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We present the role of heat and electricity storage systems on the rapid rise of renewable energy resources and the steady fall of fossil fuels. The upsurge in renewable resources and slump in fossil fuel consumptions is attributed to sustainable energy systems, energy transition, climate change, and clean energy initiatives. The fast growth of renewables brings new design and operational challenges to transition towards 100% renewable energy goal. Energy storage systems can help ride‐through energy transition from hydrocarbon fuels to renewable sources. Nuclear fusion and artificial photosynthesis are the ultimate Holy Grails for permanent clean energy solutions. Plants harvest light and store it in chemical energy to regulate the food supply chain that may be a guideline for an energy transition from fossil fuels to renewables. Heat and electricity storage devices can account for the periodic nature of solar and wind energy sources. Solar thermal systems for water and space heating are also a viable solution for subzero temperature areas. This study presents the transition of world's energy prospect from fossil fuels to renewables and new advances in energy storage systems. [ABSTRACT FROM AUTHOR]

Summary: Refrigerants bearing high global warming potential (GWP) and ozone depletion potential (ODP) were outlawed or facing time‐beared permission under the Montreal (1987), Kyoto (1997) protocols, F‐Gas law (2015), Paris Accord (2016), and recent Kigali Amendment to Montreal Protocol (2019). In order to modify followed by the paradigm shift of existing heating and cooling systems, American Society of Heating, Refrigeration, and Air‐Conditioning Engineers (ASHRAE) envisaged natural and synthetic refrigerants (Synrefs) are under investigation globally. Carbon dioxide (CO2) is a popular natural refrigerant (Natref) replacing Synrefs used in commercial heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems globally. A rampant rise is observed in markets of Asia (Japan and China), North America (the United States and Canada), the Australian continent, and Africa (South Africa) by reaching 20 000 CO2‐stores around the globe. The European markets are leading the utilization of CO2 in the heat pump, and refrigeration, CO2 based markets estimate 14% of the total food retail stores (400 m2). Japan is the second leading market of CO2 heat pump and refrigeration with more than 10 200 CO2 condensing units. CO2 transcritical systems have a share of more than 10% in only European market (large stores); however, their share is less than 10% of total stores in other major markets of the world. New pump and compressor‐driven transcritical CO2 systems integrate ejectors, condensers, and booster systems to reduce energy consumptions, enhance efficiency, efficacy, and coefficient of performance. This article reports a critical review of the CO2 based heating, cooling, and refrigeration system and presents updated literature along with barriers and challenges on commercial use of Natref‐based heating and cooling applications worldwide. [ABSTRACT FROM AUTHOR]

Distribution Flexible Alternating Current Transmission System (DFACTS) devices are evolving technologies to mitigate voltage sags, swells, flickers and harmonics during transient and steady state operations. Power electronics and communication technologies have made the conventional grid smart and artificial intelligence based algorithms even smarter but simulation studies based notion of applying the FACTS devices to damp the small or large scale power swings to improve steady state or transient stability looks like an unreliable notion. Modern FACTS devices include SVC, STATCOM, SSSC, UPFC, UPQC, DVR, TSC and TSR. Use of STATCOM, SSSC and UPFC requires a real time reference which suffers communication delay limitation. STATCOM and SSSC produce 4PU to 5PU high voltage and current impulses which are high enough to puncture insulators to compromise insulation coordination. Operation of STATCOM and SSSC renders protective relays ineffective and pollute the power quality. Best control systems clear 0.1 to 2Hz oscillations in the range of 2.5 to 7 seconds and protective relays operate in range of 0.05 to 0.5 seconds to clear faults. Power engineers believe the FACTS devices destabilize the power system due to their own presence therefore their use with some snubbing circuits may be limited to generation and distribution sides. [ABSTRACT FROM AUTHOR]