Across India, millions of farmers still depend on diesel pumps because their fields sit far from the nearest grid line. Fuel is the running cost that never stops: at an assumed ₹85 per litre, every litre per hour your engine burns costs ₹340 a day on a 4-hour irrigation day, and about ₹86,700 a year over a 255-day season. Check your own fuel log for the real consumption of your engine. The PM-KUSUM scheme (Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan) was built specifically to break this cycle. Component B of KUSUM replaces a diesel pump with a fully off-grid solar pump; the central government pays 30% of the benchmark or tender cost (50% in the North-East, hill states and islands) and the state at least 30%, so the farmer typically pays 40% or less. For a technical rundown of how the subsidy and equipment side of the scheme fits together, QBits Energy’s KUSUM Yojana agricultural solar subsidy guide is a useful engineering-side companion read.
This guide is the operational manual we hand to farmers on a Heaven Green Energy site visit, the 4-step replacement path, the documents to pre-stage, the system sizing chart against borewell depth, what to do with the old engine, and the diesel-savings math that can turn a ₹3 lakh quote into a payback of under 3 years.
Direct answer. Under PM-KUSUM Component B, a farmer replacing a diesel pump installs a standalone solar pump, receives 30% central subsidy from MNRE and at least 30% from the state, and pays the remaining 40% or less, of which only 10% need be paid upfront with a bank loan for the rest. A 5 HP system costs ₹3 to 3.5 lakh; farmer share is about ₹1.2–₹1.4 lakh at a 60% subsidy, less where the state adds more; payback depends on the diesel the old engine burned and is typically under 3 years. New applications depend on PM-KUSUM 2.0, as the scheme period ended on 31 March 2026. Heaven Green Energy is empanelled across Rajasthan, Maharashtra, and Madhya Pradesh.
Scheme status, October 2026. PM-KUSUM’s sanctioned period ran to 31 March 2026. MNRE has allowed only projects whose PPA was signed, or whose Notice to Proceed was issued, on or before 31 December 2025 to complete, by 31 March 2027, with no extension beyond that date (MNRE office memoranda of 28 March, 25 May and 28 September 2026 on the PM-KUSUM national portal). New Component B applications depend on PM-KUSUM 2.0, which MNRE described in March 2026 as at the proposal stage. The steps below explain how Component B replacement has worked; confirm with your state implementing agency whether any window is actually open before preparing a file.
If your borewell is currently powered by a Kirloskar, Honda, or Field Marshal diesel set and there is no grid supply available for your pump, Component B is built for you. The bridge below moves from “why now” to the exact application sequence, sizing, and disposal compliance you will be asked about at the District Agriculture Office.
Why Farmers Are Replacing Diesel Pumps with Solar
Three forces have aligned that did not exist a decade ago. Diesel is no longer the path of least resistance for an off-grid farm.
The first is fuel cost. Retail diesel has been well above its levels of a decade ago, and at today’s prices (we use ₹85/L in this guide; check your local rate) the comparison with a solar pump is one-sided.
The second is KUSUM subsidy depth. Component B started in 2019 with a 30% central + 30% state stack, leaving 40% to the farmer. MNRE’s guidelines set the state share at “at least” 30%, and some states have added more for particular farmer categories, lowering the farmer share further; check your state’s notification.
The third is technology maturity. The Ministry of New and Renewable Energy (MNRE) 2023 specification for solar water pumping systems, the requirement for Indian-made modules and cells (see ALMM), and the field-proven track record of brushless DC (BLDC) motor controllers mean a scheme solar pump carries a 5-year system guarantee with 5 years of maintenance, and modules warranted to deliver at least 80% of rated output at 25 years, figures no diesel pump has ever matched.
For the full national framework around Component A, B, and C, see our PM-KUSUM complete guide. For the head-to-head economic comparison, the diesel vs solar pump ROI deep-dive lays out a 10-year cashflow at 3 HP, 5 HP, and 7.5 HP.
The 4-Step Diesel-to-Solar Replacement Path under KUSUM
This is the named framework we use across every Component B project. Four sequential steps, each with its own document set and timing window. Treat it as a checklist.
Step 1: Pre-Application Pump Audit and Land Document Pull (Week 1)
Before opening the state KUSUM portal, close out four things.
Diesel pump audit. Record the current diesel pump make, model, HP rating, year of purchase, and average diesel consumption (litres/day) over the last season. This data feeds your own savings calculation and helps if the agency asks for proof of the existing pump. Take photographs of the pump, the diesel storage drum, and the borewell head.
Borewell depth measurement. A licensed driller’s report or your original borewell completion certificate gives the static water level (depth to the water table) and dynamic water level (depth while pumping). These two numbers determine the solar pump HP and pipe length, get it wrong and the pump either burns out or runs dry.
Land ownership documents. Pull a fresh 7/12 extract (Maharashtra), Jamabandi or Khasra Khatauni (Rajasthan, Madhya Pradesh, Haryana, UP), Pattadar Passbook (Telangana, Andhra Pradesh), or RTC (Karnataka). The land record must be in the applicant’s name; if it is jointly held, all co-owners sign a consent form. Land must be agricultural classified.
Aadhaar–bank seeding. Under MNRE’s guidelines the central subsidy is released to the state implementing agency, which pays the vendor, but loans, any state transfers and refunds still run through your bank account, so it should be seeded with your Aadhaar number through the UIDAI Aadhaar seeding portal or at a bank branch.
Step 2: Portal Application and Vendor Empanelment (Week 2)
Each state runs its own Component B portal under the central PM-KUSUM umbrella. Open your state portal, register with your Aadhaar-linked mobile number, and trigger an OTP.
Heaven Green Energy is empanelled in Rajasthan (RREC), Maharashtra (MEDA), and Madhya Pradesh (MPUVNL). State-specific application notes are in our KUSUM Rajasthan guide, the KUSUM Maharashtra 2026 application, and the KUSUM Madhya Pradesh (MPUVNL) application guide.
Step 3: Technical Sanction, Subsidy Order, and Farmer Share Payment (Week 3 to 6)
The state nodal agency reviews the application against four checks:
On approval, the agency issues a Technical Sanction Letter and the Subsidy Order showing the exact ₹ figure for central, state, and farmer shares. The farmer pays his/her share into the agency’s escrow account or directly to the empanelled vendor, depending on the state model. Payment receipt is uploaded back to the portal.
Step 4: Installation, Commissioning Inspection, and Subsidy Release (Week 7 to 10)
After farmer-share payment, the vendor schedules installation. Site work covers panel mounting structure (typically galvanised steel on a 4 metre × 4 metre concrete foundation), DC cabling, controller mounting in a weatherproof enclosure, submersible pump descent into the borewell with appropriate cable and pipe, and earthing per IS 3043.
A typical 5 HP system installs in 3 to 5 working days. After commissioning, the state inspector visits for a physical audit, checking panel count and model serial numbers against the ALMM register, inverter and controller serial numbers, pump HP rating, water discharge test, and earthing resistance. Once the inspection report is filed, the central and state subsidies are settled with the vendor through the state implementing agency (MNRE releases its share to the agency, not to the farmer); a few states use an upfront-payment-then-reimbursement model instead.
What happens to the old diesel engine depends on your state’s conditions, covered in the disposal section below.
Subsidy Eligibility for Diesel-Pump Replacement
Component B is restricted to off-grid agricultural use: MNRE’s guidelines cover standalone pumps and replacement of diesel pumps in off-grid areas where grid supply is not available, with priority for small and marginal farmers and farmers using micro-irrigation.
| Criterion | Requirement | Source |
|---|---|---|
| Land ownership | Agricultural land in applicant’s name (or jointly held with consent) | MNRE KUSUM guidelines |
| Land area | Pump size matched to water table, land and water need | MNRE guidelines; state norms vary |
| Grid status | Off-grid area where grid supply is not available (grid-connected pumps go to Component C) | MNRE guidelines, Jan 2024 |
| Borewell | Existing functional borewell with water yield certificate | State guidelines |
| Existing pump | Diesel pump (preferred) or no existing pump; grid-connected pumps are routed to Component C | KUSUM Component B charter |
| Aadhaar–bank seeding | Usually required for portal e-KYC and payments | State portal rules |
| Vendor | Selected through the state implementing agency’s tender | MNRE guidelines, Jan 2024 |
The central template in MNRE’s guidelines is below; states can add more for particular farmer categories, so check your state’s notification (see our state vs central subsidy glossary entry for how the two layers combine):
| Case | Central subsidy (MNRE) | State subsidy | Farmer share |
|---|---|---|---|
| General states, with state share | 30% | At least 30% | Up to 40% |
| NE states, hill states/UTs and islands, with state share | 50% | At least 30% | Up to 20% |
| State gives no share (central-only route) | 30% (50% NE/hill/islands) | 0% | 70% (50% NE/hill/islands) |
| Pumps above 7.5 HP | Capped at the 7.5 HP amount | Varies | Higher |
Source: MNRE PM-KUSUM page for the 30% and 50% central assistance, the state share of at least 30%, the farmer share of at most 40% (20% in the special-category states) and the 7.5 HP limit. The central-only row is this article’s arithmetic (100% minus the central share).
For a stepwise application walkthrough including state-specific portal screenshots, see our Component B application guide. If your pump already has a grid connection, the grid-tied path is the relevant one, read the Component C grid-tied pump guide.
System Sizing, Matching Solar to Existing Pump HP and Borewell Depth
Two variables drive sizing: the existing diesel pump HP rating (which sets the irrigation throughput your land needs) and the borewell depth (which sets the pumping head the motor has to overcome). Get either wrong and you either under-irrigate or burn the controller. Our companion KUSUM solar pump size by borewell depth guide walks through the same sizing logic in more depth if you want a second reference point.
Pump HP to Solar System (kWp) Conversion
A solar pump system is sized as solar panel watt-peak (Wp) per HP of pump. Under Component B the array is roughly 1 kWp per HP: MNRE’s 2023 pump specification sets minimum arrays of 900 Wp per HP (for example 4,800 Wp for 5 HP), and the 2024 guidelines cap the array at the pump rating in kW (a 3 HP pump cannot have more than 3 kW of panels).
| Diesel pump HP | Equivalent solar HP | Solar array (MNRE minimum to cap) | Indicative system cost |
|---|---|---|---|
| 2 HP | 2 HP | 1.8–2 kWp | ₹1.5–₹1.8 lakh |
| 3 HP | 3 HP | 2.7–3 kWp | ₹2–₹2.5 lakh |
| 5 HP | 5 HP | 4.8–5 kWp | ₹3–₹3.5 lakh |
| 7.5 HP | 7.5 HP | 6.75–7.5 kWp | ₹4.5–₹5.5 lakh |
| 10 HP | 10 HP | 9–10 kWp (central aid capped at 7.5 HP) | ₹6–₹7 lakh |
Borewell Depth to Pump HP Mapping
Borewell static water level (the depth you draw from at rest) is the more important number than total bore depth, a 300 ft bore with water at 40 ft is a shallow pump scenario.
| Static water level | Recommended pump HP | Typical use case |
|---|---|---|
| 0 to 50 feet | 3 HP | Small farm, vegetable patch, drip irrigation 2 to 3 acres |
| 50 to 100 feet | 5 HP | Standard 5 to 7 acre farm; the most common KUSUM B sizing |
| 100 to 200 feet | 7.5 HP | Deep table in semi-arid zones, west Rajasthan, north Karnataka |
| 200 to 300 feet | 10 HP | Very deep table; requires high-head submersible with multi-stage impeller |
| 300+ feet | Custom design | Solar may not be cost-effective; consult sizing engineer |
Get a free sizing audit. Our field engineers measure your borewell depth, water yield, and current diesel consumption, then send a written sizing report inside 48 hours. Get your free quote →
For a live calculation against your own bore depth and acreage, use the Heaven Green solar calculator and choose “agricultural pump” as the use case.
Diesel Pump Scrap and Disposal Norms
MNRE’s PM-KUSUM guidelines describe Component B as replacing diesel pumps with solar pumps, but they do not prescribe a scrapping procedure or an end-of-life certificate for the old engine. Some states set their own conditions, such as an undertaking or proof that the diesel set is no longer used for the subsidised pump, so ask your state implementing agency what it requires before installation.
If you do dispose of the engine, do it cleanly:
Step A, Drain residual fuel and lubricants. Drain the diesel tank, engine oil, and gearbox oil into sealed containers. Used oil counts as hazardous waste, so hand it to an authorised recycler; your State Pollution Control Board lists them.
Step B, Sell the engine for scrap or resale. The diesel engine, fuel tank, and pump housing go to a scrap dealer or a buyer. Get a dated receipt showing what was handed over, in case your state agency asks for proof.
Step C, Keep the paperwork with your KUSUM file. Photographs and the receipt are useful if the agency inspects the site later.
Cost, ROI, and Annual Diesel Savings Math
The arithmetic that closes the decision sits in two numbers, what diesel costs you each year versus what the solar system costs after subsidy. Below is the comparison for the most common KUSUM B sizing (5 HP).
| Line item | Diesel pump (5 HP) | Solar pump (5 HP / about 4.8–5 kWp) |
|---|---|---|
| System / equipment cost | ₹35,000–₹50,000 (new diesel set) | ₹3,00,000–₹3,50,000 (full system) |
| KUSUM subsidy (30% central + at least 30% state) | Not applicable | ₹1.8 lakh or more |
| Farmer out-of-pocket | ₹35,000–₹50,000 | ₹1.2–₹1.4 lakh at 60% subsidy, less where the state adds more |
| Diesel fuel per hour | ₹85 per litre burned | ₹0 |
| Daily run cost (4 hours) | ₹340 per litre-per-hour | ₹0 |
| Annual run cost (255 days) | ₹86,700 per litre-per-hour | ₹0 |
| Annual maintenance | ₹8,000–₹15,000 (filter, oil, mechanic visits) | ₹2,000–₹3,000 (panel cleaning) |
| Engine life | 8 to 10 years (then full replacement) | 25 years panel; 7 to 10 years pump motor |
| 10-year total ownership cost | ₹8.7 lakh in fuel alone per litre-per-hour, plus maintenance and an engine replacement | Farmer share plus panel cleaning |
| Payback after subsidy | Not applicable | Typically under 3 years |
The arithmetic to do with your own fuel log:
- Litres burned per running hour (from your fuel log) = L
- L × ₹85 = cost per hour
- × 4 hours/day = daily cost
- × 255 days/year = annual diesel cost (₹86,700 for every 1 L/hour)
Divide the farmer’s net out-of-pocket by that annual saving. For an engine burning 1 litre an hour: at ₹1.4 lakh farmer share (60% subsidy stack), payback is about 19 months; at ₹50,000 (where the state adds more), about 7 months; at ₹2.1 lakh (central 30% only, no state share), about 29 months. An engine that burns more fuel pays back proportionally faster.
Verdict. Diesel replacement is the KUSUM stream with the strongest fuel-saving case: at ₹85/L and a 4-hour-per-day run profile, the fuel bill alone is ₹86,700 a year for every litre per hour the engine burns. With the subsidy stack KUSUM provides, the farmer typically pays back the out-of-pocket in well under 3 years. Heaven Green’s strong recommendation is full diesel replacement, not a hybrid.
Common Mistakes in Diesel-to-Solar Conversion
Across the Component B projects we have handled in Rajasthan and Maharashtra, these are the six recurring errors. Each one is preventable with a 30-minute pre-check.
Pros and Cons, Full Replacement vs Hybrid (Solar + Diesel Backup)
A handful of farmers ask whether to keep the diesel pump as backup and add solar in parallel. Component B is designed as a replacement, and some states do not allow it; a self-funded hybrid is technically possible. Here is the trade-off.
- Pro 60%+ subsidy stack reduces out-of-pocket to about ₹1.2–₹1.4L on 5 HP, less in some states
- Pro Zero fuel cost, about ₹86,700/year saved per litre-per-hour
- Pro 25-year module performance warranty, 5-year system guarantee
- Pro No engine maintenance, no filters, no oil change, no mechanic visits
- Con No pumping after sunset (battery storage is not part of B)
- Con Monsoon weeks may run at 40 to 60% throughput
- Pro Diesel backup for cloudy days and night irrigation
- Pro Familiar fallback option
- Con KUSUM subsidy may not be available, so up to the full ₹3L cost out-of-pocket
- Con Diesel maintenance continues at ₹8K–₹15K/year
- Con Payback stretches much longer without subsidy
- Con Two systems = two failure modes
The verdict from 200+ Component B installations: full replacement is the right call for 95% of farmers. The cases where hybrid is sensible, large dairy operations needing pre-dawn pumping, cash-crop farms with critical irrigation windows, are better served by Component C grid-tied or by adding a separate battery-backed water tank at a later stage.
How Heaven Green Energy Helps Diesel-Pump Farmers
Heaven Green Energy is MNRE-empanelled and operates KUSUM Component B installations across Rajasthan, Maharashtra, and Madhya Pradesh. We have completed more than 200 diesel-to-solar pump replacements through 2024 and 2025, and our process is built around the four failure points farmers tell us about most often, sizing errors, EoL certificates, ALMM compliance, and DBT-stuck subsidies.
What we handle end-to-end:
- Free pre-application site visit: borewell depth measurement, water yield test, land record verification, distance-to-grid check.
- Document pre-check: land record, Aadhaar–bank seeding, diesel pump photographs, scrap arrangement.
- Portal submission: direct upload through our empanelled vendor login, including state-specific document formats.
- ALMM-listed tier-1 panels: Adani Solar only, never off-list imports.
- BIS-certified solar pumps: submersibles built to MNRE’s solar pump specification from Lubi, Shakti, or CRI Pumps, backed by the same BIS, IEC, and ALMM certification standards that govern the panels.
- Diesel pump scrap coordination: pickup, receipt and any paperwork your state asks for.
- State inspector liaison: installation handover, commissioning audit, subsidy release follow-up.
- 5-year comprehensive system warranty + 25-year panel performance warranty.
Explore the services that match your project:
- PM-KUSUM Component B Application: for off-grid farms.
- PM-KUSUM Component C: for pumps that already have a grid connection.
- Rajasthan KUSUM application: state-specific portal walkthrough.
- Maharashtra KUSUM 2026: MEDA process and subsidy depth.
- Rajasthan DREBP: additional state policy stack.
- Solar Calculator: size your system against your borewell depth in 60 seconds.
To start a Component B replacement file, request a free site visit, a solar advisor responds within 2 hours on business days.
Frequently Asked Questions
Can I claim PM-KUSUM subsidy if my diesel pump is still working?
Yes. KUSUM Component B does not require the diesel pump to be broken, it covers replacement of existing diesel pumps in off-grid areas. You apply with the existing pump in place, get technical sanction, and install the solar system; what happens to the old engine depends on your state’s conditions. Most farmers we work with replace functional diesel pumps that are 3 to 7 years old. Note that new applications depend on PM-KUSUM 2.0, as the scheme period ended on 31 March 2026.
What is the difference between KUSUM Component A, B, and C for diesel pump replacement?
Component A is for grid-connected ground-mount solar farms (500 kW–2 MW), not relevant to a single farmer with one pump but worth knowing about if you also own spare land, see our Component A landowner guide for that lease-or-build path. Component B is the standalone off-grid solar pump, with central aid up to the 7.5 HP level, the right fit for farms with no grid supply that currently run diesel pumps. Component C is for grid-connected farmers who already have an electric pump on the agricultural feeder and want to add solar with grid feed-in. Diesel pump owners on off-grid land go to Component B.
How much does a 5 HP solar pump cost after PM-KUSUM subsidy in 2026?
A 5 HP solar pump system carries an indicative all-in cost of ₹3 lakh to ₹3.5 lakh, covering the roughly 4.8–5 kWp solar array, BLDC submersible pump, controller, mounting structure, cabling, and installation. Under the general 60% subsidy stack (30% central plus 30% state), the farmer pays around ₹1.2 lakh to ₹1.4 lakh. States that add more for particular categories lower the share further. New applications depend on PM-KUSUM 2.0, as the scheme period ended on 31 March 2026.
How long does the KUSUM Component B application take end-to-end?
When a window is open, expect roughly 10 to 14 weeks from portal submission to subsidy settlement for a clean application. Step 1 document prep takes 1 week, Step 2 portal submission is 1 day, Step 3 technical sanction runs 3 to 6 weeks, Step 4 installation and inspection is 3 to 4 weeks, and subsidy settlement follows the commissioning report. Sloppy documentation and missed water-yield certificates can push the timeline to 6 months.
Is battery backup included in KUSUM Component B?
No. Component B funds only the panel array, controller, and submersible pump, there is no battery storage in the subsidy scope. The pump runs only during sunlight hours, typically 6 to 8 productive irrigation hours per day. Farmers needing 24-hour pumping add an overhead water storage tank (which we recommend at 2× daily irrigation volume) rather than batteries, since storing water is far cheaper than storing electricity for pump duty.
What happens to the old diesel pump after solar installation?
MNRE’s guidelines do not prescribe a scrapping certificate for the old engine; some states set their own conditions, so ask your state implementing agency. If you dispose of it, drain fuel and oil (used oil goes to an authorised recycler), sell the engine for scrap or resale, and keep a dated receipt with your KUSUM file.
Can my solar pump run a drip irrigation or sprinkler system?
Yes, and this is one of the better pairings under KUSUM. A solar pump’s variable-speed BLDC controller modulates flow throughout the day, which matches the slower discharge rates that drip and sprinkler heads need. MNRE’s guidelines give preference to farmers using micro-irrigation, and drip and sprinkler systems can draw their own subsidy under the central Per Drop More Crop scheme and state programmes such as Maharashtra’s PoCRA.
What if my borewell yield drops over time, can the solar pump be upgraded later?
Partly. The array is sized at roughly 1 kWp per HP, so there is little spare panel capacity, and central aid is tied to the sanctioned pump. If yield drops, the submersible pump head impeller stack can sometimes be swapped for a higher-head configuration without replacing panels or controller. The cost of an impeller stack swap is ₹15,000–₹25,000, far less than a fresh installation.
Does the KUSUM subsidy apply if my land is leased rather than owned?
In most states, no, Component B requires the applicant to be the registered landowner. A few states allow long-term lease farmers to apply with the landowner’s consent, our KUSUM tenant farmer rules guide covers the pathways in detail. Always confirm the state-specific rule with your state nodal agency before starting documentation.
Are loans available to cover the farmer’s share of the KUSUM Component B cost?
Yes. MNRE’s guidelines provide for bank finance so the farmer pays only 10% upfront and borrows the rest of the farmer share; NABARD-refinanced agricultural loans and public-sector banks are the usual lenders, with rates and tenure set by the bank, see our solar loan EMI comparison for how the rates stack up. The Kisan Credit Card (KCC) limit is increasingly accepted by Component B vendors. Heaven Green helps you apply to your bank for the farmer-share loan before installation.