Cut water and embodied carbon when building power plants

Submitted through the COP31 Sustainable Transformation Awards · SKD Türkiye (WBCSD Global Network Partner)

The company is an engineering and construction group with nearly 20,000 employees, working on large infrastructure and energy projects in several regions of the world (1).

Large energy infrastructure carries its environmental load in four places at once: the fuel the plant will burn for decades, the water the plant will draw for cooling, the carbon embodied in the concrete poured during construction, and the waste generated on a site that operates for years before the plant produces anything. Industry practice generally addresses the first of these at the design stage and treats the rest as construction-phase compliance against the environmental impact assessment.

The company built a delivery model that treats all four as engineering decisions taken from design onwards, on a project it owns itself. The model was applied on the Kırklareli 852 MW combined cycle power plant, an equity-funded investment whose construction started in 2022 and which was commissioned in 2026, and it was integrated into both the construction and the operating processes.

The objective was set in four parts: raise energy and water efficiency, handle waste at source under circular economy principles, bring industrial by-products into production processes, and reduce carbon intensity.

Performance is tracked against ISO 50001 for energy management and ISO 14001 for environmental management, reported against the GRI topic standards for water and effluents (GRI 303), emissions (GRI 305) and waste (GRI 306), and calculated using the GHG Protocol methodology. The results feed the corporate sustainability monitoring and reporting system, which also supports CDP disclosure and reporting aligned with ISSB (IFRS S1–S2) and TCFD (2).

Location of the initiative: Kırklareli province, Türkiye

The model brings measures that are normally taken by different disciplines at different stages under a single resource efficiency intent, applied across design, procurement, construction and operation.

On energy, the generation technology is selected on conversion efficiency. The gas and steam turbine combination installed converts 64.3 per cent of the natural gas input into electricity, which sets the emissions profile of the plant for its operating life rather than for a reporting period.

On water, the cooling system is an air-cooled condenser rather than a wet cooling system, which removes the largest single water demand of a thermal power plant. Alongside it, an advanced wastewater treatment system was installed during construction so that the site's own effluent could be recovered and reused.

On materials, slag arising as a by-product of the iron and steel industry was substituted for a portion of the cement in the mass concrete used for foundations, which is where the largest concrete volumes and therefore the largest embodied carbon quantities occur on this type of project.

On waste, packaging materials — paper, cardboard, plastic and PET — together with wood, metal and copper waste and mineral oils are separated at source. Waste plastic strapping from the site is converted for use in drip irrigation rather than discarded.

Measurement runs through the same structure. Digital flow meters installed on site, waste weighing tickets and accredited laboratory analyses generate the data, which is recorded in performance reports and integrated into corporate sustainability reporting rather than staying at project level.

Figure 1: Flow diagram of the delivery model

Sustainability impact

Climate

The model addresses two different emission categories, and they should not be added together.

The turbine selection addresses Scope 1 emissions from natural gas combustion at a plant the company owns and operates. The gas and steam turbine combination converts 64.3 per cent of the natural gas input into electricity and is expected to consume approximately 10.7 per cent less natural gas per megawatt-hour of electricity generated than conventional F-class plants, producing approximately 9.7 per cent less CO2 per megawatt-hour. Because the plant was commissioned in 2026, this is stated by the company as expected operating performance rather than as a measured operating result.

The material substitution addresses emissions embodied in purchased construction materials, which fall in Scope 3 rather than in the company's own operations. In the mass concrete foundations, 1,264 tonnes of slag were used as a cement substitute across a total of 6,176 m3 of concrete. The embodied carbon of slag is approximately 8 per cent of that of the cement it replaces — approximately 849 kg CO2 per tonne of cement against approximately 67 kg CO2 per tonne of slag — so the unit emission of the substituted material falls by 92 per cent. The substitution avoided approximately 1,070 tonnes of CO2 in total. This reduction is reported under GHG Protocol Scope 3, Category 1 (Purchased Goods and Services), which accounts for the embodied emissions of all extracted and manufactured inputs—including purchased cement and supplementary cementitious materials—procured for operations.

The initiative sits inside a corporate strategy that targets net zero emissions by 2050, and the site data is calculated on GHG Protocol methodology and reported through the corporate system.

Nature

Water is where the model produces its largest physical effect. The air-cooled condenser is expected to prevent approximately 3,000,000 m3 of water consumption per year during the operating phase of the plant, because a dry cooling system does not evaporate water to reject heat.

During construction, the advanced wastewater treatment system commissioned in Q1 2024 has recovered approximately 117,000 m3 of wastewater. The recovered water is reused for landscape irrigation and dust suppression, and abstraction of groundwater for those two purposes has been reduced by 100 per cent compared with the earlier period.

On waste, packaging materials including paper, cardboard, plastic and PET, together with wood, metal and copper waste and mineral oils, are separated at source at a rate of 100 per cent. The site reached the performance level for the Zero Waste Certificate of the Ministry of Environment, Urbanisation and Climate Change while still in the construction phase, which is earlier than such certification is normally obtained. Waste plastic strapping is converted for use in drip irrigation.

Social

Reducing groundwater abstraction for irrigation and dust suppression to zero leaves that resource available to the surrounding area, which matters in a construction phase that runs for several years and concentrates demand in one location.

Employees are treated as active participants rather than as recipients of rules. Training, site practice and continuous improvement mechanisms bring proposals for environmental performance into the decision-making process, and the awareness built on one project moves with the workforce to the next.

The local community received regular information about the project and a grievance mechanism was operated actively, with stakeholder views assessed and fed back, which the company describes as the basis for a long-term relationship built on transparency.

Business impact

Benefits

The commercial logic of the model is that the measures pay for themselves inside the project rather than depending on external funding.

Fuel is the dominant lifetime cost of a combined cycle plant, so the expected reduction of approximately 10.7 per cent in natural gas consumption per megawatt-hour is a direct operating benefit to the owner for the life of the asset.

Dry cooling removes an annual water purchase or abstraction of approximately 3,000,000 m3 from the operating cost base, and it removes exposure to water availability and water pricing in the region.

Recovering approximately 117,000 m3 of wastewater during construction displaced groundwater abstraction for irrigation and dust suppression entirely, so the treatment system was already earning during the build rather than only after handover.

Substituting an industrial by-product for cement replaces a purchased material with a lower cost input, subject to the logistics of obtaining it.

Source segregation reduces waste disposal costs and produced Zero Waste certification during construction, which removes a compliance step later.

The measures are being standardised as a site management policy across suitable projects, so the engineering work is done once and reused, and the same data set serves operational management, corporate sustainability reporting, CDP disclosure and reporting aligned with ISSB and TCFD.

Costs

The model carries higher capital cost at four points: the high-efficiency gas and steam turbine combination, the air-cooled condenser, the advanced wastewater treatment system, and the monitoring instrumentation that makes the results verifiable. The wastewater system also adds an operating cost during construction.

Two further constraints are practical rather than financial. Access to industrial by-products such as slag depends on local market logistics, and a project located far from an iron and steel producer may not obtain the material at a workable cost. And the model requires technical expertise on site, which is a constraint in markets where that expertise is scarce.

The measures were funded from the project's own operational budget without external financing, and the company describes the economics as self-financing over the long term through natural resource savings and lower waste disposal costs. Investments needed for long-term sustainability are included in project budgets from the outset rather than requested afterwards.

Costs are contained by taking the decisions at design stage, when specification changes are cheap, and by reusing the same measurement data for operational, environmental and disclosure purposes instead of running separate reporting exercises.

Slag, which is used in mass concrete foundations instead of cement, is approximately 10-15% cheaper than cement. The wastewater treatment system, which features an advanced treatment process making its effluent eligible for use in agricultural irrigation and dust suppression, costs approximately USD 90,000 in total for the capacity of 300 m3/day. The capital cost of an Air-Cooled Condenser (ACC) is approximately 20% lower than that of a Heller system designed to provide equivalent performance under nominal conditions. Furthermore, the ACC is less sensitive than the Heller system to extreme ambient conditions, such as high ambient temperatures and low atmospheric pressures, resulting in lower degradation of overall power plant performance under such conditions.

Impact beyond sustainability and business

Co-benefits

The strongest secondary effect is on the supply chain. Specifying an industrial by-product in mass concrete creates demand for low-carbon material, gives the iron and steel industry a route for a by-product, and directs subcontractors towards resource efficiency practices they then carry to other clients. Industrial symbiosis of this kind only develops when a buyer of scale asks for it.

The model is modular, and the company reports it as adaptable to infrastructure projects, industrial facilities and data centres in different geographies and at different scales, not only to power plants.

Environmental awareness built among employees during a multi-year construction project is transferable to later projects, and the improvement mechanism gives it a route into engineering decisions.

Potential side-effects

Slag substitution was applied in mass concrete foundations, which is where the setting behaviour of a slag-blended mix is an advantage. It does not automatically transfer to structural concrete with different strength development requirements, so a contractor should qualify each concrete class rather than assume a general substitution rate. Slag substitution was applied in C30 and C50 concrete classes with substitution rates ranging between 41% and 67%.

Dry cooling removes the water demand of wet cooling, and dry and wet cooling do not perform identically under all ambient conditions. While wet cooling towers are more efficient in terms of power consumption and heat transfer due to water's superior thermal properties, dry cooling—specifically via Air Cooled Condensers (ACC)—is increasingly prioritised due to water scarcity and tightening environmental regulations. From a performance standpoint, ACC systems do incur an output penalty compared to wet cooling. Because ACCs cannot achieve the low condenser pressures possible with wet systems (e.g., reaching 45–50 mbar compared to 25–30 mbar in wet cooling), the plant's total energy output is inherently lower, particularly during peak summer temperatures. Furthermore, ACCs face operational challenges such as higher steam duct pressure drops and significantly longer start-up times (minimum 45 minutes versus 3–5 minutes for wet systems). In regions with severe water scarcity, where wet cooling is unfeasible, dry cooling remains the primary viable solution. Despite the associated efficiency and output penalties, ACC is currently the preferred investment choice over alternative dry-cooling technologies, such as Heller systems, due to its comparatively lower capital costs and reduced auxiliary power consumption.

Recovered water is used for landscape irrigation and dust suppression, both non-potable applications. Extending recovery to higher-grade uses would require additional treatment and additional quality assurance.

The by-product supply is a dependency rather than a certainty: where slag is scarce or distant, the transport emissions of moving it can erode the embodied carbon benefit that justified the substitution.

Typical business profile

The model suits engineering, procurement and construction contractors and owner-operators delivering large energy or industrial infrastructure, particularly where the same organisation controls design, procurement and construction and can therefore take resource efficiency decisions before the specification is fixed.

It is most applicable on projects with a long construction period and large concrete volumes, and on sites in regions where water availability is a constraint on the operating phase.

Delivery engages engineering, project management, site engineering, procurement, and a corporate sustainability and compliance function with authority to set requirements that go beyond the environmental impact assessment.

Approach

1. Set the environmental targets above the permit baseline at design stage: Define the energy, water, material and waste outcomes the project will deliver beyond legal requirements and beyond the environmental impact assessment, so that every later engineering decision is measured against a target that already exists.

2. Select the generation technology on conversion efficiency: Specify the gas and steam turbine combination on the basis of fuel converted per unit of electricity delivered, because this single decision fixes most of the operating-stage emissions of a thermal plant for its entire life.

3. Choose the cooling system against water risk rather than capital cost alone: Compare wet cooling with an air-cooled condenser on the volume of water each would draw over the operating life of the plant, and carry the water availability risk of the region into the investment decision.

4. Commission wastewater treatment during construction, not at handover: Install the advanced treatment system early so that construction-phase demand for irrigation and dust suppression is met from recovered water, which removes groundwater abstraction while the site is still being built.

5. Qualify an industrial by-product for the concrete classes where it fits: Test slag as a partial cement substitute in mass concrete, confirm the embodied carbon differential per tonne against the cement it replaces, and secure the supply logistics from the iron and steel industry before the pour programme begins.

6. Segregate every waste stream at the point it arises: Separate packaging, wood, metal and copper and mineral oils on site and record quantities on weighing tickets, so that zero waste performance can be certified during the construction phase instead of being reconstructed afterwards.

7. Instrument the site so the results are verifiable: Install digital flow meters, use accredited laboratory analysis for effluent quality, keep waste weighing records, and feed the data into the corporate sustainability monitoring and reporting system rather than into a project spreadsheet.

8. Convert the project into a standard and pull the supply chain with it: Turn the measures that worked into a site management policy applied on every suitable project, and use procurement specifications to move suppliers and subcontractors towards low-carbon materials and resource efficiency.

Stakeholders involved

• Project leads: The model is owned at Board and shareholder level, since the plant is the company's own equity investment, and strategic direction is provided by senior management. Implementation is led by the Project Manager and carried out by site engineers, with the Engineering function and the Corporate Sustainability and Compliance function working in close cooperation. This places sustainability inside engineering decision-making rather than alongside it as a compliance review.

• Company functions: Engineering sets the technical specification for the turbine combination, the cooling system, the wastewater treatment plant and the concrete mix. Corporate Sustainability and Compliance defines the performance framework, the standards applied and the reporting route. Site engineering runs the measurement and the waste segregation in daily practice, and procurement secures the by-product supply and carries the requirements into subcontracts. The measures are aligned with the corporate sustainability strategy on climate action, water management and circular economy, and the investments required are built into project budgets.

• Main providers: Suppliers contributed as technical partners in developing the solutions rather than only as equipment vendors, which is how the specification for the high-efficiency turbine combination, the air-cooled condenser and the advanced wastewater treatment system was developed. Subcontractors deliver the site work under the same resource efficiency requirements. The iron and steel industry supplies the slag used as a cement substitute, and accredited laboratories carry out the analyses that verify effluent quality.

• Other: Public institutions took part through permitting, inspection and technical evaluation, which the company describes as supporting the development of good practice rather than only verifying compliance. The Zero Waste Certificate performance level is defined by the Ministry of Environment, Urbanisation and Climate Change and was reached during construction. Academic knowledge and sector developments were used as a reference when engineering solutions were evaluated. Employees participate through training, site practice and continuous improvement mechanisms, and their proposals on environmental performance are reflected in decisions. The local community received regular project information and an active grievance mechanism, with stakeholder views assessed and used.

Key parameters to consider

The model was applied on an 852 MW combined cycle plant whose construction began in 2022 and which was commissioned in 2026, so the construction-stage results are measured while several operating-stage figures are stated as expected performance.

Five indicators are tracked: KPI 1, energy efficiency of the turbine combination; KPI 2, water efficiency and recovery; KPI 3, industrial by-product use and circularity; KPI 4, carbon intensity reduction; and KPI 5, the zero waste system. Each has its own basis, and the water and material results are the ones already realised.

The framework is ISO 50001, ISO 14001, GRI 303, GRI 305 and GRI 306, with GHG Protocol methodology for emissions. Data comes from digital flow meters, waste weighing tickets and accredited laboratory analyses.

The principal risks are the initial investment cost of the high-efficiency turbine combination, the air-cooled condenser and the advanced wastewater treatment system, the logistics of obtaining industrial by-products such as slag in local markets, and the availability of technical expertise. No external financing is required; the measures are funded from the project's operational budget.

The regulatory anchors are the Zero Waste Regulation and the environmental impact assessment regime, with the model designed to operate above both.

Implementation and operations tips

Take the decisions before the specification is frozen. Cooling system selection, turbine selection and concrete mix design are cheap to change at design stage and expensive or impossible to change once procurement has started.

Install the wastewater treatment system for the construction phase, not only for operations. A multi-year build consumes large volumes of water for dust suppression and irrigation, and that demand is usually met from groundwater by default because nobody has costed the alternative.

Qualify the by-product early and locally. The embodied carbon differential between slag and cement is large, but it is only realised if the material can be obtained near the site; transport distance is part of the calculation, not an afterthought.

Measure during construction rather than reconstructing afterwards. Flow meters, weighing tickets and accredited analyses are inexpensive relative to the project, and they are what turns an environmental intention into a certifiable and auditable result.

Write the requirements into subcontracts. The measures that survive across projects are the ones that appear in procurement documents, not the ones that depend on a particular site team.

External links

• Sustainability report 2025

• Corporate sustainability disclosure

Source list

• (1) ENKA sustainability report 2025

• (2) ENKA corporate sustainability disclosure