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Replacing Fossil Fuel Engines with Electric Motors or Renewable Natural Gas (RNG) Engines

alternative practice names:

Fuel Switching; Beneficial Electrification

Dairy farms often rely on internal combustion engines (ICEs) powered by fossil fuels for various operations, including crop irrigation, tractors, and utility vehicles. Transitioning from an ICE to an electric motor, also known as "fuel switching" or "beneficial electrification," offers significant efficiency improvements. By switching to electric motors, farms can achieve substantial reductions in energy consumption and emissions. Alternatively, if a dairy farm has access to renewable natural gas (RNG), replacing fossil fuels can be a viable option without converting to electric motors. This is especially relevant for farms prioritizing decarbonization, as RNG provides a renewable energy source that can power existing equipment.

When used, in what regions in the U.S. is the practice found: 

Northwest, West, Upper Midwest, Southwest, Northeast, Southeast

FARM SIZE 

When used, typically found on farms of the following sizes:

All Sizes

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Practice Benefits 

Cost savings: Replacing internal combustion engines (ICEs) with electric motors or engines powered by renewable natural gas (RNG) can lead to significant operational cost savings. Electric motors, in particular, have lower energy costs when compared to fossil fuels, especially for farms generating their own renewable energy (e.g., solar or wind). This reduces dependency on external energy sources and maximizes cost efficiency. However, the financial viability of conversion must be evaluated on a case-by-case basis, factoring in the engine’s runtime, electricity rates, and available rebates or incentives. For farms producing RNG (e.g., through anaerobic digesters), using RNG engines can also reduce costs by leveraging on-farm resources, although this is less likely if RNG must be purchased externally.


Reduced labor and maintenance: Electric motors are mechanically simpler and more efficient than ICEs, leading to reduced maintenance needs and labor costs. With fewer moving parts and no need for oil changes or fuel management, electric systems are easier to maintain. Furthermore, electric motors often come with advanced digital controls, such as variable frequency drives (VFDs), which optimize performance and energy use. These smart systems can also be managed through mobile applications, allowing for further automation and efficiency, resulting in additional cost savings and streamlined operations.

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Implementation Insights

Site-specific or Farm-specific requirements 

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  • Economic feasibility: Any farm utilizing fossil fuel-powered engines is a candidate for replacing them with electric motors. The most common example of economically feasible on-farm electrification pumps (ie irrigation pumps and manure pumps).

  • Equipment availability and size: Electric tractors are still early in their commercialization and are only currently available in small sizes. Dairy farms that have large tractors would not be good candidates for electric tractors due to the lack of suitable options available on the market today.

  • Access to RNG: For farms considering powering ICEs with RNG, access to RNG is the main barrier. There is high demand for RNG, but limited supply for pipeline, compressed, and liquid RNG. For farms with readily available RNG, replacing natural gas or propane with RNG is straightforward provided the RNG is a suitable fuel for the engine.

Required Capital Expenditures (CapEx)

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  • Electric motors: The primary expense of this practice is the electric motor to replace existing fossil fuel-powered equipment, along with the labor required to install and enable ongoing operations (e.g., charging stations for electric vehicles).  

  • Power System: Additional costs may be incurred for running electric lines to the site for electric motors that will utilize grid electricity. If a three-phase motor is being installed and it is cost-prohibitive to run three-phase electricity to the motor, additional costs will be needed to install a phase converter. 

  • Implements: In the case of electric tractors, new farming implements may also be needed if the currently used implements are not compatible with the electric tractor. Small electric tractors have recently become commercially available, but the market for off-road electric farm vehicles is in its infancy.

Required Operational Expenditures (OpEx)

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  • Maintenance: Ongoing maintenance costs for electric motors and electric vehicles are generally lower than those of fossil fuel engine-powered counterparts. Labor expenses can also be decreased in cases where fossil fuel engines require refueling using farm labor (mainly in the case of diesel engines). Electric motors should be inspected and cleaned regularly in accordance with manufacturer guidelines. If an installed electric motor has a V-belt, it should be replaced with notched belts or synchronous belts to improve efficiency. There are generally no differences in operating expenses for an ICE when switching from fossil fuels to RNG, but if a conversion kit is used to enable the use of RNG, ongoing maintenance may be needed for the retrofitted components.

  • Batteries: Onboard batteries are an additional operational consideration for electric tractors and utility vehicles. While batteries generally have a long useful life, it is best to discuss performance and maintenance considerations with the vendor to ensure that the vehicle will function as expected, particularly in cold climates.

Implementation Considerations

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  • Stationary electric engines: It is important to install motors that are appropriately sized for the required load, and it is recommended to use variable speed motor controls if there is a variable demand on the motor. Selecting motor models that are compatible with connected equipment, such as irrigation pumps, is critical, as is installing motors that are enclosed if they are in wet or dusty locations. Note that electric motors typically have a lower nameplate horsepower than the rated horsepower of the ICE they are replacing, so it is important to work with the vendor to properly size the motor. 

  • Electric vehicles: Converting a conventional tractor, all-terrain vehicle, or farm utility vehicle to an electric model requires more planning and research as it is still a relatively new option with little research and real-world case studies to reference. Additional considerations when considering an electric tractor include the weight of the tractor and potential impacts on soil compaction, as well as the cost of electricity and logistics of charging the vehicle on the farm. 

  • RNG conversion: Converting from fossil fuels to RNG often requires modifying the tractor unless it runs on natural gas or propane.

  • Motoer Sizing: It is critical to work with an experienced vendor to ensure that an electric motor being installed is properly sized to replace the existing ICE; often, the rated horsepower of an electric motor is less than the nameplate horsepower of an ICE due to higher efficiency.  

Financial Considerations and Revenue Streams

FEDERAL COST-SHARE AND CONSERVATION FUNDING

Funding is available for this practice through USDA's Natural Resources Conservation Service (NRCS) Environmental Quality Incentives Program (EQIP) On-Farm Energy Initiative.

Notes:

  • Check with the local NRCS office on payment rates and practice requirements relevant to your location.


The USDA Rural Development Rural Energy for America Program (REAP) also offers competitive grants and loan guarantees for installing energy efficiency projects. 

Note: 

  • Vehicles are not eligible for REAP grants because they are considered mobile equipment.


INCENTIVES AND REBATES

Incentives and rebates for switching from an ICE to an electric motor are sometimes available through the farm’s electric utility company. Utility rebate programs usually pay rebates based on a per-horsepower basis, and often require that motors are National Electrical Manufacturers Association (NEMA) Premium Efficiency certified and/or meet a minimum efficiency level.  


PAYBACK PERIOD

When installing a stationary electric motor to replace an ICE, it is important to evaluate the simple payback period of the motor. The payback period is mainly driven by the size of the ICE, the annual runtime, the labor costs required to maintain it, and the comparative cost of electricity versus the fossil fuel being used. For farms with on-farm renewable energy generation from solar, wind, or digester projects, the cost of generated electricity should be considered, as well as the percentage of time that the electric motor is estimated to utilize generated electricity versus grid electricity. Demand charges are another important factor when switching to electric motors, which are driven by electric utility tariff rules and the amount of time the motor is anticipated to run at on-peak versus off-peak hours. Consulting with the farm’s electric utility company is recommended, particularly when converting a high-horsepower engine to an electric motor. 


ELECTRIC VEHICLES

Rebates and incentives for off-road electric vehicles, such as tractors, are less common but are available in several states. Electric tractor vendors are usually knowledgeable about available incentives and financing opportunities and can help the farm navigate them.


FINANCIAL RESOURCES, TOOLS,  AND CASE STUDIES

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Environmental Impacts

REDUCES FARM GREENHOUSE GAS FOOTPRINT

Replacing fossil-fuel engines with electric motors or renewable natural gas (RNG) engines can reduce a farm's environmental footprint. When switching from fossil fuels to electricity, the net environmental impact depends largely on the source of the electricity. For instance, if coal-fired power plants supply electricity, the emissions reductions may be minimal compared to those achieved with electricity sourced from renewable energy, whether from the grid or through on-farm generation. Therefore, maximizing environmental benefits from electrification requires using low-carbon or renewable energy sources.

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Alignment with FARM Program

FARM Environmental Stewardship (ES) V2-V3 Alignment

FARM ES captures a farm's energy usage and calculates the associated greenhouse gas (GHG) emissions based on regional energy production and transmission averages. Any practice that reduces farm energy consumption will directly lower the farm's GHG footprint. The reduction in GHG emissions is particularly pronounced in regions where a larger proportion of energy is derived from coal, natural gas, or other fossil fuel sources, as these energy types have higher carbon footprints compared to renewable energy sources.

Contents

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We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights. 

We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights. 

Contents

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Practice Overview

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Practical Insights.png
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Research Results.png
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Dairy farms often rely on internal combustion engines (ICEs) powered by fossil fuels for various operations, including crop irrigation, tractors, and utility vehicles. Transitioning from an ICE to an electric motor, also known as "fuel switching" or "beneficial electrification," offers significant efficiency improvements. By switching to electric motors, farms can achieve substantial reductions in energy consumption and emissions. Alternatively, if a dairy farm has access to renewable natural gas (RNG), replacing fossil fuels can be a viable option without converting to electric motors. This is especially relevant for farms prioritizing decarbonization, as RNG provides a renewable energy source that can power existing equipment.

Practices and technologies

Replacing Fossil Fuel Engines with Electric Motors or Renewable Natural Gas (RNG) Engines

alternative practice name:

Fuel Switching; Beneficial Electrification