How to make room for electricity infrastructure

Grid expansion is not just limited to erecting pylons and laying cables. Over the next few years, dozens of new high-voltage substations, crucial junctions in the electricity grid, will also be erected. Engineers help TenneT with design and integration in the surroundings. 'Electricity? I never really talked about that.''No access', reads a sign screwed crookedly onto a wooden post. 'Vulnerable nature reserve,' reads the explanation above it. We are at the edge of Huis ter Heide, a nature reserve north of Tilburg that this year marks 50 years of management by Natuurmonumenten association.A little further on, at the end of the closed forest lane, we see a yellow excavator calmly turning, turning and shovelling. In recent months, pools have been dug here, fences installed and trees and bushes planted. This is how nature is created - a new ecological connection zone as compensatory nature. Because just beyond the forest edge, TenneT is putting the finishing touches to a new 380 kilovolt (kV) high-voltage substation.Transport deficitOver the next few years, grid operators such as TenneT, which is responsible for the national high-voltage grid, and regional grid operators such as Stedin, Alliander and Enexis, which supply power from the high-voltage grid to users, face the immense task of substantially expanding the electricity grid. While we are slowly reducing the use of fossil fuels, both consumption and production of electricity are actually increasing.The electricity grid is not designed for this. The maximum amount of energy it can transport is no longer sufficient. The consequences of this nationwide capacity shortage for transporting electrons are huge and affect almost everyone. From the sports club that cannot switch on the new field lights to the property developer that has to abandon the construction of an entire residential area, and from the multinational that cannot put its new production site into operation to the just-completed solar park that cannot be connected.Large consumers who need power end up on a sometimes hopeless waiting list. In some parts of the country, such as the province of Utrecht, this threatens to happen this summer even for small consumers. It will simply not be possible to add a single charging station.Het hoogspanningsnet wordt het komende decennium uitgebreid met vele tientallen hoogspanningsstations. Die vormen de knooppunten van het net: ze sluiten hoogspanningsverbindingen op elkaar aan en veranderen de spanning. Kaart: TenneTSpinder siteA year ago, the then climate and green growth minister Sophie Hermans calculated that expanding the grid by 2040 would require investments of 195 billion euros. TenneT itself has budgeted the expansion and capacity increase of the high-voltage grid alone at €160 billion (see box Higher gear ).Despite that widely shared sense of urgency, reality feels different at the Spinder site, where Tilburg's new high-voltage substation is located. 'To start this project at all, we first created a badger sett,' says Jules Rutten, environment consultancy team leader at engineering firm Sweco. 'This way, we wanted to entice the badgers to move to a slightly more northern area.'Flight routesNext it was the bats' turn. 'We had to keep their flight routes intact,' says Roel Jannink of TenneT, project manager of the high-voltage substation. 'We therefore placed trees in big bags. For the welfare of the trees, that turned out not to be such a success, but the bats survived.'And then a beaver also came along and gnawed down the bats' trees, says Martijn Elings, Antea Group's environment and energy project manager.De bouw van het hoogspanningsstation begon met de aanleg van een kunstmatige dassenburcht. Foto: Evert van Moor380 kV ringNow more than 15 years ago, the first plans and designs were made for this high-voltage substation. Even then, it was clear that bottlenecks would arise in the 150 kV grid in North Brabant.A new 380 kV high-voltage substation could provide a solution for the Tilburg region. That substation would then also be the perfect terminus for a completely new, eighty-kilometre-long 380 kV connection between Tilburg in North Brabant and Rilland in Zeeland, where power from offshore wind farms would come ashore in the future.The substation in Tilburg will also have a connection to the national 380 kV ring, the backbone of the power supply in our country, and will be connected to the 150 kV grid via underground cables to reduce pressure on the grid in the region.Fifty hectaresThe station itself measures 6.5 hectares. The tightly landscaped field, covered with sown grass, now houses three huge transformers, each weighing 350 tonnes, with room for a fourth. Four large lattice towers have also been erected: TenneT commissioned a new design, the Moldaumast, especially for this purpose (see box Mast models).However, the work involved an area many times larger than those thirteen football pitches the station is big. 'We were busy adjusting things on at least fifty hectares,' says Jannink.That had to do with the choice of location. 'There are no direct neighbours here, which ensures limited disturbance to the surrounding area. We can also connect nearby to the existing high-voltage line and there are two 150kV substations nearby, with which we can connect.'Blue locksThe site also had its share of disadvantages. The land here belongs to the former flow fields. The textile industry that brought Tilburg prosperity in the past had a downside in the form of so-called blue ditches, open sewers into which factories allowed their untreated wastewater to flow. 'We have treated the whole work as a soil remediation, with remediation and resource plan,' says Jannink. 'This is certainly one of the biggest soil clean-ups in recent years.'Jannink points to an embankment further along the new station. 'That used to be here. It is the 1995 soil clean-up.' At the time, the contaminated soil was wrapped in foil, after which a clean layer of soil was poured on top. 'We demolished the entire dyke including foil construction and rebuilt it there. A complex operation involving engineering firms, Strukton that prepared the land for construction and other stakeholders.'In this way, the soil balance remained neutral during the project: no (contaminated) soil had to be removed.'NBRkmtxNQ2gldc0b30fdb16602333c94c8d534cbf1b4cNBRkmtxNQ2gldDescendantOf_%d0dbe915091d400bd8ee7f27f0791303%_985aa9bf-df42-4856-b549-70911c11e9c2,Node_%d0dbe915091d400bd8ee7f27f0791303%_985aa9bf-df42-4856-b549-70911c11e9c2,NodeDynamicTag_%d0dbe915091d400bd8ee7f27f0791303%_5f7e504e-32b2-4408-a830-e91777b52283NBRkmtxNQ2gldNBRkmtxNQ2gldBefore the construction of the high-voltage substation and the necessary diversion of the ecological corridor, the sewage treatment plant's water storage was in the way. Photo 1: most of the effluent from the sewage treatment plant is still on the west side of the road, the large pond in the middle above. Photo 2: in phase two, the pond has already been dredged almost empty. Photo 3: in phase three, the embankment has been moved and a new electricity pylon has been erected, with the largely completed high-voltage substation in the background. Photos: Koen van Rens/Antea GroupIsolate, control, monitorJannink learned a lot from that clean-up operation, he says. Like the key terms in remediation Isolate, Contain, Control, known by its Dutch acronym IBC. The contamination is then not cleaned up, but properly packed and covered.'The soil is even better packed now than it has been for the past 30 years,' he assures. Moreover, with an aftercare plan, careful monitoring is carried out.Water storageApart from the contaminated soil, there was another problem for which the engineers had to find a solution. Right next to the high-voltage station, the De Dommel Water Board has its sewage treatment plant (rwzi) and the station would come exactly where part of the water storage of this rwzi is located. The relocation of that effluent pond, largely to the other side of the Midden-Brabantweg (N261), had a lot of problems.Along this important provincial road on the west side of the station, we pause for a moment. We look out over part of the water storage area, now enclosed by a brand-new dike. Above our heads run high-voltage power lines that pass the station rakishly, as if they had nothing to do with each other.However, the new Moldaumast is already ready to be 'looped in', in other words to be fitted with conductors and connected to the new high-voltage station. TenneT is in fact shifting the lines here a little to the north to avoid potentially risky crossings between the 150 and 380 kV grids.RecropassageThe water storage in front of us is what remains of the earlier effluent pond. A new water storage area has been built on the west and east side of the road, connected to the pond in front of us by a weir. Like a kind of drawbridge, this enables the De Dommel Water Board to regulate the water flow and determine how high the water in the storage will be.The ecological connecting structure that has now been constructed here runs right alongside it. A 'recropassage' has therefore also been constructed under the N261, a wildlife tunnel that cyclists and pedestrians can also use.Uitzicht van de kant van de Midden-Brabantweg, met in de verte het nieuwe hoogspanningsstation in Tilburg-Noord. Foto: De IngenieurFaster and fasterDuring the lengthy works, the rwzi was not out of operation for a single moment, Jannink stresses. 'I sometimes jokingly say: if we can take people to the moon, surely we should be able to build a high-voltage station at a location like this,' he says. 'But it did require constant involvement of all stakeholders and creative solutions from everyone.'Technology was not the main problem here: rather, that was the constant interplay of technology, environment, flora and fauna. 'All these things have to come together, and then everything has to go faster and faster as the project progresses. That did make it complex.'Not welcome everywhereThe station will be commissioned next year. The new nature will already be returned to Natuurmonumenten in May. With appropriately spaced pools of exactly the depth at which tree frogs thrive, and other pools tailor-made for the crested newt. But the ecologists from Waardenburg Ecology also thought about deer and roe deer, and recreationalists, although they are not welcome everywhere.'How can you combine all these requirements into an area that works,' says Rutten of Sweco. Whether it really works must then be proven in practice. 'We are constantly monitoring and keeping a logbook. With the larger interventions, such as the new pools, we can no longer shift, but if it turns out that it does not work well after all, we can decide to adjust the vegetation, for instance to create more shade.'This will be done in consultation with Natuurmonumenten, which sets great store by the new connecting zone between Huis ter Heide and the Noorderbos and Landschap Pauwels located on the opposite side of the N261.Ambitions got bigger and biggerAnyone working on such a big project must have grand plans and be full of the finest ambitions. Otherwise, it is difficult to embark at all on a process that has taken more than 15 years since the very beginning. The downside is often that once fundamental parts of the the dreamed future have to be sacrificed along the way, and more and more concessions are needed to maintain momentum, keep other stakeholders on board and ensure progress.Or isn't it? Rutten points to an initial design sketch, hanging on the wall in a construction shack. 'It is not that much different from what we have realised here now.'And concessions? 'I would rather say that the ambitions got bigger and bigger as the project progressed. On the contrary, it has become better than we dared to think at the time.' Jannink agrees. 'We are helping the energy transition and we are helping nature a bit further. Even though the latter is not our main task, we can be quite proud of it.'De natuur in de omgeving is niet geschaad, maar heeft juist een positieve impuls gekregen, zeggen de betrokken ecologen en ingenieurs. Foto: De IngenieurFriendly relationshipYet in doing so, TenneT is also acting on advice from the Board of Chief Government Architects and Government Advisors. In a report last year, the Board stated that the landscape impact of grid expansion is so great that it should be used to give landscapes a 'positive impulse'.Dozens more high-voltage substations will be added in the coming years. Even for engineers, this task offers more work than they can handle. Is that also the secret of the friendly relationship between the engineers of the different offices?'We don't actually see each other as competitors at all, says Elings of Antea Group. 'There is so much work these days that we just want to help each other and work together. That may be a very different way of working, but it is a lot of fun. Moreover, by working together so closely, you get a nice peek into each other's kitchen and that can be instructive.''Together, as one team'The relationship with TenneT is also different from the traditional relationship between client and engineering firm. 'We see each other more as colleagues. That requires trust and constant contact, but it allows us to switch much faster,' says Elings. 'Not everything has to be laid down in contract form beforehand. The employer mentioned on my pay slip is not so relevant here. We do this together, as one team'In doing so, everyone does have their own expertise and responsibilities. 'That creates a funny dynamic: we work on the same project, within the same time frame, but we don't sit around the table together that much Because even though we work here as one team, if you ask the engineers involved for their perspective on the project, you will all get different answers. Rutten: 'Throughout the entire project, not once did I think about power.'Higher gearTo speed up tackling grid congestion, new measures have been in place since the beginning of this year. Under this 'national acceleration package', grid operators who need to build new infrastructure, such as a mast or a high-voltage substation, are allowed to start preparatory works on site immediately. Although landowners may lodge objections, under the new 'automatic tolerance obligation for design work in energy projects of general interest', the grid operator does not have to wait for the outcome. It can therefore immediately start soil measurements, ecological or archaeological soil research, installing monitoring wells and drilling. However, the grid operator must inform the landowner four days in advance of the planned work.For provinces and municipalities struggling with grid expansion tasks, there is a central government 'expert pool'. Whether it is about choosing the location of new energy infrastructure, the permit process, adapting the environment plan or anything else: municipalities can hire temporary help from external experts. A sum of EUR 22.5 million is available from the Climate Fund to hire them.Mast modelsFrom left to right: Moldau, Wintrack, Danube and HammerheadRecognise the electricity mastMoldaumastTruss mast with three traverses. Almost sixty metres high and thirty metres wide, but if, for example, a (water) road has to be bridged, a higher variant is chosen. TenneT will use this model to expand the high-voltage grid in the coming years.Wintrack mastThis model, consisting of two white tubes with V-shaped insulators, was the standard between 2010 and 2020. The idea was that these 'toothpicks' would hardly stand out because of their slender shape, but because they differ so much from the earlier model, they actually do.DonaumastTruss model with two traverses. First applied in 1927 and in general use until the introduction of the Wintrack mast. The mast is generally a bit lower than the Moldaum model, but they can be found throughout the country in all shapes and sizes.HammerheadTruss model with only one traverse, easily recognisable thanks to its remarkably wide shape. Because the mast is so low, it can be placed near airports. Rarely used in the high-voltage grid in the Netherlands, and never for the transmission of 380 kilovolts.Which masts do you find on which line?Next to the new high-voltage substation, the first Moldau-type pylon was erected last summer. The new 380 kV line to Rilland in Zeeland will be built entirely from these pylons. At least 1,200 will be erected throughout the Netherlands along more than 400 kilometres of new connections. Apart from Noord-Brabant and Zeeland, the mast will be in Friesland, North and South Holland, Flevoland and Limburg.According to TenneT, thanks to its standardised and modular design, the self-designed Moldaum mast can be manufactured, transported and installed more efficiently and faster. Moreover, the mast is more durable than previous models: the new design requires less concrete for the foundation. The mast also brings more uniformity and matches existing lattice towers better than the Wintrack mast. This reduces visual fragmentation and contributes to more unity in the landscape.Moreover, the Wintrack mast, the Moldaumast's predecessor, was often considered ugly by local residents. Compared to even earlier models, such as the Danube mast designed in Germany in 1927 and the Hamerkop mast, which incidentally was rarely used for the high-voltage grid, the Moldaum mast has a relatively small electromagnetic field.KIVI seminarOn 12 May, the KIVI Departments of Electrical Engineering, Engineering and Energy Transition and Region Gelderland are organising a major seminar on the theme of Electricity System Now and in the Future. How can we meet the exploding demand for power due to far-reaching electrification? Experts from national grid operator TenneT, regional grid company Alliander, research institute TNO, Eindhoven University of Technology and energy company Essent will each give their views on the electricity system of the future from their own perspective. The seminar will take place at the Greentech Park in Arnhem and everyone is welcome. More info can be found here.

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How to make room for electricity infrastructure

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