Pardon my trench: reflections on the uptake of trenchless technologies in the Norwegian water sector

The Norwegian water infrastructure is ageing, and consequently facing an increasing renewal and rehabilitation need (RIF 2021), as is the case for many other countries in the industrialised world (Abebe & Tesfamariam 2020; Kaushal et al. 2020). The national renewal rate for drinking water and sewer pipes in Norwegian municipalities (Statistics Norway 2021a, 2021b) has been lower than recommended (Aas et al. 2016; Bruaset 2019) for several years, with a near-flat trendline. Consequently, the backlog in pipe renewal is increasing.

Budgets for renewal of ageing pipe infrastructure represent the lion's share of the expected future costs for Norwegian water systems managers, and the current reinvestment need is estimated to be 195 billion Norwegian Kroner by 2040 for Norwegian water and wastewater pipes (Bruaset et al. 2021). Considerable costs for pipe infrastructure rehabilitation is also expected elsewhere, e.g., in the USA and Canada, where 271 and 61 billion dollars, respectively, are expected investment levels needed to upgrade water, wastewater and sewer pipes in poor condition (Francisque et al. 2017; Abebe & Tesfamariam 2020). Water managers are furthermore expected to transition towards a more sustainable management of their systems, e.g., by using rehabilitation techniques with lower carbon footprints, which often favours trenchless rehabilitation (Fuselli et al. 2022). At the same time, their systems are subject to increasing demands in terms of level of service (capacity, reliability, etc.) triggered by external factors (e.g., climate change and urbanisation), exasperating the need for continuous system renewal and upgrade. Effective technologies for renewing pipe infrastructure are therefore paramount for achieving a sustainable management of urban water systems.

Trenchless technologies can in many cases be a highly effective means for renewing pipes, in terms of cost, environmental impact, and time needed for planning and execution (Jakobsen et al. 2010). They can also contribute to minimising service disruptions of adjacent infrastructure, e.g., traffic and public transport (Daulat et al. 2022), because of the reduced trench volume and quicker execution time, compared to traditional open-trench solutions. Trenchless solutions can be particularly beneficial in cold climates (such as in Norway), since pipes often are buried deep (>2 m) to avoid frost problems, and open trenches consequently need to be deep and wide, triggering the need for large volume displacement and a large trench footprint on the surface. They are even more beneficial in terms of construction time during the winter months when the ground is frozen and therefore difficult and time-consuming to cut open.

Yet, the experience is that the uptake of trenchless technologies is limited in the Norwegian water sector, and its market share is still low. Only approximately 12% of the water distribution and 20% of the wastewater network is currently renewed using trenchless technologies in Norway, and only 25% of the municipalities report that they apply trenchless technology (Krogh & Rostad 2019). Bruaset et al. (2017) looked at the application of no-dig in five large Norwegian municipalities and found that no-dig is applied to a varying degree, from 5 to 50% of total rehabilitated length. Mostly the larger municipalities apply no-dig methods, while the smaller municipalities use such methods to a lesser extent or not at all. The four largest municipalities in Norway apply 20–40% no-dig in rehabilitation of water pipes and 40–80% no-dig in rehabilitation of wastewater pipes, according to a survey performed among project partners in the Norwegian research project B for VA-nett (SINTEF 2020). This is cost-related, since the excavation cost is correlated to the degree of urbanisation, but it is also connected to the perceived risks associated with taking up new technologies. The techniques most frequently used in those municipalities are pipe bursting and sliplining for drinking water pipes, with some use of Cured In Place Pipe (CIPP). Sliplining is mostly selected when the cross-section of the pipe can be reduced, with regards to capacity. If not, pipe bursting is the preferred method. For sewer pipes rehabilitation, CIPP is mostly used, but there is also some use of pipe bursting. These methods are applied because the municipalities have good experience with them for their designated purpose and therefore perceive the risks of application to be low. All municipalities of the B for VA-nett project have a desire to increase the use of no-dig renovation, given the methods applied provide satisfactory results. Good documentation and dissemination of successful pilots will be important to meet these requirements. One municipality would like to use no-dig in all projects when and wherever it is possible, which is mainly if separation of existing combined sewers is not part of the project. The reason that the municipalities would like to implement more no-dig in rehabilitation is that the solutions are more cost-effective, they are less inconvenient for the surrounding areas, and that they generally produce less greenhouse gas emission per rehabilitated unit. In order to increase the use of no-dig, there are some barriers that have to overcome: (i) the need to excavate at service connection points to connect to the main implies that no-dig is not a fully trenchless technology (many service connections lead to a lot of digging), (ii) trenchless methods are not good at handling a change in diameter, (iii) a need for increased knowledge in the consultancy sector about available no-dig technologies and the possibilities in the combination of rehabilitation approaches, and (iv) no-dig technologies availability for pressurised pipes must be improved.

Such barriers to project implementation and execution may explain some of the factors hindering the use of trenchless technology in pipe renewal. These barriers occur throughout all phases of a project (Zidane et al. 2015). The project management institute (PMI) defines a project as a temporary endeavour undertaken to create a unique product or service (Samset 2015). Project organisations are temporary administrative systems, for instance a pipe renewal project. Skaar et al. (2023) found that the most barriers to pipe renewal occur in the front end of projects and are related to organisational and project-related factors, impacting the choice of technology for pipe renewal. These choices will be a root cause for installing solutions that will act as technical barriers in later pipe renewal. They found that the one of the most significant barriers to pipe renewal in Norwegian municipalities is related to lack of resources, and in consequence available time spent on each project and the ability to coordinate with other infrastructure stakeholders. Furthermore, the lack of resources will impact the municipalities opportunity to build and develop competence related to pipe renewal and trenchless technologies. Larger municipalities have more resources available and will therefore be better rigged to use a variation of technology for pipe renewal.

Turnpenny et al. (2008) defined constraints when assessing administrative systems at macro-, meso-, and micro-levels. The macro-level covers the broader context, including the network of stakeholders and administrative aspects of a project. The meso-level covers organisational norms and culture, procedures for coordination within an organisation or across different organisations, and political leadership. In a project context, project governance may parallel political leadership. The micro-level assesses resources in the organisation. This includes the availability of human resources, time and funding, and competence related to human resources. Findings from Skaar et al. (2023) identified that these organisational mechanisms are found in the municipal pipe renewal.

Nykvist & Nilsson (2009) used a three-level analytical framework containing these definitions to analyse barriers in the three levels of the Swedish committee system in policymaking. They found a lack of coordination between resources and committees, knowledge, and lack of key personnel as important barriers. Grahn et al. (2021) used interviews and workshops to identify barriers to value specification in digitisation projects and found limited knowledge in among other specifications, measurement and evaluation as a barrier, and limited resources to do the specification for the projects.

Typical barriers to using and applying tools and technology in infrastructure may be categorised and grouped into a framework to differentiate them and better analyse them. They may be sorted in the framework based on the general properties of the barriers (Yee et al. 2017), a part of an infrastructure system (Grigg 2019), or a part of a process (Ullah et al. 2019; Purup & Petersen 2020).

The aim of this paper is to gain a deeper understanding of why the market share of trenchless technologies is at the current level and identify factors enabling and hindering trenchless technology uptake in the Norwegian market, and furthermore gain insights in the motivation of the individual stakeholders. This is done by addressing three research questions pertaining to the uptake of trenchless technologies in the Norwegian water infrastructure market:

• (1) How do the different actors choose the appropriate renewal method in water and wastewater renewal projects, and which criteria are most important for them to consider?

• (2) How can the choice of project delivery method (PDM) and contract type affect the prevalence of trenchless technology application?

• (3) How can the available trenchless technology solutions increase their market share in the water industry?

To answer the research questions (in Table 1) and establish an overview of the current perception of obstacles and opportunities for the uptake of trenchless technologies in the Norwegian water industry, a series of semi-structured, in-depth interviews with the three most important stakeholder groups was performed:

• 1. The municipalities (three utilities), who own and manage the pipe systems.

• 2. The chartered engineers (two consultants), who are hired by the utilities to plan the rehabilitation projects.

• 3. Three contractors, who execute the rehabilitation projects planned by the consultants.

Semi-structured interviews (Magaldi & Berler 2020) were chosen, as the aim of the study was to gain a deeper understanding of the motivations of the individual stakeholders, building on the findings from surveys uncovering general barriers and drivers for trenchless technology uptake (Skaar et al. 2023). As such, the semi-structured interview allows for focusing on a core topic, but at the same time discovering information depending on the respondent's answers (Magaldi & Berler 2020). The interviews were performed as part of a MSc thesis (Borgen & Røgenes 2020), and the interview preparation, guide (interview protocol), interpretation, and analysis was made in accordance with Dilley (2000), Magaldi & Berler (2020), and Adeoye-Olatunde & Olenik (2021).

One limitation of the study is that only larger utilities were involved in the interview process. This had several reasons. First, those were the ones with the most insight into the technology and experience using it. Second, in Norway, they usually ‘lead the way’ in technology uptake, as they have more capacity to adapt to new knowledge. This becomes apparent when one looks at involvement in research and development projects, as it is usually the larger utilities that partake. Knowledge and experience are subsequently often shared through forums in interest groups. Finally, it is also more probable to encounter a ‘champion of change’ (Taylor 2009) in such a utility, taking a leadership role in implementing and advocation for novel technology. A lighthouse project for such an endeavour was the RENVANN project, which was an innovation project aiming at increased efficiency in drinking water pipe renewal in Norway, hosted by Oslo and Trondheim municipality, two of the largest municipalities in Norway (trondheim.kommune.no 2023).

The interviews were conducted using a semi-structured interview guide, containing a set of complete questions, all written down before the actual interviews were performed (see Table 1). The written interview questions were sent by email to the interviewees beforehand, thus allowing the interviewees to prepare their answers. The interviews were all performed in Norwegian (the mother tongue of all interviewers and interviewees), allowing the participants to be precise in their answers and argumentation, with minimal language barriers and hindrances of translation. Answers are subjective, but since different actors have been interviewed, one can assess the credibility of the answers by ‘triangulation’ (Friberg 2019).

The interviewees have been kept anonymous. The anonymity contributes to the interviewees ‘speaking their minds’ when answering the questions, without risking negative reactions from other stakeholders who may disagree with their opinions. Due to the COVID-19 outbreak and consequent travel restrictions, the interviews were carried out as teleconferences, all of which were recorded with the permission of the interviewees. The interviews were transcribed and sent to the interviewees for corrections afterwards.

All interviews were transcribed verbatim in Norwegian and included in Supplementary Appendix A. The transcripts have been included in Norwegian, as they were performed in Norwegian. The main points of the interviews are highlighted and discussed in this result section. Factors hindering the uptake of trenchless technologies in the Norwegian market identified are:

• Market conservativism, both with regards to application of novel technologies as well as project organisation, is mentioned by several respondents. The Norwegian utilities seldomly have anything to gain from taking a risk as no incentives exist. The risk of underinvesting is low for the stakeholders involved, because of the long timespan before the consequences of underinvestment become apparent (van Riel 2016), the utilities neither experience gains nor losses because their budgets are constrained by full-cost recovery, and the pressure for innovative solutions to increase efficiency is consequently low as well.

• Several interviewees expressed that there is a lack of trust in the market. On the one side, the contractors are reluctant to invest in new equipment necessary to enable implementation of more trenchless technology projects, because they fear that the utilities will not tender projects requiring said equipment to a degree sufficient to justify their investments. On the other side, the utilities are discouraged by the lack of innovation from the contractor side and their experience that the contractors' main goal is profit and not always function as an ‘honest broker’. In a conservative market with a low level of trust, the consultants tend to suggest only tried-and-tested solutions, avoiding innovative technologies that may leave them exposed to litigation in case of project failure. Another perspective is that there is possible friction between technology providing contractors who are ‘overselling’ to a conservative market, implying that their solutions are suitable in ‘all’ projects, when the market experience is that they are not.

• The distribution of (economic) risk. By default, the proprietor carries the economic risk of unforeseen circumstances in the construction phase. Uncertainty about soil conditions is considered the biggest risk when applying trenchless solutions. During the interviews, it became clear that some contractors are interested in carrying the risk of the soil conditions. However, this usually entails a significant price increase (uncertainty premium). This situation tends to emerge in markets where the contractors have a strong price competition with diminishing profit margins – accepting to carry the risk of soil conditions entails a potential for a significant monetary gain (unless there actually are problems with the soil conditions). Moving the soil condition risk to the contractor will usually be costly for the utility. The utilities usually have a superior economic solvency compared to the contractors – transitioning the risk of soil conditions to the contractors should therefore be considered with care, as it may also lead to bankruptcy of the contractor.

• Missing knowledge and resources in the utilities. Three hundred and thirty-seven of the 356 municipalities in Norway have less than 50,000 inhabitants; the water utility managers in the smaller municipalities usually must be ‘jacks of all trades’, with limited capacity to specialise themselves in, e.g., novel rehabilitation techniques. It is difficult to enable innovation and novel technologies to system proprietors which are not up to date especially in a low trust market environment. Larger municipalities can specialise more, which is reflected in their relatively advanced uptake of novel technologies.

Factors identified that can potentially enable the uptake of trenchless technologies are:

• Several respondents highlighted the important role of the consultants that are hired to make the plans for rehabilitation projects. A knowledgeable consultant is considered a key prerequisite for choosing the appropriate rehabilitation technique when the plans are being made, especially when working for the smaller utilities which have limited knowledge on the subject themselves. Under ideal conditions, the consultant also acts as a knowledge bridge between the contractors and the utilities. However, the knowledge about trenchless technologies is varied within the Norwegian consultancy market and highly dependent on the experience of the personnel at each specific consultancy office. There is also a regional aspect to this, as the consultants in the larger cities usually have more experience with trenchless technology, compared to the smalltown consultancy offices. Knowledge acquisition and distribution among the consultancy offices is therefore identified as a key enabling factor for trenchless technology uptake.

• The project delivery method (enterprise form) and choices made in the tendering process are stated to have a high impact on the outcome of a rehabilitation project, and the choice of the technologies applied. Several interviewees stated that traditional project delivery methods (e.g., design-build or design-bid-build contracts) can hinder the exchange of ideas because of the lack of interaction between the stakeholders (proprietor, consultant, and contractor). Oftentimes, the consultant may suggest a technology in the design phase that the contractor later advises against (due to technical or economic considerations) in the building phase. This lack of interaction leads to a suboptimal utilisation of each stakeholder's expertise, which can lead to inappropriate design solutions. The use of alternative project delivery methods, such as partnering contracts, are viewed by the interviewees as a potential means for achieving a more flexible planning and execution of projects, enabling the appropriate choice of technology for each specific project.

• Issues with the tendering process itself were also raised. The experience of the interviewees is that the project cost criterion often overshadows other criteria (e.g., quality and experience of contractor) when traditional scoring methods are applied, even if project cost is only moderately weighted, because the bids often have a high range in the cost criterion.

When identifying barriers, it is natural to seek opportunities. The construction industry is dynamic and thus open to various opportunities (Bayhan et al. 2019). Trenchless technologies may reduce costs, installation time, impact social benefits, and emissions in pipe renewal compared to open-trench methods (Kaushal 2019; Kaushal et al. 2020; Kvitsjøen et al. 2021).

Through a series of interviews with central stakeholders, important factors influencing the uptake of trenchless technologies in the Norwegian water market have been identified. The factors have been categorised as either hindering or enabling factors, according to the interviewees' perception of the status quo. This categorisation is not static, and may change, depending on how the market evolves in the future. For instance, if the issue of trust were resolved, it would of course be changed from a hindering to an enabling factor. Based on the identified factors, a set of recommendations for improving the market conditions for trenchless technologies may be suggested:

• The issues of conservativism and lack of trust may be resolved by stakeholder-independent trade organisations. An active role from a trade organisation, stimulating a balanced dialogue, could help resolve the friction between the stakeholders, and at the same time raise awareness about the consequences of underinvestment. One of the possible problems may be the friction between a technology providing industry which is ‘overselling’ and a conservative market. The conservatism was one of the main discussion points brought up by the interviewees and pertains both to the uptake of specific technologies but also the way in which projects are carried out.

• Knowledge creation and maintenance among utilities and consultants can partly be undertaken by trade organisations, but cooperation between smaller, rural utilities is recommended, to allow them to pool resources, thereby enabling them to specialise more and focus on novel technology implementation.

• The utilities must increase their focus on careful design of the award criteria and evaluation method, ensuring that the tendering process reflects the requirements of their project, and that the price criterion does not disproportionately overshadow other criteria. This, in combination with choosing the correct PDM, is regarded as key success factors for a pipe rehabilitation project. Best practices/industry standards on how to distribute risk among stakeholders should be made and followed.

The interviews referred to in this paper were performed as part of E.O. Borgen's and H. Røgenes' M.Sc. thesis, and the authors would like to thank H. Røgenes for his contribution. The authors also thank all who participated in and contributed to the interviews. A part of the research presented in this paper has been financed through The Research Council of Norway's project RENVANN (project number 310749).

All relevant data are included in the paper or its Supplementary Information.

The authors declare there is no conflict.