Our main objective is to transport electricity in a safe, efficient, reliable and sustainable way. To power homes and businesses, energy has to travel long distances across many different landscapes. This inevitably has an effect on the environment. TenneT takes measures to limit and compensate the impact of its activities on nature - in terms of landscape or biodiversity. Beyond taking measures to limit and compensate for our own carbon emissions, we also contribute to reducing the overall carbon footprint of the Netherlands and Germany by facilitating the transition to renewable energy, in line with European Union targets.
Our main environmental impact relates to carbon footprint, oil leakage and biodiversity. We do our utmost to reduce each of these impact areas.
The carbon footprint of TenneT's operations comprises carbon emissions related to grid losses, SF6 emissions and our own operations.
Grid losses are calculated as the difference between the amount of electricity entering into TenneT's transmission system and the amount delivered. Grid losses are an unavoidable side-effect of transporting electricity, especially over long distances.
Unfortunately, increased grid loss can be a side effect of renewable energy production, due to the long distances it often has to be carried (e.g. offshore).
There are limited opportunities to reduce grid losses. Therefore TenneT has purchased guarantees of origin ("green certificates") to compensate for all grid losses in the Dutch grid during 2014. In Germany legal restrictions prevent us from doing the same. During 2015, TenneT will be looking for alternative ways to compensate the environmental impact of its German grid losses.
Sulphur Hexafluoride (SF6)
Sulphur Hexafluoride ( SF6 ) is used in high voltage equipment on substations, because it is an excellent electrical insulator and in particular necessary for interrupting currents in circuit breakers. SF6 is, however, a strong contributor to greenhouse gas emissions. In 2014, TenneT developed an SF6 policy, striving to minimise usage and emission of SF6.
The SF6 leakage rate measurements in the Netherlands and Germany will be aligned starting from January 2015. In addition, we have set ourselves the ambition to reduce our relative SF6 emissions by 20% in 2020 compared to 2015. On top of that an absolute target has been set that SF6 leakage until 2020 will not exceed the 2015 level, knowing that our asset base will increase. To achieve this, we opt to build open air-insulated substations where possible, as this design requires significantly less SF6 than gas ( SF6 ) insulated substations. As from January 2015, TenneT will compensate for the carbon footprint related to its SF6 leakage.
TenneT uses oil to insulate and cool transformers at its high-voltage installations and to insulate certain types of existing, older design cables. New high-voltage cables are insulated with plastic (cross-linked polyethylene). Oil leakage can contaminate the soil and groundwater. To limit this, TenneT has a strict policy to swiftly repair leaking oil cables and cleaning of related contamination. We are looking into the option of implementing a tracer injection system that can detect smaller leaks faster. We are also investigating preventative measures for early detection of oil pressure cables leaking in large water crossings, which would be difficult to clean.
We work closely with our stakeholders to balance environmental concerns with a secure and stable energy supply. We take these concerns seriously and take steps to address them the best we can.