New CAFE 3 Draft Brings Revised Fuel Consumption Variables, Reduced Derogation Factor For Strong Hybrid & More

The Bureau of Energy Efficiency (BEE) has published a new draft for the upcoming CAFE 3 (Corporate Average Fuel Efficiency) norms that are due to come into force from April 2027. The latest drafts bring some notable changes over previous drafts, including stricter Annual Average Fuel Consumption calculations every year, new Derogation factors for alternative powertrains and a clause for adding a Carbon Neutrality Factor provision for biofuel blending in diesel.

New Annual Average Fuel Consumption Standard Computation Variables

The updated norms bring some changes over the previous draft, the biggest of which is a reduction of the Constant Multiplier (CM) used in the computation. While the previous draft called for a fixed CM of 0.002 l/100 km per kg, it has been reduced to 0.00158 for FY2028 and will reduce yearly to 0.00131 for FY2032.

The weight fixed constant has been increased from 1170 kg to 1229 kg. Similarly, the fuel consumption fixed constant starts at 3.9960 l/100 km per kg and reduces to 3.3273 l/100 km per kg for FY2032 - higher than the previously proposed 3.7264 for FY2028 and 3.019 for FY2032.

The overall computation formula has stayed unchanged.

In terms of overall calculations, the reduced CM and higher weight constant seemingly reduce the Average Fuel Consumption Standard compared to the metrics in the previous draft based on rough calculations. The formula calls for multiplying the CM by the difference between the Annual weighted average unladen mass and the weight constant. To this, the fixed fuel consumption constant is added. So if the weighted average unladen mass were to be 2500 kg, the computation for FY2028 comes out as follows:

Opens Doors For New Technologies To Be Factored Into Fuel Consumption Calculations

The new draft adds a new clause under ‘Performance Assessment’ that will allow the Ministry of Road Transport & Highways to ‘separately develop appropriate certification methodologies to certify reduction of fuel consumption’ for elements such as mild-hybrid tech and more.

The new clause lists a host of technologies including engine stop-start, tyre pressure monitoring, regenerative braking, using a gearbox with 6- or more forward ratios, 12/48 V motor generators (mild hybrid tech), LED exterior lighting, high-efficiency AC system and Solar-reflective paint. The technologies will be required to meet some minimum criteria such as an engagement time of less than or equal to 2 seconds for the stop-start system, 6 per cent or greater energy recovery on MIDC for regenerative braking and a minimum motor efficiency of 78 per cent for mild hybrid tech.

Carbon Neutrality Factor For Diesel Added

Another update over previous drafts is the addition of a clause for diesel under the Carbon Neutrality Factor (CNF). The document states that ‘For Diesel vehicles, CNF on tailpipe CO2 emission shall be as per biofuel blending percentage notified by MoPNG’ (Ministry of Petroleum & Natural Gas). Unlike for CNG, flex fuel and e20 vehicles, no CNF percentage has yet been provided.

Other smaller changes are the addition of the terms SHEV and PHEV alongside ethanol-blended petrol for Carbon Neutrality Factor (8 per cent; 22.3 per cent if engine uses flex fuel), while the ethanol blends have been left open-ended on the upper end - whereas the older draft only stated E20 to E30. The draft also reduces the Volume Derogation factor for super credits for strong hybrid vehicles (non-flex-fuel) from 2.0 to 1.6, which will affect the Annual Average of Actual Fuel Consumption computations.

The Annual Average Fuel Consumption and Annual Average of Actual Fuel Consumption calculations will be used for the computation of compliance credits. Lower Actual Fuel Consumption means additional credits for the manufacturer and vice versa.

New Credit Buyout Scheme

Continuing with the compliance credit scheme, the new draft allows manufacturers to buy compliance credits from the BEE to offset a debit balance. Each credit will be priced at Rs 2,500 per gCO2 per km for FY2028, rising to Rs 4,500 in FY2032.