Power electronics is the implementation of solid-state electronics to the control and conversion of electric power. It also refers to a subject of research in electrical and electronic engineering which deals with the design, control, computation and unification of nonlinear, time-varying energy-processing electronic systems with fast dynamics. The first high power electronic devices were mercury-arc valves. The potentialities and economy of power electronics system are determined by the active devices that are available. Formerly, the mercury arc valve, the high-vacuum and gas-filled diode thermionic rectifiers were widely used in power electronics. As the ratings of solid-state devices enhance in both current-handling capacity and voltage, vacuum devices have been nearly entirely replaced by solid-state devices. 

An electric power system is a network of electrical constituent used to supply, transmit and use electric power. An example of electric power system is the network that gives a region's homes and industry with power—for sizable regions, this power system is known as the grid and can be widely divided into the generators that supply the power, the transmission system that carries the power from a generating centres to the load centres and the distribution system that feeds the power to nearby industries and homes. Smaller power systems are also found in industry, hospitals, commercial homes and buildings. Direct current power can be supplied by batteries, fuel cells or photovoltaic cells. Alternating current power is typically contribute by a rotor that spins in a magnetic field in a device known as a turbo generator. The speed at which the rotor spins in mixture with the number of generator poles determines the frequency of the alternating current produced by the generator.

Electric power transmission is merely the bulk transfer of electrical energy, from generating power plants to electrical substations located near demand centres. This is well defined from the local wiring between high-voltage substations and customers, which is typically mention to as electric power distribution. Transmission lines, when interconnected with each other, become transmission networks. The consolidate transmission and distribution network is known as the "power grid" in North America. Within UK, "power grid" is also known as the "National Grid”. A wide area synchronous grid, called an "interconnection" in North America, sprightly connects a large number of generators distributing AC power with the same corresponding frequency, to a large number of consumers.

Power-system protection is a sub field of electrical power engineering that deals with the protection of electrical power systems from defect through the isolation of faulted parts from the rest of the electrical network. The objective of a protection strategy is to keep the power system stable by isolating only the components that are under fault, whilst leaving as much of the network as possible still in working. Thus, protection schemes must apply a very pragmatic and pessimistic approach to clearing system faults.

A smart grid is a system which includes a diversity of operational and energy measures including renewable energy resources, smart meters, smart appliances and energy efficiency resources. Electronic power conditioning and control of the production and distribution of electricity are salient appearance of the smart grid.

Atmospheric electricity is the specimen of electrical charges in the Earth's atmosphere (or less commonly, that of another planet). The normal movement of electric charges between the Earth's surfaces, the various layers of the atmosphere, and particularly the ionosphere, taken together, are known as the global atmospheric electrical circuit. Much of the reasoning required to describe these currents lies within the field of electrostatics, but also requires understanding of other disciplines within Earth science.

Natural resources, known as renewable resources, are restoring by natural processes and forces persistent in the natural environment. There are irregular and reoccurring renewable and recyclable materials, which are utilized during a cycle across a certain amount of time, and can be exploit for any number of cycles.

The production of goods and services by manufacturing products in economic systems generate many types of waste during production and after the consumer has made use of it. The materials are then carbonize, buried in a landfill or recycled for reuse. Recycling turns materials of value that would otherwise become waste into expensive resources again.       

Energy economics is a wide scientific subject area which includes topics related to supply and use of energy in societies. Due to diversity of issues and methods shared and applied with a number of academic disciplines, energy economics does not contemporary itself as a self-contained academic discipline, but it is an applied sub discipline of economics. Energy economics also draws deliberately on results of energy engineering, geology, political sciences, ecology etc. Recent focus of energy economics includes the following issues. Risk analysis and security of supply, climate change and climate policy, Demand response, Sustainability, Energy and economic growth.

As the world struggles to come out from a global economic decline and financial crisis, countries are looking for solutions to upgrade domestic economic performance and put people back to work. Global energy demand and prices have been resilient throughout the recession, leading policy-makers in countries with the potential to produce energy to look to that sector as a potential engine for economic furtherance. The energy sector constitutes a relatively modest share of GDP in most countries, except for those in which gas and oil income loom large. However, the energy sector’s impact on the economy is greater than the volume of its parts. Most importantly, energy is an input to nearly every good and service in the economy. For this reason, reasonable and stable energy prices are beneficial to reigniting, sustaining and expanding economic growth.

Energy economics is a huge scientific subject area which includes topics related to supply and use of energy in societies. Due to diversity of issues and methods shared and applied with a number of academic disciplines, energy economics does not present itself as an independent academic discipline, but it is an applied sub discipline of economics.

Energy policy is the approach in which a given entity (often governmental) has decided to address issues of energy development including energy consumption, production and distribution. The attributes of energy policy may include legislation, international exposition, incentives to investment, and guidelines for energy conservation, taxation and other public policy techniques.

Energy engineering or Energy systems is a wide field of engineering dealing with energy efficiency, energy services, facility management, plant engineering, environmental  acquiescence and alternative energy technologies. Energy engineering is one of the more recent engineering disciplines to appear. Energy engineering combines knowledge from the fields of mathematics, physics, and chemistry with economic and environmental engineering practices. Energy engineers apply their skills to increase efficiency and further advance renewable sources of energy. The main job of energy engineers is to find the most systematic and sustainable ways to operate buildings and manufacturing processes.