Triple test in Geneva

Implenia is testing out the construction site of the future at its Pont-Rouge ­project. A whole series of new ­approaches designed to make ­construction more efficient are getting a thorough workout in Geneva’s Lancy district. We report from a construction site that lies on the very edge of ­Switzerland, but right at the heart of Implenia’s philosophy.

Read the reportage

Respect for the environment

Implenia has set itself ambitious environmental targets. The company is particularly keen to increase its energy efficiency and in so doing cut its greenhouse gas emissions and resource consumption. Implenia uses a tailor-made system for systematic monitoring of its environmental performance.

What we achieved in 2014 / 2015

Our goals for 2017

  • We are reducing Implenia Switzerland’s sales-ad­justed CO2 emissions by 5 percent.
  • We are recording inter­national CO2 emissions and initiating operational reduction measures.
  • We are using electricity from hydropower and offsetting power taken from non-renewable sources as well as aircraft emissions.
  • We are establishing a standardised environmental concept for construction sites and carrying out group-wide environmental protection training courses.

­4.1Certified environmental management

Implenia has created a data capture system tailored to its activities so that it can monitor its environmental performance. The company uses a customised set of indicators to record its main energy and material flows, from the extraction of raw materials to the finished structure. However, the system only captures those values that the company can influence itself, i.e. the ones where it has operational management of the processes concerned. The data recorded for greenhouse gas emissions is exclusively from business activities in Switzerland. Data from international locations is not included.

Implenia started this systematic recording of environmental data in 2011. Since then, data has been recorded for production facilities, workshops, office premises, building sites and development projects, as well as for transportation and paper consumption (see data recording matrix). Since 2013 Implenia has used a web-based tool to record the figures. This software allows Implenia to capture data continuously from various sources and show it in real time, as well as to generate specific analyses to help monitor outcomes.

Implenia still isn’t where it wants to be in terms of regional detail, so it has started to carry out comprehensive recording at selected individual building sites engaged in different types of work. Total energy and resource flows, including waste, have thus been recorded at several pilot sites engaged in surfacing, building construction and tunnelling. Results from these pilot sites should help Implenia identify exactly where and how it is having a significant impact on the environment.G4-22

Data recording matrix

4.2Reducing energy consumption and climate-damaging emissions

­­Implenia uses approximately 171 gigawatt hours of energy each year. The company’s biggest energy source by far (final energy) is the diesel it uses for machinery, commercial vehicles and passenger cars. Next come fuels such as natural gas and heating oil that are used for process heat in the surfacing works. Total energy consumption as a percentage of revenue has fallen slightly in recent years.

Implenia is trying to optimise its energy consumption and use the cleanest possible energy sources. In the previous reporting period, the company commissioned a study to look into buying green electricity. As part of the study, external specialists analysed the purchase and origin of electricity used at Implenia production facilities and properties with annual consumption of more than 100 megawatt hours.

Based on the analysis, Implenia decided that from 2014 the largest consumers of electricity – two office buildings, three workshops and a production facility – would only buy electricity on the open market that comes from hydroelectric power stations. At other locations where it is tied to local providers, Implenia decided to offset all electricity from non-renewable sources with hydroelectric certificates.

In 2015 Implenia launched another pilot project to look at electricity consumption at its construction sites. The idea was to switch the electricity mix at sites that consume more than 100,000 kilowatt hours of electrical energy to certified hydroelectric power. The company examined 26 major project sites within the Infrastructure and Tunnelling business. Analysis showed that only 5 projects fulfilled the criteria: most of the sites either required less electricity, or were provided with electricity by the client. Of these 5 qualifying sites 2 already use 100% renewable electricity, while the electricity mix at another 2 is already heavily skewed towards renewables.

This left just one construction site, the Galgenbucktunnel in Schaffhausen, which thus became the focus of the pilot project. The Galgenbuck site previously took its electricity from non-verifiable energy sources, including brown coal and other fossil fuels. Implenia switched the site over to Swiss hydroelectric power (with proof of origin) and as a result is saving around 300 tonnes of CO2 over the remaining construction period.

Implenia is also producing its own electricity in some places: since 2012 the company’s two workshops in Satigny (GE), and Vétroz (VS) have had solar roofs. During the period under review a new photovoltaic system was installed on the roof of the Claie-aux-Moines gravel plant near Savigny (VD). Two new systems were also installed at the beginning of 2016 at the workshop in Echadens (VD) and the refurbished surfacing works in Ecublens (VD). The solar power systems running during the reporting period together generate more than 430,000 kilowatt hours of green electricity a year.

Most of the fuel Implenia uses for vehicles, machinery and heating is from fossil sources, so the company’s greenhouse emissions profile is similar to its energy consumption profile. More than 80 percent of all emissions are generated by building sites, workshops and surfacing, concrete and gravel plants, i.e. by construction operations. Most of this is from engine fuels like diesel and petrol. Around half as many emissions come from the fuel used for heat production (oil and gas). Finally, electricity consumption only makes up 5 percent of Implenia’s greenhouse gas emissions, not least because it prioritises hydroelectricity.

The greenhouse gas emissions recorded in this report include direct emissions from the operation of our own construction machinery, lorries and heating at production facilities and workshops, (“Scope 1”), as well as indirect greenhouse gas emissions from networked energy like electricity (“Scope 2”). Other indirect emissions within the up- or downstream process chain (“Scope 3”) were analysed using benchmark figures. This showed that the procurement of construction materials was the most important indirect source of emissions, followed by the subsequent use of the buildings Implenia constructs. These two sources account for several times the volume of Scope 1 and 2 emissions, and are therefore very significant. However, Implenia’s influence on these processes is often small.

In 2013 Implenia set itself the goal of a 10 percent reduction in greenhouse gas emissions per franc of revenue by 2017. Measured against revenue, the company has so far managed a reduction of 1.2 percent. This corresponds to an 8.2% absolute cut in greenhouse gas emissions. Implenia thus failed to achieve the average revenue-related reduction target of 2.5 percent per year, but it is confident that it will hit this target in the next few years. Measures such as the refurbishment of the Trois-Ponts surfacing plant in Ecublens (see box), the switch to hydroelectricity and the installation of solar energy systems will facilitate a continued annual reduction in greenhouse gas emissions and help the company achieve its goal.

Other measures initiated during the period under review include the rule that greenhouse emissions caused by employee flights must be offset by climate protection projects managed by the myclimate foundation (see Mobility chapter). In addition, the share of electrical energy sourced from fossil fuels was offset by purchasing proof of origin certificates for hydroelectric power.

Paper consumption, Implenia Switzerland

4.3Economical use of resources

Alongside energy consumption, the use of building materials is one of the main factors in the construction industry’s impact on the environment. Consequently, Implenia’s target is to close its material cycles and recycle as much as possible. On various sites the company has come up with project-specific ways of saving, processing and reusing building materials.

Falling paper consumption

­The environmental impact of paper consumption is comparatively low in construction companies. However, paper usage has a symbolic status in an office environment, so Implenia measures this too. It is pleasing to note that overall paper consumption at the company has trended downwards in recent years, and the proportion of environmentally certified paper has risen to almost 100 percent in recent years (see chart).


The mobile gravel production plant in Oberwinthur saves transportation, time and landfill space, as well as cutting emissions.

4.3.1Mobile concrete and gravel processing plant in Oberwinterthur

Implenia installed a pilot plant for concrete and gravel processing in Oberwinterthur two years ago. Daniel Hardegger, Head of Region East, is pleased with the results of the recycling project so far: “Excavated material is washed and processed to make concrete on site, and then used for the project itself, so we save on transport, time and landfill space, as well as cutting emissions. This pilot system has proved itself economically and environmentally, and should become standard at similar Implenia construction sites. The overall costs were a little lower than predicted. A total of 8,500 tonnes of gravel was saved across the three neighbouring construction projects. The original advance calculations suggested that 775,000 litres of diesel and 2,300 tonnes of CO2 would be saved during the construction period. These targets were not quite achieved because of delays in the opening of the processing plant. However, we are extremely pleased with the benefits that on-site recycling has brought us.”

4.3.2Ecublens surfacing plant renovated

Making asphalt requires a lot of energy. In fact, the plants where Implenia makes asphalt and related bitumen-based products accounts for more than a fifth of the company’s total greenhouse gas emissions in Switzerland. In 2015, Implenia renovated its “Trois-Ponts” production facility in Ecublens in order to ensure employee safety, improve the quality of manufacturing processes, and increase production capacity. It also optimised the plant’s environmental performance. The bitumen tanks were replaced and now have much better thermal insulation. Conveyor belts were upgraded and coordination between the belts was optimised.

The new facility’s sustainability credentials have been greatly enhanced by the fact that it can now use old asphalt as a production input. A second production line was set up to handle this recycled material. In 2015, the plant was already able to cover more than 20 percent of its requirements with recycled material, and this percentage is rising all the time. The recycling process requires a higher temperature, however, which releases more pollutants. To ensure that emissions are nevertheless lower, a more powerful carbon filter has been installed. Thanks to this, the plant has the lowest air pollution levels of any asphalt producer in of the whole of Switzerland, coming in below the very strict emissions thresholds imposed by Canton Vaud.

The refurbishment of the plant has led to an overall reduction in greenhouse gas emissions of around 15 percent. Over the next few years, further measures will reduce emissions even more. For example, a 2,500 m2 photovoltaic array started operating in 2016 and produce more than 300,000 kWh of electricity a year, 150,000 kWh of which Implenia will use on site.

Nant de Drance, one of Europe’s most powerful pumped storage power stations, goes on line in 2018. Implenia used a sustainable type of concrete for the construction.

4.3.3Nant de Drance – generating renewable energy

High in the mountains of the Lower Valais one of the most powerful pumped storage power plants in Europe is scheduled to go on grid in 2018. The plant uses the height difference of nearly 400 metres between two existing reservoirs, Emosson and Vieux Emosson, to generate 2.5 billion kilowatt hours of electricity each year, with a peak output of 900 megawatts. For this complex and challenging construction project, Implenia has teamed up with Marti AG to form the GMI consortium.

The two firms have been working together on this complex infrastructure project since 2008, often in very cramped conditions. Around 1.7 million cubic metres of rock have been excavated to make the 17 kilometres of tunnels. A fifth of this rock was broken up directly on site to make concrete, so there was no need to bring material all the way up from the Rhone Valley. The project also set new standards by incorporating the very latest findings into its choice of concrete and preparation methods.

The dam wall, the lining of the caverns and tunnels, and the road surfacing required half a million cubic metres of concrete in total. Concrete technologist Jürg Steiner and his team found a clever way of meeting this need by using self-compacting concrete (SCC) for about a quarter of the total quantity (142,000 cubic metres). SCC is compressed by its own weight, meaning that workers are spared all the additional labour that would be required for conventional vibropressed concrete. As well as pioneering their work on the logistics, the Nant de Drance builders were ahead of the curve on sustainability, succeeding in their desire to establish the new power station as a beacon project.


Most of the environmental benefits came from the type of concrete used. Around 300,000 cubic metres of concrete were made using a particularly environmentally friendly CEM II cement, which uses an admixture of slate and slag sand rather than energy-intensive Portland clinker. This choice reduced CO2 emissions during production by 21 percent, thus saving almost 25,000 tonnes of greenhouse gas emissions. Another 4,700 tonnes of COwere saved by using rail transport for most of the cement and additives. On the other hand, more fly ash was needed to mix with the SCC, which resulted in additional transport-related emissions of around 3,000 tonnes of CO2. Nevertheless, there was still a total net saving of more than 26,000 tons of CO2.


The use of self-compacting concrete made for much better working conditions and significantly improved safety for construction workers. With SCC there is no need to use poker vibrators to compact the high walls, for example. As a result there is less physical stress, less risk of falling from exposed sites, less back pain, fewer hours lost and less risk of the circulatory condition known as vibration syndrome. Another health benefit was the significantly lower dust pollution compared with the compaction of conventional vibrated concrete. Noise pollution, which can reach 115 decibels with conventional compaction, was also much lower, making the process less mentally stressful for workers. All in all, the innovative concreting process reduced the risk of illness and increased productivity accordingly.


The notable flow properties of SCC compared to conventional vibrated concrete also make it a financially attractive option. It puts much less stress on the pumps and pipework, thus extending the life of the whole pumping system and reducing maintenance and repair costs. The lower pumping pressure also saves energy, and there is no need for the compressed air supply that a vibrator would require. Nor is there any need for expensive concrete finishing work, which can also be problematic in terms of quality, because SCC dries out smooth and virtually pore-free. Finally, thanks to the greater fall height of SCC, fewer filling stops are needed, which once again means that fewer workers and fewer framework elements are required. SCC can be a little more expensive to make than conventional concrete, and it does need more extensive process controls and, in some cases, a higher standard of formwork. However, the overall economic advantages are clear. In the case of the Nant de Drance power station, total project costs within the chosen system limits were 14 percent lower, even before the reduced lifecycle and repair costs are taken into account.

Thanks to the use of a gravel recycling machine, the old foundations can be reused, reducing the need for new gravel

4.3.4Closed material cycles at Birmenstorfer Chrüz

The municipality of Birmenstorf in Canton Aargau suffers from high levels of traffic. At peak times in particular, queues of vehicles stretch out along the highway towards Fislisbach and Baden. A new roundabout is being built to ease the problem and get the traffic moving more quickly. With a budget of 7 million Swiss francs and a construction timetable of about two years, it’s not the size of this refurbishment and new build project that makes it remarkable. In terms of sustainability and the use of closed materials cycles, however, it is setting new standards.

IIn a closed material cycle, used raw materials are processed and recycled for the same or a similar function, so fewer new raw materials are required. Appropriately for a roundabout job, the Birmenstorfer Chrüz project is creating two such circular systems: the material excavated to make way for cabling and drainage pipes is being processed on site and reused, as is the gravel from the old foundations.

The standard process in Switzerland is to cover cabling and drains with expensive new gravel and take the spoil away to the nearest landfill site. Birmenstorf is close to both a landfill site and a gravel works, so it would have been very easy to use this traditional approach, but for various reasons project manager Alexander Stritt decided to do something different. By re-using the excavated spoil and gravel, he avoided transport-related delays, made it easier to keep to the timetable, and reduced the cost of disposal, transport and new gravel. All that was needed to make this plan work was the relevant specialist skills, sufficient storage space and the consent of the client. Canton Aargau was very positive about the closed material cycles because they fit perfectly with the canton’s environmental strategy, and because landfill capacity is scarce in the region. Ultimately the closed cycles also allowed Implenia to offer the client a retrospective discount.

Only the clay-rich spoil presented Alexander Stritt and team with a real technical challenge. Around 4,000 cubic metres of spoil had to be mixed with 100 tonnes of lime to ensure that it would compress enough to bear loads of around 30 meganewtons. The lime was brought 260 kilometres by lorry from Freiburg and then mixed in on site.

By recycling the spoil in this way, the project saved around 44,000 francs, or 26 percent, compared with the standard method. Buying and transporting the lime was much cheaper than the costs that would have been incurred for taking the spoil to landfill. Re-use of the gravel brought a saving of 166,000 francs, or 64 percent. Using recycled material from the site was therefore considerably cheaper than buying in new gravel.

The innovative approach also significantly reduced CO2 emissions. The use of recycled spoil and gravel saved a total of 28.6 tonnes of CO2, and also saved on landfill space. The Birmenstorfer Chrüz project is a good example of how an innovative approach can pay off financially and environmentally, with benefits for everyone involved. The key is to deliberately question and reconfigure standard procedures.

The old bridge piers on the E16 Rud – Vøyenenga highway in Norway are not being thrown away but have been given away to a new user. The new bridge piers were built in March 2016.

4.3.5Recycling old bridges (Norway)

Four concrete bridges need to be replaced as part of the work being done on the E16 Rud–Vøyenenga highway in Norway. Instead of just demolishing and throwing away the four old and apparently obsolete concrete bridges, Implenia has found a new use for them. The bridge piers were offered for free on one of Norway’s most popular online market places –

The unusual advert even caught the attention of the Norwegian construction industry’s largest trade magazine,, which featured an article about the “free bridges” on its website and interviewed site manager Henning Holand: “There has been huge interest. We’ve received around thirty inquiries from private individuals, several clubs and associations, and the army.” The bridges were finally given to the Norwegian ski resort of Uvdal, where they will be erected across the downhill pistes in 2017 and 2018.

The bridges, between 40 and 80 metres in length, will be removed from their original locations in winter 2016 / 17 and winter 2018 / 19. Implenia is responsible for dismantling them, while the new owner has to arrange for them to be taken away. Implenia will therefore save on transport and disposal costs. Project manager Dan Granerud explains that it was purely economic considerations that originally prompted the offer. “The recycling and reuse is, of course, a very welcome side effect. It’s interesting how often economic and environmental benefits complement each other,” says Granerud. “When we sharpen our environmental focus, we often find that profits go up too.” It’s always worth checking whether materials or individual components can be reused, even if it takes a bit of lateral thinking.

Meanwhile, scaffolding is already going up next to the old bridges. Two new bridges are being built there, each 94 metres long and three lanes wide.

4.4On-site environmental protection

Implenia is currently testing its in-house “Environmental concept for construction sites” on various pilot sites in Zurich, Geneva and Aarau. Group-wide introduction of the concept is planned for the forthcoming reporting period. The ultimate aim is to standardise environmental protection measures on all of Implenia’s construction sites. The concept has a modular structure so the relevant challenges can be tackled appropriately according to the local situation. Whatever type of construction site it may be – whether a building or a civil engineering or infrastructure project – the concept centres on the way Implenia deals with waste, water, noise land and air. It gives the responsible people background information on norms and standards, explains the measures to be taken and provides helpful tools such as calculation tables, check lists and training materials.

This 1:10 scale model of a renovation was used to plan and illustrate processes and situations.



Professional handling of harmful substances in rehabilitation projects

Anyone attempting to convert, maintain or renovate buildings built before 1990 must be prepared to cope with harmful materials. Typically these are asbestos or PCB (polychlorinated biphenyls), which can hurt people and the environment when exposed. They therefore have to be treated with great professional care. If a client suspects there may be harmful substances on site, they must identify the danger immediately and assess the associated risks. Implenia has had its own SUVA-recognised department for dealing with hazardous substances since 2014. The Building Decontamination Team, which is based at three locations, Aarau, Birsfelden and Zurich, offers a comprehensive range of services. These include initial assessments, preparation of decontamination concepts, coordination with the authorities, dismantling and professional disposal. It makes its services available to all Implenia Business Units as well as to external companies.

4.5Sensitising employees

Employees can significantly influence their company’s consumption of energy and other resources, which is why Implenia carries out regular awareness-raising campaigns. There were three during the reporting period. These were designed to enhance people’s ability to spot savings opportunities and motivate all personnel to reduce the use of energy and water, as well as to dispose of waste water correctly.

The awareness campaigns consist of various strands, including 15-minute training sessions and multi-lingual information posters that are put up in highly visible locations for a number of weeks. The posters deliver the key messages concisely in words and images. Internal newsletters, the half-year report and “Impact”, the staff magazine, keep project managers up to date with the latest campaign activities and progress made, as well as providing background information. At the same time, project managers are trained in the relevant subjects and provided with in-depth documentation through the intranet.

As part of Implenia’s environmental strategy, posters are used to make site personnel aware of specific things they can do to protect the environment.

Environment day for foremen

­The Implenia Buildings Unit holds a Swiss-wide foreman’s day every year. The 2014 event in Spreitenbach was dedicated to the environment and there were discussions about various related themes, including energy consumption and waste disposal. An exhibition about environmentally friendly products reminded participants, who included project and office managers, how important it is to manage resources carefully. They were also given the opportunity to test out some environmentally friendly transportation.

­4.6Climate-friendly mobility

Implenia uses hundreds of vehicles every day: cars, lorries, diggers, steamrollers and more. Altogether they consume a massive 11 million litres of fuel each year.

In order to reduce its fuel consumption Implenia asks employees to drive more efficiently. Implenia’s professional drivers and engineers took part in a broad-based training campaign in 2010 and 2011, and since then all new employees have been sent on the EcoDrive course. In 2012 Implenia also offered an EcoDrive course to office staff; a third of them in total took part.

Implenia uses 11 million litres of fuel a year for cars and construction equipment.

There is an even greater savings potential when actually buying the vehicles and machinery, so Implenia always tries to find low-emission options. Several hybrid vehicles have already been purchased.

Implenia has also issued rules for business vehicles that stipulate the maximum permissible CO2 emissions. Cars are not allowed to emit more than 120 grams of CO2 per kilometre. The original figure was 150 grams of CO2, but this was reduced by 20% during the period under review.

These measures relating to vehicles paid off: specific CO2 emissions continued to fall during the reporting period. At the same time, airline miles remained at a constant level

Greenhouse gas emissions from air travel, Implenia Switzerland

Offsetting emissions from business flights

Since the start of 2014, Implenia has offset all business flights through a scheme run by the myclimate foundation. The project supported by the offset scheme not only cuts CO2 emissions, but also improves public health and reduces pressure on local forests. In six different regions of Bolivia and Paraguay inefficient wood ovens have been replaced by solar ovens or more efficient cookers. The use of 50,000 environmentally friendly ovens in households in towns and rural areas should save the equivalent of around half a million metric tons of CO2 over seven years.