Solar Power Systems for factories: Panels, 3-Phase Inverters & Electrical Protection

In 2025, more and more factories in and around Navi Mumbai are switching to solar. Whether it’s a manufacturing unit in Taloja MIDC, a logistics warehouse in Turbhe, a fabrication workshop in Rabale, or an industrial plant in Mahape, solar power is now powering production floors across the region.

Why? Because solar power for commercial use is no longer expensive. It’s smart, reliable, and easy to install. With government push, dropping panel prices, and clear return on investment, industrial solar is now mainstream.

But setting up a solar power system for a factory is very different from doing it for a house. You need bigger panels, 3-phase inverters, and strong electrical protection, including components like a solar earthing kit, surge arrestors, fuses, breakers, and more.

In this article, we’ll explain everything factory owners and facility managers need to know:

What panels are ideal for industrial rooftops
Why 3-phase ongrid inverters are essential
Key protection devices every system must have
And finally, how to get expert help from companies like VidyutSetu

Why Commercial Solar Power Makes Sense for Factories

Factories usually run machines, motors, and equipment all day. That means power consumption is high, and so are electricity bills.

A 25kW to 200kW load is common in medium-sized industrial units. These can generate power bills of ₹40,000 to ₹3 lakh per month.

Installing a commercial solar power system can reduce these costs by up to 80%. You use free solar power during daytime and draw from the grid only when needed.

Solar also helps:

Improve energy independence
Reduce diesel generator usage
Get green certifications
Save on demand charges (in some states)
Achieve payback in just 3 to 5 years

Type of Panels Used in Factory Solar Systems

For factories, the focus is on high-output and long-life solar panels. Most EPC companies use monocrystalline panels today, which give better efficiency.

Common Panel Specs for Commercial Use

Panel Type	Typical Wattage	Typical Efficiency	Best For
Monocrystalline (Standard)	450–550W	20–21%	Industrial rooftops
Monocrystalline PERC	450–550W	20.5–21.5%	Higher output rooftop systems
Bifacial Panels	540–600W	21–23% (combined)	Open sheds, elevated racks, ground-mounted
TOPCon (Tunnel Oxide Passivated Contact)	500–600W	21.5–23.5%	Premium industrial installations
HJT (Heterojunction Technology)	540–620W	22–24%	High-efficiency commercial rooftops
IBC (Interdigitated Back Contact)	450–550W	21–22%	High performance panels with better temperature coefficient
N-type Bifacial	540–600W	21.5–23.5%	Industrial & ground mount with rear side gain
Half-Cut Cell Panels	400–530W	20.5–22%	Higher shade tolerance, lower resistive loss

How These Technologies Compare

Monocrystalline and PERC panels are the most widely used for commercial rooftops due to a strong balance of cost and performance.
Bifacial and N-type Bifacial panels can generate extra power from reflected light on open sheds or raised structures, increasing energy yield.
TOPCon and HJT are advanced panel technologies with higher efficiencies and better performance under real-world conditions such as heat and partial shading.
IBC cells offer good performance and reliability, especially in systems where quality and long-term ROI are priorities.
Half-Cut Cell panels improve performance by reducing internal resistive loss and handling partial shading more effectively.

Why 3-Phase Ongrid Inverters Are Required

Most factories have 3-phase electricity supply, especially if they run motors or CNC machines. That’s why you need a commercial ongrid inverter that handles 3-phase load properly.

Features of 3-Phase Ongrid Inverters

Converts DC from solar panels to 3-phase AC
Syncs with factory’s existing power supply
Allows net metering or export to grid
Includes built-in protections for voltage, current, and fault detection
Works with monitoring apps to track generation

Top Brands in India (2025)

Sungrow
Fronius
SolarEdge
SMA
GoodWe
Delta
ABB (now part of Hitachi Energy)
Schneider Electric
Huawei
TMEIC
Schneider Electric
KACO New Energy
Growatt
Solis (Ginlong)
Luminous (India)
Polycab Solar Inverters
Havells Solar Inverters
Panasonic Solar Inverters
Emerson (with solar solutions)
TATA Power Solar Inverters

Make sure the inverter comes with at least 5 years warranty and remote monitoring capability. Larger factories may also use multiple inverters connected to a central panel.

What Electrical Protection Does a Factory Solar System Need?

A factory solar setup handles high voltage and current. If not protected properly, it can damage machines or cause safety risks.

That’s why the electrical protection part of the system, often called solar BOS (Balance of System), is very important.

Here’s what every factory solar power system must include:

DCDB (DC Distribution Box)

Placed between solar panels and inverter. Contains:

Fuses
DC surge protection device (SPD)
DC isolator switch

ACDB (AC Distribution Box)

Placed between inverter and main power panel. Contains:

MCBs/MCCBs
AC surge protection
Energy meter
Overload protection

Solar Earthing Kit

This is used to safely carry fault current into the ground. A full solar earthing kit includes:

Copper/galvanized earthing rod
Ground wire
Earth pit and cover
Test clamp and earthing plate

This protects both your solar system and your factory equipment.

Lightning Arrestor

Prevents damage from lightning strikes, especially in open areas or taller buildings.

Approximate System Size & Cost for Factories

Assumptions used for ROI:

Commercial tariff band: ₹8 to ₹11 per kWh
Generation is site-dependent (roof orientation, shadows, module tech, downtime). Use as indicative planning numbers.

System Size	Factory Type	Daily Units	Approx CAPEX (2025)	Approx Annual Savings (₹8 to ₹11 per unit)	Typical Payback Range
25kW	Small unit / workshop	100 to 110	₹11 to ₹13 lakh	₹2.9 to ₹4.4 lakh	~3 to 5 years
50kW	Mid-size manufacturing	200 to 220	₹18 to ₹22 lakh	₹5.8 to ₹8.8 lakh	~3 to 4 years
100kW	Large plant	400 to 450	₹35 to ₹42 lakh	₹11.7 to ₹18.1 lakh	~3 to 4 years
250kW+	Multi-shift factory	1,000+	₹85 lakh+	₹29 lakh+ (can be higher)	~3 to 4 years

Note: Payback of 3 to 4 years is commonly seen for well-designed C&I systems when tariffs are in the ₹8 to ₹11 range and the plant is engineered properly.

ROI (Return on Investment) quick explanation you can add below the table

Simple Payback = Total CAPEX ÷ Annual savings
Typical ROI band for factory solar is strong because most generation happens during working hours and offsets high daytime tariffs.

Corporate Tax Benefits for Solar CAPEX in India

1) Accelerated Depreciation (Section 32)

Businesses can claim accelerated depreciation on solar assets at 40% under the Income-tax Act (commonly referenced for solar plant and machinery).

2) Additional Depreciation (potential extra benefit for eligible businesses)

Some businesses may also be able to claim additional depreciation of up to 20% in the year the asset is put to use (subject to eligibility conditions under Section 32 provisions).

Practical takeaway:

In many cases, this is communicated as up to 60% depreciation in year 1 (40% accelerated depreciation + up to 20% additional depreciation), depending on eligibility and compliance.

Important implementation note:

Depreciation applicability can depend on factors like the asset being “put to use” and the number of days used in the financial year, plus the company’s tax profile and regime.

Does Commercial Solar Get Subsidy?

Currently, solar subsidy projects in India apply only to residential rooftop systems. For factories and commercial buildings, there is no central government subsidy as of today.

However, businesses and factories still have significant financial benefits from installing solar power. These go beyond simple electricity bill savings and are often more impactful than a traditional subsidy.

Key Financial Benefits for Commercial & Industrial Solar Projects

1. Accelerated Depreciation Under Income Tax Laws

Corporates can claim accelerated depreciation on solar plant assets under Section 32 of the Income-Tax Act. This tax benefit allows a large portion of the project cost (e.g., ~40 %) to be deducted as depreciation in the first year, reducing taxable income substantially.

The standard depreciation rate for fixed assets is much lower, so this accelerated rate creates a significant tax shield in year 1.

In some cases, additional depreciation under specific conditions can be claimed in the second year as well, further strengthening tax savings.

Practical impact for businesses:

– Reduced corporate tax liability in early years
– Higher net cash flow immediately after commissioning
– Lower effective cost of capital

2. GST & Input Tax Credit Benefits

Solar equipment enjoys a lower GST rate (5 %) compared to many other industrial equipment categories.

Businesses often can claim input tax credit (ITC) on GST paid for solar panels and related equipment, which further lowers the effective project cost.

This is indirectly a financial incentive that reduces working capital outlay and increases project ROI.

3. Net Metering and Preferential Billing

Commercial and industrial solar installations are eligible for net metering or net billing under most state policies, which allows excess generation to be exported to the grid in exchange for credits or favourable tariff offsets.

Businesses can reduce their monthly electricity draw from the grid and cash out or credit surplus energy.
In some states, the billing mechanism rewards surplus supply at reasonable rates.

Net metering significantly improves cash flow because generated energy offsets high industrial tariffs, which often range between ₹8 to ₹12 per unit.

4. State-Level Capital Support and Incentives

While central subsidies don’t cover large commercial systems, state renewable policies and industrial promotion schemes in places like Gujarat, Rajasthan, and Maharashtra sometimes offer additional incentives, such as capital rebates or preferential tariff plans, for commercial and MSME solar installations.

For MSMEs specifically, some incentives are structured as interest concessions, lower financing costs, or partial capital subsidies under state/central programmes aimed at industrial growth.

5. Sustainability and Green Compliance Advantages

In addition to financial incentives, solar investments help corporates meet ESG (Environmental, Social & Governance) criteria, green supply chain requirements, and CSR objectives.

This can enable:

• Better investor perception
• Improved brand value and sustainability ratings
• Compliance with green procurement policies

Key Design Tips for Industrial Solar

If you’re planning solar for your factory, here are 5 things to keep in mind:

Get a detailed site survey: Check for shadow, roof strength, and load panel location.
Use 3-phase commercial ongrid inverters only.
Include full protection: DC/ACDBs, SPD, MCBs, solar earthing kit.
Plan future expansion: Keep space and inverter margin ready.
Choose a good EPC partner: Get warranty, service, and documentation.

Why VidyutSetu Is the Right Partner for Factory Solar

Choosing the right system is important. But choosing the right installer is even more important.

VidyutSetu is a professional EPC company that handles everything, from engineering and installation to after-sales sservice, for commercial solar power projects across India.

Here’s what you get with them: