A 100kW solar plant costs about ₹45 lakh to ₹52 lakh in India in 2026, or roughly ₹45, 000 to ₹52, 000 per kW, for a turnkey on-grid rooftop system. It suits factories and commercial buildings with 100–150 kW of daytime load, a contract demand of at least 100 kW and around 8, 000–10, 000 sq ft of shadow-free roof. Payback is typically 4 to 5 years. Here is what most quotes leave out: per kW, 100kW is one of the most expensive sizes you can buy. The same class of plant costs 15–18% less per kW at 500kW, and in Madhya Pradesh a 100kW project can trigger a connection upgrade that costs more than a discount on panels will ever save. What does a 100kW solar plant cost in India in 2026? Market quotes for a turnkey 100kW on-grid rooftop plant in 2025–26 sit between ₹45, 000 and ₹52, 000 per kW. Where your project lands depends mostly on your roof and your module choice. Cost per kW: ₹45, 000–52, 000 for a complete system, including modules, inverters, structure, cabling, protection, installation and net-metering liaison. Total project cost: ₹45–52 lakh. Metal sheet roofs usually land near the lower end because the rails fix directly to the purlins. RCC flat roofs cost more: elevated structures are needed to clear parapet shadows and allow cleaning access, which pushes the price toward ₹52, 000 per kW. GST is lower than many older quotes show: since 22 September 2025, solar equipment attracts 5% GST, and a turnkey EPC contract works out to an effective rate of 8.9% under the 70:30 goods-to-services rule, down from 13.8%. On a ₹48 lakh project, that is roughly ₹2 lakh less tax for the same scope. If a vendor's quote still calculates GST at 13.8%, the quote is out of date. Key takeaway: budget ₹45–52 lakh for a 100kW rooftop plant, and check that the quote uses the post-September 2025 GST rate. 100kW solar plant cost breakdown: where the money goes On a typical ₹48 lakh project, modules take the largest share. The smaller line items are what decide whether a quote is fair. Solar modules, 50–60%: about ₹24–29 lakh. Net-metered projects must use modules on MNRE's ALMM List-I, and the exact model number on your quote should appear on that list. Inverters, 10–20%: about ₹5–10 lakh, usually two 50kW or three 33kW string inverters so one fault does not shut down the whole plant. Mounting structure, 8–15%: about ₹4–7 lakh. This is where RCC and sheet roofs differ most. Cabling, distribution boxes and surge protection, 5–9%: about ₹2.5–4.5 lakh, rising sharply if your LT panel sits more than 100 metres from the roof. Earthing, lightning protection and monitoring, 1.5–3.5%: about ₹0.7–1.7 lakh. Installation, civil work, design and approvals, 5–11%: about ₹2.5–5.5 lakh, including net-metering drawings and discom liaison. Transport, contingency and EPC margin, 4–8%: about ₹2–4 lakh. What pushes a 100kW quote higher Elevated structures on RCC roofs, or reinforcement of old sheds with weak purlins. Long cable runs between the roof and the LT panel. Premium TOPCon or bifacial modules instead of mono PERC. Raising your contract demand, or worse, a forced move from LT to HT supply. Key takeaway: modules are the biggest cost, but structure, cabling and connection work are where two 100kW quotes quietly differ by several lakh rupees. Why 100kW costs more per kW than 500kW A 500kW rooftop plant costs about ₹38, 000–45, 000 per kW in the current market. At 100kW you pay ₹45, 000–52, 000. That is a 15–18% premium, roughly ₹7 lakh extra on a 100kW project for the same class of equipment. The reason is that several costs are fixed per project, not per kW: Engineering design takes a similar number of hours whether the plant is 100kW or 500kW. Discom approvals usually involve two to three rounds of drawing revisions regardless of size. Site survey, mobilisation and the net meter cost roughly the same for any commercial project. Smaller inverters cost more per kW than the larger units a 500kW plant can use. For the economics one bracket up, read our 500kW solar plant cost guide for factory owners. The LT-to-HT trap in Madhya Pradesh Under MPERC's grid-interactive renewable energy regulations (RG-39 of 2024), your solar capacity cannot exceed your sanctioned load or contract demand, and net metering is capped at 500 kW. A factory with an 80 kW contract demand cannot simply install 100kW. It must raise its contract demand first. That is where the trap sits. LT supply in MP has a contract-demand ceiling, and published figures range from 75 kW to 112 kW (150 HP) depending on category and discom. Cross it, and you move to an 11kV HT connection: a transformer, HT metering and electrical inspectorate approval. That work can add several lakh rupees before a single panel goes up. Connectivity is also allocated first-come, first-served against the spare capacity of your local distribution transformer, so a heavily loaded feeder can delay or limit your approval. In simple terms: check your contract demand and your LT limit before you ask for a 100kW quote. If raising demand pushes you into HT, size the plant to your current contract demand instead. 100kW solar plant ROI: generation, savings and payback Western Madhya Pradesh gets strong sun. Irradiance data from tools such as the World Bank's Global Solar Atlas puts yield at about 1, 450–1, 550 units per kW per year across Indore, Dewas and Pithampur. Monthly generation: about 1, 45, 000 units a year from 100kW, which is roughly 12, 000 units a month or 400 units a day on average. Output peaks from March to May and dips from July to September. Monthly savings: about ₹85, 000–97, 000 at an avoided cost of ₹7–8 per unit, or ₹10–11.6 lakh a year. Payback period: 4.4 to 5 years after allowing for maintenance. 25-year return: about ₹2.5 crore net, after the plant cost, maintenance and one inverter replacement. These figures assume ₹48 lakh capex, ₹7.5 saved per unit rising 2% a year, 0.5% annual module degradation, ₹60, 000 maintenance rising 3% a year, and one ₹6 lakh inverter replacement. Why real savings are lower than many quotes claim Solar removes the energy charge on each unit you no longer buy. It rarely removes your fixed or demand charges, because your maximum demand often occurs when the sun is weak. MPERC's LT industrial tariff schedule is demand-based, so any ROI calculation that divides your whole bill by your total units overstates what solar will save. Accelerated depreciation Solar plants qualify for 40% depreciation on written-down value in the first year, halved if the plant runs fewer than 180 days in that financial year. On ₹48 lakh, that is a ₹19.2 lakh deduction and roughly ₹4.8 lakh of tax saved at a 25% tax rate, which brings payback to a little over 4 years. Confirm eligibility with your CA. For more commercial numbers, see our commercial solar cost and ROI guide for Indore businesses. In simple terms: a 100kW plant saves close to ₹1 lakh a month in Indore and pays for itself in 4 to 5 years. A quote promising payback in under 3 years is probably counting demand charges that solar cannot remove. Should you wait? The 31 December 2026 ALMM deadline Waiting for cheaper panels is the most common reason factories delay. In 2026, waiting carries a specific cost. From 1 June 2026, MNRE made ALMM List-II, the approved list of Indian-made solar cells, mandatory. Net-metering and open-access projects received a narrow exemption: plants commissioned on or before 31 December 2026 can still use ALMM-listed modules built with cells outside List-II, as the ministry confirmed on 18 July 2026. From 1 January 2027, net-metered projects must use modules made with List-II cells. Approved domestic cell capacity is around 30 GW, far below India's module assembly capacity, so compliant modules face tighter supply. The deadline counts from commissioning, not installation, and discom net-metering approval is usually the slowest step. Key takeaway: if you plan to install solar within the next year, the practical decision date is now, not December. Hidden costs in a 100kW solar plant This is where most businesses lose money: not in the price of the panels, but in costs nobody put in the proposal. Maintenance: budget ₹50, 000–65, 000 a year for cleaning, thermal scans and electrical checks. Neglected cleaning in dusty industrial belts can cost 3–5% of output. Inverter replacement: modules carry 25-year performance warranties, but string inverters typically carry 5–10 years. Plan for at least one replacement at around ₹5–10 lakh. Heat losses: output falls by about 0.3–0.35% for every degree above 25°C at the module, so May afternoons in Indore produce less than the nameplate suggests. Structural work: panels add only 15–20 kg per square metre, but older sheds with corroded purlins may need reinforcement against wind uplift. Insist on a structural audit before the quote is final. Approval delays: repeated drawing revisions push commissioning back, and in 2026 they could push you past the ALMM deadline. Contract demand changes: the LT-to-HT upgrade is the single largest hidden cost at this size. Key takeaway: add roughly ₹60, 000 a year for maintenance and set aside ₹5–10 lakh for an inverter replacement when you model returns. How much roof space does a 100kW solar plant need? Plan for about 8, 000–10, 000 sq ft of shadow-free roof. Metal sheet roofs with flush-mounted rails sit at the lower end. Flat RCC roofs need row spacing to avoid winter self-shading and sit near 10, 000 sq ft. Inverter layout: two 50kW or three 33kW string inverters, with a DC-to-AC ratio of about 1.15–1.25. Module standards: BIS-certified to IS 14286 (IEC 61215) and IS/IEC 61730, and listed on ALMM List-I. Inverter standards: IS 16221 (IEC 62109) for safety, and IEC 61727 for grid interconnection and anti-islanding protection. Grid connection: CEA technical standards for connectivity of distributed generation. For smaller systems, our guide on how much space solar panels need breaks area down by system size. In simple terms: 100kW needs roughly the roof of a small warehouse, and every component's datasheet should carry the standard numbers above. Is 100kW the right size for your factory? 100kW makes sense when: Your daytime load is 100–150 kW and runs most days of the week. Your contract demand is already 100 kW or more, so no load increase is needed. You have about 10, 000 sq ft of usable roof. Consider a different size when: Your contract demand is well below 100 kW. Size the plant to it rather than raise demand into HT territory. Your load and roof could support 150–250kW. The per-kW price falls as you scale, and net metering allows up to 500 kW. Most of your consumption happens at night. Solar would then mostly export, and any surplus left at the end of the October–September settlement year is paid only at the discom's average power purchase cost. Compare larger brackets in our analysis of solar power plant cost per MW in Madhya Pradesh, or see how the numbers change at utility scale in our 10MW solar power plant cost guide. Key takeaway: size to your contract demand, daytime load and roof, in that order, not to your electricity bill. Example: a 100kW plant for an Indore engineering unit This is an illustrative scenario built from current market figures, not a specific client project. The factory: an auto-component machining unit on Sanwer Road, Indore, with a 110 kW contract demand, running one long day shift six days a week. The roof: an 11, 000 sq ft metal sheet shed that passed its structural audit without reinforcement. The investment: ₹47 lakh all-in, near the lower end of the range thanks to the sheet roof and a short cable run. The output: about 1, 45, 000 units a year. Sunday generation is exported and netted against weekday imports. The savings: about ₹10.9 lakh a year at ₹7.5 per unit, or ₹10.3 lakh after maintenance. The payback: about 4.6 years, or roughly 4.1 years once the first-year depreciation benefit of about ₹4.7 lakh is counted. In simple terms: because the contract demand was already above 100 kW, this unit avoided the connection trap entirely. That one fact was worth more than any discount on panels. How to choose a solar company for a 100kW project At ₹45–52 lakh, the vendor matters more than the panel brand. Check these before you compare prices. What to check Did they review your electricity bills, contract demand and connection type before quoting? Did an engineer visit the roof and assess structure, shading and cable route? Is the exact module model on MNRE's ALMM List-I, and are the inverters BIS-certified? Can they show commissioned commercial projects of similar size, with references you can call? Who handles maintenance after handover, and with what response time? Questions to ask 'Will this project require me to increase my contract demand?' 'Does the price include GST at 8.9%, net-metering liaison and structural work?' 'Can you commission before 31 December 2026, and what happens if the discom delays?' 'What annual generation do you guarantee, and how is it measured?' Red flags A quote issued without a site visit. Generation claims well above 1, 550 units per kW per year for Indore. Payback under 3 years without accelerated depreciation. No mention of contract demand, discom approvals or ALMM compliance. A single 'all-inclusive' figure with no bill of quantities. The most common mistake is choosing the lowest per-kW price. A quote ₹3, 000 per kW cheaper that ignores a needed demand increase can cost far more by commissioning day. Full-scope solar EPC services should cover design, approvals, installation and commissioning under one contract, so no gap sits between vendors. Key takeaway: the right 100kW vendor asks about your contract demand before they talk about panels. Why factory owners in Madhya Pradesh work with Autosys Autosys Sunergy is an Indore-based solar EPC company that has installed more than 20 MW across over 2, 000 projects in Madhya Pradesh, and is an Avaada distributor for the state. For a 100kW project, that local experience matters in three places: Approvals: working knowledge of MPPKVVCL net-metering procedures and drawing requirements. Design before price: contract demand, roof structure and cable route are checked before a quote is issued. Honest ROI: savings are modelled on your actual tariff and load profile, not on a blended bill rate. In simple terms: you get a quote built around your connection and your roof, from a team that deals with MP's discoms routinely. Frequently asked questions about 100kW solar plant cost How much does a 100kW solar plant cost in India in 2026? A turnkey 100kW on-grid rooftop solar plant costs about ₹45–52 lakh in 2026, or ₹45, 000–52, 000 per kW. Metal sheet roofs sit near the lower end; RCC roofs with elevated structures sit near the upper end. Quotes should apply GST at the effective 8.9% rate that has applied to solar EPC contracts since September 2025. How many units does a 100kW solar plant generate? In Indore and western Madhya Pradesh, a 100kW plant generates about 1, 45, 000–1, 55, 000 units a year, roughly 12, 000 units a month or 400 units a day on average. Output is highest from March to May and lowest during the July to September monsoon. What is the payback period of a 100kW solar plant? About 4.4 to 5 years at an avoided cost of ₹7–8 per unit, after maintenance costs. Profitable companies claiming 40% accelerated depreciation in the first year can bring it to a little over 4 years. Payback claims under 3 years usually count demand charges that solar does not remove. How much roof space does a 100kW solar plant need? Plan for 8, 000–10, 000 sq ft of shadow-free roof. Metal sheet roofs with flush-mounted rails need less; flat RCC roofs need extra row spacing to avoid winter shading. The array adds about 15–20 kg per square metre, so older sheds should get a structural audit first. What is the GST on a 100kW solar plant? Solar modules and equipment have attracted 5% GST since 22 September 2025. A turnkey EPC contract is taxed under a 70:30 goods-to-services split, giving an effective rate of about 8.9%. Before the cut, the same contract was taxed at about 13.8%. Is there a subsidy for a 100kW commercial solar plant in Madhya Pradesh? No. PM Surya Ghar subsidies apply to residential rooftop systems only. Businesses benefit through 40% accelerated depreciation on the plant and lower electricity bills. The September 2025 GST cut also reduced the effective tax on solar EPC contracts from 13.8% to 8.9%. Can I install a 100kW solar plant on an LT connection in Madhya Pradesh? Yes, if your contract demand is at least 100 kW and still within the LT limit for your category. MPERC caps net-metered solar at your sanctioned load or contract demand. If you must raise demand to fit 100kW, check first whether that forces an HT connection. Do I need ALMM-listed panels for a 100kW net-metered plant? Yes. Net-metered projects must use modules from MNRE's ALMM List-I. Plants commissioned on or before 31 December 2026 are exempt from the List-II rule on Indian-made cells. From 1 January 2027, modules must also use ALMM List-II cells. Before you sign a ₹50 lakh solar quote A 100kW plant is a 25-year decision, and the panels are rarely where it goes wrong. It goes wrong in the contract demand nobody checked, the savings calculation that counted demand charges, or a commissioning date that slips past 31 December 2026. Get a site-specific assessment before you compare prices. Share your last 12 months of electricity bills, your contract demand and a few roof photos, and the Autosys team will tell you whether 100kW is the right size, whether your connection can take it, and what it will really return. Start with our commercial solar installation services. Key takeaway: the cheapest 100kW plant is the one sized correctly the first time. Sources MPERC (Grid Interactive Renewable Energy Systems and Related Matters) Regulations, RG-39 of 2024, summary via SolarQuarter MPERC LT tariff schedule, MP discom portal MNRE extension of the ALMM List-II exemption for net-metering projects, 18 July 2026, Business Standard GST on renewable energy devices and the 70:30 EPC valuation rule, SAG Infotech Solar irradiance and yield data, Global Solar Atlas, World Bank Last updated: September 2026.