Press Releases

A major automotive component manufacturing company in Pune that supplies Tier-1 auto parts was in the news recently when it decided to go ahead with a rooftop 1MW solar setup at the factory after getting the lowest Engineering, Procurement, and Construction (EPC) bid. As one would imagine from such a decision made by a top manufacturer in the country, the commercial deal, on paper, seemed almost perfect -- a quick payback period and a drastic reduction in DISCOM grid tariffs, which were quite high.

In the period between six and twelve months after the installation, the team started noticing deflection of the roof due to the roof having standing seam sheet. It later came out that the EPC, the one that won the tender, had not hot-dip zinc-coated the mounting structure, made the DC cabling underspec to save on the copper bill, and had gone for non-ALMM (Approved List of Models and Manufacturers) modules with the degradation light-induced (LID) rate much higher. They found, by looking at thermal cameras, that it was very bad, with spot heating that affected whole sets of strings; but worse, it was a regular situation that the plant's main circuit breakers would be tripped over and over thanks to harmonic distortion from lower-tier inverters during the period of peak load.

What had started as an 8% CAPEX saving was soon lost when they were shut down a lot because the equipment was failing; they had to invest again in structure, and they found out they had to go for major structural retrofitting work.

Such a case clearly shows that C&I green energy purchases and industrial rooftop solar panels are not a one-and-done, but they are very much long-term investments. It's a physical plant, a major investment, that runs 25 or more years. So, choosing the right type of system means you are thinking of CAPEX upfront and TCO over time, grid code compliance, and structure.

About Industrial Rooftop Solar Panel System

The term "industrial rooftop solar panel system" refers to a combined, grid-connected or off-grid power facility specially designed to be set up on factory rooftops, warehouses, logistics centers, and processing plants of industrial units.

In comparison with residential systems or small-scale commercial systems, these larger systems operate in much more complicated electrical surroundings that include many inductive loads, very high peak loads, harmonic interference, to name a few, in addition to very strict safety requirements.

They consist of basically four elements:

• Photovoltaic (PV) Module Array: Solar PV modules capture solar illumination and convert it into electricity. It is DC power initially. This stage involves high-yield monocrystalline PERC, TOPCon (Tunnel Oxide Passivated Contact), or N-type bifacial modules. It is quite standard in the industry.
• Power Conversion Electronics: A string of inverters takes the DC electricity and turns it into AC, which matches the voltage and frequency standards of the facility.
• Balance of System (BOS): BOS encompasses roof-mounted structural systems like fixed-tilt, flush-mount, or ballasted elevated systems; DC/AC wiring systems; earthing systems; lightning arrestors; and junction boxes for the array.
• Grid Interface & Control Infrastructure: Includes net-metering equipment, isolation transformers, SCADA systems, and anti-islanding protective relays, to name a few.

The Significance of Industrial Rooftop Solar for Procurement

Manufacturing, processing, and logistics are the sectors that usually have a hard time treating energy as a "soft" expenditure. This is a key expense and directly affects profitability. So, an industrial solar panel rooftop system is more than just a purchase; it's basically the solution that you adopt.

Operational Expenses & Grid tariffs reduced to the fullest.

DISCOM industrial electricity prices, in the case of the top centers of manufacturing, are often about ₹8.00 and up to ₹12.00+ per kWh. (In the above figure, the cross-subsidies, fuel adjustment charges, and demand surcharges are all included.) With solar Levelized Cost of Energy (LCOE) during a 25-year asset lifecycle, one gets a very low cost of ₹2.20, ₹3.2. Thus, the difference between the rates is quite big, yielding immediate operating margin expansion.

2. Tariff Inflation Hedging

State Electricity Regulatory Commissions keep on raising the commercial and industrial tariffs, as they are a vehicle to support the residential and agricultural segments. A generation asset that is either owned or leased helps to lock in a major chunk of a facility's energy input cost at a favorable price for thirty years at maximum.

3. Tax and Regulatory Incentives: An Opportunity for Growth

According to Section 32 of the Indian Income Tax Act, a company can claim Accelerated Depreciation (AD) of 40% benefit in the first year for the solar asset. Along with that, tax credit under the GST is also availed, which leads to a significant drop in the company's after-tax capital outlay for a project, effectively reducing the payback period to 2.5, 3.5 years.

Technical and Commercial Evaluation Parameters

At the stage when assessing whether industrial rooftops are to carry solar panels, the purchase team has to consider far more than just the price per watt. An intricate technical and commercial evaluation must, therefore, be done.

The kind of panel used is a critical factor in determining how much energy will be produced out of the available rooftop space, i.e., generation density (kWh per sq.m. of the roof):

• N-Type TOPCon vs. Mono PERC: Mono PERC (Passivated Emitter and Rear Cell) has long been the industry's go-to workhorse solution. N-Type TOPCon solar panels, however, are capable of delivering cell efficiencies exceeding 22.5%; they have a lower temperature coefficient of -0.30%/°C as opposed to -0.35%/°C for MONO PERC and have negligible initial Light-Induced Degradation (LID). Due to these features, they can yield 3-5% more annually in regions with high air temperatures.
• ALMM Compliance: You will have to make sure that panels are sourced from the List-I under the Approved List of Models and Manufacturers (ALMM) published by the Ministry of New and Renewable Energy (MNRE). Non-ALMM (approved model and manufacturer) units stand some risk of being denied interconnecting power to the public electricity grid, or getting one's net-metering permission revoked by the state DISCOMs.
• Bifacial on Reflective Roofs: When the underside or the surrounding areas of the reflective roof are a light-reflecting surface of some sort, the use of bifacial photovoltaic modules allows you to utilize the reflections that come from them, thereby increasing energy produced by 5-12% based on tilt and the height of clearance, respectively.

Choice 2. Inverter and Power Quality

The requirement of power quality from industrial loads (VFDs, CNC machinery, arc furnaces, heavy induction motors) is quite high.

• String Inverters vs. Central Inverters: The use of distributed string inverters on rooftop systems is usually favored as opposed to the central inverter. Their multiple Maximum Power Point Trackers (MPPTs) can reduce any yield loss that is caused by roof shading, dirt buildup, or variations in construction. Further, they help make a single point inverter failure not the downfall of the entire 1 MW plant.
• The harmonic distortion factor is also critical (Total Harmonic Distortion (THD)). In order to be sure and not to cause problems, choose devices with THD < 3%. These harmonics may lead to tripping of sensitive automated equipment in a production line; besides, they may attract power quality fines by the grid operator.

Selecting Structural Support and Rooftop Engineering

Whether industrial roofs are made of standing seam, trapezoidal metal sheet, or RCC, they need to be sturdy and be able to withstand not only the static loads due to panels, mounting structure, and cables, but also wind uplift (a dynamic load).

• Dead Loads of Solar Installations: Standard flush-mount solar arrays bring the addition of 12- 18 kg/m² of dead load. Only if a certified Third-party Structural Engineer has done a structural audit and verified purlin capacity&roof truss margins can the design be finalized.
• Blasting Corrosion: Structural frames for clamping should be made from high-grade aluminium, or Hot-dip galvanized iron with at least 80 microns 550 g/m² of zinc coating to avoid corrosion caused by industrial emissions, chemical vapors, and coastal humidity.
• Keeping Roof Intact: On standing-seam roofs, the installation of clamp-type fixing (penetration-free) is required, besides, to safeguard the rooftop warranty as well as avoid water seepage in monsoons.

4. Balance of System (BOS) Quality

BOS constitutes less than 20% of the capital costs, but it causes over 80% of operational downtime if quality is compromised.

• DC Cabling: DC tinned copper solar cables with XLP insulation should be specified, and the cables also need to be certified to EN 50618. Under-sizing of DC cables results in high resistive heating losses (I2R), which can lead to the PR (performance ratio) of the plant dropping below the design thresholds.
• Earthing and Surge Protection: DC, AC, and structural grounds of industrial installations should have chemical gel earthing pits, and Type 1+2 Surge Protection Devices (SPDs) must be installed as well for lightning and switching surges.

Evaluating EPC Suppliers: A Procurement Framework

Not all EPC contractors do have the necessary skills and technology to carry out an integrated industrial system. Procurement officers, therefore, should look at the following four aspects while assessing potential suppliers:

Common Sourcing Mistakes to Avoid

• Buying Cheapest Per-Watt to Save the Big Picture Bill: A contractor who offers 10% less in initial project cost can still be profitable while using low-quality AC/DC cables, junction boxes without certifications, galvalume structures made thinner, and cheap inverters. This leads to greater losses from time to time, besides increasing maintenance expenses, in the long run.
• Not Paying Attention to DISCOM Regulatory and Net-Metering Restrictions: Different states in India have varying policies with regard to net-metering, transformer capacity restrictions (usually up to 30-50% of the distribution transformer rating), and open-access charges. Not technically getting approved by a nearby DISCOM for setting up an industrial rooftop solar power plant may delay grid connection.
• Missing out on Roof Waterproofing and Terms of Warranty: Making direct holes in trapezoidal sheets without either EPDM rubber washers or UV protection seals will lead to roof leaks which, in turn, if not rectified, can damage the stock and other assets located below.
• Missed Performance Ratio (PR) Guarantees: PR guarantees of a weather-adjusted nature (about 75-80% for industrial rooftop systems) should be included in the contract with liquidated damages (LDs) for non-performance, instead of just depending on generation numbers.

Indian Market Considerations

Acquiring an industrial rooftop solar panel system in India requires a comprehensive understanding of the legal framework, production capabilities, and operational environment unique to the country:

• Supply chain & Manufacturing clusters: India has created strong domestic production centers of PV modules and BOS parts- most importantly in Gujarat, Tamil Nadu, Andhra Pradesh, Telangana, and Maharashtra. Using the products manufactured at India's own solar companies and available at these cluster centres will reduce costs of transport, ease the management of materials at the site, and facilitate getting warranty claims done at short notice.
• Financing models (CAPEX vs. OPEX/RESCO):
• DISCOM Feasibility & Regulatory Interaction: DISCOM approval procedure involves getting around various technicalities, including allocation, CEIG inspectorates, and synchronization to a bi-directional net-meter. Choosing an EPC with a strong local representative can greatly reduce the risk of long grid-synchronization delays.

Knowing the Details

1. What is the minimum amount of roof area required for a 1 MW solar PV installation?

In today's solar market, solar panel module efficiency is a key point. TOPCon and bifacial modules are the ones you get from high-efficiency modules having wattage ratings of 520Wp, 670Wp. They are the ones requiring 6 sq. meters to 7.5 sq. meters per kWp of shade-free and structurally sound roof space. Consequently, for a 1 MW unit installation, the requirement for open-air shade-free rooftop area will be in the range of 6000 to 2500 m sq (approx 3.5-5 acres).

2. What are normally industrial solar projects' ROI and time to recovery?

A CAPEX-based project that fully exploits an incentive of Accelerated Depreciation as well as the benefit of input tax credits under GST may be fully paid out in approximately 3 to 2.5 years, depending on a state's electricity tariff level. The return that owners can get from equity in an industrial solar asset, on average, will be 20-25% over the period of 25 years that an industrial solar system is in operation.

3. What if we run a factory 24x7 or consume high amounts during the hours when it is not sunny?

With a solar roof panel system that is connected to the electricity network, industrial plants will use whichever is less: grid power or the solar power produced during the day. The grid power will be the source of supply at night or on a cloudy day. An extra advantage is that such a system can also be a source of energy that is connected to the grid through the use of diesel generation (via DG controller systems of synchronization). In addition, it will be possible to add Battery Energy Storage Systems (BESS) to enable storage of the solar power produced during the day for use at night when peak demand is high.

4. Will our existing industrial roof sheets support our rooftop photovoltaic systems without damage?

Industrial buildings with trapezoidal roof structures will most likely be able to handle a static solar module load of approximately 9.5 lbs/m² (12~15 kg/m²). But before installation, it is important to have an on-site engineer carry out a structural stability audit to ensure that the spacing requirements, truss strength, and wind load resistance have been fulfilled, considering the wind speeds of the area concerned (e.g., 93~112 mph as per IS 875 Part 3).

5. What maintenance is needed for an industrial solar plant to function at full capacity?

Cleaning the surface of solar cells on the PV modules regularly (at intervals depending on the extent of dust/soiling exposure) is the prime element of the maintenance plan, while also conducting quarterly preventive electrical audits (junction boxes and inverter thermography scans, structural bolt torque checks, and string current inspection). With such large industrial solar roofs, it is quite common for the manufacturers to incorporate automated or at most semi-automated solutions like robotic cleaning or dry cleaning technologies to not only cut back on water use but also lower labor costs significantly.

Conclusion: Strategic Procurement for Long-Term Value

Having an industrial solar roof system is considered a solid business opportunity in reducing operational costs, protecting against rising electricity tariffs, and, even more, supporting a company's environmental sustainability and social responsibility goals.

If, on the other hand, they really want to get the cash benefits, the industrial buyer must make the procurement process their main point of discussion since there is a lot of work to do at that stage. The key areas they need to investigate and probably find an experienced expert partner to help with are component bill of materials (BOM), structural load engineering, ALMM compliance, and EPC track records. By mainly focusing on structural safety, power quality, and lifetime performance ratio (PR) guarantees that have the industrial customer's interests at heart, they can easily convert an old factory roof area into a steady, high-output power generator over the 25 years that follow.