This experimental computer chip reuses energy

Researchers have unveiled an innovative computer chip, named Ice River, which is capable of reusing the energy it consumes, marking a significant advancement in computer technology.

Unlike conventional computer chips that convert all drawn electrical energy into waste heat—rendering it ineffective after a single use—Ice River holds the potential to retain and recycle some of this energy. “A typical device, whether it’s your phone or laptop, expends energy once, only to discard it as useless heat,” explains Michael Frank, a scientist at Vaire Computing in London, the company responsible for developing this groundbreaking test chip. The warmth emanating from your device under heavy use highlights the inefficiencies of current technology.

Data centers, often relying on substantial water cooling systems and powerful fans, are battling overheating issues as artificial intelligence demands more advanced chips with higher electricity consumption than their predecessors. The surge in technology use is driving up the environmental and energy costs associated with computing.

In tests conducted in August, Ice River demonstrated a remarkable energy efficiency, consuming approximately 30% less power than traditional chips while executing the same computations. This chip reuses a portion of its electrical energy rather than dissipating it as heat. “This is truly exciting,” remarks Aatmesh Shrivastava, a computer engineer at Northeastern University in Boston. “There’s a widespread desire for computing systems capable of energy recovery.”

The development of Ice River involved rethinking two significant inefficiencies typically found in modern computer chips.

Firstly, conventional chips lose energy through the erasure of information. A standard chip processes data in a linear, irreversible manner, erasing original 1s and 0s during computations and generating heat in the process. In contrast, Ice River employs reversible logic, allowing the chip to “un-compute,” thus retrieving the original data without producing excessive heat.

Secondly, traditional chips waste energy during rapid voltage changes, akin to a hammer striking a surface. While this method facilitates swift computations, it generates significant heat. Ice River adopts a technique known as adiabatic computing, where voltage levels gradually rise and fall. “Think of the energy oscillating like a pendulum instead of crashing down like a hammer,” Frank states. This method allows the system to partially sustain itself and recycle energy for subsequent operations. Crucially, the power supply is integrated directly onto the chip.

Back in the 1990s at MIT, Frank explored test systems that demonstrated reversible logic, but Ice River is the first physical chip to successfully merge reversible logic with a pendulum-like onboard power supply. Frank notes that using either method alone fails to achieve meaningful energy reuse.

The test conducted in August was a crucial milestone in the chip’s development. “Prior to that, I was sketching the design and running simulations on paper,” shares Vaire co-founder Hannah Earley, who was elated to finally witness Ice River’s real-world performance.

According to Erik DeBenedictis, who leads the computing company Zettaflops in Albuquerque, New Mexico, Vaire is closer than any previous efforts to creating a practical reversible chip for real-world applications.

Despite this progress, the journey to mainstream adoption is still lengthy. Shrivastava cautions, “This technology will take time to become widely accepted.” Adiabatic computing, while beneficial for heat reduction, operates at slower speeds, requiring careful consideration of design and production costs. As the chips can be packed more densely due to their reduced heat output, Vaire faces challenges in scaling up operations and maximizing energy reuse. “They have hurdles to overcome ahead,” DeBenedictis concludes.