Sustainable approaches for reusing concrete

Enel is seeking an innovative, cost-effective, and environmentally friendly solution to reuse or recycle the concrete coming from the demolition of our plants within the framework of circularity and sustainability.

As a multinational company founded in Italy, the Enel Group is a leader in the world of renewables, innovation, and social responsibility. A number of assets are built using large amounts of concrete and when these are decommissioned, it is vital to find innovative and sustainable ways to reuse or recycle the concrete in a manner that is environmentally conscious. 

OVERVIEW

Concrete is known as the most widely used construction material in the world, but also as a major contributor to climate change. The chemical and thermal combustion processes involved in the production of cement, a key input for concrete, are a large source of carbon dioxide (CO2) emissions. Each year, more than 4 billion tons of cement are produced, accounting for around 8% of global CO2 emissions.

Enel is committed to a global net zero strategy - net zero CO2 emission by 2040 - which requires a very fast energy transition with a significant growth in renewable generation, and together with it, the phase-out of several fossil fueled facilities across the world.

This has also led to increased awareness of the importance of developing sustainable practices and standards for decommissioning. 

One of the most relevant issues we are going to face is the production of huge quantities of concrete rubble coming from the decommissioning process of Enel assets. Nowadays only a small portion of the dismissed concrete gets reused for other applications, hence the Enel Group is looking for the best available methods to recycle and/or reuse the materials coming from the demolition of concrete in our plants in a sustainable and circular way. 

SCENARIO 

Reuse or recycling of all the materials that come from the concrete decommissioning has the potential to produce value, both internally and externally, and reduce its environmental impact, while eliminating the need to dispose the rubble to external sites. It is crucial, in this scenario, to search for innovative solutions and circular business models aimed to make the reuse of concrete from decommissioning more sustainable and to postpone the End Of Life (EOL) of concrete, minimizing its impact on climate change. 

BACKGROUND

As mentioned above, the estimated quantities of decommissioned concrete for Enel are significant. Here below are mentioned the two main use cases thought for Enel to be extended at Global level.

First use case:

•  There are several sites listed for phase-out (more than 30 only in Italy), which are estimated to generate more than 1000 ktons of concrete in the next 5 years (800 estimated in Italy).
• The concrete is coming mainly from the demolition of buildings (turbine hall, auxiliary buildings, etc.), above ground foundations (tanks basements rings, etc.), and only in rare cases foundations below zero quota, (foundations, retaining walls, etc.)
• At the moment, the dismissed concrete is used especially in presence of depressed areas to be filled. The material is characterized, separated from iron steel bars, crushed and recovered on-site for filling the voids resulting from demolitions. Otherwise, it is disposed of or, in case of inert concrete, sent to off-site facilities for recovery as filling of roads.
• The dismissed material has the following characteristics: if there is no crushing, the size of the pieces is about 20-30 cm, a suitable size to be able to load it on a truck and compact the space as much as possible. 
• No additional treatment is foreseen at site in case of disposal. 
• Enel locations, where this material will be mainly available, are concentrated in Italy and Spain.

Second use case:

• The concrete is coming mainly from the demolition of reinforced concrete poles, reinforced concrete secondary substations and poles’ foundations.
• At the moment, the dismissed concrete is strongly suggested to be reused, but demolition is entrusted to companies that are paid a decommissioning value to bring the concrete to the landfill; hence there is no visibility into the recycling process.
• The dismissed material has the following characteristics:
  • Pole Heights: from 9 m to 14 m. The diameter of the section varies from 200 mm to 400 mm.
  • Foundations from 1x1x1 (m) up to 2.7x3.1x3.1 (m)
  • Secondary substations
    • Width=1600 mm x Depth=2000 mm x Height=1800 mm (minimum)
    • Width=2300 mm x Depth=5530 mm x Height=[min. 2300 to max. 2600] mm (maximum)
    • Ceiling and walls thickness is 9/11 cm

THE CHALLENGE

Enel is seeking an innovative, cost-effective, and environmentally friendly solution to reuse or recycle the concrete coming from the demolition of our plants within the framework of circularity and sustainability. The proposed opportunity must be applicable at a local level, minimizing the impact of transportation and logistics, and should be a low-intensity process to limit the emissions of CO2. Solutions may focus upon either scenario described above.

SOLUTION REQUIREMENTS

Submissions should address the following Solution Requirements. 

The proposed solutions must:

• Be ready to use: the practice must have some applications at the global level and the ability to be applied at the local level in Italy or Spain.
• Be sustainable: the solution must positively affect the environment and the community, considering the impacts upstream and downstream, and the life cycle assessment (LCA). 
• Maximize the use of secondary materials, minimize the use of water and greenhouse gas (GHG) emissions.
• Address local opportunities for reuse and recycle, in order to avoid or minimize the impact of transportation for long distances due to the big quantities of material.
• Be able to deal with large amounts of material in terms of volumes and weights.
• Be feasible, simple, smart, fast to apply, which translates to having the minimum number of processing steps from the collection until the new use.
• Be innovative, which means different from the following practices: 
  • Filling of the voids resulting from demolitions
  • Filling of roads
  • Recovery of aggregates for inert material

Moreover, the solution should: 

• Be scalable, with possible deployment on a global scale, hence following the best practices in terms of handling and disposal regulations.
• Be in compliance with the Italian/Spanish regulations in terms of waste handling and disposal, treatment, recovery, etc.

PROJECT DELIVERABLES

The submitted proposal should include the following:

• (Required) Detailed description of the proposed solution that includes at least: 
  • The scope of the reuse or recycle process
  • Details on the characteristics and requirements of the waste material that can be used for the process: size, shape, legislations, compositions (Gravel, Sand, Cement, Metal, Water, …), amounts
  • A description of the chemical/mechanical/physical processes involved
  • Details on the materials/components streams resulting from the process 
  • Indication of the use that the materials/components resulting from the process are intended for, whether they can be used internally or externally of Enel sites.
  • Estimation of the environmental impact of the process: emissions, materials/streams to be disposed, chemicals to be used, water demand, etc.
  • Description of a proposed business model and associated economics for project implementation with Enel 
  • Applicable legislation and evidence of how this will be addressed
   

• Desired information:
  • Description of the necessary infrastructure, logistics of the process
  • List of partners and third parties involved, if any
   

• Address as many of the following key performance indicators (KPIs) as possible:
  • Tons of material that can be treated per year: t/day
  • Tons of material recoverable/tons of material treated 
  • Water required by the process: kg/kg concrete treated
  • CO2 produced by the process: Kg Co2 eq/Kg concrete treated 
  • % of concrete reused/recycled
  • % of secondary materials used in the process
  • Chemicals used in the process: kg/kg concrete 
  • Flexibility of the solution – range of applicability: % of material (Gravel, Sand, Cement, Metal,…) required
  • Waste production from the process (kg/kg treated)

The proposal should include a summary where the Solver explains the rationale of the idea and how it responds to the solution requirements as well as a list of references, articles, patent information (if any) with respect to the Solver’s idea.

The proposal should not include any personal identifying information (name, username, company, address, phone, email, personal website, resume, etc.) or any information the Solvers may consider as their Intellectual Property they do not want to share.

SDGs

This challenge provides contribution to the following sustainable development goals (SDGs) to transform our world:

• SDG 7: Affordable and Clean Energy
• SDG 9: Industry, Innovation and Infrastructure
• SDG 11: Sustainable Cities and Communities
• SDG 12: Responsible Consumption and Production
• SDG 13: Climate Action
• SDG 17: Partnerships to achieve the Goal