

Use home-produced solar energy

The impact on emissions depends on how much fossil-based electricity is replaced on the farm and the carbon intensity of the electricity in the reference scenario, which is determined by the national grid mix. Greater emission reductions are achieved when a larger share of solar energy is used directly on the farm rather than exported to the grid. This self-consumption rate varies widely and is influenced by factors such as the number of solar panels, the availability of battery storage, and the extent to which energy-intensive activities coincide with solar production.

Use home-produced wind energy

The impact on emissions depends on how much fossil-based electricity is replaced on the farm and the carbon intensity of the electricity in the reference scenario, which is determined by the national grid mix. Greater emission reductions are achieved when a larger share of wind energy is used directly on the farm rather than exported to the grid. The self-consumption depends on several factors, including the farm’s overall energy demand, the size and energy output of the wind turbine, the availability of battery storage, and the extent to which energy-intensive activities coincide with wind energy production.