IN ancient Chinese mythology, the Monkey King feared nothing except the golden loop he had to wear on his head. His head throbbed whenever his monk master began to read incantations to it.

In 2016, the Year of the Monkey, China’s auto industry is wearing a “golden loop” that is green, and talk about reductions in fuel consumption is giving everyone headaches.

Last week, the official verdict on fuel savings in 2015 came out. Only 72 percent of automakers in China had achieved the expected sales-weighted average of 6.9 liters per kilometer. Overall, the industry missed the target.

And the path ahead isn’t very golden either. By 2020, the criteria will drop to 5 liters per kilometer, and authorities are threatening severe punishment for those who fall shy of the standards.

This 28 percent cut poses a huge challenge for everyone, according to Cui Dongshu, secretary-general of the China Passenger Car Association.

No one wants to gaze into this abyss. Volkswagen’s green cheating scandal is just one example of diversionary tactics gone wrong.

Carmakers in China face several avenues to follow in meeting fuel targets. Lightweight materials and engine downsizing aside, the most crowded crossroad is where the 12-volt start-stop system and the 48-volt hybrid solution recently collided head-on.

The competition basically relates to how much the engine should step aside and leave its work to an electric system, and to the manufacturing costs of vehicle electrification when all-electric, cars and plug-in hybrids have yet to show commercial viability.

Last year, less than 1 percent of cars sold in China were mainly powered by electricity. Despite huge investments to develop a whole new drivetrain for them, fuel savings ended up a mere drop in the bucket.

On the other hand, there were 17 times more gasoline-powered cars sold with 12-volt start-stop functions in China. That technology boasts about a 5 percent fuel savings for each car and requires very little change to car architecture.

This system is designed to sustain electrical equipment in the car, such as GPS navigation, stereo system and air conditioning, as an alternative power source when the engine is shut down to run idle at a red light. The electric power also helps the engine kick back into action quietly when the brake is released.

To deliver sufficient back-up power, the function needs special batteries like AGM, with deep charge and discharge capabilities, and a higher life-cycle performance. It is an area where battery specialists like Johnson Controls stand to benefit.

“By 2020, 15 million new cars in China may come out with a start-stop function, comprising half of auto sales,” said Kenneth Yeng, vice president and China general manager at Johnson Controls Power Solutions, the largest player globally in the field of automotive batteries.

At its biggest Chinese manufacturing base in Zhejiang Province, the US company has just doubled production capacity of AGM batteries for 12 volt start-stop to 3 million units. Further manufacturing capacity next year will take that to 3.75 million units.

AGM, the target of a US$780 million global investment by Johnson Controls over the next five years, is now at the center of the company’s full spectrum of global battery offers, which start from basic lead-acid batteries for the vehicle starter to lithium-ion batteries for high-voltage electric powertrains.

The company supplies every stage of vehicle electrification and now says it has the most confidence in those that are “less visionary.” AGM batteries alone are expected to contribute to one-third of the company’s growth in China in the near future.

But looking further forward, when connected and autonomous-driving cars come more squarely to the fore, the need for electricity in cars will be surging, more than a 12-volt system can bear. It is a mega-trend that the industry all sees all too clearly but cannot afford to rush into.

Zhu Jiabing, director of the customer business unit at Johnson Controls Power Solutions, said to achieve 1 percent fuel savings on a highly electrified cars, a carmaker would need to charge buyers US$150-US$300 a car to cover the cost of research and development.

For an entire start-stop system, the price would be around 2,000 yuan (US$296).

It all boils down to the math. There is only so much buyers will pay for a start-stop system, and there is only so much fuel the technology can save, said French auto parts maker Valeo.

Also a supplier of start-stop systems, the company recently suggested a new avenue for carmakers in China — 48-volt technology. Rival Continental is also promoting that technology with much fanfare this year, while Johnson Controls said it is still studying its potential, with an agenda to provide it one day in China.

One step further down the road of electrification from 12-volt, Valeo’s 48-volt system will be ready for mass production next year — first in China and first for a domestic car brand.

“The big international plants are all in. You will see the momentum take off in 2018 on some high-volume products to bring down average fuel consumption,” Yang Hua, business development director of Valeo powertrain, said of a technology that remains quite obscure to the public at present.

“Mild hybrid” may sound more familiar. The technology adds a 48-volt system to the existing 12-volt one on a gasoline-powered car so that there will more electric power available to assist or even decommission the engine while the car is coasting or at a stop.

Though more complicated than the 12-volt, the 48-volt doesn’t change a car’s architecture or safety requirements for voltage very much, compared with the high-voltage systems in full hybrids, plug-in hybrids or all-electric cars.

According to Valeo, 48-volt technology is a cost-effective, middle-of-the-road solution because it can improve fuel economy by up to 14 percent. That would be enough to help carmakers reach the half-way mark toward 2020 fuel-consumption standards.

But can this too-convenient choice empower the industry after 2020? By 2025, automakers may well face standards requiring consumption of 4 liters per 100 kilometers.

It can, if the 48-volt solution is extendable, said Yang.

At the recent Paris Auto Show, the company unveiled an upgraded 48-volt solution that includes a supercharger to boost the engine for acceleration, and also an electric rear-axle drive to enable an all-electric mode.

It suggests a possibility of fuel-saving solutions going modular and layered. It is all about getting the right combination to save just the right amount of fuel.

“From a wider perspective, a carmaker must think about how much fuel is saved with 12-volt start-stop systems, electric cars and 48-volt mild hybrids, each, and together, to meet the fuel consumption target,” said Yang.

As long as gasoline cars still dominate the road, the 12-volt start-stop and the 48-volt mild hybrid are not supposed to fight against one another, creating a “green headache” for carmakers.