If the system needs QC (see Frequently Asked Questions), surplus H-gas will be converted into G-gas. The 'QC meter' and related graphical or numerical retrievals provide information about the quantities of QC available and used.
The total quantity of QC is subdivided into three categories:
- QC L-gas enrichment. The quantity of QC which is used to upgrade G-gas to L-gas for exporting to Zevenaar, Winterswijk and Hilvarenbeek
- QC G-gas enrichment. The quantity of QC which is used to enrich incoming G-gas to the maximum possible Wobbe.
- QC G-gas N2. The quantity of QC (H-gas) which is converted into 'pseudo' G-gas by adding nitrogen.
How QC is actually used does not have to take place in the order indicated above. The order of use and which installations are used depends on various gas transport circumstances and optimisations in the gas transport system.
The QC meter shows the status of the amount of QC used in the past hour (in kWh). The QC meter scale runs from zero (bottom left) to the maximum possible quantity of QC (bottom right). This scale contains four colours. The three categories indicated above come first, from left to right (three different colours green). The black section shows the unused quantity of QC. A pointer on this scale shows the total used QC and this value is also shown as a number under the meter.
The QC graph shows the quantity of QC used per hour (in kWh) in the past 14 days. This is subdivided by using three colours green according to the three categories indicated above. The yellow line gives the total used QC.
The QC report above gives the QC volumes (in kWh), subdivided into the three categories. Users can choose from various aggregations (hour, day, month, calendar year and gas year) and various periods.
The GTS transport system contains two physically separate networks that are linked together by blending stations. There is a low-calorific system intended to supply exits with G-gas or L-gas and an high-calorific system for H-gas exits.
Most entries are linked directly to the G-gas or H-gas system. However, some entries lie between G-gas and H-gas in terms of quality. They are incorporated into the G-gas or H-gas system via QC or RQC.
High-quality gases are converted into lower-quality gases by means of a process called QC (Quality Conversion) .
The G-gas system regularly experiences entry shortages, while there is a surplus of gases with a higher Wobbe ( H-gas). The surplus H-gas is converted into G-gas (QC) via blending stations. The amount of QC (converted H-gas) will be shown via the ‘QC-meter’ on the QC/RQC dashboard. If there is little QC, then the H-gas can be blended at no cost with other gases into G-gas quality (this is called enrichment). If a large amount of H-gas has to be converted, then it must be converted into G-gas by adding nitrogen (this gas is called ‘pseudo G-gas’).
When nitrogen is used, the gas transport network must be controlled in such a way that the H-gases with the lowest Wobbes are the first to be transported to the blending stations. This gives the greatest capacity for conversion at the lowest costs.
The amount of nitrogen available and the level of its use are shown on this dashboard via the Nitrogen meter on the QC/RQC dashboard. This means that the maximum QC limits can be clearly distinguished by the amount of nitrogen not yet used. See more detailed information at the Nitrogen report.
Part of the nitrogen may be delivered out of a nitrogen storage. The ‘N2-storage meter’ on the QC/RQC dashboard shows the actual volume available of this storage.
The process of converting low-quality gases into higher-quality gases (H-gas) is called RQC (Reverse Quality Conversion).
Sometimes the gas transport system has a shortage of H-gas entries and a surplus of gases with a lower Wobbe. The surplus low-Wobbe gases are added to the H-gas via blending stations.
It is impossible to indicate the RQC capacity in advance, as it depends on the current qualities of all gases. The RQC capacity can be between 0 m3(n)/h and approximately 1,5 mln. m3(n)/h. The amount of use of RQC will be shown by the ‘RQC-meter’ on the QC/RQC dashboard.
As already indicated, many entries lie between G-gas and H-gas in terms of quality. In general, the QC need is high, so all these gases are converted into G-gas by means of QC. But if the QC need decreases continuously, then gradually more of these gases will be converted to H-gas by means of RQC. At the borderline, both RQC and QC take place simultaneously. It is assumed by definition that the total transport system is in RQC mode if the amount of converted RQC gas exceeds the amount of converted QC gas.
About 40 minutes after every hour the information of that hour becomes available.The ‘meters’ show the status of the last available hour. The graphs and reports show the hourly data updated to include the last available hour. The daily, monthly and yearly aggregations contain data up to and including the last complete gas day.
One of the meters on the QC/RQC dashboard is the most important, depending on the current QC/RQC status. The current status is displayed below the meters on the dashboard. The most important meter is displayed on the home page of the GTS website.
If the gas transport system is using nitrogen for QC, then the Nitrogen meter is important and will be displayed on the home page. If no nitrogen is used but the transport system is still in QC-mode than the ‘QC-meter’ will be displayed. If the transport system is in RQC-mode than the ‘RQC-meter’ will be displayed.