Abbas Bahreini

Introduction and Objective:

Reducing greenhouse gas emissions and achieving net zero carbon targets have become global priorities in addressing climate change, requiring comprehensive and interdisciplinary solutions. Energy efficiency and reducing energy losses are key strategies in this pathway, playing a crucial role in directly minimizing greenhouse gas emissions. This study aims to review and analyze various net zero carbon initiatives and projects across different countries and continents that focus on enhancing energy efficiency and reducing energy waste, as well as to examine their measurable impacts on greenhouse gas emission reductions.

Methodology:

This systematic review was conducted up to August 2025 by two independent reviewers. Initially, keywords related to energy, energy efficiency, greenhouse gas reduction, climate change, decarbonization, and sustainability were identified. Comprehensive searches were performed in reputable global databases such as Scopus, Web of Science, PubMed, and Google Scholar to collect research articles, policy reports, and case studies. Data regarding article characteristics, study types, geographic regions, technologies or solutions discussed, environmental and economic impacts, and data quality were extracted and analyzed using a customized form developed by the researchers. Collected sources were categorized into developed and developing regions and reviewed. Technical innovations, key projects, and evidence of environmental and economic impacts were critically described and analyzed to provide a comprehensive global overview with regional differences.

Results:

Policy reviews and decarbonization projects across various regions revealed the following:

Western and Northern Europe

• The European Union leads with stringent greenhouse gas reduction policies. Their projects include optimized district heating systems, net-zero energy buildings, and advanced energy management utilizing digital twins.


• Advanced technologies encompass energy recovery in wastewater treatment, innovative building insulations, and improved efficiency in maritime transport powered by clean fuels.


• Energy efficiency improvements in buildings and district heating have reduced up to 30% of energy losses.


• Digital twin technologies have played an essential role in monitoring and optimizing energy usage, reducing costs and emissions.

North America

• Successful projects include net-zero-energy wastewater treatment, industrial and building energy efficiency upgrades, and the use of carbon-neutral biogas.


• Integration of digital technologies with renewable energies in regional grids has significantly reduced greenhouse gas emissions.


• Increased efficiency and emissions reduction across various industrial sectors are among the key achievements.

Asia

• China and India are recognized as key players in clean energy projects.


• The adoption of innovative technologies such as clean hydrogen production, artificial intelligence, energy system digitalization, port energy management, and advanced transportation has contributed to optimizing energy consumption and carbon reduction.


• Diverse projects targeting decarbonization of key industries and the transportation sector using novel technologies like hydrogen and ammonia are underway.

Africa and Latin America

• Focus is placed on optimizing agricultural practices, rural electrification combining solar and gas energy, and low-cost local energy management projects.


• Localized projects adapted to regional conditions have lowered energy costs and contributed to decarbonization.


• Effectiveness and Progress


• In steel, cement, and oil industries, decarbonization and energy efficiency initiatives have led to significant reductions in greenhouse gas emissions.


• Net-zero carbon buildings and district heating systems reported up to 30% reductions in energy waste.


• Digital technologies, including digital twins, have been key to cost reductions and effectiveness improvements.


• Emerging technologies such as methane-to-hydrogen conversion and the use of carbon-neutral biogas have effectively expanded in specific sectors.

Key Innovations in Decarbonization

• Advanced membrane-based carbon capture technologies


• Clean hydrogen production using liquid metal catalysts


• AI-driven digitalization of energy management


• Application of phase change materials (PCM) in buildings for energy optimization


• Integration of renewable energies with effective consumption management


• Upgrading transportation systems with alternative fuels like hydrogen and ammonia


• Enhancing efficiency of maritime and land fleets with cutting-edge technologies

All of these technologies and policies have played effective roles in reducing greenhouse gas emissions and improving energy efficiency.

Conclusion:

Overall, the global decarbonization trend is primarily driven by the development and deployment of advanced technologies, implementation of stringent environmental policies, and enhancement of energy efficiency. These approaches manifest differently according to regional conditions, priorities, and specific needs of each country or area. Digital technologies and clean energies are recognized as key enablers of this transformation, playing vital roles in improving energy management and reducing environmental impacts.

Co-author/s:

Mehdi Saberi, Oil Company Employee, Pars Special Economic Energy Zone (PSEEZ), National Iranian Oil Company (NIOC).

Fatemeh Kamraninia, Oil Company Employee, Pars Special Economic Energy Zone (PSEEZ), National Iranian Oil Company (NIOC).