Skip to main content


AGS: Stands for Alternative Gas Supplier. A non-utility who is approved by the Illinois Commerce Commission to sell natural gas.

ARES: Stands for Alternative Retail Electric Supplier. A non-utility who is approved by the Illinois Commerce Commission to sell electricity.

Ampere: The standard unit of electrical current. Often referred to as an amp.

Baseload: The minimum amount of power that a buyer needs to meet their demands.

Broker: An independent marketer who sells energy to commercial and/or residential customers. Brokers are not part of a utility and often work with ARES and AGS suppliers.

Btu (British Thermal Unit): Standard unit of measurement often seen on appliances that measures the heat of a fuel source.

Capacity: The maximum amount of power that a system or subsystem can carry or produce at a specific moment. Capacity is typically measured in megawatts.

Capacity Charge: An additional charge that covers the difference between a customer's peak energy use and their normal use during the same billing cycle.

Circuit: A conductor or a system of conductors through which electric current flows.

Contract Price: An agreed upon price between the seller and the buyer. The terms can be monthly, quarterly, yearly.

Day-Ahead Market: The market for energy for the following day.

Day-Ahead Schedule: Scheduling your energy needs 24 hrs in advance of your requirement, allowing more flexibility to adjust energy needs.

Delivery: The physical of of delivering electricity or gas over the utility's system.

Demand: the rate at which electricity is delivered to or required over a designated period, usually expressed in kilowatts or megawatts.

Deregulation: click here for more information.

Direct Access: The ability of a retail energy customer to purchase energy directly on the wholesale market without going through the utility.

Distribution: Transporting energy to customers/end-users.

Energy Efficiency: The effective use of, management of, or creation of energy to minimize waste.

Federal Energy Regulatory Commission (FERC): United States Commission that paved the way for de-regulation of the energy industry.

Firm Gas: Also referred to as uninterruptible, it is gas required to be delivered and taken under the terms of an agreement.

Firm Power: Guaranteeing a pre-determined amount of energy is available at a specific timeframe.

Fixed Rate: A rate that will not change over the course of the agreement.

Forced Outage: A shutdown in energy delivery stemming from unanticipated breakdowns during generation or transmission.

Futures Market: Market for not-yet-produced commodities. These commodities are bought and sold to mainly hedge against future price increases.

Generation: Producing energy.

Generator: A producer of energy.

Gigawatt: Unit of measure used for large power plants or grids, equals 1000 megawatts.

Hedging Contracts: Locking in at a predetermined cost for energy that is independent from the market value at the time it is delivered. A hedging contract allows you to lock-in to a rate that is equal to or slightly more than the current market price for an extended period of time to protect against market increases.

ICAP: Installed Capacity: Generating capacity of a system.

Independent Power Producers: A producer that is not a public utility.

Index Rate: A rate plan that changes based on a specific market.

Kilowatt (kW): Unit of measure typically used to outline power consumption of a device.

Kilowatthour (kWh): Most commonly used unit to measure electricity usage. Refers to usage of 1000 watts of power over the course of one hour.

Load (Electric): The power required of an energy generation system for a particular area at a specific time.

Market-Based Pricing: A price agreed upon by the buyer and seller based on current market conditions and the energy spot market.

Market Clearing Price: The highest price that can be expected given that all demand is met and supply is sold.

Maximum Demand: The highest average value of power taken from averages of successive time periods.

Megawatt (MW): Equals one million watts, typically reserved for a large commercial building or application.

Megawatthour (MWh): Term used for metering larger commercial customers.

Non-Firm Power: Purchase of available energy that is not required by customers who arranged for its production.

Off-Peak Gas: Gas obtained when it is not at its peak demand.

Open Access: When a utility’s transmission lines are available for use to receive energy from another supplier.

Outage: Interruption in service that prevents power from being delivered.

Peak Demand: Maximum amount of power required to service customers that are on a particular system.

Peaking Capacity: Generating capacity to meet peak supply needs.

Power Exchange: "Stock Exchange" for energy producers to buy and sell energy.

Reliability: The ability of your provider to have sufficient supply and quality transmission.

Renewable Resources: Energy sourced that is restored by the environment or natural processes with assistance by people.

Reserve Margin: Available power beyond what is needed to meet normal peak demand.

Retail Wheeling: Ability for a consumer to purchase or a supplier to transmit energy over another utility’s line.

Scheduled Outage: Interruption in service that has been pre-planned, typically for maintenance to a transmission system.

Spinning Reserve: Back-up capacity that can be available in ten minutes and operate for two hours.

Spot Purchases: Fast and fair transactions among energy producers and consumers for power required in the near future over short periods of time.

Transmission: Transportation of energy across a grid or power lines.

Usage: Amount of energy consumed typically measured in KWh.

Variable Rate: A cost that changes based on variables: energy generation, transportation, delivery, maintenance, etc.

Back to top