What is MACRS depreciation and how does it apply to commercial solar?

MACRS (Modified Accelerated Cost Recovery System) is the US federal tax depreciation system that allows businesses to recover the cost of certain assets over a specified period using accelerated depreciation methods. Solar energy property is classified as 5-year property under MACRS, meaning the full asset cost can be depreciated over a 5-year schedule using the 200% declining balance method, switching to straight-line when that method gives a larger deduction. The MACRS 5-year schedule for solar generates the following approximate depreciation percentages by year: Year 1: 20%, Year 2: 32%, Year 3: 19.2%, Year 4: 11.5%, Year 5: 11.5%, Year 6: 5.8%.

How does the ITC affect the MACRS depreciable basis?

When a business claims the full federal ITC, the depreciable basis of the solar system under MACRS must be reduced by 50% of the ITC claimed. For a 30% ITC, this means the depreciable basis is reduced by 15% (50% of 30%). If you install a $1,000,000 solar system and claim a $300,000 ITC, your MACRS depreciable basis is $850,000 (the $1,000,000 cost minus $150,000 basis adjustment). The remaining $850,000 is then depreciated over the 5-year MACRS schedule.