Complete Guide to 40% Solar Depreciation (Section 32)

What is Section 32 Solar Depreciation?

Section 32 of the Income Tax Act, 1961, allows Indian businesses to claim accelerated depreciation of 40% on solar energy equipment in the very first year of installation. This is one of the most powerful tax incentives available for green energy adoption — yet most business owners either don't know about it or underestimate its financial impact.

Here's how it works: if your business invests ₹10 lakh in a rooftop solar system, you can deduct ₹4 lakh from your taxable income in Year 1 itself. For a company in the 30% tax bracket, this translates to an actual cash saving of ₹1.2 lakh in reduced tax liability — effectively making the government pay for 12% of your solar system.

How Accelerated Depreciation Works

Year 1: The 40% Benefit

In the first year of installation, you claim 40% of the asset cost as depreciation. On a ₹25 lakh solar installation, that's ₹10 lakh deducted from your taxable profit. The Written Down Value (WDV) after Year 1 becomes ₹15 lakh.

Year 2 Onwards: 15% WDV Method

From the second year, the remaining value depreciates at 15% per year on the WDV. So Year 2 depreciation is ₹15 lakh × 15% = ₹2.25 lakh. Year 3 is ₹12.75 lakh × 15% = ₹1.91 lakh, and so on. The asset continues depreciating over its useful life (typically 25 years for solar).

Total Tax Benefit Over Time

For a ₹25 lakh system at a 30% tax rate, the total depreciation tax shield over 10 years exceeds ₹18 lakh — recovering more than 70% of the investment through tax savings alone, on top of the electricity bill savings.

Who Can Claim This Benefit?

This benefit is available to any entity that files income tax under the "Profits and Gains of Business or Profession" head:

Companies: Private Limited, LLP, One Person Company
Partnership firms with business income
Sole proprietors running a business
Professionals: Doctors, lawyers, architects, CAs with professional income
Manufacturing units, factories, warehouses, hotels, hospitals

Not eligible: Salaried individuals (unless they have separate business income), entities using presumptive taxation (Section 44AD/44ADA), and residential installations used purely for personal consumption.

Key Conditions and Rules

The Asset Must Be New

Section 32 accelerated depreciation applies only to new solar equipment — not second-hand or refurbished systems. The solar panels, inverters, mounting structures, and wiring must all be purchased new from authorized manufacturers/dealers.

The System Must Be Used for Business

The solar system must be installed at your business premises and used for business purposes. Residential systems on your home do not qualify unless your home is your registered place of business and electricity is used for business operations.

Half-Year Rule

If the solar system is installed and put to use for less than 180 days in the financial year, only half the depreciation rate (20% instead of 40%) can be claimed in that year. Plan your installation timing accordingly — installing before September gives you the full 40% benefit in the same financial year.

Documentation Required

Keep these documents for your tax filing: the purchase invoice showing equipment cost, installation certificate from the vendor, commissioning certificate from the local DISCOM (power distribution company), net metering approval (if applicable), and photographs of the installed system.

Real-World Example

Consider a manufacturing unit in Pune investing ₹20 lakh in a 30 kW rooftop solar system:

Annual electricity savings: ~₹3.5 lakh (replacing grid power at ₹8/unit)
Year 1 depreciation: ₹8 lakh (40% of ₹20 lakh)
Tax saving at 30% bracket: ₹2.4 lakh in Year 1 alone
Effective Year 1 benefit: ₹3.5L electricity + ₹2.4L tax = ₹5.9 lakh
Simple payback: Under 3.5 years (vs. 5.5 years without depreciation)

Use our Solar Depreciation Calculator to compute the exact benefit for your investment amount and tax bracket.