How Lenovo's Neptune Is Tackling the AI Energy Challenge

Lenovo is expanding its Neptune liquid cooling technology throughout its data centre portfolio to address the thermal and energy challenges posed by modern AI environments.

Lenovo's focus on high-density and energy-efficient computing is reflected in its top rankings on both the Top500 and Green500 lists, where Neptune-enabled supercomputers are prominent.

The Neptune design aims to decrease the total power consumption of a facility. Traditional air cooling methods are proving insufficient for managing the heat produced by dense AI and High-Performance Computing (HPC) systems.

According to Lenovo, servers equipped with Neptune technology can operate with up to 40% less power than air-cooled equivalents.

This could provide a pathway to stable performance without incurring higher cooling costs.

The growing thermal demands of AI

A considerable increase in AI workloads has led to a step-change in heat generation, pushing conventional air-based cooling systems toward their practical limits.

The IDC & Lenovo CIO Playbook 2025 highlights sustainability as a key priority for technology leaders, which includes lowering the energy expenditure associated with cooling.

Neptune Direct Water Cooling tackles this by circulating warm water directly to processors and memory modules to capture heat at its source.

Unlike chilled water systems that typically require coolant temperatures around 18°C, Neptune operates effectively with water temperatures up to approximately 45°C.

This design can eliminate the need for chillers and reduce reliance on air handling equipment, thereby increasing efficiency for high-density racks.

Now in its sixth generation, Neptune is the result of over a decade of engineering. Lenovo has also launched a new vertical liquid-cooled chassis to accommodate accelerated computing within a smaller footprint.

This fully liquid-cooled system removes the need for internal fans, further lowering energy use in the data hall.

Integrating liquid cooling with net zero goals

The Neptune technology is a central component of Lenovo’s strategy to achieve net zero carbon emissions by 2050, a goal validated by the Science Based Targets initiative.

By reducing cooling needs and enabling warm water loops that can be integrated into existing facilities, Neptune supports long-term emissions reduction and energy efficiency objectives.

Demand for such solutions is increasing in the Asia Pacific region, where electricity consumption tied to AI cloud services and digital transformation is growing.

Lenovo forecasts that regional data centre consumption could increase from 320TWh in 2024 to 780TWh by 2030. In this context, energy efficiency is closely linked to commercial viability.

Kumar Mitra, Executive Director for Lenovo Infrastructure Solutions Group in Central Asia Pacific and Australia & New Zealand, says: “Across Asia Pacific, organisations are looking for AI infrastructure that is not only powerful but also fundamentally more energy efficient.

“Neptune gives our customers that advantage. Our leadership on the Top500 and Green500 rankings demonstrates the real-world impact of these innovations.

“As AI scales, solutions that combine performance with responsible energy use will define the next era of digital growth and that is exactly what Lenovo is delivering.”

Performance in real-world deployments

The Neptune ecosystem uses a combination of Direct to Node warm water cooling, Rear Door Heat Exchangers and Thermal Transfer Modules in a closed-loop architecture.

Warm coolant passes through cold plates on key components and returns approximately 10°C to 15°C hotter before transferring its heat into a separate facility loop. This process stabilises performance at high rack densities without using chilled water.

Lenovo’s ThinkSystem SR780a, which incorporates Neptune cooling, has achieved a Power Usage Effectiveness (PUE) of 1.1. PUE is a ratio of total facility power to IT power and a score of 1.1 suggests that for every watt of computing power, only 0.1 watts are used for cooling. Such efficiency levels are seldom possible with air-cooled systems.

Neptune-powered platforms are currently operational in some of the world's most demanding environments. DreamWorks Animation reported a 20% performance increase alongside reduced cooling needs after adopting Neptune-cooled HPC systems.

Neptune is also utilised by meteorological agencies in Korea and Malaysia, as well as university research centres and digital content studios across the Asia Pacific region.