Why does the Bureau of Energy Efficiency Bhimavaram 60 horse power ice plant motor report save more power than the 75 horse power one?

Three Bureau of Energy Efficiency (BEE) Bhimavaram reports replace an ice plant compressor motor of 60, 75 or 150 horse power (HP) for rupees (Rs) 1.46, 1.88 and 3.32 lakh. The 60 HP report saves 30,095 kilowatt hours (kWh) a year, more than the 75 HP one's 29,147, and the likely cause, my reading, is its older old motor.

The three reports side by side

• 60 HP: baseline draw 37.80 kilowatts (kW), from the first of three listed plants. Old motor 85% efficient, new 93.9%. New draw 34.22 kW, saving 3.58 kW. Cost Rs 1.46 lakh, payback 1.29 years, internal rate of return (IRR) 60.32%.
• 75 HP: 52.72 kW from the first of three listed plants. 88% to 94.2%. New 49.25 kW, saving 3.47 kW. Cost Rs 1.88 lakh, payback 1.72 years, IRR 42.53%.
• 150 HP: 103.70 kW at one plant. 89% to 94.5%. New 97.66 kW, saving 6.04 kW. Cost Rs 3.32 lakh, payback 1.75 years, IRR 41.80%.
• All three run 24 hours a day on 350 days, which is 8,400 hours, price power at Rs 3.75 a kWh and allow two days of process downtime. Savings are 30,095, 29,147 and 50,698 kWh a year, worth Rs 1.13, 1.09 and 1.90 lakh.

Why 60 HP beats 75 HP

Each report starts from a different plant's draw and a different old-motor efficiency. The 60 HP report assumes 85%, so its efficiency gain is 8.9 points. The 75 HP report assumes 88%, a gain of 6.2 points, and the 150 HP report 89%, a gain of 5.5. The saving as a share of draw falls the same way: 9.5%, 6.6% and 5.8% (my arithmetic).

My reading: the 60 HP plant also runs at 84% of its motor's 44.8 kW rating, against 94% and 93% for the others (my division of the draw by the rating; the reports print no loading). Project cost is about Rs 2,400 and Rs 2,500 an HP in the first two reports and Rs 2,200 in the third.

My reading: the paybacks mostly reflect how bad the old motor is assumed to be, though the reports do not say so. Check your own motor before you choose by size.

Printed figures to treat with care

• Carbon dioxide (CO2): the 60 HP summary prints 12 tonnes a year and its body prints 24. The 75 and 150 HP reports print 23 and 41. The 24 fits the roughly 0.8 kilograms (kg) a kWh that the other two imply; the 12 does not (my own division).
• At the grid factor of 0.675 kg CO2 a kWh for financial year (FY) 2025-26, the three savings are about 20.3, 19.7 and 34.2 tonnes.
• Efficiencies are audit estimates, not readings from one plant. Each report says audits across various units of the cluster found about 85% (60 HP), about 88% (75 HP) and around 89 to 90% (150 HP, where 89% is used), from motor age and the number of rewinds. Only the kW draw is a single plant's figure: the 60 and 75 HP reports list three plants each (60 HP: 37.80, 39.79 and 40.70 kW; 75 HP: 52.72, 54.40 and 53.31 kW) and use the first row, and the 150 HP report uses one plant.
• All three use the formula new draw = old draw x old efficiency / new efficiency, which checks: 37.80 x 85 / 93.9 = 34.22 kW.
• 75 HP cost: section 4.3.2 uses Rs 1.68 lakh with a saving of Rs 1.09 lakh and prints 1.72 years, while the summary and Table 4.1 total Rs 1.88 lakh. 1.88 / 1.09 is 1.72, so the printed payback fits Rs 1.88 lakh, not the Rs 1.68 lakh quoted beside it.

Before you order

• Put a meter on the compressor motor for a full day. The saving is 6 to 10% of the draw, so the draw is what you need to know.
• Check how many hours the plant runs. All three assume the motor runs 24 hours a day on 350 days.
• Ask the supplier for the guaranteed efficiency at your load, not the full-load figure.

The 60 HP report as printed, then with the 75 HP report's old efficiency

• Draw 37.80 kW x 85 / 93.9 = 34.22 kW. Saving 3.58 kW
• 3.58 kW x 8,400 hours = 30,095 kWh x Rs 3.75 = Rs 1.13 lakh. Rs 1.46 lakh / 1.13 lakh = 1.29 years
• My reading with an old efficiency of 88%: 37.80 x (1 minus 88 / 93.9) = 2.38 kW
• 2.38 x 8,400 = about 19,950 kWh x Rs 3.75 = about Rs 0.75 lakh, and Rs 1.46 lakh / 0.75 lakh = about 1.95 years

First two lines are the report's own. The last two are an example of my own reading, using the report's draw and the 75 HP report's assumption.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so your monthly units are on file next to a report's yearly kWh. A bill covers the whole plant, so the motor's own draw still needs a meter. The green loan check shows what a lender asks for.

• Green loan readiness check
• VFD on an ice plant compressor
• New refrigeration compressor in an ice plant
• Bhimavaram ice plants electricity per tonne

Sources: BEE, Detailed project report: energy efficient motor for compressor 60 HP, Bhimavaram ice making cluster (SAMEEEKSHA), BEE, Detailed project report: energy efficient motor for compressor 75 HP, Bhimavaram ice making cluster (SAMEEEKSHA), BEE, Detailed project report: energy efficient motor for compressor 150 HP, Bhimavaram ice making cluster (SAMEEEKSHA), Central Electricity Authority (CEA), CO2 Baseline Database for the Indian Power Sector

Last reviewed 2026-11-05. Report figures are from BEE's Small and Medium Enterprises (SME) programme project reports of 2010, at a Rs 3.75 a kWh tariff. Check today's tariff, a current quote and your own motor readings before you rely on the payback.