regions it serves into grids. The company is able to allocate the power it generates based on the usage and needs of a particular grid. Certain grids use more power at certain times of the day, so companies often shift power around to different grids at various times. On any given day, the company makes several changes in the power allocation to Grid 1. First, it increases the power by 20%. Then, it decreases it by 10%. Finally, it increases it by 30%. What is the net percent increase in this grid's power allocation? Round to the nearest whole percent and ignore the percent sign when entering your answer.

interconnected network for delivering electricity from producers to consumers. It consists of:[1]

generating stations that produce electric power

electrical substations for stepping electrical voltage up for transmission, or down for distribution

high voltage transmission lines that carry power from distant sources to demand-centers

distribution lines that connect individual customers

General layout of electricity networks. Voltages and depictions of electrical lines are typical for Germany and other European systems.

Electrical grids vary in size from covering a single building through national grids (which cover whole countries) to transnational grids (which can cross continents).

Power stations connected to grids are often located near energy resources such as a source of fuel or to take advantage of renewable energy resources, and away from heavily-populated areas. A bulk-power transmission network is therefore used to move the power long distances, sometimes across international boundaries, until it reaches its wholesale customer (usually the organisation that owns the local electric power distribution network). The electric power is therefore stepped up to a high voltage for the electric power transmission system. On arrival at a substation, the power will be stepped down from a transmission level voltage to a distribution-level voltage. As it exits the substation, it enters the distribution wiring. Finally, upon arrival at the service location, the power is stepped down again from the distribution voltage to the required service voltage(s).

Although electrical grids are widespread, as of 2016 1.4 billion people worldwide were not connected to an electricity grid.[2]

Electrical grids can be prone to malicious intrusion or attack; thus, there is a need for electric grid security. Also as electric grids modernize and introduce computers, cyber threats also start to become a security risk.[3] Particular concerns relate to the more complex computer systems needed to manage grids.[4]