Fertilizer has become one of the most volatile line items on a farm’s budget, swinging with energy markets and geopolitics. That has pushed a once-niche idea into the mainstream of agtech: producing ammonia fertilizer on site, using air, water, and electricity. Modular “green ammonia” systems promise price stability, tighter agronomic control, and lower emissions by shrinking a sprawling global supply chain down to a few shipping containers at the edge of a field.

What on-farm green ammonia actually is

Ammonia (NH3) is the world’s most-used nitrogen fertilizer. Conventional production relies on the century‑old Haber–Bosch process, which reacts hydrogen with nitrogen from the air at high temperature and pressure. Today, most hydrogen is made from natural gas or coal, making ammonia both energy intensive and carbon intensive. The idea behind green ammonia is simple: make hydrogen with electricity and water, harvest nitrogen from air, and synthesize ammonia without fossil fuels—ideally right where it will be used.

On-farm systems come in two broad flavors:

• Electrolyzer + micro Haber–Bosch (e‑Haber): An electrolyzer splits water to produce hydrogen; a compact air-separation unit provides nitrogen; a small reactor synthesizes ammonia. This approach adapts proven industrial chemistry to farm scale.
• Direct electrochemical routes: Emerging technologies attempt to reduce nitrogen to ammonia in a single electrochemical step, avoiding high-pressure synthesis. Approaches include plasma-assisted, aqueous electrochemical, and lithium-mediated pathways. These are promising but, for now, less mature.

Why farmers are paying attention

• Cost control: Electricity becomes the primary input cost. If a farm can access low-cost power—especially from on-site wind or solar—ammonia prices become more predictable.
• Supply security: Local production reduces dependency on distant plants, import terminals, and seasonal bottlenecks.
• Operational flexibility: Producing and storing ammonia ahead of application windows can de-risk weather delays and logistics.
• Emissions reduction: Using renewable electricity cuts production emissions and reduces transport miles. Field emissions still depend on application practices, but cleaner production is a significant step.

How the technology works, step by step

Most near-term systems follow a three-unit architecture:

• Electrolysis: Water is purified and split into hydrogen and oxygen. Modern electrolyzers typically require on the order of 50–55 kWh per kilogram of hydrogen. Producing the hydrogen needed for one metric ton of ammonia therefore takes roughly 9 MWh of electricity, not counting downstream steps.
• Air separation: Ambient air is filtered to produce nitrogen, usually via pressure swing adsorption or membrane separation.
• Ammonia synthesis and handling: Hydrogen and nitrogen are reacted to form ammonia, which is then cooled, stored as anhydrous NH3 or converted to aqua ammonia (ammonia dissolved in water) depending on application preferences and local regulations.

Small systems carry extra efficiency penalties versus massive industrial plants. When you include compression, refrigeration, and balance-of-plant loads, total electricity for modular green ammonia commonly lands in the low double-digit megawatt-hours per ton. Designs continue to improve as vendors optimize heat integration and controls.

What it costs and how to think about economics

Three factors dominate the levelized cost of ammonia from a modular system:

• Electricity price and capacity factor: Power is the largest operating cost. Running the plant at high utilization with low-cost electricity is key. Pairing with on-site renewables and time‑of‑use tariffs can help.
• Capital expenditure (capex): Electrolyzers, compressors, reactors, storage, and safety systems add up. Spreading those costs over more run hours lowers unit cost.
• Maintenance and water: Purified water, filter media, catalyst replacements, and routine service need to be budgeted in.

As a rule of thumb, when farms can source electricity in the low single-digit cents per kWh range and keep systems running most of the year, on‑site production can approach or beat delivered fertilizer prices in many regions, especially where trucking and seasonal scarcity add premiums. Incentives for clean hydrogen or clean ammonia, where available, further improve the math.

Where it fits on the farm

• Anhydrous ammonia application: Many row-crop operations already apply anhydrous NH3. On-farm production allows pre‑positioning fuel and aligning supply with application windows.
• Aqua ammonia for blending: Some systems produce or convert to aqueous ammonia, which can be incorporated into liquid blends.
• Co-op hubs: Producer groups can share a slightly larger unit and storage, smoothing seasonal load and improving capacity utilization.

Power and storage strategy

Because compressors and synthesis loops prefer steady operation, farms often size storage to buffer plant output and field demand. A common approach is to run near-continuously when power is cheap and store ammonia for later use. With on-site solar or wind, systems can ramp output opportunistically, using controls to protect equipment from too-frequent cycling. In regions with demand-response programs, plants can also curtail during grid peaks to earn revenue.

Safety, siting, and permitting

Ammonia is a hazardous chemical with stringent handling requirements. Modular systems include leak detection, ventilation, emergency shutdown, and appropriate pressure relief. Tanks must be sited on suitable foundations with required setbacks, fencing, and signage, and operators need proper training and protective equipment. Specific permits, reporting thresholds, and storage limits vary by jurisdiction; early engagement with local authorities and insurers is essential.

Technology readiness today

Several companies offer containerized e‑Haber systems sized from tens to a few hundred kilograms of ammonia per day, with early deployments at dairies, grain farms, and ag co‑ops. These units typically integrate water treatment, electrolyzers, air separation, ammonia synthesis, controls, and storage. Direct electrochemical nitrogen reduction—promising room‑temperature, low‑pressure synthesis—has advanced in laboratories and pilots, but efficiency and durability must improve before broad commercial use.

Environmental impact beyond the plant fence

Green ammonia targets production emissions. Field emissions of nitrous oxide—a potent greenhouse gas—depend on agronomy. The biggest reductions come from matching nitrogen supply to crop demand in time, place, and amount. On‑farm production complements precision application strategies, variable-rate technology, and decision support tools by ensuring the right form of nitrogen is available exactly when planned.

What to ask vendors before you buy

• Energy balance and efficiency: What is the guaranteed electricity use per ton of NH3, including all auxiliaries?
• Turn‑down range and cycling: How does the plant perform under variable power? What are minimum stable loads and ramp rates?
• Water quality: What inlet water purity is required, and how is wastewater handled?
• Air separation details: PSA vs. membrane? Purity, maintenance intervals, and sensitivity to dust or humidity.
• Catalyst life and service: Replacement schedules, remote monitoring, and local service coverage.
• Storage and integration: Tank size options, transfer equipment, and compatibility with existing application hardware.
• Certification and incentives: How is carbon intensity documented? Which programs or credits are applicable in your region?
• Siting and compliance: Support for permitting, hazard analyses, emergency planning, and operator training.

Data and software integration

Modern systems expose operating data via APIs or dashboards. Tying production to farm management software lets growers coordinate batches with forecasted field work, fuel weather-adjusted yield models, and track nitrogen use efficiency. Over time, these datasets can inform better sizing, maintenance scheduling, and power contracting.

Looking ahead

The near term belongs to electrolyzer‑based modular plants, benefiting from steady improvements in stack efficiency, lower capex through manufacturing scale, and smarter integration with renewables. If direct electrochemical routes achieve higher selectivity and longer lifetimes, they could simplify hardware by eliminating compressors and high‑pressure synthesis loops. Either way, the direction of travel is clear: bringing nitrogen manufacturing closer to the field, coupling it to clean power, and weaving it into digital agronomy.

For growers, the practical question is no longer whether on‑farm ammonia is technically possible, but when it pencils out under local power prices, incentives, and operational needs. For regions that can line up cheap electricity, favorable permitting, and strong service networks, the ability to make fertilizer from air and water on the back forty could become a lasting competitive edge.