Historic, Conventional and Futuristic Energy Storage

Energy storage has evolved significantly over time, adapting to technological advancements and changing energy needs. Below is an overview of historic, conventional, and futuristic means of energy storage, categorized based on their development stages and applications.

Category	Technology	Efficiency (%)	Energy Density (MJ/kg)	Cost (USD/kWh)	Carbon Emissions (kg CO2/kWh)	Applications
Historic	Firewood / Biomass	Low	~15	10-30	High (~0.5-1.5)	Heating, Cooking
Historic	Water / Wind Mills	Moderate	N/A	5-20	Low (0)	Grinding, Pumping
Historic	Ice Storage	Low	~0.33	1-5	Low (0)	Cooling
Historic	Gravity Storage	Low	~0.01	20-50	Low (0)	Clocks, Irrigation
Conventional	Pumped Hydro	70-85	~0.5-1	100-200	Low (0.01-0.05)	Grid Storage
Conventional	Lead-Acid Batteries	70-80	~0.03-0.05	50-150	Moderate (0.1-0.2)	Automobiles, Backup
Conventional	Lithium-Ion Batteries	90-95	~0.2-0.26	150-300	Moderate (0.05-0.15)	EVs, Electronics
Conventional	Flywheels	85-95	~0.1-0.2	200-500	Low (0.01-0.05)	UPS, Frequency Regulation
Conventional	Compressed Air Storage (CAES)	40-70	~0.1-0.5	50-150	Moderate (0.1-0.3)	Grid Storage
Conventional	Thermal Energy Storage (TES)	70-90	~0.2-1.0	10-50	Low (0.01-0.05)	Heating, Cooling
Futuristic	Hydrogen Storage	30-50	~120	500-1000	Moderate (0.1-0.3)	Transport, Long-Term Storage
Futuristic	Solid-State Batteries	95+	~0.3	300-600	Low (0.01-0.05)	EVs, Aerospace
Futuristic	Gravity-Based Storage	80-90	~0.01	100-300	Low (0)	Grid Storage
Futuristic	Liquid Metal Batteries	70-80	~0.2	200-400	Moderate (0.05-0.15)	Grid Storage
Futuristic	Supercapacitors	90-98	~0.01-0.02	100-300	Low (0.01-0.05)	Rapid Power Delivery
Futuristic	Flow Batteries	60-80	~0.04-0.08	400-700	Low (0.01-0.05)	Renewables Integration
Futuristic	Carbon-Based Storage	95+	~0.3-0.5	500-1000	Low (0.01-0.05)	Future Electronics
Futuristic	Biological Energy Storage	Low	~0.01	Unknown	Negligible (0)	Wastewater Treatment

 The data presented here is derived from a combination of reputable sources, including academic research papers, industry reports, and technical publications from organizations such as the International Energy Agency (IEA), U.S. Department of Energy (DOE), and National Renewable Energy Laboratory (NREL). Specific numerical values for energy density, efficiency, and cost estimates have been compiled from various reports, such as the IEA's Energy Storage Tracking Reports, DOE's Energy Storage Grand Challenge Roadmap, and market analyses from consulting firms like BloombergNEF and McKinsey & Company. Additionally, real-world case studies and manufacturer specifications from leading companies in energy storage, such as Tesla (for lithium-ion batteries), Siemens (for compressed air storage), and Energy Vault (for gravity storage), have been referenced to provide the most accurate and up-to-date information. The historic storage methods were informed by historical records and energy transition studies, while futuristic technologies are based on ongoing research publications and experimental findings published in journals like Nature Energy and IEEE Transactions on Energy Conversion. Given the rapidly evolving nature of energy storage technologies, the values in the table represent current industry consensus and may vary with future technological advancements and market conditions.