Excess Electricity

Wind turbines and solar panels are subject to volatile natural patterns. It can be difficult to match this volatile pattern with the demand pattern. As a result, excesses in electricity can occur, especially with a large capacity of volatile production. To prevent curtailment of this excess electricity, the ETM contains several flexibility technologies that can make good use of it. You can find these options in the Flexibility > 'Excess electricity' section of the ETM. This page explains the different flexibility options in the ETM.

Checkout: the 'Merit Order' infopage for more information on how the ETM deals with volatile, must-run and dispatchable production.

Checkout: the 'Hydrogen' infopage for further explanations on the hydrogen hour calculations.

Excess Electricity#

The ETM contains several technologies to deal with excess electricity. You can decide which of these options to use first, second and so on, by changing the order of the options in the 'Excess electricity' sub-section within Flexibility. Curtailment (switchin off wind or solar panels) is always the last resort and hence locked in the last position. The flexibility options are modelled such that excess electricity is first used by the technology that is position 1. Once the full capacity of the technology is reached or its entire volume is filled (in case of batteries), any remaining excess electricity will be used by the technology in position 2 and so on.

Storage#

Storage options for excess electricity can be set under 'Storage' in the ETM. Here you can change the percentage of household batteries and car batteries that is used to store excess electricity from the grid which is then released at another moment. The specs of household batteries are documented in their node source analysis and for electric vehicles in their node source analysis. For both options you need to have installed household batteries or electric cars in your scenario in order to see an effect. You can also choose to store electricity in large-scale battery systems connected to the grid or underground pumped hydro storage.

Conversion#

Heat#

Converting excess electricity into heat is easy. At times of excess electricity supply, an electric boiler can be used to (pre-)heat water for hot water consumption. If the volume of the boiler is selected appropriately, the boiler will on average be emptied once a day, leaving it ready to convert more excess electricity. You can set the percentage of households that is equipped with a power-to-heat boiler. At the end of a merit order run, the heat generated by power-to-heat for the entire year will be subtracted from the heat demand that needs to be fulfilled by other heating technologies. The specs of power-to-heat are described in a node source analysis.

Gas#

Excess electricity can be used to produce hydrogen using electrolysis. In the ETM, the hydrogen produced by power-to-gas will be used in the transport sector (if you have included hydrogen cars in your scenario). Any excess hydrogen will be exported. You can set the percentage of hydrogen cars in the Demand > Transport > Passenger transport sub-section and change the hydrogen production method in the Supply > Hydrogen sub-section of the ETM. You can decide how many power-to-gas plants to built (their specs are documented in the node source analysis).

Import/Export#

Excess electricity can be exported to neighbouring countries through the interconnectors between these countries. The capacity of these interconnectors is limited and can be adjusted in the Flexibility > 'Import/Export' sub-section. Also, at times of excess electricity due to large amounts of solar or wind energy, neighbouring countries will most likely also have to deal with this excess electricity. To avoid unrealistic estimations of electricity that can be exported you can limit the interconnector capacity.