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Glossary

  • A
    Accession process.
    Process that applicants for interruptibility service must complete in order to adopt the stablished legal framework.
    AIT (Average Interruption Time).
    Time, in minutes, which results from dividing the ENS (energy not supplied to the system due to interruptions of the service occurred in the transmission grid), by the average power of the peninsular system.
    Allocated capacity.
    The capacity (MW) that a participant in an explicit auction acquired by notification of the auction results and when the contestation period is closed if existing.
    Allocation.
    Commitment to energy production, energy consumption or transmission right, result of a market or auction.
    Ancillary services.
    Services which are necessary to ensure the electricity supply under the suitable conditions of security, quality and reliability. These include: primary control, secondary control, tertiary control and voltage control of the transmission grid.
    Auction product.
    Auction in which a product will be assigned. There will be as much product auctions as products to be assigned in an auction call.
    Auctions cancellation.
    Cancellation of auctions by TSOs in case of auction IT tool unavailability or technical difficulties and/or anomalies in the information exchanges.
    Auctions specifications.
    The specific characteristics of an auction, including amongst other the product made available, the day of the auction, the conditions that bids must meet in order to be accepted, the conditions for notifying the results of the auction, the deadlines for contestation and the auction session opening and closing times.
    Authorized capacity.
    Quantity of MW authorized by the TSOs for each direction of the inteconnection and for each time period for an specific day on the set of explicit auctions, after having taken into account any capacity reductions that may affect the assigned capacities.
    Auto-producer.
    A natural or legal person who generates electricity mainly for own use. Under the terms of 2818/1998 RD this translates into an average annual minimum of own consumption equivalent to:
    • 30% of the electrical energy produced if the power of the installation is inferior to 25 MW.
    • 50% of the electrical energy produced if the power of the installation is equal or superior to 25 MW.
    In order that the electrical surpluses of these facilities may be included under the special regime, they must be included in one of the following groups:
    • Waste energy power stations.
    • Co-generation power stations.
    Available transmission capacity.
    The Capacity made available jointly by the respective TSOs for an auction and which they offer under the terms of the Auction Rules.
    Average hourly power.
    Is the total of all instantaneous power values within an interval of time equal to one hour.
    Avoidable CO2.
    CO2 emissions (Tn) that could be avoided in case of an interruption order.
  • B
    Balance markets.
    Are those system adjustment services markets which allow the generation and demand to be balanced (deviation management services and tertiary and secondary control energy).
    Balance Responsible Party.
    Entity which may access the Spanish electricity market as a participant, not just to buy energy, but also to sell it. The following may act as balance responsible parties: electricity producers, distributors and commercial agents, qualified electricity consumers, and also companies or consumers who reside in other countries and have the external agent qualification.
    Bay.
    A set of equipment comprising of switches, switchgear, measurement and protection tools whose purpose is to manoeuvre and protect a circuit (line, transformer, etc.).
    Bilateral contracts.
    Trade agreement, off-market, between two or more entities who come to it.
    Block.
    Power or energy bid per hour by an unit in a market session. For certain markets several blocks per period are allowed.
    Busbar.
    The power plant busbar, is that point beyond the generator but prior to the voltage transformation point in the plant switchyard, it is the starting point of the electric transmission system. The nominal net electrical output is measured at these points and the electricity for auxiliary and house loads consumed in any way related to the generation are deducted.
  • C
    CAP.
    Limit applied to the compensation to be paid by TSO.
    Capacity auction.
    Process used to allocate interconnection capacity based on market mechanisms by means of explicit annual auctions, monthly auctions, daily and intraday auctions.
    Capacity bids curves.
    Offers submitted by market partitipants to the capacity explicit auctions sorted by price (merit order).
    Capacity curtailments.
    Changes in the long term allocated capacity prior to sending of the Authoritation as a result of a reduction in the exchange capacity.
    Capacity explicit aution.
    Mechanism used to allocate capacity physical transmission rights.
    Capacity implicit aution.
    Mechanism for simultaneous allocation of capacity and energy.
    Capacity payments.
    Regulated payment to finance the medium and long-term power capacity service, offered by the generation facilities to the electricity system.
    Closed-cycle pump storage generation.
    Production of electricity carried out by the hydroelectric power stations whose higher elevation reservoir does not receive any type of natural contributions of water, but uses water solely from the lower elevation reservoir.
    CNMC Circular 2/2014.
    Regulation approving the methodology relating to cross-border infrastructure access, including procedures for capacity allocation and congestion management, as well as the methodology related to balancing services between systems managed by different TSOs.
    Combined cycle.
    Technology for the generation of electricity in which two thermodynamic cycles coexist within one system: one involves the use of steam, and the other one involves the use of gas. In a power station, the gas cycle generates electrical energy by means of a gas turbine and the steam cycle involves the use of one or more steam turbines. The heat generated by combustion in the gas turbine is passed to a conventional boiler or to a heat-recovery element to produce steam which is then used to move one or more steam turbines, increasing the yield of the process. Electricity generators are coupled to both the gas and steam turbines.
    Commercial exchange capacity.
    Technical maximum import and export capacity of the Spanish electricity system with that of a neighbouring country's system and that is both compatible and which complies with the security criteria established for each system.
    Commercial schedules.
    Exchange programs (MWh) in both flow directions of an interconnection resulting from transactions between market participants by means of market mechanisms.
    Compensations for capacity curtailments.
    Payments (euros) of Electrical Systems for annual and monthly capacity reductions that have been necessary to apply.
    Compensatory energy.
    Energy withdrawn from the market matching as compensation for the energy added due to grid restrictions, or vice versa.
    Congestion
    A situation in which the link which interconnects two national transmission grids is not able to accept all the resulting physical flows of the international trade which has been requested by market participants. This is done through bilateral contracts or as a result of the Market Splitting process, due to an insufficient interconnection capacity of the elements and/or the own national transmission grids in question.
    Congestion incomes.
    Revenues derived from the management of the interconnection capacity between electricity systems..
    Congestion rents from explicit auctions.
    Total gross income from the explicit allocation of exchange capacity.
    Congestion rents from implicit mechanisms.
    Total gross income from management implicit mechanisms of exchange capacity management.
    Consumers.
    Natural or legal persons who buy energy for their own use. Those consumers who acquire energy directly from the production market are known as Direct Market Consumers.
    Consumption of pumps.
    Electrical energy used by pumped storage hydroelectric plants for elevating water from the lower to the upper reservoir for the generation of electricity.
    Control band.
    Energy band established by the system for controlling and maintaining the generation-demand balance, correcting unintentional deviations which take place during operation in real time with the European system, or of the frequency deviations of the system with respect to the programmed values.
    Control deviations.
    Deviations which occur between two electricity systems and are measured as the difference between the scheduled international exchanges and the international physical energy exchanges.
    Countertrading.
    Coordinated program established by System Operators in an interconnection, superimposed on the existing exchange programs, in an appropriate magnitude and direction so that the net flow of exchange programs between the two electrical systems respects the value of the existing exchange capacity ensuring the resolution of a congestion identified in the interconnection in real time.
  • D
    D-1 Schedule.
    International exchange program the day before the energy delivery date established by contracts in the Day-ahead Markets and / or bilateral contracting with physical delivery. (It represents the Daily Base Operating Program (PDBF) in MIBEL).
    Daily base operating schedule (PDBF).
    Is the daily energy schedule, broken-down in scheduled periods for the different energy generation selling and purchasing agents/units within the Spanish peninsular electricity system. This schedule is established by the System Operator based on the schedule resulting from matching the day-ahead market and the data regarding the execution of bilateral contracts with physical dispatch of energy.
    Daily horizon.
    Limit of 24 hours for which the different hourly programmes are devised. A weekly horizon also exists which considers the following seven days and the rolling annual horizon, which considers the next 12 months, with a weekly breakdown.
    Day Ahead market prices and spreads.
    Day-ahead Market prices and price differences (euro / MWh) on both sides of the interconnection PT-ES and FR-ES interconnection.
    Day-ahead market.
    This is the market in which the purchasing and sales transactions of electricty for the following day are carried out.
    Decoupling.
    Situation where day-ahead markets are solved independently, without implicit allocation of exchange capacity.
    Demand (at power station busbars).
    Energy injected in to the transmission grid from the ordinary and special regime power stations and imports, after deducting the consumption of pumps and exports. In order to transport this energy to the consumption points it would be necessary to subtract the losses originated in the transmission and distribution grid.
    Demand in regulated market for last resort supply.
    Electricity demand of the consumers on the peninsula (measured at power station busbars after subtracting standard losses) who contract energy from a last resort trader/reseller.
    Deviation management.
    The mechanism of deviation management is an optional service managed and remunerated by market mechanisms. The objective is to resolve the deviations between generation and demand superior to 300 MWh which could appear in the period between the end of one intraday market and the beginning of the next intraday market horizon.
    Discharging.
    A situation in which a transmission grid facility (line, transformer, busbar, etc.) is disconnected from the rest of the electricity system and, therefore, does not allow the flow of electricity through it. Additionally, the facility during unloading is earthed at one or more points with the purpose of assuring that their voltage differential remains at zero. This way, works of any type can be carried out on the element without risking the security of the people carrying them out.
    Disparo (Trigger).
    Non-programmed interruption of the electricity supply.
    Distribution network technical restrictions.
    Are those technical restrictions, corresponding to requests sent by the distribution network managers to the System Operator, to guarantee the security of the distribution network under its management.
    Distributors.
    Those mercantile societies which have the function of distributing electricity, as well as to construct, maintain and operate the distribution facilities required to transfer and distribute the energy at the consumption points.
  • E
    Emergency support exchanges.
    Energy exchange program established through the interconnection between two electrical systems, in order to ensure the security of supply in any of the two interconnected systems, to resolve a particular risk in the operation of the system, with the agreement of the operators of the respective electrical systems and in the absence of other available ways of resolution in the system that needs support.
    Electricity control centre.
    This is the centre responsible for the coordination, operation and supervision of the security of the whole of the Spanish electricity system. Amongst its functions are the scheduling of the coverage for electricity demand and programming of international exchanges, as well as zone operation and remote control. It is also the sole regulator of the Peninsular Shared Control (RCP). More information ...
    Energy capability factor.
    The ratio of energy capability to mean energy capability, and both referred to the same period and hydroelectric generation set.
    Energy capability.
    The energy capability or potential energy of a hydro-electric head installation during a given period of time is the maximum quantity of electrical energy which all the observed corrected inflows, limited to the plant capacity flow, would enable it to produce under the most favourable conditions.
    Energy market balance.
    This is the balance resulting from the difference between the measured losses in transmission and distribution and the standard losses used in the balancing procedure of the system as a whole.
    Explicit auction.
    A congestion management method used to allocate solely the interconnection capacity right.
    External agents.
    Are those introducing electrical energy in to or taking electrical energy from exterior systems. This is done under the terms set out in articles 9 and 13 of Law 54/1997. Law 17/2007 establishes that, as of 2008, the figure of the external agent no longer exists and that its role is now included in that of the commercial agent. The application of this measure requires prior legal development.
  • F
    Final schedule.
    International exchange program established at the close of the daily schedule. (It represents the Operational Programme Schedule (P48) in the Spanish Electricity System and Final Operational Programme Schedule (PHOF) in the Portuguese Electricity System).
    Functioning base programme (PBF)
    Is the result of aggregating to the base matching programme (resulting from the daily market), the special regime energy purchased by distributors and the bilateral contracts executed. It also includes the breakdown of the generation anticipated by the group of generators. This breakdown is a pre-requisite that is necessary in order to perform the PBF security analysis.
  • G
    Generation consumption.
    Energy used by the auxiliary elements of power stations, necessary for the everyday functioning of the production facilities.
    Generation market.
    This is comprised of the set of commercial purchase transactions and the sale of energy and other services related to the supply of electricity. It is structured on credit markets, day-ahead market, intraday market, non-organised markets and system adjustment services, understanding as such the resolution of technical restrictions of the system, ancillary services and deviation management.
    Generation Unit.
    Thermal Group, pumped-storage hydroelectric plant, hydroelectric plants management unit or wind turbine generator group management unit, that provided the electric network with energy at the same point.
    Generation-consumption deviations.
    These are the deviations originated by the modifications in the generation schedule due to the total or partial non-availability of one or several generators, variations in demand forecast of the energy buying agents, or by a new demand forecast carried out by the System Operator and which differs from the total demand matched resulting from the previous session of the Intraday Market.
    Generator terminals.
    Are the terminals of the main and auxiliary generator/s. The gross electrical energy production is measured at the generator terminals.
    Generic units.
    Programming units used to conduct operations in the market as a portfolio (by company) in the daily market and bilateral contracts.
  • H
    HAR rules.
    Legislation establishing the terms and conditions governing the allocation by explicit auctions of available capacity in both directions on the France-Spain in the long-term horizon and if applicable shadow auctions.
    Hydroelectric reserves.
    The hydroelectric reserve of a reservoir is the quantity of electricity that could be produced in its own power station and in all the power stations situated downstream, with the total drainage of its current useable water reserves and providing that drainage occurs without natural contributions. The annual regime reservoirs are those in which complete drainage would take place in less than one year. Hyper-annual regime reservoirs are those in which the total drainage time takes more than one year.
  • I
    ID schedule.
    International exchange program established after adjustments in the several sessions of Intraday Market MIBEL. (Represents the Final Hours Program (PHF-N) in MIBEL).
    IFE Rules.
    Legislation establishing the terms and conditions governing the allocation by explicit auctions of available capacity in both directions on the France-Spain in the intraday horizon.
    Installed power.
    Maximum power that a production unit can reach, during a determined period of time, measured at the generator terminals.
    Instantaneous Power.
    Instantaneous power is the energy absorbed by the demand at any given moment of time.
    International physical exchanges.
    The movements of energy which have taken place across lines of international interconnection during a certain period of time. It includes the loop flow of energy as a consequence of the grid design.
    International scheduled exchanges.
    These are the schedules that are established between two electricity systems as a consequence of a set of scheduled individual transactions in the market by Market Participants, or by means of bilateral contracts.
    Interruptibility.
    This is a demand management tool managed by Red Eléctrica as system operator and is used to provide an efficient and rapid response to the needs of the electricity system. The concept of interruptibility has changed into that of demand management in which large consumers who acquire energy through the electricity market can take part and can establish the corresponding service level contracts with the system operator. These companies obtain discounts on their invoices in exchange for a reduction in their electrical consumption, upon demand, and under special circumstances as determined by the system operator. In any case, the reductions of consumption to which these consumers must agree to are typified in the regulation and have as fundamental variables, the notice period, its duration and the number of times it can happen in an electrical year (November 1 - October 31).
    Interruptible demand.
    Diference between agreggated active power consumed by the service providers and aggregated residual power.
    Intraday market.
    The objective is to manage the adjustments occurring in the generation and demand of energy which may be produced after having fixed the day-ahead market.
    Intraday market prices and spreads.
    Intraday Market prices and price differences (euro / MWh) on both sides of the PT-ES interconnection.
    IPE Rules.
    Rules that establish the terms and conditions which govern the allocation, by means of auctions, of the capacity available in both directions in the Portugal-Spain interconnection.
  • L
    Load factor.
    Measures the relationship between the energy produced during a period of time and that which would have been produced in this period working at normal power.
    Last resort supply.
    Electricity power supply scheme that replaces the integral tariffs, and that is established for specific consumers who, owing to their characteristics, may have trouble contracting their consumption in the free market, and to whom last resort tariffs (TUR) would be applied. The TUR sets out the maximum and minimum prices which may be charged by traders/resellers assigned the role of last resort supply (also called last resort traders/resellers), to consumers who meet the established criteria that allow power supply under this scheme and who willingly choose to sign-up to this regime. As of July 1, 2009, last resort consumers are those low-voltage electricity consumers whose contracted power is less than or equal to 10KW.
  • M
    Marginal price.
    Price of the last bid allocated whose acceptance has been required in order to meet the demand required in a market call.
    Market agent.
    Entity which may access the Spanish electricity market as a participant, not just to buy energy, but also to sell it. The following may act as market agents: electricity producers, distributors and commercial agents, qualified electricity consumers, and also companies or consumers who reside in other countries and have the external agent qualification.
    Market clearing.
    Daily generation and demand programme, with hourly breakdown, carried out by the Market Operator based on the matching process between generation and demand bids received from market agents. This programme also includes, in an individualised manner, the programmed energy excepted from the obligation to present bids in the daily market.
    Market Coupling.
    Market mechanism between several interconnected bidding zones by which simultaneously day-ahead market price is determined in each bidding zone by performing implicit auctions.
    This process determines simultaneously by implicit auctions volumes and prices of energy in all interconnected areas, assigning the exchage capacity between those areas.
    The coupling via certain Country Borders of day-ahead electricity markets which simultaneously effects an implicit allocation of Daily Physical Transmission Rights and a clearing of energy offers-demands.
    Market Operator.
    A mercantile society which assumes the management of the bid system for the purchase and sale of electricity in the day-ahead and intraday market under the established regulations.
    Market Splitting.
    Situation in which the energy matched in the market for one interconnection is equal to the value of ATC usually meaning different prices between bidding zones.
    Measured deviation.
    Difference between the energy measured at the power station busbars and the energy scheduled in the market.
    Measured downward deviations.
    Measured downward deviations are those which result when the production measured at the power station busbars is smaller than that scheduled in the market, or when the consumption measured at the busbars is higher than that scheduled in the market. Therefore, the system must manage that difference by increasing production through the adjustment markets in real time.
    Measured upward deviations.
    Measured upward deviations are those which result when the production measured at the power station busbars is greater than that scheduled in the market, or when the consumption measured at the busbars is lower than that scheduled in the market: Therefore, the system must manage that difference by reducing production through the adjustment markets in real time.
  • N
    National demand in free market.
    Electricity demand of the consumers on the peninsula (measured at power station busbars) who directly contract energy from a trader or in the market.
    National demand in regulated market.
    Electrical energy demand (measured at busbar) of the consumers on the peninsula who contract energy from with an energy distributor on a tariff.
    Net energy.
    Maximum energy which a production unit can reach measured at outgoing feeder connections of the power station, that is to say, subtracting the power consumed in any way in electricity generation.
    Net generation.
    Production of energy measured at the generator terminals, minus the consumption in the auxiliary services and the losses in the transformers.
    Net national consumption.
    This is energy introduced into the electrical transmission grid from the ordinary regime power plants (conventional), special regime (cogeneration and renewables) and from the balance of the international exchanges. In order to transfer this energy to the point of consumption it would be necessary to deduct the losses originating from the transmission and distribution grid.
    Net Production.
    The electricity production of a generation unit, measured at the generator terminals, having subtracted that consumed by the auxiliary services and transformer losses.
    Net program and flow direction.
    Net balance (MWh) of all programs and flow direction.
    Network Transmission Capacity.
    Maximum exchange between two control areas compatible with security standards applicable in both areas and taking into account the technical uncertainties on future network conditions.
    Nominated capacity.
    The effective capacity whose use has been notified and becomes into a firm exchange program. The nomination of a capacity right is a strong statement of use.
    Non-availability factor.
    Relationship between the energy that has not been produced due to shutdowns or power reductions, scheduled or non-scheduled, attributable to the energy that could have been produced during the same period working at nominal power.
    Non-renewable energies.
    Those obtained from fossil fuels (liquid or solid) and their derivatives.
    Non-supplied energy (NSE).
    This is the energy not introduced into the electricity system due to service interruptions occurred in the transmission grid.
  • O
    Offered transmission capacity.
    Available transmission capacity along with the resales and capacities withdrawn from suspended or excluded participants.
    Offer.
    Set of blocks associated to a Bidding Unit for a certain session of the market.
    Operation Markets.
    The objective is to adapt the resulting generation programmes for the daily and intraday markets to the technical needs of quality and security required by the supply of electrical energy. These are composed of the solution of technical restrictions, the allocation of the ancillary services and deviation management. These markets are managed by Red Eléctrica in its role as system operator.
    Ordinary regime.
    The production of electricity from all those facilities which are not included under the special regime.
  • P
    Participant.
    Entity which participates in the capacity allocation auctions, buying physical capacity rights (PCR) or later selling them directly to other entities. These entities are subject to the arranged operating (P.O. 4.1 and P.O. 4.2) and in the Rules of Capacity Allocation of the France-Spain Interconnection (IFE Rules) or Rules of Capacity Allocation of the Portugal-Spain Interconnection (IPE Rules). The participants are the counterparts of the respective TSO in the Declaration of Acceptance of Rules IFE/IPE.
    Participants entitled to nominate Transmission rights at FR-ES border.
    List of participants entitled to exchange energy between electrical systems of France and Spain.
    Percentage of hours with 100% of use.
    Percentage of hours where 100% of NTC was used.
    Physical flow through the interconnections.
    Physical measure of the energy exchanged at the interconnection (MWh).
    Power guarantee.
    Regulated payment that is included in the price of the peninsular demand to guarantee the availability of sufficient power, in the long term, to cover of the supply of electrical energy. Since 1 January of 2008 it has been replaced by the Capacity Payment whose object is to guarantee that there exists sufficient available power to cover the supply of electrical energy in all of the grid nodes, both in the medium and long term.
    Price.
    Balance hourly value generation / demand result of a market session.
    Price convergence.
    Situation in which the energy matched in the market for an interconnection does not exceed the value of ATC and therefore the same price is recorded in both bidding zones on each side of the interconnection.
    Producible energy.
    Maximum quantity of electrical energy that theoretically could be produced considering the water supplies registered during a specific period of time and once the supplies used for irrigation or uses other than the production of electrical energy have been deducted.
    Producible hydroelectric index.
    This is the quotient between the producible energy and the average producible energy, both related to the same period and to the same hydroelectric equipment.
    Producible hydroelectric.
    Maximum quantity of electricity that theoretically could be produced considering the water supplies registered during a specific period of time, and once the supplies used for irrigation or uses other than the generation of electricity have been subtracted.
    Product.
    Amount (in MW) of interruptible power. There are 2 different products depending on the amount of interrumpibility power provided to the system (5 MW and 90 MW).
    Production (at generator terminals).
    The electricity production of a generation unit, measured at the outgoing generator terminals.
    Production (at power station busbars).
    Energy measured at the generator terminals having deducted the consumption required for generation and pumped storage.
    Programming Unit.
    Thermal group, pumping power station, management unit of hydroelectric power stations or management unit of a set of wind mills in a wind farm which evacuate energy in the same grid node.
    Programming unit.
    Minimum element with bidding ability in a market.
    PTR.
    Physical Transmission Right.
    Pump consumption.
    Electrical energy used by pumped storage hydroelectric power stations for elevating water from the lower to the upper reservoir for the generation of electricity.
    Pumped storage.
    This is a type of hydroelectric power generation used by some power plants for load balancing. The method stores energy in the form of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost off-peak electric power is used to run the pumps. During periods of high demand of electricity, the stored water is released through turbines.
  • Q
    Qualification process.
    Pre-qualification process that applicants for interruptibility service must complete in order to participate in the auctions.
    Qualified consumers.
    Is a consumer who can choose the supplier of their electrical energy in accordance with Royal Decree Law 6/2000 of 23 June. As from 1 January 2003 all consumers of electrical energy are considered as qualified consumers. With Law 17/2007 of 4 July coming in to force, which modified Law 54/1997, the figure of qualified consumer disappeared and remained integrated under the concept of consumer. In accordance with the cited law, consumers who acquire energy directly from the generation market are known as Direct Market Consumers.
  • R
    Real time restrictions.
    The process carried out by the System Operator consisting of the resolution of the technical restrictions identified during real-time operation of the system by means of the modification of the schedules of the Programming Units.
    Re-dispatching.
    Variation on the energy matched in the daily market, as a result of the execution of the successive intraday markets or ancillary services.
    REE Contract.
    This corresponds to the existing agreements prior to the implementation of the electricity market between Spain and France, Portugal, Morocco or Andorra. Entities have been created separating importing from exporting. They cannot access the regulation markets.
    Regulation band.
    Energy band established by the system for regulation. This is done with the objective of maintaining the generation-demand balance, correcting involuntary deviations which take place during operation in real time with the European system, or of the frequency deviations of the system with respect to the programmed values.
    Regulation deviations.
    Deviations which occur between two electrical systems and are measured as the difference between the programmed international exchanges and the physical international exchanges.
    Renewable energies.
    Those obtained from natural resources and also from both industrial and urban waste. These different types of energy sources include biogas, biomass, wind, hydroelectric, marine-hydroelectric, solar and industrial/ urban residues.
    Requirement.
    Detected needs which are attempted to be covered during a market session.
    Residual power.
    Reference residual power for interruptibility service provision.
    Restriction.
    Any limitation derived from the situation of the transmission grid or the system so that the supply of electricity can be carried out under the defined conditions of security, quality and reliability in the procedure of operation P.O. - 1.1. Additionally, restrictions a can take place due to:
    • Insufficient secondary and tertiary regulation reserve.
    • Insufficient reserve capacity for voltage control.
    • Insufficient reserve capacity for service restoration.
    For the resolution of these types of restrictions, the mechanisms established in the corresponding ancillary services shall be applied.
    Restrictions due to security of supply.
    A security of supply restriction is understood as the generation from thermal electricity production sources using local primary energy fuel deemed necessary to ensure security of supply in the Spanish electricity system, taking into account the limit established in Article 25 of Law 54/1997 of November 27, and taking into account the possible safety limitations for energy delivery schedules that, in accordance with the system operation procedures, might be necessary to apply. To solve security of supply restrictions, power delivery schedules of certain production units can be modified to contemplate the thermal production of those power stations using local coal as fuel, whereby only enabled power stations as providers of this service can participate in this process.
    Results from Explicit Auctions.
    Capacity allocated in the auction and resulting price.
    Rolling year.
    The period of time elapsed in the last twelve months.
  • S
    Secondary capacity market.
    A mechanism which allows the transfer and resale, on behalf of a participant, of acquired physical capacity rights in the annual and monthly auctions, or by means of transfers.
    Secondary control band and secondary control.
    Secondary control is an optional ancillary service with the objective of maintaining the generation-demand balance, correcting deviations with respect to the anticipated power exchange schedules between Spain and France, and frequency deviations. Its temporary action horizon stretches from 20 seconds to 15 minutes. This service is remunerated by means of market mechanisms via two concepts: availability (control band) and usage (energy).
    Secondary regulation.
    An ancillary service whose purpose is to maintain the balance between generation and demand, correcting the involuntary unintentional deviations which occur in the real-time operation of exchanges with the European system or the deviations in the system frequency with respect to the programmed values. Its temporal working horizon ranges from 30 seconds to 15 minutes. It is remunerated under two concepts: capacity (regulation band) and usage (energy).
    SEIE.
    Insular and extra-peninsular electricity systems. Refers to the electricity systems of the Balearic Islands, the Canary Islands and autonomous cities of Ceuta and Melilla.
    Session.
    Meeting of the Market.
    Shadow Auctions.
    Explicit auctions that are used as emergency solution for allocating the exchange capacity in the France-Spain interconnection when MIBEL is decoupled from the other European markets. It is an explicit capacity auction taking place in parallel to the session of market coupling, but in the shade and are only activated if decoupling happens.
    SIMEL.
    The measurement system intends to obtain the real data of the energy sold and bought in the electrical system for its settlement to the different companies involved (generators, traders and clients mainly) as well as for the calculation of the access tariffs billing.
    The Power Measurement Information System (SIMEL) comprises all these elements, that is, the measurement equipment installed at border points among activities, the secondary hubs, which receive information from the measurement equipment allocated to each of them and the main hub of electrical measurement, as well as the communications among them. More information...
    SIOS.
    System Operator's Information System. More information...
    Solar photovoltaic.
    Sunlight converted into electricity through the use of solar cells, generally made of semiconductor material that, when exposed to sunlight, generates electricity.
    Solar thermoelectric.
    Heat produced by solar radiation that can be taken advantage of for the production of mechanical energy and, subsequently, electricity.
    Special regime.
    Production of electricity which falls under a unique economic regime, originating from facilities with installed power not exceeding 50 MW whose production originates from cogeneration, or other forms of electricity generation associated with non-electrical activities, if and when they entail a high energy yield: Groups that use renewable non-consumable energies, biomass or any type of biofuel as a primary energy source: Groups which use non-renewable or agricultural waste, livestock and service sector waste as primary energy sources, with an installed power lower than or equal to 25 MW, when they entail a high energy yield.
    Support exchanges.
    Schedules which are established between two electricity systems to guarantee the conditions for the security of supply of either of the two interconnected systems. This is done in case of emergency to solve a specific risk situation in the operation of one of the systems and with the previous agreement between the respective operators and in the absence of alternative means of resolution in the system requiring support.
    Surplus/deficit of deviations.
    Difference between the amount of the settlements of the deviations and the energy used to maintain the generation-demand balance.
    System adjustment services.
    Services required to ensure the electricity supply under the necessary conditions of quality, reliability and security. The adjustment services can be of an obligatory or optional character. Resolution of restrictions due to guarantee of supply, resolution of technical restrictions of the system, ancillary services and deviation management are all considered adjustment services.
    System operation processes.
    Those system adjustment services which are necessary to assure the electricity supply under the necessary conditions of quality, reliability and security. The adjustment services can have obligatory or optional character. Adjustment services are understood as the resolution of technical restrictions of the system, ancillary services and deviation management.
    System Operator.
    A mercantile society whose main function is to guarantee the continuity and security of the electricity supply, as well as the correct coordination of the generation and transmission system. It carries out its functions in coordination with the operators and particpants of the Iberian Electricity Market under the principles of transparency, objectivity and independence. Under the current Spanish model, the system operator is also the manager of the transmission grid.
  • T
    Technical restrictions due to insufficient reserve to raise.
    Are those technical restrictions associated to the existence of insufficient energy reserve to raise in the system.
    Technical restrictions PDBF.
    A mechanism integrated in the electricity production market carried out by the System Operator consisting of the resolution of the technical restrictions identified in the Daily Base Operating Schedule by means of the modification of the schedules of the Programming Units and the subsequent process of re-balancing generation-demand.
    Tertiary control.
    An optional ancillary service that, if subscribed to, is accompanied by the obligation to bid and is managed and compensated by market mechanisms. Its objective is to resolve the deviations between generation and consumption and the restitution of the secondary control reserve which has been used. This is done by means of the adaptation of the operating schedules of the programming units corresponding to generation stations and pumped storage consumption facilities. The tertiary reserve is defined as the maximum variation of power generation that a generation unit can carry out within a maximum of 15 minutes, and which can be maintained for at least 2 hours.
    Thermal line rating.
    The maximum energy which can be transported by an electricity line without breaking the established safety distances. This value depends on the characteristics of the line and on the environmental characteristics (temperature, wind and solar heating).
    TIEPI.
    This is the time of interruption equivalent to the installed power in the medium voltage transformation centres.
    TIM (Average Interruption Time).
    Time, in minutes, which results from dividing the ENS (energy not supplied to the system due to interruptions of the service occurred in the transmission grid), by the average power of the peninsular system.
    Total interconnection schedules.
    Added value of the whole exchange programs (MWh) per flow direction of the interconnection.
    Traders/Retailers.
    Those mercantile societies that, accessing the transmission grid or distribution network, acquire energy to sell to consumers, to other system participants or to carry out international exchange transactions under the terms established in Law 54/1997.
    Transmission grid.
    The complete set of lines, facilities, transformers and other electrical elements with volatages greater than or equal to 220 kV, and those other facilities, regardless of their power, which fulfil transmission functions, international interconnections and the interconnections with the Spanish insular and extra-peninsular power systems.
    Transmission grid availability rate.
    Indicates the percentage of total time in which each element of the transmission grid has been available for service. It is calculated from the nominal power of each installation once the downtime due to preventive and corrective maintenance, unforeseen unavailability, or other causes (such as the construction of new facilities, renovations and improvements) have been subtracted.
    Transmission grid technical restrictions.
    Are those technical restrictions identified within the global system (generation-transmission grid), that require a modification to the schedules in order to comply with the operation and security criteria for operating the system.
  • U
    UGH (Hydro unit).
    Each set of hydroelectric power stations belonging to the same catchment basin and to the same individual holder.
    UIOLI.
    Use it or lose it.
    UIOSI.
    Use It Or Sell It.
    UIOSI compensation.
    Payments (euros) by the Electrical Systems to holders of non nominated long-term rights, due to MW of UIOSI that could not be made available to the day-ahead market market.
    Unavailability of the production units.
    A production unit is completely available if it can participate in production without any limitation in generation capacity or, when applicable, pumped storage consumption. Otherwise, it is considered unavailable, such unavailability being of a partial or total nature. The net unavailable power of a generation unit is determined by the difference between the installed net power at the power station busbars and the net power truly available.
    Unavailability rate.
    Indicates the percentage of time during which the transmission lines have not been in service.
    Utilization rate per flow direction in the interconnection.
    Percentage ratio between the net balance of all programs in the interconnection and exchange capacity (NTC).
  • V
    Voltage control.
    This is an ancillary system service whose aim is to guarantee the suitable voltage control in the nodes of the transmission grid, so that the operation of the system meets the established security and reliability requirements, to ensure that the energy supplied to the final consumers is in compliance with the required quality and that the generators can work in the established conditions for its normal operation.
  • A
    Accompanying measures.
    Voluntary actions developed by the company under its corporate responsibility charter. They are aimed at the integration of the project in the environmental, institutional and social environments by means of the project achieving sustainability with the participation of the social and environmental agents.
  • B
    Bird safety devices or Spirals.
    A white or orange spiral of polypropylene (PVC) which resemble a bobbin of 30-35 centimetres in diameter and a length of 1 metre, which is coiled around the earth cable or conductor to alert birds and therefore reduce the risk of accidents caused by bird collision. (Own definition of REE).​
  • C
    Compensatory measures.
    Measures imposed by the Environmental Impact Declaration (EID) which allow the placement of an installation within the defined area of the Nature Network 2000. They are exclusively environmental and are designed to maintain and respect the Nature Network area.
    Corrective measures.
    Set of actions carried out retrospectively to the completion of a works and that correct or minimise environmental impacts. These are usually imposed by the Environmental Impact Declaration (EID).
  • E
    Electric field.
    In a point in space, the force exerted on a static load located at that point. Expressed in volts per metre (V/m). ( 50 Hz. Electrical and Magnetic fields REE and UNESA, 1998).
    Environmental aspect.
    An element of the activities, products or services of an organisation having or which may an impact on the environment. (Regulation (EU) No 1221/2009 of the European Parliament and of the Council of 25 November 2009 on the voluntary participation by organisations in a Community eco-management and audit scheme (EMAS)).
    Environmental audit.
    A management instrument which includes a regular documented systematic and objective evaluation of the organisation, its management systems, and the procedure for protecting the environement with a view to facilitating operational control over practices that could have an impact on the environment and evaluates compliance of the environmental policies of the organisation, and in particular, its environmental objectives and goals. (European Parliament and Council Regulation no. 761/2001 dated 19 March 2001, permitting companies in the industrial sector to voluntarily join a community environmental management and auditing system (EMAS)).
    Environmental impact.
    Any change in the environment, either adverse or beneficial, that is caused in full or in part by the activity, products or services of any organisation. (Regulation (EU) No 1221/2009 of the European Parliament and of the Council of 25 November 2009 on the voluntary participation by organisations in a Community eco-management and audit scheme (EMAS)).
    Environmental behaviour indicator.
    Specific expression providing information on environmental behaviour in an organisation. (Standard UNE-EN ISO 14031 Environmental management. General Guidelines).
    Environmental Impact Declaration (EID-DIA, in Spanish).
    Declaration by the accredited environmental authority in which the anticipated environmental effects of the project are determined. The suitability or non-suitability of carrying out the projected activity is also assessed, and in the case of being suitable, the conditions must have processes established for the adequate protection of the environment or natural resources. (Royal Decree 1131/1988, 30 September, which approves the Ruling of the execution of Royal Decree Legislation, regarding Environmental Impact Evaluation).
    Environmental Impact Evaluation (EIE).
    Set of technical studies and systems that assist in estimating the environmental effects that may be caused by carrying out a specific project, works or activity. (Royal Decree 1131/1988, 30 September, which approves the Ruling of the execution of Royal Decree Legislation, regarding Environmental Impact Evaluation).
    Environmental Impact Study (EIS).
    A detailed technical study of the potential effects on the local environment which can stem from the execution of a project, activity or political decision. Environmental impact studies should assess the existing site and conditions and evaluate the anticipated impacts on the flora, fauna, economy, historical and social factors of project or activity. Constitutes the basic document for the Enironmental Impact Evaluation process.
    Environmental Management System (EMS).
    That part of the general management system that includes the organisational structure, the planning of activities, responsibilities, good practices, procedures, processes and resources to develop, apply, achieve, revise and maintain the environmental policy and manage the environmental aspects. (Regulation (EU) No 1221/2009 of the European Parliament and of the Council of 25 November 2009 on the voluntary participation by organisations in a Community eco-management and audit scheme (EMAS)).
    Environmental objective.
    A general environmental objective, which originates from the Environmental Policy and is set out as a goal to be fulfilled by the organisation and which, insofar as is possible, is measured. (Regulation (EU) No 1221/2009 of the European Parliament and of the Council of 25 November 2009 on the voluntary participation by organisations in a Community eco-management and audit scheme (EMAS)).
    Environmental policy.
    The general management and intentions of an organisation with respect to its environmental behaviour, put forward officially by its management teams, including the compliance with all the legal requirements applicable to environment matters, as well as the commitment to continuously improve environmental behaviour. It establishes a framework for the company's activities, environmental targets and objectives. (Regulation (EU) No 1221/2009 of the European Parliament and of the Council of 25 November 2009 on the voluntary participation by organisations in a Community eco-management and audit scheme (EMAS)).
  • H
    Hazardous waste.
    Those that appear on the list of dangerous residues, approved in Royal Decree 952/1997, including the containers and packages which contained them, those which have been described as dangerous by communitarian regulations and those which might be designated by the Government in accordance with that established under European regulations or in international treaties of which Spain is a part. (Law 10/1998, dated 21 April on Waste).
  • M
    Magnetic field.
    In a point in space, the force exerted on a live element located at that point. Expressed in amps per metre (A/m). The international measuring unit is Tesla (T) or any fraction thereof, and in particular the microtesla (µT). (50 Hz. Electrical and Magnetic fields. REE and UNESA, 1998).
  • N
    Nest-preventing device.
    A device formed by several elements made of galvanised steel, of different sizes, that prevents birds from building their nests and settling in the places where they are installed or on the device itself. (Own definition of REE).
    Nesting deterrents.
    These are strategically placed devices consisting of several different-sized elements of galvanized steel, which deter birds from nesting in that location and encourage them to use the safer, suitably placed artificial nests.
  • P
    Place of community importance (LIC).
    A place that, based on the biographic region or regions where it is located, contributes greatly to maintaining or restoring a type of natural habitat (…) in a favourable state of conservation so that it can help considerably in establishing the cohesion of Natura 2000 (…) and/or contribute noticeably to maintaining biological diversity in the biogeographic region or regions in question. For the animal species occupying large areas, the places of community importance will usually correspond to specific locations inside the area in which that species is naturally distributed, presenting the physical or biological elements that are essential for them to live and reproduce. (Directive (92/43), of May 21, on the conservation of natural habits and wild fauna and flora).
    Preventative measures.
    Actions performed, prior to carrying out a project, with the objective of avoiding possible environmental impacts.
  • R
    RED NATURA 2000 (NATURA 2000 NETWORK).
    The European Natura 2000 Ecological Network is a coherent ecological network comprised of Areas of Community Interest to be designated as Special Areas of Conservation, said Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) for Birdlife, whose management shall take into account the economic, social and cultural requirements, as well as the special regional and local characteristics. (Law 42/2007 of 13 December, on Natural Heritage and Biodiversity).
  • S
    Significant environmental aspect.
    An environmental aspect having or which may have a significant impact on the environment. (Regulation (EU) No 1221/2009 of the European Parliament and of the Council of 25 November 2009 on the voluntary participation by organisations in a Community eco-management and audit scheme (EMAS)).
    Special birdlife protection zone (ZEPA).
    An area of community interest for the protection of birds listed in appendix I of the Council Directive 79/409/CE of 2nd April 1979, on the conservation of birdlife.
  • V
    Visual simulation.
    An infographic technique (based on computer applications for graphic representation) applied to obtaining the representation of a project to give an approximate idea of what it will look like in the real future situation, and showing the elements that constitute it and its integration into the execution environment. (Own definition REE).
  • W
    Waste.
    Any substance or object belonging to any of the categories established in the appendix to the Waste Act, in which the owner disposes of or has the intention to dispose of it. In all cases, the items listed in the European Waste Catalogue (CER) will be classified as such. (Law 10/1998, 21st April, on Waste).