Energy is crucial for various functions, including transportation, mobility, food preparation, and communication. Global population growth and economic expansion have increased energy use, leading to an energy crisis. While technological advancements and energy efficiency legislation have improved end-use service efficiency, this hasn't always offset increased demand. The Russia-Ukraine conflict exacerbated the crisis, affecting heating, cooling, and transportation costs. The EU's heavy reliance on Russian gas imports (over 45% in 2021) highlights the vulnerability of energy supplies. The crisis also inflated prices across global supply chains. The predominant source of carbon dioxide emissions, a primary greenhouse gas, is the widespread use of fossil fuels. Achieving carbon neutrality by mid-century, as outlined in the Paris Agreement, requires reducing global energy demand and employing negative emissions technologies. Energy savings from efficiency and conservation offer co-benefits, including reduced pollution, enhanced business competitiveness, and lower household energy costs. However, achieving substantial energy savings requires behavioral changes among energy end-users, going beyond technological investments. Historically, energy efficiency innovations have been driven by energy performance criteria and financial incentives for new technologies. In 2016, the EU's building and transportation sectors consumed over 60% of total energy, making efficiency improvements in these sectors crucial for meeting the EU's 2050 emissions reduction targets (80% reduction from 1990 levels). This review examines policy instruments to promote energy sufficiency and conservation, explores the potential of renewable energy sources to address the energy crisis, and investigates energy savings in buildings and transportation, along with the role of artificial intelligence in maximizing energy efficiency.

The paper extensively reviews existing literature on various energy-saving strategies, focusing on green alternatives for home heating, energy-efficient building systems, and advancements in transportation technologies like electric vehicles and automated driving. It synthesizes findings from numerous studies on biomass boilers and stoves, hybrid heat pumps, geothermal heating, solar thermal and photovoltaic systems integrated with electric boilers, and compressed natural gas and methane as alternatives to fossil fuel heating. The literature review also covers energy-saving measures in buildings, including passive design strategies, smart grid analytics, and intelligent energy monitoring. Furthermore, the review delves into the applications of artificial intelligence in optimizing energy efficiency across multiple sectors—from improving weather forecasting and machine maintenance to automating grid operations and enhancing connectivity across homes, workplaces, and transportation. Case studies from Germany (100% renewable energy transition) and China (compressed air energy storage) are included to illustrate successful energy-saving initiatives and technical solutions.

This review article employed a systematic literature review methodology. The authors searched relevant databases (specific databases are not explicitly mentioned) for peer-reviewed publications focusing on energy-saving strategies in the context of the current energy crisis. Inclusion criteria likely centered on papers published in reputable journals, covering relevant themes such as renewable energy technologies, energy-efficient building design, transportation sector improvements (EVs, automated driving), and the role of artificial intelligence in optimizing energy systems. Exclusion criteria likely excluded non-peer-reviewed publications, papers lacking empirical data or detailed analysis, and those outside the defined scope. The identified papers were screened for relevance, and relevant data points, such as energy savings percentages, emission reduction estimates, and economic cost-benefit analyses, were extracted and synthesized. The review followed a structured approach, categorizing energy-saving strategies into specific sections (green home heating, energy-efficient buildings, transportation, and the role of artificial intelligence) and utilizing tables and figures to present and compare findings from different studies. The authors conducted a qualitative synthesis of the findings and discussed the implications for environment and society, including potential barriers to implementation and future research directions. Specific details about the search terms, date ranges, and selection process are not explicitly detailed in the paper.

The review highlights that significant energy savings (10–40%) are achievable through a multifaceted approach encompassing renewable energy sources, passive design strategies in buildings, smart grid analytics, energy-efficient building systems, and intelligent energy monitoring. Electric vehicles demonstrate the highest cost-per-kilometer reduction (75%) and the lowest energy loss (33%), although battery-related challenges remain. Automated and networked vehicles show potential for 5–30% energy savings. Artificial intelligence offers substantial energy-saving potential, particularly in buildings (18.97–42.60% reduction through deep neural networking) and grid management. Green alternatives to fossil fuel heating, including biomass boilers and stoves, hybrid heat pumps, geothermal heating, and solar thermal/photovoltaic systems, present opportunities for decarbonization and cost savings, although each option has its own economic and practical considerations. Case studies of Germany's planned 100% renewable energy transition and China's compressed air energy storage development illustrate the complexities and potentials of large-scale energy system transformations. The review also emphasizes the importance of individual actions in reducing energy consumption and carbon footprints. The findings highlight a significant need for policy changes to promote renewable energy adoption, energy efficiency measures, and behavioral changes to achieve substantial reductions in global energy demand and greenhouse gas emissions.

The findings underscore that addressing the energy crisis and mitigating climate change necessitates a multi-pronged approach encompassing technological advancements, policy changes, and behavioral shifts. The review's emphasis on various renewable energy technologies, energy efficiency measures in buildings and transportation, and the application of artificial intelligence in optimizing energy systems aligns with the global effort to decarbonize the energy sector. The case studies from Germany and China illustrate both the opportunities and challenges associated with large-scale energy system transitions, highlighting the necessity of long-term planning, technological innovation, and effective policy frameworks. The review also stresses that while technological solutions are crucial, behavioral changes among individuals and households are equally essential for achieving substantial energy savings. The need for addressing the economic and practical barriers to implementing energy-saving technologies and promoting societal acceptance of such changes are critical considerations for policy-makers.

This review emphasizes the urgency of implementing comprehensive strategies to address the global energy crisis and mitigate climate change. The key takeaway is that a multi-sectoral, holistic approach combining technological innovation, policy intervention, and behavioral shifts is necessary to achieve substantial and sustainable energy savings. Future research should focus on optimizing the integration of renewable energy sources, enhancing the efficiency and cost-effectiveness of energy storage technologies, further developing artificial intelligence applications for energy management, and investigating effective strategies for promoting behavioral changes among energy consumers. Furthermore, thorough life-cycle assessments of various energy-saving technologies are vital to ensure their long-term sustainability and environmental impact.

The review primarily relies on existing literature and may not fully capture all relevant research on energy-saving strategies. The synthesis of findings from diverse studies presents a challenge in directly comparing results due to variations in methodologies, geographical contexts, and data collection techniques. The economic analyses presented are often based on specific scenarios and may not reflect the full complexity of economic factors influencing energy transitions. Moreover, the review does not explicitly detail the selection process for included studies, potentially introducing bias.