Current Situation of Next-generation Energy Research at NTT Space Environment and Energy Laboratories

1. Introduction

NTT Space Environment and Energy Laboratories was established in July 2020 with the aim of contributing to the regeneration and innovation of the global environment. It seeks to re-examine our home planet and social environment from the elevated perspective and broad vision of space, unconstrained by conventional environmental energy frameworks. The vision of this laboratory is as follows.

To contribute to zero environmental impact while creating innovative next-generation energy technologies and flexible environmental adaptation technologies, aiming for the regeneration of the global environment and the realization of an inclusive and sustainable society.

Through this vision, we seek a hyper-resilient and flexible society. This society not only will balance the impact it has on the global environment to net zero but also possess the capacity to absorb the impact it receives from changes in the global environment. To achieve such a society, our laboratory pursues research and development under the fundamental concept of “The Future of the Earth, from Space,” focusing on two pillars (Fig. 1): “zero environmental impact technologies,” including overwhelmingly clean and highly efficient next-generation energy technologies and sustainable system technologies such as CO₂ conversion technologies, and proactive “environmental adaptation technologies” that enable ultra-high-precision future predictions of the global environment and society, along with risk avoidance and reduction.

Fig. 1. Research themes.

Since many of the research themes pursued at our laboratory are not found in traditional NTT research laboratories, the number of researchers was initially less than 40. We have thus focused on expanding our research staff and strengthening collaborations with external research institutions. Notably, our owned media platform Beyond Our Planet (Fig. 2), launched specifically to enhance external outreach and recruitment, has achieved over 100 articles and monthly page views exceeding 100,000 through continuous active content creation. This has significantly contributed to raising awareness of our laboratory and has received considerable external recognition, including for the quality of its content.

Fig. 2. Our owned media.

Marking its fifth anniversary since establishment, the laboratory has surpassed 90 researchers through continuous staffing growth and strengthened external collaborations. It has also begun generating research outcomes through partnerships with over 40 external institutions. This collection of feature articles focuses specifically on energy-related technologies, introducing their current status and future initiatives.

2. Maximizing renewable energy utilization: Watt-bit collaboration

The rapid adoption of generative artificial intelligence (AI) has significantly increased the power consumption of datacenters (DCs), which house large numbers of servers executing AI training and inference. Global DC power consumption was estimated at approximately 415 TWh in 2024, accounting for about 1.5% of worldwide electricity consumption. By 2030, DC power consumption is estimated to more than double, reaching approximately 945 TWh, or about 3% of global electricity consumption [1].

Achieving a decarbonized society requires maximizing the use of renewable energy (RE) to meet this rapidly growing demand. Japan, aiming for carbon neutrality by 2050 as declared in 2020, is advancing efforts to increase the proportion of RE, primarily solar and wind power. However, the output of RE fluctuates significantly depending on weather and season, leading to a geographical and temporal mismatch between electricity demand and supply.

When generation exceeds demand, output curtailment (generation suppression) of RE occurs, reducing the utilization efficiency of RE and making it difficult to recover investments. Particularly in regions rich in renewable resources, such as Hokkaido and Kyushu, the long distances to demand centers necessitate large-scale transmission infrastructure development. However, this faces significant constraints in terms of cost, construction time, and environmental impact.

Against this background, and with DC demand rapidly increasing due to AI expansion, the policy concept of “watt-bit collaboration” aims to simultaneously achieve growth and decarbonization by integrating the development and operation of power (watts) and communications (bits). The Ministry of Economy, Trade and Industry (METI) and the Ministry of Internal Affairs and Communications (MIC) concluded that to rapidly deploy power-intensive DC facilities while accommodating expanding DC demand and increasing communication traffic, power, telecommunications, and DC operators must collaborate to select suitable sites and efficiently establish infrastructure. On the basis of this understanding, the two ministries launched the Public-Private Advisory Council on Watt-Bit Collaboration in March 2025. Following discussions among public and private stakeholders, they published the “Report 1.0” in June [2].

The report organizes initiatives into three main areas: Addressing Current DC Demand, Realizing New DC Aggregation Hubs, and Promoting Regional Dispersion and Advancement of DCs. Our laboratory is developing technologies to support the third initiative, Promoting Regional Dispersion and Advancement of DCs. These include distributed control technology for DC processing loads based on regional power generation conditions and optimization technology for the placement of new DCs according to RE adoption levels. A feature article in this issue, “Maximizing Renewable Energy Use in Datacenters through Watt-bit Collaboration,” details these initiatives [3].

3. Turning disaster into blessing: Lightning control and charging technology

Lightning has caused significant damage to people’s lives. Within the NTT Group, numerous failures due to lightning strikes occur across vast amounts of equipment, including communication facilities. While the results of long-term research on lightning countermeasures have been applied to communication buildings and equipment, lightning damage still persists. Therefore, our laboratory is shifting focus from conventional lightning damage countermeasures to developing lightning control technology that suppresses lightning strikes.

Many traditional lightning countermeasures use lightning rods. However, the area protected by a single lightning rod is limited. Installing lightning rods is often impractical in certain locations, such as wind turbines for wind power generation or outdoor event venues. Our laboratory is thus advancing research on lightning attraction using drones—the development of which has advanced—as an alternative to lightning rods.

Lightning attraction involves intentionally inducing lightning beneath a thundercloud and guiding it to a safe location, thus preventing lightning strikes on critical infrastructure and urban areas. The core of our research on lightning attraction using drones involves two key technologies: lightning-protection drones capable of withstanding direct lightning strikes and techniques that induce lightning using electric-field fluctuations. Our lightning-protection drones feature lightweight aluminum cages that divert lightning currents away from the main body, and we have confirmed they can still function even when exposed to simulated artificial lightning. Research is also underway on lightning induction technology that connects the drone to the ground via a wire and alters the electric-field distribution through switch operation to induce lightning.

To demonstrate the feasibility of drone-induced lightning, we conducted repeated experiments supplementing natural lightning in regions prone to winter lightning starting in the winter of 2021. On December 13, 2024, in our fourth year, we finally achieved the world’s first successful attempt at intentionally inducing lightning using a drone in Shimane Prefecture. Following the press release [4], we received an unprecedented number of media inquiries and requests for information. This not only highlighted the high level of technical capability at our laboratory but also reaffirmed the significant interest and concern society has in this research theme.

While the induced lightning current is currently discharged directly into the ground, we are also exploring lightning charging technology to use it more effectively. We have confirmed the effectiveness of compressed air as an energy storage method. Details are introduced in a feature article, “Lightning Control and Charging Technologies that Protect People and Equipment and Harness Energy” [5].

4. Using space energy: Space solar power systems

To achieve global decarbonization and ensure energy security, the development of long-term, stable power generation technologies is essential. While solar power is currently the most widely adopted RE source, it suffers from significant fluctuations in output due to sunlight conditions (limited to daytime, affected by weather and seasons) and cloud cover.

In response, in 1968, Dr. Peter E. Glaser of the United States proposed the concept of a space solar power system (SSPS) [6]. This concept involves converting solar energy using massive solar panels mounted on satellites in geostationary orbit approximately 36,000 km above the Earth’s surface. The converted energy is transmitted via power transmission antennas to receiving antennas installed on the ground, where it is reconverted into electricity for use as an energy source. Theoretically, it is not affected by the atmosphere or weather, enabling nearly continuous 24-hour power generation. Since solar intensity is stronger and more stable than on the ground, it is expected to be a next-generation clean energy source capable of continuously supplying large amounts of stable energy (1 GW, equivalent to one nuclear power plant) while being renewable.

However, numerous technical, safety, and economic challenges must be overcome for its actualization. While NASA (National Aeronautics and Space Administration) led SSPS research and development in the 1970s, it withdrew in the 1980s due to financial reasons. Japan now leads this research and development.

Our laboratory is tackling the technical challenges by conducting research and development on technologies such as solar-pumped laser technology for efficiently converting solar energy, long-distance energy transmission technology for conveying the converted energy to the ground, and high-intensity beam energy conversion technology for converting the high-intensity energy into electricity at the ground. These technologies are not only applicable to the ultimate goal of SSPS but also to terrestrial laser wireless power transmission systems. They are expected to enable power supply to remote locations such as islands and disaster-stricken areas, as well as wireless power transmission to mobile objects such as drones and high-altitude platform stations. Details on these technologies are introduced in a feature article, “Space Solar Power System with Optical Technology” [7].

5. The ultimate energy: Fusion energy

Nuclear fusion (fusion energy) is a phenomenon in which light atomic nuclei fuse to form heavier ones, releasing enormous amounts of energy. This process occurs at the core of the Sun. While artificially replicating the conditions of the Sun’s core—extreme pressure and density—on Earth is extremely difficult, it is attracting attention because, if achieved, it could become a clean and virtually inexhaustible energy source. Fusion is the exact opposite reaction to fission. It is safe because it ceases immediately when fuel supply stops, like a gas stove (unlike fission’s chain reaction), produces no high-level radioactive waste, and its fuel can be extracted endlessly from seawater.

Nuclear fusion power generation is being researched worldwide with commercialization targeted around 2050. Our laboratory, in collaboration with the Quantum Science and Technology Research Development Organization (QST) and the ITER International Fusion Energy Organization, is researching a high-speed, real-time control system using IOWN (Innovative Optical and Wireless Network) and AI/ML (machine learning) technologies as part of the optimal fusion reactor operation technology.

With the tokamak method, the most advanced way of fusion, plasma generates a confinement magnetic field through its own current flow, necessitating a continuous current within the plasma. However, instabilities arising from this current and pressure must be predicted and controlled proactively. Therefore, our laboratory has established technology for high-precision plasma prediction by applying a Mixture of Experts (MoE) model. This model integrates optimal AI models with weighted contributions on the basis of sequentially changing conditions.

When this technology was applied and evaluated on the actual plasma confinement magnetic field of the world’s largest tokamak superconducting plasma experimental device, JT-60SA, it succeeded for the first time globally in reproducing the position and shape of the plasma, which depend on the magnetic field structure, with the precision required for actual plasma control. This achievement was announced jointly with QST in a press release on March 17, 2025 [8], securing prospects for implementing the collaborative research results into JT-60SA. Details are introduced in a feature article, “Toward Fusion Energy—Integrating Knowledge through AI and Data Science” [9].

6. Conclusion

Our laboratory has achieved significant results in establishing research foundations and strengthening external collaborations, driving the creation of innovative next-generation energy technologies. The following feature articles detail the latest progress in the four topics introduced in this article: watt-bit collaboration, lightning control and charging, SSPS, and fusion energy.

Each of these initiatives directly contributes to restoring the global environment and achieving a sustainable society. Moving forward, we will deepen co-creation with external partners to introduce research outcomes into society, advancing toward zero environmental impact and resilient society.

References

[1]	IEA, “Energy and AI,” Apr. 2025. License: CC BY 4.0. https://www.iea.org/reports/energy-and-ai/energy-demand-from-ai
[2]	Press release issued by METI, “Report 1.0 of the Public-Private Advisory Council on Watt-Bit Collaboration Published,” June 12, 2025. https://www.meti.go.jp/english/press/2025/0612_001.html
[3]	F. Mahmood, M. Suwabe, K. Nakanishi, Y. Morisawa, and T. Hayashi, “Maximizing Renewable Energy Use in Datacenters through Watt-bit Collaboration,” NTT Technical Review, Vol. 23, No.12, pp. 26–32, Dec. 2025. https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr202512fa2.html
[4]	Press release issued by NTT, “World’s First Successful Lightning Triggering and Guiding Using a Drone—Protecting cities and infrastructure with a lightning drone toward a society free from lightning damage—,” Apr. 18, 2025. https://group.ntt/en/newsrelease/2025/04/18/250418a.html
[5]	A. Nagao and M. Maruyama, “Lightning Control and Charging Technologies that Protect People and Equipment and Harness Energy,” NTT Technical Review, Vol. 23, No.12, pp. 33–39, Dec. 2025. https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr202512fa3.html
[6]	P. E. Glaser, “Power from the Sun: Its Future,” Science, Vol. 162, No. 3856, pp. 857–861, 1968. https://www.science.org/doi/10.1126/science.162.3856.857
[7]	Y. Toriumi, S. Aonuki, and M. Takahashi, “Space Solar Power System with Optical Technology,” NTT Technical Review, Vol. 23, No.12, pp. 40–45, Dec. 2025. https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr202512fa4.html
[8]	Press release issued by QST and NTT, “World’s First Application of Highly Accurate AI Technology to Predict Plasma Confinement Magnetic Fields in Large-scale Fusion Devices—QST and NTT Joint Research Achievements Advanced the Practical Application of Innovative Technology—,” Mar. 17, 2025. https://group.ntt/en/newsrelease/2025/03/17/250317a.html
[9]	T. Kojima, Y. Shirasawa, R. Yoneda, and M. Takahashi, “Toward Fusion Energy—Integrating Knowledge through AI and Data Science,” NTT Technical Review, Vol. 23, No.12, pp. 46–51, Dec. 2025. https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr202512fa5.html