A Guide to the BM Reports Website

1
A Guide to the BM Reports Website
2
What is BM Reports?
http//www.bmreports.com

• The Balancing Mechanism Reporting System (BMRS)
  website provides near real time and historic
  actual data associated with the Balancing
  Mechanism. Forecasting data about the
  Transmission System is also shown.
• National Grid (System Operator) manages the
  Balancing Mechanism and uses it to continuously
  balance power flows throughout the electricity
  transmission network in Great Britain.
• The data displayed on this website is shown in
  graphical and/or tabular form using information
  provided by the System Operator and is updated
  throughout the day as new and updated information
  is received.
• Logica is the Service Provider responsible for
  the development and maintenance of the BMRS
• If you have any questions about the BMRS, please
  contact the BSC Service Desk on 0870 010 6950 or
  at bscservicedesk_at_logica.com

3
How do I access the data?

• The High Grade service is a dedicated private
  communications network. Balancing Mechanism
  Reporting Agent (BMRA) data is broadcast to
  participants as soon as it is available. Pages
  accessed using the High Grade service will
  receive Near Real Time updates. This service is a
  subscription service and messages are sent using
  a software program called TIBCO.
• The Low Grade service is the public website,
  http//www.bmreports.com. Data is made available
  to the High and Low Grade services at the same
  time, but if youre accessing the Low Grade
  service youll need to use the Refresh facility
  to retrieve the latest data as it becomes
  available.
• Click here for more information on Communications
  options and details on how to get a High Grade
  service.

4
How do I use this Guide?

• This guide explains all the pages on the BMRS
  website.
• To navigate the guide either click all the way
  through or click on the links on the contents
  page. The contents page links lead to the
  beginning of each section.
• This symbol returns you to the contents
  page.
• This symbol returns you to the beginning of
  that section, where you can return to the
  contents page.

5
What Types of Information are There?
The information on the website is split into four
categories

• General Data information that isnt contained
  within the three categories below.
• National Data this is information across the
  entire system and includes demand forecast data,
  pricing data and actual demand data.
• Zonal Data this section has forecast data split
  into five zones (these zones are BMRA zones and
  are not the same as the zones used by National
  Grid).
• BM Unit Data this section shows data for
  specific BM Units. It includes information about
  that units capabilities, Final Physical
  Notifications and Bid-Offer Data. Click here for
  a description of what a BM Unit is.

6
Contents (1)
General Data Market View (inner
homepage) Electricity Data Summary -
Overview - Warnings and Peak Demand - Triad and
System Prices - Market Imbalance - System
Demand - Rolling System Frequency - Rolling
System Demand - Temperature - Peak Wind
Generation - Generation by Fuel
Type - Daily Generation - Interconnector
Flows - Other Data Other General Data Large
Combustion Plant Directive
National DataMarket DepthMarket ActivityDay
Day Ahead (Demand)Day Day Ahead (Margin)2-14
Day Ahead2-52 Week AheadInitial Demand
Out-turn Non-BM STOR System PricesBalancing
Services Adjustment DataMarket Index Data
7
Contents (2)
Zonal DataZonal Day Day Ahead (Demand)Zonal
Day Day Ahead (Margin)DF Pictorial
RepresentationINDDEM Pictorial
RepresentationINDGEN Pictorial
RepresentationMELNGC Pictorial
RepresentationIMBALNGC Pictorial
RepresentationBM Unit Data BM Unit
DataDynamic DataBid-Offer DataDerived
DataHistoric Balancing Services Volume Data
- Same as national data graphs but for each zone
8
General Data
9
Market View(Inner Homepage)
This is an overview of the market. The individual
graphs are covered in the National and Zonal Data
sections.
10
Market View (cont.)

• System warnings inform you of any major
  operational
• news, e.g. a National Grid outage.
• Credit Default Notices let you know if a Party
  has
• entered authorised Credit Default. Level 1
  is if they go
• above 80, Level 2 above 90.

11
Electricity Data Summary (1) - Overview
The left hand menu lets you select the data you
want to view. The colour of the text tells you
when this data was last updated. An information
box is below each table/graph on this page.
Hovering over it brings up a detailed
explanation of the table or graph. If there is
historic data available, you can click on the
button below the table/graph to access it.
12
Electricity Data Summary (2) Warnings and Peak
Demand

• The system warnings are as seen on the inner
  
• homepage.
• The Peak Demands table gives information
  on peak
• national demand for yesterday, today and
  tomorrow.

13
Electricity Data Summary (3) Triad and System
Prices

• The Triad Demand Information table has
  details on the
• three Settlement periods with the highest
  Transmission
• System Demand over the last year.
• Recent System Prices highlights useful daily
  
• information from the system prices found in
  National Data.

14
Electricity Data Summary (4) Market Imbalance

• This is based on the Net Imbalance Volume (NIV)
• If NIV is positive, the market is short of
  electricity.
• If NIV is negative, the market is long.
• NIV is used in setting imbalance prices.

15
Electricity Data Summary (5) System Demand
This graph contains the forecast demand for the
remainder of today and tomorrow. A similar graph
can be found in National Data, but without the
forecast data.
16
Electricity Data Summary (6) Rolling System
Frequency
This is a real-time graph of system frequency.
The System Operator (National Grid) aims to keep
it as close to 50Hz as possible, at all times.
17
Electricity Data Summary (7) Rolling System
Demand
This is a real time representation of current
System Demand.
18
Electricity Data Summary (8) Temperature

• The reference temperatures are forecasts with
  the normal
• being the average. The high and low
  temperatures provide
• an estimate of the expected temperature
  variance.
• Out-turn is real time temperature data.

19
Electricity Data Summary (9) Peak Wind
Generation

• Forecast of when Wind Generation will peak for
  today
• and tomorrow, with a peak generation value in
  MW.
• The Power Park Modules spreadsheet contains a
  list of all
• wind farms registered with National Grid.

20
Electricity Data Summary (10) Wind Forecast

• The forecast data is for yesterday, today and
  the day ahead.
• We have the Initial and latest forecasts, plus
  real-time
• generation (out-turn).

21
Electricity Data Summary (11) Generation by
Fuel Type

• Real-time half-hourly generation by fuel type
• Its available as either a graph or a table.
• CCGT Combined Cycle Gas Turbine -I/C
  Interconnector
• OCGT Open Cycle Gas Turbine -PS Pumped
  Storage

22
Electricity Data Summary (12) Daily Generation

• Total national generation measured as energy
  transported
• across the transmission network.
• Normal reference is the forecast and the
  High and Low
• references cover the expected variance in
  generation.

23
Electricity Data Summary (13) Interconnector
flows

• Half-hourly flows across both French and Moyle
  (Irish) Interconnectors.
• Positive values indicate energy being imported
  into GB.
• Negative values indicate energy export.

24
Electricity Data Summary (14) Other Data

• The electricity data summary page also includes
• the following information
• System prices
• Day/Day Ahead Demand and Generation
• 2-14 Day Ahead Demand
• 2-14 Day Ahead Surplus
• Long Term Surplus
• This data is also contained within the National
  Data section,
• where you can find more details.

25
Other General Data

• Another link to System warnings and Credit
  Defaults.
• Trades between System Operators across the
• interconnector (screenshot below).

• A link to the Trading Operation Report.
• Links to other useful websites ELEXON, National
  Grid and
• Ofgem.

26
Large Combustion Plant Directive
27
Large Combustion Plant Directive (cont.)

• This page contains the following Large Combustion
  Plant data
• A list of the Large Combustion Plant (LCP)
• Their current status (Opted Out, Opted In etc.)
• Their cumulative running hours
• The number of hours they have remaining to run
• The limits on emissions
• Any traded emission limits and
• Any derogations the plant have in place.
• You can find out more on LCP on the Environment
  Agencys
• website.

28
National Data
29
Market Depth
30
Contents of Market Depth Graph

• Indicated Imbalance (IMBALNGC) MW
• Offer Volume/ Bid Volume MWh
• Accepted Offer Volume (AOV)/ Accepted Bid Volume
  (ABV) MWh
• Unpriced Accepted Offer Volume (UAOV)/Unpriced
  Accepted Bid Volume (UABV) MWh
• Priced Accepted Offer Volume (PAOV) and Priced
  Accepted Bid Volume (PABV) MWh
• This page publishes data as it becomes available,
  from the first period of the
• previous day up to the current period today.

31
Indicated Imbalance (IMBALNCG)
The Indicated Imbalance is the difference between
the Physical Notifications submitted by
generation (i.e. the Indicated Generation) and
the National demand forecast made by National
Grid (NG).
32
Indicated Imbalance Cont.

• The System Operator National Demand Forecast is
  based on historically metered (three-four years)
  generation output for Great Britain. It is the
  amount of power that needs to be generated and
  includes embedded generation. The 8.45am forecast
  doesnt include station transformer load, pump
  storage demand and interconnector demand. This
  data is included in the 11.00am forecast, once it
  becomes available. The 1100am forecast
  overwrites the 845am.
• A forecast of Indicated Imbalance is received
  each day for each of the Settlement Periods of
  the following day, normally by 12.00pm.
• Indicated Imbalance is measured in MW.

33
Offer Volume/Bid Volume

• The Offer volume is the total volume of offers
  made available in that period for all BM Units
  across the system.
• The Bid volume is the total volume of bids made
  available in that period for all BM Units across
  the system.
• A Bid is the willingness for a BM Unit to
  decrease generation or increase demand.
• An Offer is to increase generation or decrease
  demand.

34
Accepted Offer Volume (AOV)/ Accepted Bid Volume
(BOV)

• The BOV is also known as the System Total
  Accepted Bid Volume.
• It is the sum of all the Period BM Unit Total
  Accepted Bid Volumes (i.e the Accepted Bid Volume
  for each BM unit).
• They are calculated by adding up either the
  positive (offers) or negative (bids) parts of the
  Accepted Bid-Offer Volumes, for all the
  acceptances in a period.

• The AOV is also known as the System Total
  Accepted Offer Volume.
• It is the sum of all the Period BM Unit Total
  Accepted Offer Volumes (i.e the Accepted Offer
  Volume for each BM unit).

35
Example
The diagram shows the activity for one
(generation) BM Unit. The Offer Volume is
produced above the FPN and the Bid Volume below.
36
Unpriced Acceptance Volumes (UAOV/UABV)

• Unpriced Acceptance Volumes are those that are
  removed by the Continuous Acceptance Duration
  Limit (CADL) i.e. are shorter than 15 minutes
• Unpriced Accepted Offer Volume is the volume of
  accepted offers that are CADLd out.
• - Unpriced Accepted Bid Volume is the volume of
  accepted bids that are CADLd out.

37
Priced Accepted Offer Volume/Priced Accepted Bid
Volume (PAOV/PABV)

• Its important to remember that there are two
  prices, System Sell Price (SSP) and System Buy
  Price (SBP). Only one of these is calculated
  using Bids and Offers. This price is known as
  the main price the other price is the
  reverse price.
• PAOV/PABV are used in calculating the main price.
• As only one price is calculated using Bid-Offer
  data, either PAOV or PABV must be zero (the
  reverse price is calculated using Market Index
  Data well cover this later).
• PAOV/PABV is the total volume of Offers/Bids
  still in the stack once theyve been netted off
  against each other (Bids minus Offers).
• A PABV volume means there was a higher volume of
  Bids accepted than Offers.
• A PAOV volumes means there was a higher volume of
  Offers accepted than Bids.
• Click here to find out more about System Prices.

38
Historic Market Depth

• To find the Market Depth data for past dates,
  use the Historic Market Depth page and enter the
  date.
• A full date must be entered in the yyyy-mm-dd
  format.
• The information shown will be the same as on the
  Market Depth page.

39
Market Activity
40
Market Activity (2)

• This page shows a list of Bid/Offer Acceptances
  (BOA). These are the latest BOAs that have been
  recorded by the System Operator.
• Each BOA shows the BM Unit ID and the Acceptance
  ID, which is a number allocated by the System
  Operator.
• It also shows the time at which the BOA was
  issued and the time it must commence. These times
  are usually a few minutes apart.
• They are listed in reverse chronological order.
  The most recent BOA is listed at the top left.
• The High Grade service operates at near
  real-time. The chart will update automatically
  and the new acceptances will appear in red. The
  Low Grade service shows the 84 latest acceptances
  but doesnt update automatically.

41
Historic Market Activity

• The Historic Market Activity chart allows you to
  enter a date and a Settlement Period to view.
  Youll be able to see all of the Bid/Offer
  Acceptances that were issued for that Settlement
  period.
• Both the Market Activity and the Historic
  Market Activity charts allow the data to be
  viewed in Comma Separated Value (CSV) format by
  clicking the icon in the top right-hand corner.

42
Day and Day Ahead (Demand)

• This page displays the Demand Forecast,
  Indicated Demand and Indicated Generation data
  for the current and following days.
• The data for the following day is published at
  around midday. Its produced by the System
  Operator for the Operational Day, which runs from
  500am to 500am.

43
Demand Forecast (MW)

• The System Operators National Demand Forecast
  is based on historically metered (three-four
  years) generation output for Great Britain. Its
  the amount of power that needs to be generated
  and includes embedded generation.
• The National Demand Forecast (NDF) is published
  at 8.45am and doesnt include station transformer
  load, pump storage demand and interconnector
  demand.
• The System Operator only receives this
  information at 11.00am and publishes the
  Transmission System Demand Forecast (TSDF), that
  does include this data.
• This means that only the NDF for is directly
  comparable to the Initial Demand Out-Turn (INDO),
  as in they include the same variables.

44
Indicated Demand (MW)

• The Indicated Demand (INDDEM) is a forecast
  provided by the System Operator.
• Its the half-hour average expected demand in
  each Settlement Period. Its calculated as the
  sum of all Physical Notifications for that
  Settlement Period at the time of the forecast.
  It only includes BM Units whose Physical
  Notifications are negative, i.e. theyll be
  importing energy.

45
Indicated Generation (MW)

• The Indicated Generation (INDGEN) is a forecast
  provided by the System Operator. Its referred to
  as the Margin Forecast on the website.
• Its the half-hour average expected generation
  in each Settlement Period calculated as the sum
  of all Physical Notifications for that Settlement
  Period. It only includes BM Units for which the
  Physical Notifications are positive, i.e. will be
  exporting energy.

46
Day and Day Ahead (Margin)

• This page displays the Indicated Margin data and
  Indicated Imbalance data for the current and
  following days.
• Like the Day and Day Ahead (Demand) forecast,
  the data for the following Operational Day is
  published at around 12pm by the System Operator.

47
Indicated Margin (MELNGC) (MW)

• This is a forecast for the system on the
  following day, its received from the System
  Operator.
• The Indicated Margin forecast for each
  Settlement Period is the difference between the
  sum of the Maximum Export Limits of all BM Units
  for that period and the Demand Forecast made by
  the System Operator.
• The greater the value the more spare capacity
  there is forecast to be in the system.
• Small margins are a usually an indicator of high
  system prices.

48
Indicated Imbalance (IMBALNGC) (MW)

• The Indicated Imbalance is the difference
  between the Physical Notifications submitted by
  generators (i.e. the Indicated Generation) and
  the National Demand Forecast (NDF) made by
  National Grid (NG) as the System Operator.
• A forecast of Indicated Imbalance in the system
  is received each day for each of the Settlement
  Periods of the following day. The System
  Operator normally sends this by 1200 hours.
  Indicated Imbalance is measured in MW.

49
2-14 Day Ahead Data

• This page contains the
• Following data
• National Demand Forecast
• Day (NDFD) in Black
• Transmission System
• Demand Forecast Day
• (TSDFD) in Yellow
• OCNMFD Surplus (SPLD) in
• Green
• We describe each in more detail on the next page

50
Forecast Data NDFD and TSDFD (MW)

• The NDFD and TSDFD are the predicted peak periods
  for each of the days 2-14 ahead.
• These forecasts are produced by 300pm each day
  by the System Operator.
• Only the TSDFD includes station transformer load,
  pump storage demand and interconnector demand.
• Forecasted weather is used for week 1 but
  weighted to include normal weather which is
  used for all of week 2. Normal weather is based
  on a 30 year history of British weather. Great
  Britain is split into six weather zones for
  forecasting.

51
Surplus (SPLD)(MW)

• The Surplus is the difference between the sum of
  forecast Generation availability i.e. the sum of
  the Maximum Export Limits (the maximum power
  export level of all BM Units) and the National
  Demand Forecast (NDF).
• This is calculated for the predicted peak period
  of the day.
• The numbers are not inclusive of any transfers
  across the Interconnectors.

52
2-52 Week Ahead Data
This is laid out in an Identical fashion to
the 2-14 Day Ahead Data, just for a longer
period. Week 1 is the first week of the year. A
week begins on a Monday and ends on a Sunday.
53
Yesterday/Today Initial Demand Out-Turn
54
Initial Demand Out-Turn (MW)

• The Initial Demand Out-Turn is the average demand
  in a particular period. Its provided by the
  System Operator within 15 minutes of the end of a
  Settlement Period.
• Its derived from operational metering (not
  Settlement metering) associated with all "Large"
  generators and Imports from the interconnectors. 
  The term "Large" is all generators gt 100MW in
  England Wales, all generators gt 30 MW in South
  of Scotland and all generators gt 10MW in North of
  Scotland.
• It takes into account transmission losses but the
  INDO does not include station transformer load,
  pumped storage demand or interconnector demand.
  This data is included in the ITSDO.

55
Historic Initial Demand Out-Turn

• This page allows you to define a previous date
  and view the information for Initial Demand
  Out-Turn for that date in graphical and tabular
  form.
• A whole date must be entered, wildcard characters
  cant be used.

56
Non-BM STOR
This data is available as both current and
historic, in tabular and graphical formats. What
is Non-BM STOR? find out on the next page.
57
Non-BM STOR

• This is the volume of Short Term Operating
  Reserve (STOR) instructions that the
  Transmission Company has asked of Non BM Units.
• It can be to either increase generation or
  reduce demand.

58
Yesterday/Today System Sell System Buy Prices
This data is displayed from the first period of
the last day until the period of today for which
the calculations have most recently been
completed.
59
System Sell Price (/MWh)
SSP sum of (cost x volume of priced accepted
bids) ESCA SPA total volume of priced
accepted bids ESVA

• This is the formula for the System Sell Price. It
  combines the priced accepted bids (the volume and
  how it comes about can be seen in the Market
  Depth pages) and Energy Sell Cost/Volume
  Adjustments and also the Sell Price Adjustments.
• All of the Adjustments can be found in the
  Balancing Services Adjustment Data (BSAD) pages.
  This is data that includes any pre-gate closure
  balancing actions made by the System Operator
  (actions taken more than one hour before
  real-time).

60
Cont.

• Dividing costs on the top in by volumes on the
  bottom in MWh gives the units as /MWh. The Sell
  Price Adjustment is already in /MWh so it can
  just be added on at the end.
• The System Sell Price is calculated in this way
  only if more Bids than Offers were accepted. It
  is then called the main price. The System Buy
  Price is then called the reverse price and is
  calculated using Market Index Data.
• As a final step prices are capped e.g. If the
  reverse price was greater than the main price the
  reverse price would be capped to the main price
  (see Price Derivation Code).

61
System Buy Price /MWh
SBP sum of (cost x volume of priced accepted
offers) EBCA BPA total volume of priced
accepted offers EBVA

• This is the formula for the System Buy Price. It
  combines the priced accepted offers (the volume
  and how it comes about can be seen in the Market
  Depth pages) and Energy Buy Cost/Volume
  Adjustments and also the Buy Price Adjustments.
• All of the Adjustments can be found in the
  Balancing Services Adjustment Data (BSAD) pages.
  This is data that includes any pre-gate closure
  balancing actions made by the System Operator
  (see Price Derivation Code).

62
Cont.

• Dividing costs on the top in by volumes on the
  bottom in MWh gives the units as /MWh. The Buy
  Price Adjustment is already in /MWh so it can
  just be added on at the end.
• The System Buy Price is calculated in this way
  only if more Offers than Bids were accepted. It
  is then called the main price. The System Sell
  Price is then called the reverse price and is
  calculated using Market Index Data.
• As a final step prices are capped e.g. If the
  reverse price was greater than the main price the
  reverse price would be capped to the main price.

63
BSAD Defaulted

• If no BSAD data is received from the System
  Operator, before the pricing calculations are
  carried out, default values of zero are used for
  all BSAD components.
• This field indicates whether the BSAD data for
  that period is default data and will either
  contain a T for true or an F for false. T
  indicates default data will be used.

64
Price Derivation Code (PDC)

• This indicates how the system prices were
  calculated. They range from A to L.
• A SBPMain Price, SSPReverse Price - Net
  Imbalance Volume (NIV) is positive (Offer stack
  is larger), Market Index Volume is non-zero.
• B SSP Capped to SBP - NIV is positive (Offer
  stack is larger), Market Index Volume is non-zero
  but SSP greater than SBP.
• C SSP Defaulted to SBP NIV is positive but
  Market Index Volume is zero.
• D SBP and SSP Defaulted to Market Price NIV is
  positive but consists only of unpriced (CADLd)
  Offers and SBVA, Market Index Volume is non-zero.
• E SBP and SSP Defaulted to Zero NIV is
  positive but consists only of unpriced (CADLd)
  Offers and SBVA, Market Index Volume is zero.
• F SSPMain Price, SBPReverse Price- NIV is
  negative (Bid stack is larger), Market Index
  Volume is non-zero.

65
Price Derivation Code (PDC) Cont.

• G SBP Capped to SSP - NIV is negative (Bid stack
  is larger), Market Index Volume is non-zero but
  SBP greater than SSP.
• H SBP Defaulted to SSP- NIV is negative but
  Market Index Volume is zero.
• I SBP and SSP Defaulted to Market Price - NIV
  negative but consists only of unpriced (CADLd)
  Offers and SSVA, Market Index Volume is non-zero.
• J SSP and SBP Defaulted to Zero NIV is
  negative but consists only of unpriced (CADLd)
  Offers and SSVA and Market Index Volume is zero.
• K SSP and SBP Defaulted to Market Price NIV is
  zero but Market Index Volume is non-zero.
• L SSP and SBP Defaulted to Zero NIV is zero
  and Market Index Volume is zero.

66
Net Imbalance Volume (NIV) (MWh)

• The Net Imbalance Volume is the volume left after
  the smaller stack of either Bids or Offers has
  been taken away from the larger.
• It includes Bids or Offers (depending on which
  stack is larger) and any Energy Buy/Sell Volume
  Adjustments (EBVA/ESVA) SEE BSAD DATA. It can
  also include unpriced actions such as System BSAD
  or CADLd volumes. The most expensively priced
  500MWh of the NIV (called PAR) will go into
  calculating the main price.

67
Historic System Prices

• To find the system prices data for a past date
  use the Historic System Prices page and enter the
  date.
• A full date must be entered and no wildcard
  characters can be used.
• The information shown will be the same as on the
  System Prices page.

68
Yesterday/Today Balancing Services Adjustment
Data (BSAD)
69
Contents of Yesterday/Today Balancing Services
Adjustment Data Table

• Net Sell Price Cost Adjustment Energy (ESCA)
  
• Net Sell Price Volume Adjustment - Energy (ESVA)
  MWh
• Net Sell Price Volume Adjustment - System (SSVA)
  MWh
• Sell Price Price Adjustment (SPA) /MWh
• Net Buy Price Cost Adjustment - Energy (EBCA)
• Net Buy Price Volume Adjustment Energy (EBVA)
  MWh
• Net Buy Price Volume Adjustment System (SBVA)
  MWh
• Buy Price Price Adjustment (BPA) /MWh
• But what does it all mean? We cover this is the
  next slide.

70
Balancing Services Adjustment Data

• This is how the balancing actions, taken pre-gate
  closure, by the System Operator are taken into
  account when calculating the Energy Imbalance
  Prices (SSP/SBP).
• The actions are split into two categories
  - Energy Balancing Ensuring supply
  matches demand - System
  Balancing Ensuring stability of the transmission
  system
• The system balancing actions are not considered
  in the pricing calculations.
• The data is submitted by the System operator
  before 5pm for the following day starting at
  0030. Its then submitted on a half hourly basis
  after gate closure and can be resubmitted if
  required.
• The BSAD values on the BSAD page may differ from
  those on the System Prices page. This is because
  the values displayed on the System Prices page
  are the values used in the pricing calculation
  and may have been resubmitted later with a
  different value.
• Click here to find out what goes into the BSAD
  values and how they are calculated or
• Click here to find out how BSAD affects the
  pricing calculations.

71
Historic BSAD Data

• To find the BSAD data for past dates, use the
  Historic BSAD Data page and enter the date.
• A full date must be entered and no wildcard
  characters can be used.
• The information shown will be the same as on the
  BSAD Data page.

72
Latest Market Index Data
73
Market Index Data

• This reflects prices in the short term markets in
  Great Britain for wholesale electricity and shows
  information covering each Settlement Period today
  and yesterday.
• It is provided by Market Index Data Providers
  (MIDP).
• It consists of a Market Index Volume and a Market
  Index Price. The data is a weighted average of
  the data provided by the MIDPs. The volumes
  submitted by the MIDPs are a weighted average of
  the trades in that period for each MIDP.
• The volume and price will be displayed as zero if
  the Market Index Volume is below the Liquidity
  Threshold (a minimum traded volume requirement).
  If the MIDP has failed to submit the data in
  time for a particular calculation no data will be
  published.
• The Market Index Price is used as the reverse
  price.

74
Historic Market Index Data

• This page displays the Market index Data for
  previous settlement days.
• The user must enter a specified date and single
  period.

75
Zonal Data
76
Zonal Data

• We show the following information by zone
• Day and Day Ahead (demand)
• Day and Day Ahead (margin)
• Demand Forecast (DF) Pictorial Representation
• Indicated Demand (INDEM) Pictorial Representation
• Indicated Generation (INDGEN) Pictorial
  Representation
• Indicated Margin (MELNGC) Pictorial
  Representation
• Indicated Imbalance (IMBALNGC) Pictorial
  Representation

77
Zones

• Great Britain is split into five zones to reflect
  the original constraints on the Transmission
  Network
• These zones are
• They are labelled export or import according to
  the net flow across them.

78
Pictorial Graphs

• There are graphs for Demand Forecast (DF),
  Indicated Demand (INDEM), Indicated Generation
  (INDGEN), Indicated Margin (MELNGC) and Indicated
  Imbalance (IMBALNGC).
• The peak forecasted values are shown for each
  zone as well as the forecast time and the
  Settlement Date and Period.
• The values are shown numerically and also on a
  colour coded dial for easy comparison.

79
Demand Forecast (MW)

• The System Operator National Demand Forecast is
  based on historically metered (three-four years)
  generation output for Great Britain. This value
  takes into account transmission losses. Only the
  forecast received after 1100am takes into
  account station transformer load, pump storage
  demand and interconnector demand.

80
Indicated Demand (MW)

• The Indicated Demand (INDDEM) is a forecast
  provided by the System Operator.
• Its the half-hour average expected demand in
  each Settlement Period. Its the sum of all
  Physical Notifications for that Settlement Period
  and for BM Units for which the Physical
  Notifications are negative, i.e. will be
  importing energy.

81
Indicated Generation (MW)

• The Indicated Generation (INDGEN) is a forecast
  provided by the System Operator.
• Its the half-hour average expected generation in
  each Settlement Period. Its the sum of all
  Physical Notifications for that Settlement
  Period, and for BM Units for which the Physical
  Notifications are positive, i.e. will be
  exporting energy.

82
Indicated Margin (MW)

• The Indicated Margin forecast is the difference
  between the sum of the Maximum Export Limits (the
  maximum power export level of a particular BM
  Unit at a particular time) and the Demand
  Forecast made by the System Operator.
• The greater the value the higher the margin. This
  means theres greater capacity for additional
  generation, if required.

83
Indicated Imbalance (MW)

• The Indicated Imbalance is the difference between
  the Physical Notifications submitted by
  generation (i.e. the Indicated Generation) and
  the Demand Forecast made by National Grid as the
  System Operator.
• It can be either positive or negative.

84
BM Unit Data
85
BM Unit Data

• These pages contain data specific to particular
  BM Units.
• Click here to see a list of BM Unit IDs.
• Types of BM Unit
  T - Directly Connected to Transmission SystemE
  - Embedded in Distribution SystemI -
  Interconnector UserG - Supplier (base)S -
  Supplier (additional)M Other
• By convention the first letter of a BM Unit ID
  indicates what type of unit it is (T, E, I, M).
  Supplier BM Unit IDs (G and S) begin with a 2.
• Some of the pages will allow the use of wildcard
  characters () in order to select more than one
  BMU if the user is unsure of the exact ID. E.g.
  EGG will select any BMUs with EGG anywhere in
  their ID. T_ will select all BMUs with an ID
  beginning T_.

86
Latest Physical BM Unit Data

• This page shows data in a graphical and tabular
  form for the latest Settlement Period available
  (hence the greyed out day and period options).
• It shows the Final Physical Notification (FPN),
  the expected generation of the BM Unit
• The Quiescent Physical Notification (QPN), the
  expected power generated or consumed by an
  underlying process of the BM Unit. Its optional
  to submit this and its not used in Settlement
• The Maximum Import Level (MIL) and Maximum Export
  Level (MEL), the maximum power a BM Unit can
  import/export at a particular time and
• The Bid-Offer Acceptances for this BM Unit  

87
Historic Physical BM Unit Data

• The historic page will allow the user to choose
  either a range of BMUs or a range of periods by
  using the wildcard character. The date must be
  entered fully.
• If a range is produced, the page will only show
  data in tabular from. For a single BMU and period
  the page will show the data both as a graph and
  in a table.

88
Latest Dynamic Data
89
Latest Dynamic Data Contents

• The Run-Up/Run-Down Import/Export Rates is how
  quickly the BM Unit can increase its rate of
  generation or consumption. Its expressed in
  MW/minute and there can be up to three of each in
  a settlement period.
• The Notice to Deviate from Zero is the length of
  time in minutes a BM Unit will need to start
  importing/exporting from a zero level because of
  a Bid-Offer Acceptance.
• Notice to Deliver Offers/Bids are expressed in
  minutes. Theyre the time required for a BM Unit
  to start delivering Offers and Bids respectively
  from the time that the Bid-Offer Acceptance is
  issued.
• The Minimum Zero Time is the minimum time that a
  BM Unit which has been exporting must operate at
  zero or be importing before returning to
  exporting. It can also be the minimum time that
  a BM Unit which has been importing must operate
  at zero or be exporting before returning to
  importing as a result of a Bid-Offer Acceptance.
  Its shown in minutes.

90
Latest Dynamic Data Contents (2)

• The Minimum Non-Zero Time is also expressed in
  minutes and is the minimum time that a BM Unit
  can operate at a non-zero level as a result of a
  Bid-Offer Acceptance.
• Stable Export/Import Limits are the minimum value
  at which the BM Unit can, under stable
  conditions, export/import to or from the GB
  Transmission System. They are expressed in MW at
  the Grid Entry Point or Grid Supply Point.
• The Maximum Delivery Volume (MDV) is the maximum
  volume of energy MWh of Offer (or Bid if
  negative) that a particular BM Unit can deliver
  within the associated Maximum Delivery Period
  which is the maximum period over which the MDV
  applies in minutes.

91
Historic Dynamic Data

• The historic page will allow the user to choose
  either a range of BM Units or a range of periods
  by using the wildcard character. The date must be
  entered fully.
• The Lead Party Name and NG BM Unit Name are just
  descriptive entries.

92
Latest Bid Offer Data

• This page shows all the Bid-Offer Pairs submitted
  by a particular BM Unit two periods ahead i.e.
  the period for which gate closure has just
  occurred.
• It can be shown diagrammatically like this

Bid-Offer Pair No.2 645MW Offer 150 Bid 21.5
Bid-Offer Pair No.1 100MW Offer 45 Bid 21.5
FPN
Bid-Offer Pair No.-1 95MW Offer 38 Bid 21.08
Bid-Offer Pair No.-2 135MW Offer 38 Bid 18.15
Bid-Offer Pair No.-3 115MW Offer 38 Bid 17.15
Bid-Offer Pair No.-4 645MW Offer 38 Bid 125
93
Historic Bid Offer Data

• The historic page will allow the user to choose
  either a range of BM Units or a range of periods
  by using the wildcard character. The date must be
  entered fully.
• The Lead Party Name and NG BM Unit Name are just
  textual descriptions.
• When choosing a range of periods, the information
  displayed does not indicate which period it is
  for, only the timings for the pair.

94
Latest Derived Data
95
Latest Derived Data (2)

• The Bid/Offer Acceptance Volumes are an estimate
  of the Bid and Offer volumes accepted, for a
  particular BM Unit.
• - For each acceptance theres an indication of
  its duration ('S' for short and 'L' for long).
• The Indicative Period BM Unit Acceptance Volumes
  is a summary of all accepted Bid and Offer
  volumes.
• The cash flow for the BM Unit is provided as a
  summary of accepted Bids and Offers.

96
Historic Derived Data

• The historic page will allow the user to choose
  either a range of BM Units or a range of periods
  by using the wildcard character. The date must be
  entered fully.
• The Lead Party Name and NG BM Unit Name are just
  textual descriptions.

97
Historic Balancing Services Volume Data

• The Balancing Services Volume Data MWh for a BM
  Unit is the net volume of energy
  production/consumption by that BM Unit due to
  Balancing Services.
• The Balancing Services are those actions carried
  out by the System Operator prior to Gate Closure
  and does not include Bids and Offers.
• Its only available historically and must be
  submitted by the System Operator within 2 working
  days.