Innovation in practice
Innovation is essential for the continued development of a robust electricity supply system. Some examples:
Primary reserve pilot with four parties
The increase in electricity from renewable sources will introduce more need for flexibility in the electricity system and will, in time, lead to a decline in the capacity offered by fossil-fueled generation. At times, these larger power stations will be switched off. We need new solutions to cope with these fluctuations. For that reason, TenneT, together with four other suppliers, kicked off a pilot for providing primary reserve capacity using alternative technologies. We are already working on another pilot with The New Motion, involving the use of charging stations for electric cars as primary reserve capacity. We will use these pilots to assess whether other parties, i.e. apart from conventional power plants, can help provide primary reserve capacity. The four parties, besides The New Motion, participating in the pilot are ENGIE, KPN, Peeeks and Senfal. They intend to do so using methods including (control of) combinations of water pumping stations, cooling installations, CHP plants, (used) batteries, thermal boilers, solar panels and wind turbines.
We are currently conducting tests of underground HTSC cables (High-Temperature Super Conductors) that can transport three to five times more electricity than conventional cables. The results of this Dutch pilot project – the world’s longest HTSC route – will be critical for the future development of transmission capacity, especially in densely populated areas. Read more >>
380 kV cable research programme
The 380 kV cable research programme has been ongoing for a number of years now. The main goal of this programme is to answer the question: ‘How many kilometres of 380 kV underground cable can be used in the Dutch 380 kV grid?’ To answer this question, we work together with universities and research institutions to focus on topics like load flow and transient behaviour. Besides this academic approach, we are also conducting another, more practical investigation. Austria Power Grid (APG), Wiener Netz (WN) and TenneT are working together on a number of papers. These papers deal with practical topics and can be used by all parties involved. Determining the maximum feasible length of 380 kV underground cables is still a ‘work in progress’. The maximum cable length will be investigated and customized on a case-by-case basis for upcoming projects.
In our substations we use air-conditioning systems to cool our buildings, maintaining a temperature level between 5 and 35 degrees Celsius and a humidity level between 20 and 90 percent. Our aim is to reduce the consumption of energy and cooling fluids by replacing air-conditioning systems with free cooling. The use of the outside temperature, low energy costs and a low maintenance requirement results in a positive business case. If this pilot project is a success, we will investigate where replacement of other air-conditioning systems would be beneficial. Read more >>
Minimize SF6 emissions
TenneT uses SF6, an inorganic compound of sulfur with fluorine in high-voltage substations as a fire-extinguishing and insulating gas in the gas-insulated switchgear (Gas-Insulated Switchgear GIS), and to a limited extent in the air isolated systems (Air Insulated Systems - AIS) such as converters and power switches. SF6 is very suitable to interrupt high currents at high voltages. However, SF6 is the most potent greenhouse gas. Therefore TenneT does everything possible to minimize SF6 emissions, for example using a refill installation which colleagues have developed in Lehrte. Despite great care, until now during refilling, and maintenance work leakage SF6 was inevitable because of technical circumstances. To have this occur TenneT developed a modern refill installation for TenneT service groups. The new mobile filling installation consists of a trailer on which the actual refill installation with SF6-bottles is mounted. The special thing about this is that it is equipped with various components (such as a compressor, an evaporator and a vacuum pump) to suck up the gas that is left in the hoses after the refill or the suction, and to re-establish the delivery pressure without leaking SF6. So far, eight trailers are converted as specified by TenneT experts and delivered to German TenneT service groups.
One of the ways in which TenneT finances its extensive investment portfolio is by issuing so-called ‘green bonds’. This issuance programme has resulted in investments totalling 2 billion euros from parties interested in supporting sustainable projects that benefit the common good. Green bonds are an attractive way for TenneT to fund the energy transition. Read more >>