1 Overview
Welcome to your pGrid Study
Your study looks at how the generation of electricity and production of gas (Natural or Hydrogen) meets demand. In both gas and electricity the system must balance. In electricity, demand and generation are balanced in each half hour of the year, for gas they are balanced in each gas day. Storage assets (incl. Hydrogen storage) are included and are used to meet shortfalls or to store excess energy production.
Your Study is defined by four aspects ;
- Grid Scope - The point at which demand is managed (National, Regional, Local, before the meter or after etc.) e.g. Total consumer demand (before the meter)
- Demand Source - This is where the demand data was sourced e.g. VIL (the demand forecasting part of pGrid)
- Study Year - The calendar year that is being studied e.g. 2050
- Scenario - The scenario being studied e.g. the FES 2050 System Transformation scenario from National Grid.
Where reference data is available you can add it to align your analysis with the objective, so where for example a FES scenario is being analysed you would add the FES data as references.
The report below shows the currently loaded Study Summary data:
There are over 50 reports to help you 'get to know your grid', we have presented the overview of each of the main sections of the website below:
Do the lights stay on?
Perhaps the most important chart is of the percentage excess generation available to meet demand, this is shown here. A plant margin of a few percent (at least) is needed to have a reliable system.
Plant Margin - Do the lights stay on in this study?
What is demand (as modelled by pGrid) and how does it compare with the reference?
The demand schema compares the pGrid annual demand results (in TWh) with the references for both the electricity network and the gas network.
What generation is running ?
The electricity network is balanced in each half hour. pGrid achieves this by dividing half hourly demand data into equal groups of half hours selected by the level of load on the system. These are Tranches and pGrid can look at a single Tranche for the year or deciles where there are ten Tranches and centiles with 100 Tranches. This simple chart compares the tranche load with the generation that meets this load. Tranche 1 is the lowest load, the peak load is to the left. The generation stack is in order of bid price (merit order) with the marginal generation type at the top. The curve along the top is the load duration curve.
Generation Stack and Load Duration
What is the power price?
The price duration curve is showing how prices change with the highest prices on the left. Further price details are in the Prices section.
How does the gas system meet daily demand?
The gas network can contain natural gas and/or hydrogen, it is balanced by pGrid on a daily energy balance basis, with any excess hydrogen being stored or gas shortfall supplied from the hydrogen store. The gas year can be reviewed here for each of the 365 days in the study.
Contents
2 Demand
2.1 Duration Curve
The load duration curve graph shows how tranche load varies with each tranche from lowest to the highest 'peak' tranche.
Each half hour of grid demand is stacked in order of load, then divided into tranches, each with an equal number of half hours. For example, with tranches set at 10 there would be 876 * 2 = 1752 half hours in each of the ten tranches. Tranche 1 is the minimum load and the maximum load is in the largest tranche. The peak demand is set at the maximum demand load seen in any half hour (when G=100).
The grid demand in GWh is the total energy recorded by National Grid for the demand year as National Demand (ND).
2.2 Demand by Half Hour in any Day
Look at any specific day in the current study year (select the day and the month).
2.2 Demand by Half Hour in any Day
2.3 Demand Shape
The maximum, minimum, average and standard deviation of demand is shown by month, Business Day (BD) or Non-Business Day (NBD). The numbers represent the load level where the minimum load is 1 and the maximum equal to the number of tranches analysed.
2.4 Demand Schema
The demand schema shows how demand is built up with grid losses, generator losses, exports and imports to produce the stack balance load.
2.5 Demand Sectors
Demand sectors are as follows
- Agriculture (A)
- Industry (I)
- Small and medium sized companies/SME's (S)
- Transport (T)
- Domestic (D)
2.5. Demand Sectors
2.5.1 Electricity Sectors
2.5.1.1 Sectors - A Day
The demand forecast for all sectors by V100 can be viewed for any day here
2.5.1.2 Domestic Sector - A Day
The demand forecast for the Domestic sector by V100 can be viewed for any day here
2.5.1.2 Domestic Sector - A Day
2.5.1.3 Sectors - Grid Demand - A Day (Matrix)
2.5.1.3 Sectors - Grid Demand - A Day ( Matrix)
2.5.1.4 Exports, Imports and Electrolysis
The daily profiles for the inter connector exports and imports are shown together with the load for the electrolysis of water into hydrogen.
2.5.1.4 Exports Imports and Electrolysis
2.5.2 Gas Sectors
2.5.2.1 Sectors in Grid Demand - Gas - A Day (Matrix)
2.5.2.1 Sectors in Grid Demand - Gas - A Day (Matrix)
3 Generation Classification
GSCs are ‘Generation Short Codes' composed of a 'letter number number’ format that allow pGrid to simplify the generation types.
The different GSCs are shown with their respective inputs
- primaryFuelGSC
- availTypeGSC
- thermalEfficiencyGSC
- emissionsGSC
- gensetCostGSC
3.1 Generation Short Codes (GSC) - Genset Characterisation
GSCs are automatically assigned by pGrid depending on the technology type, all GSCs default to the availability GSC. Where a GSC is in variance with the availability GSC, the revised GSC is shown. These revised GSC types are then the basis of the genset aggregation. The report shows a list of all the aggregated gensets and their GSCs for the selected availability GSC, with any GSCs that are not set to the default highlighted. The blank cells are where GSCs remain set to the default availability GSC.
3.1 GSC Overview – Genset Characterisation
3.2 Primary Fuel GSC
Primary fuels are the source of the raw energy converted into power by the respective technologies. A list of the primary fuel GSC types is used by pGrid however they may not all be used in any study.
3.3 Availability Type GSC
A list of the technology types that have differing availability profiles, may not all be used in any study.
3.4 Thermal Efficiency GSC
A list of the thermal efficiency of fossil fuel generating plant, may not all be used in any study.
3.5 Carbon Emissions GSC
A list of the carbon emission of fossil fuel generating plant in g/kWh of generation.
3.6 Genset Cost GSC
The fixed generation cost assumptions. These are the costs other than fuel, emissions, and bid strategy cost.
4 Village 100
4.1 Your Village
Your village is a conceptual place where 100 villagers live and where offices, public buildings and various industries are based. The village is used as a proxy to forecast demand in any area e.g. the UK. The data used in any village must represent the area being studied.
In each village there are places such as homes, offices, public buildings etc. Each place has a number of things within it that provide a service to villagers.
For example each home (a place) might have a toaster (a thing) that is used by a villager to make toast (a service).
Your village is a representation of demand as if the demand was produced by a village with 100 villagers. Each villager lives in a different property, using different things at different places to provide different services.
4.1.0 Villagers
There are 100 villagers that you can select by name or number to see where they live and what services they use.
4.1.1 V100 Duration Curve
The duration curve shows how demand changes from peak to the lowest demand half hours shown as a duration curve. If available a reference duration curve is shown.
4.1.2 Things
Things are electrical devices that you typically plug in at home, or are wired into your home's electricity supply. (e.g. a toaster)
4.1.3 Village Places
Places are the buildings in the Village like houses, flats, offices and factories etc.
4.1.4 Electric Vehicles (EV)
This is a list of available electric vehicles.
4.1.5 EV Chargers
EV Chargers are what drives demand on the system not the vehicles themselves. When and how we charge our cars matters to the grid.
4.2 Services
Services are where a villager calls on a thing that uses power in a specified period of time each day. The profile is analysed to produce the village power load in each half hour of the year.
4.2.1 Services for a Villager - Individual
Select a villager and look at the services they use.
4.2.1 Services for a Villager - Individual
4.2.2 All Services for all Villagers
Energy services for all 100 villagers
4.2.2 All Services for all Villagers
4.2.3 Energy Use by Place and Meter Type
This report looks at energy use in each place by heating and electricity load in kWh
4.2.3 Energy Use by Place and Meter Type
4.3 Profiles
Profiles are a way of thinking about how things that use power are used by villagers to provide services like making toast. Typically we make toast now and then, a toaster is not running like a generator all the time.
4.3.1 Appliance profiles
Profiles are a way of thinking about how appliances (things that use power) are used by villagers to provide services e.g. using a toaster to make toast. Typically we make toast now and then, a toaster is not running like a generator all the time.
Profiles are constructed using up to 6 blocks of demand that can specify how much power the appliance uses each half hour as a fraction of the appliance's maximum power rating and the time period being the consecutive half hours that the demand exists. These blocks can be defined for any month and any business day or non business day in any month and with five separate blocks of time as well as a baseload element. In this way demand profiles can be built quickly and accurately.
4.3.2 Meter profiles
ESO’s publish profiles for meter types. In the UK, Elexon publish profiles for each meter type: - DOM1 is the standard unrestricted domestic meter which is what most homes in the UK have, DOM2 is the economy 7 meter where prices are set for day and night, and SME 3 is an unrestricted profile for small to medium sized businesses. These profiles are used to review with the V100 demand forecast. The profiles themselves can be viewed here.
4.3.2 Electricity Meter Profiles
4.3.3 Sector profiles
Each sector from Agriculture to the Domestic sector is provided with a matrix profile and these can be reviewed here.
4.4 Village Demand
V100 adds up all the profiles of all the services used by all the villagers in the village to produce a demand forecast for the village in MWh
4.4.1 Village Energy MWh - A Year
V100 adds up all the profiles of all the services used by all the villagers in the village to produce a demand forecast for the village in MWh. The demand forecast can be viewed for any day below.
4.4.1 Village Energy MWh - A Year
4.4.2 Village Demand - Load MW - A Day
The profiles used to create demand are visible for any day.
4.4.2 Village Demand - Load MW - A Day
4.4.3 Village Domestic Demand - Load - MW - A Day
The profiles used to create demand are visible for any day. This is just the Domestic Sector (without EV's which are included in the Transport Sector)
4.4.3 Village Domestic Demand - Load - MW - A Day
4.4.4 Village Transport Demand - Load - MW - A Day
The profiles used to create demand are visible for any day. This is just the Transport Sector with EV's.
4.4.4 Village Transport Demand - Load - MW - A Day
5 Generation
5.1 Genset Inputs
Genset inputs shows all the gensets that have been used in the study, prior to any genset aggregation. The gensets are selected by availability type GSC and the aggregated genset name (AGN) is shown (an output of the result of the resolution selected see 5.2).
5.2 Aggregated Gensets
The input genset data can be very detailed with modern energy grids having many hundreds of gensets. This is too many to help in understanding the grid as a whole so pGrid aggregates generators by fuel type, availability type and thermal efficiency to produce an aggregated genset (AGG). The aggregated genset name is AGG + FuelTypeGSC +Thermal EfficiencyTypeGSC.
As part of the resolution settings, a user can determine a level of genset aggregation. Genset aggregation results in all gensets with similar technical characteristics (GSCs) being aggregated if they are below a specified size in GW. For most studies a single large genset is useful, many hundreds of small ones with the same characteristics can be viewed as if they were one big genset. The results of the genset aggregation process (AGN) are presented in this report. The gensets are aggregated depending on the minimum size selected in the resolution of the study. The aggregated genset is given a name as follows " AGN + FuelTypeGSC +Thermal EfficiencyTypeGSC" e.g. AGGG01G22 being a gas CCGT genset with a thermal efficiency GSC of 59%. The aggregated gensets are listed in order of decreasing Capacity in MW.
5.3 Embedded Gensets
A genset is 'embedded' if it's generation is included in the local demand forecast and so does not in effect generate power to the grid but reduces the load at a given grid entry point. The report is a list of all aggregated gensets showing the capacity by availability GSC that is embedded alongside the grid level generation and the total of both embedded and not embedded. Embedded gensets are disregarded if the grid scope is at the national transmission level (in the UK National Grid level).
5.4 Genset Bid Strategies
The bid strategies used for the study to increase or decrease the calculated bid prices. These then affect the relative merit order and hence load factor.
5.5 Genset Profits
The profits are calculated for any aggregated genset with the assumed revenues, expenses etc. (Excluding capacity revenues) . Genset revenues are an estimate of the contracts a genset can sign in the market (Selected by availability type and in order of descending Profit per kW).
5.5.2 System Profits
5.6 Retirements
Gensets are likely to be retired if they are loss making, this report looks at those gensets that are loss making below a threshold that can be set in the report. The report is by availability type selected.
5.7 Genset Operations
Gensets operational, running, load factor and bid construction.
5.8 Hydrogen Producers
5.9 Hydrogen Production- A Year
5.9 Hydrogen Production- A Year
6 System Operation
Electricity System Operator (ESO)
The role of the System Operator in a wholesale electricity market is to manage the security of the power system in real time and co-ordinate the supply of and demand for electricity, in a manner that avoids fluctuations in frequency or interruptions of supply.
pGrid has data for that balance for each half hour of the study year being 365 days * 24 hours / 2 = 17,520 half hours. This amount of data is difficult to work with so we sort these half hours into groups of half hour that are at the same level of system load, the peak hours go in the highest tranche and the off peak hours in the lowest tranche etc
We can choose the number of tranches we wish to have, the more tranches the more detailed the analysis, pGrid calls this resolution “granularity” and you can choose granularity of a single tranche, deciles (10) or centiles (100).
6.1 System Overview
6.1.1 Plant Margin
The plant margin shows the amount by which available capacity exceeds peak demand in any tranche. If the plant margin falls to a level of 5% or less then there is a possibility that the grid will fail and the lights will go out!
6.1.2 Tranche Results
The run results are shown by tranche, with the load and the tranche capacity which is the capacity of the plants in merit adjusted for the availability they have in that tranche. The plant margin is the percentage by which tranche capacity in that tranche exceeds peak demand.
Avail Type GSC is a short code to identify what type of capacity the marginal price was set by. The bid price is the price bid by the marginal generator. System marginal price (SMP) is the calculated price for the grid system for any tranche. Normally this is assumed to be equal to the marginal bid price which is the price bid by the marginal plant in each tranche.
6.1.3 Gas Days - Year
The gas year is presented as 365 days with the Grid Gas Demand and any reference demand data, the power station gas demand and the system gas balance is also shown.
6.2 System Details
6.2.1 A Tranche Stack in detail
Review the merit order for each plant in an individual tranche. Select the tranche from the drop down.
6.2.1 A Tranche Stack in detail
6.2.2 A Gas Day in Detail
6.2.3 Storage Asset Tranche Utilisation
The ESO calls on storage assets when the system has Free Energy - where an excess supply of renewables is available for storage and makes Storage Calls from storage assets to deliver energy when the system is short.
6.2.3 Storage Asset Utilisation
6.2.4 Gas Year Detail
6.3 Energy Storage
6.3.1 Storage Assets
6.3.2 Electricity Storage Assets Operations - A Day
6.3.2 Electricity Storage Assets Operations - A Day
6.3.3 Electricity ESO Actions
Where the Electricity System operator needs to take action to deal with a surplus or deficit of power on the grid these are summarised here. We consider a surplus of electricity available from renewable sources to be 'Free Energy', where the is a deficit this is a 'Storage Call.
Where the storage is full but we have Free Energy this is Curtailment, where we have a Storage Call but the storage assets are empty this is an 'Unstable System'.
6.3.4 Gas Storage Assets Operation - A Year
6.3.4 Gas Storage Assets Operation - A Year
6.3.5 Free Energy - A Day
7 Capacity Available
7.1 Capacity
The system will have a capacity to deliver power based on the generators and their availability. For pGrid we consider availability to be the percent of capacity of a genset that is available in any given tranche. This will take into consideration the availability of the primary fuel so for wind, for example, when the wind is blowing and the technical availability that deal with outages and breakdowns.
Availability is not affected by the bid prices and the despatch of a generator in the merit order as seen in each tranche stack.
If available a comparison is made between your pgrid run and any published capacity information. For example in the UK Elexon publishes the generation running by Primary Fuel Type. There are reports to compare these two datasets.
7.1.1 Capacity Available
A summary of the available capacity by GSC with bid prices in order of bid price (merit order). The availability figure is an annual average. The capacity available to deliver the required load in any tranche is adjusted for the availability assumption at peak for each technology. The despatched capacity is the capacity despatched at peak. Set bid price overrules any calculated bid price, if a set bid price is supplied in the genset input data.
7.1.2 Capacity References - Annual
Where annual output data is available for the scenario per generation type they are compared here with the pGrid result.
7.1.2 Capacity References - Annual
7.1.3 Historical Capacity Reference
These reports review the total installed capacity and how that produces the despatched capacity in any tranche used to meet consumer demand. The despatched capacity is the actual running of a genset. In the UK, Elexon publish these running despatched capacity figures for each half hour of the year. pGrid compares pGrid's output with this actual outturn, and a delta (the difference) between the two is also reported below.
7.1.3.1 Side by Side
Elexon publish half hourly data showing which type of generation is running. They use codes that can be aligned to GSC’s to compare to the pGrid output. These graphs show the comparison between the pGrid data derived from DUKES and the Elexon data set IF present . A delta is calculated being the difference (Delta GW), this is a key source of information to trigger a trial run to attempt a closer alignment between pGrid and Elexon.
7.1.3.1 Side by Side
7.1.3.2 Delta
The delta from above in more detail.
7.1.3.2 Delta
7.1.3.3 Delta by GSC
Compares the Elexon outturn with pGrid for a specific availTypeGSC.
7.1.3.3 Delta by GSC
7.2 Availability
The monthly availability of renewable generation to deliver power in any tranche is also considered as 'availability' where wind availability is determined by when the wind is expected to blow and solar availability is determined by the sun's irradiance. These assumptions can be reviewed below.
The utilisation of a genset is measured by load factor being the output of a genset relative to the maximum output the genset could produce with it's full installed capacity and a full year (8,760 hrs). Utilisation is affected by availability and merit order.
7.2 Availability and Load Factors
The availability assumptions used to calculate generator availability in each tranche are reviewed in these reports. The availability assumptions are input by month. For wind power there is an additional availability assumption to deal with intraday effects as it is windier in the day than at night etc.
Load factors are the percent of output from a generator as a ratio of the output that generator would achieve if its availability and utilisation were 100% i.e. if it was to produce the maximum it possibly could.
So a load factor for a generator takes into account the availability issues above and the despatch in each tranche stack on economic grounds (utilisation).
Capacity availability considers the effect of availability on installed capacity figures. The maximum a genset can produce is its installed capacity multiplied by its assumed availability to deliver power in any tranche. Availability is assumed for each genset availability GSC by month and this data is used to produce an availability by Tranche. Tranches contain time periods from multiple months as a Tranche is not time dependant but load (MW) dependant.
7.2.1 Availability - Monthly - Major Generator
7.2.1 Availability – Monthly - Major Generator
A chart showing the monthly availability of the major generators.
7.2.2 Availability - Monthly - GSC
7.2.2 Availability – Monthly - GSC
A chart showing the monthly availability of any generator using a drop down of all GSCs used in this Study.
8.0 Grid Power, Generator and Storage Prices
8.1 Power Prices
8.1.1 Grid Power Prices for the Study Year
The pGrid IPI Index for the study year can be compared with the published ICIS IPI which is an index using the demand weighted front season and second season baseload prices on the ICIS exchange weighted for demand.
8.1.1 Grid Power Prices for the Study Year
8.1.2 Grid Power Prices by Month
The reference price day ahead contract market prices are compared to the pGrid system marginal prices for the month. Elexon system sell prices are also shown.
8.1.2 Grid Power Prices by Month
8.1.3 Grid Power Prices by Tranche
For each tranche the pGrid SMP and contract reference prices are compared.
8.1.3 Grid Power Prices by Tranche
8.1.3.2 Grid Power Prices Duration
The price duration curve.
8.1.3 Grid Power Price Duration
8.1.4 Grid Power Prices by Tranche - Delta
For each tranche pGrid SMP and contract reference prices are compared in a Delta chart.
8.1.4 Grid Power Prices By Tranche - Delta
8.1.5 Grid Power Prices by Day
Report shows daily prices for a month and Business Day (BD/NBD) and half hour. Matrix price is the pGrid result.
8.1.5 Grid Power Prices by Day
8.1.6 Grid Power Prices by Day - Table
8.1.6 Grid Power Prices by Day - Table
8.2 Generator Prices
8.2.1 Primary Fuel Prices
A table of the fuel prices used by generators from DUKES.
8.3 Generator Capture Prices
8.3.1 Capture Prices
The annual average price each technology (GSC) earns in the market. If no capture price is shown then that genset class has no revenue and so capture price is not applicable.
8.4 Storage Prices
8.4.1 Storage Value
The value of 1 MW of electricity storage in diurnal operation. The storage capacity is despatched in full at the highest priced period in each day and filled to capacity in the lowest priced period in each day. The storage capacity is in MWh the number of hours a 1MW storage device can fill at maximum rate.
The maximum storage is 4 MWh being 1 MW of capacity delivered for 4 hours in a storage slot. Therefore in a day there are 8 potential storage slots (4*8 = 24 hr).
9.0 Environmental Results
9.1 Carbon Emissions including BECCS
Fossil fuel generators emit carbon to atmosphere at the emission rate shown in the report 'Thermal Plant Carbon Emissions GSC'. Any fossil fuel generator connected to Carbon Capture and Storage has a new primary fuel reflecting the rate of carbon emissions abated. Bio Energy with Carbon Capture and Storage (BECCS) is also listed.
The carbon emissions for the system as a whole are shown below.