- To demolish the three towers, one of the most complex tasks of the dismantling process at which the installation is located, 275 kg of explosive were used.
- The demolition produced approximately 40,000 tonnes of waste, which will be recovered as filling material given its inert nature, separating the iron it contains for its reuse.
- The Andorra thermal power plant is currently in the process of being dismantled. While these works are on going, Endesa is in the process of developing a plan for the future, Futur-e, which seeks to revive the industrial fabric in the area with the construction of 1,830 MW of renewable power.
Today, Endesa completed the simultaneous demolition of three cooling towers at the Andorra thermal power plant, which represents one step further in the process of closing the company's coal plants, to be completed on the Spanish mainland in 2027.
The Teruel thermal power plant (Andorra) was built between 1974 and 1979 and has been in operation for more than four decades, creating a deep-entrenched link in the area. Once Endesa ordered the closure of the plant in 2019, the decommissioning process began with plan for the future of the region drawn up that includes the deployment of new industry and the development of 1,830 MW of new power, in this case, renewable.
"Today represents a historic occasion in the energy world. It is a symbol of the decarbonisation process in which Endesa is immersed; however, this does not mean that an era has come to an end, rather, it represents the start of another era in which the development of new industry and new renewable energy production will be the protagonist in areas in which we are closing our thermal power plants", asserted Rafael González, Endesa's Managing Director of Generation, emphasising "the difficulty of these dismantling processes, which require specialised manpower and which will generate more than 800 jobs throughout Spain over the next 5 years."
To this end, Endesa has developed training courses in Workplace Risk Prevention in dismantling and operation works at industrial facilities, with 170 people in the area having participated in these courses to encourage the local recruitment of specialist personnel. This action has seen more than 2,000 people receive training across Spain for different qualifications related to our activity.
Demolition of the towers
As part of the work to dismantle the Teruel thermal power plant (Andorra), the demolition by blasting of the plant's three cooling towers represents a milestone on account of the symbolism of the structures, but most importantly from a technical perspective. In this sense, to undertake this work, an exhaustive procedure was designed with a view to guaranteeing absolute safety and effective demolition conditions. This prevention approach is being employed in all the processes involved in the plant dismantling and demolition, which also aims to give a second life to 90% of the waste generated as part of these works.
The process of blasting the three cooling towers has been particularly complex, as it has been supported by a specific project as part of which the conditions of the preparatory works has been subject to a structural analysis, as well as the dynamics of the blasting process, the sequence of activities, directions in which material would fall, measures to mitigate impacts, vibration measurements and the safety of all affected elements and structures.
The works prior to the demolition of the cooling towers began in March 2021 and will end in this May, after 273 days of activity, during which more than 6,100 tonnes of asbestos-containing material, located mainly in the towers' heat exchange area, have been removed, pursuant to the work plans approved by the Administration. This material has been managed as hazardous waste in line with all the legal aspects established in the applicable regulations.
Before this work was performed, the heat exchange equipment was removed and managed; this essentially consisted of plastic filling materials, as well as materials containing asbestos (non-crumbly), located inside. Work was also performed to condition and separate the external part from the internal part, the elements attached to the tower were uncoupled and the equipment located in the affected area was dismantled.
To demolish the three towers, 1,164 holes containing of a total of 275 kg of explosive were used, drilled into the pillars of the towers in a distributed manner to direct the fall of material in the direction planned in the project. In the project, a safety radius of 800 metres was set up from each of the structures.
The detonation of the three towers was performed in a sequence (in 1.5 seconds, all the explosives were detonated) to minimise ground vibrations and material projections.
The demolition generated approximately 40,000 tonnes of waste (in essence, concrete), which will be managed in line with environmental regulations. This waste will be given a second life on site, as it will be used as a filling material given its inert nature, with the iron given a new, second use.
To minimise the impact of the dust generated by the explosion, 37 pools with a capacity of 2 cubic metres were installed around the perimeter of the towers detonated at the same time as the blasting of the three cooling towers using detonating cords introduced into the pools in the form of a spiral.
Technical data
The 3 towers at the Teruel thermal power plant has identical measurements and geometric features: 107.3 m in height, 83 m in diameter at the base and 50.7 m in diameter at the top. They were built in 1978 and 1979 using concrete and each weighed a total of 13,000 tonnes.
They were one of the core components of the steam production cycle that moved the turbines to generate electricity. Their function was to cool the hot water from the condensers in the energy production units (where the steam from the water-steam cycle condenses once it has passed through the turbine).
The circular hyperboloid shape of the towers allowed air to flow from the base upwards without the need for any air to be introduced using an external energy source. This is how the heat was transferred, as part of a thermal exchange between the water to be cooled and the air, giving rise to the characteristic plume of water vapour that could be seen when they were in operation.
Dismantling work
The dismantling of the Teruel thermal power plant is a task that entails great technical complexity, mobilising huge resources: around 200 people will perform these tasks until the work is completed in 2025.
The human team taking care of the works consists mostly of former contractors or residents in the Andorra-Sierra de Arcos region and surrounding areas, since Endesa, as part of its commitment to sustainability, gave priority in the tender for the award of the work to bids that included the largest number of local workers.
Exhaustive planning and coordination of all health and safety and environmental aspects were considered a priority. To this end, the management of the demolition project is being undertaken by a highly qualified team, which a complex task like the one being undertaken in Andorra requires. The works follow a meticulous plan, with the aim of avoiding occupational incidents despite the high number of staff involved.
From an environmental perspective, a selective demolition system is being employed to separate and characterise each of the 260,000 259,780 tonnes that make up the volume of the demolition. An exhaustive environmental monitoring plan has been implemented, with special attention paid to emissions and discharges during the execution of the works, in order to reduce the effects on the environment as much as possible.
As part of Endesa's commitment to the circular economy, concrete waste is due to be reused, to which end Endesa has installed high-capacity equipment in Teruel to fully recover this recycled aggregate, which will be used to fill the holes generated by the works, as well as in the morphological remodelling of the landscape after the demolitions.
Gypsum materials, bituminous mixtures, uncontaminated soil and rocks, refractory coatings, sludge containing hazardous substances, calcium waste, ash and wood containing hazardous substances will all be sent to an authorised manager.
Seven demolition zones
Endesa has grouped the demolition areas into on-site homogeneous systems and installations. The demolition zones are as follows:
Zone 1 - Turbines: consisting of the turbine buildings for units 1, 2 and 3. This also includes the main equipment, such as the generators, turbines, condensers, heaters, transformers and other associated facilities.
Zone 2 - Boilers: includes the boilers, preheaters, electrostatic precipitators and gas conducts.
Zone 3 - Gas desulphurisation plants: the three gas desulphurisation plants with their components, the gypsum dehydration building, water treatment plant, pump house, electrical building, belts and plaster silos.
Zone 4 - Tall slender structures: facilities to be dismantled and demolished by blasting, such as the chimney, measuring 343 m in height (to be demolished in 2023) and the three cooling towers.
Zone 5 - Coal storage installations: all the installations in the coal storage park, stacking machines, collectors, retro extractors, trippers, the coal crushing building, ore transfer towers, electric coking buildings, sampling towers, scales, coal hoppers, fuel transport belts, coal unloading hoppers, etc.
Zone 6 - Buildings and sundry structures: This area includes general installations that are outside the jurisdiction of the above zones, such as the office building, the raw water tank and water pre-treatment area, the cooling water ponds, warehouses and workshops, etc.
Zone 7 - Specialist elements: internal railway for unloading coal and loading ash as well as buried galleries.
Andorra Thermal Plant
The "Teruel" thermal power plant, located in Andorra, consisted of three units, with a total capacity of 1,100 MW. Each unit had a boiler, turboalternator and cooling tower. The site was rounded off the coal and limestone park, the ash and slag evacuation system, the desulphurisation plant and the 343-m high chimney for the evacuation of combustion gases.
It was built between 1974 and 1979 in order to make extensive use of black lignite from mines located in the Turolense mining basin, mixed with imported coals. The lignite was transported to the plant's coal park and the imported coal was transported by ship to the port of Tarragona and, from there, by rail to the plant. Natural gas was used as an auxiliary fuel for start-ups and combustion support.
It was active for four decades and produced 224,000 GWh, equivalent to mainland electricity consumption for a year. To this end, it needed 142 million tonnes of coal, of which 110.9 million tonnes were domestic coal and 31.7 million tonnes were imported.
From the outset, all environmental parameters were of particular importance in the operation of the plant, especially in relation to the control of emissions and environmental air quality, given the high sulphur and ash content of local lignite.
As a result, to ensure the compatibility of the economic development of the plant and use of these lignites with the conservation of the environment during the plant's useful life, a series of actions were undertaken that involved investments of more than 400 million euros. As a result of these investments, the plant managed to stabilise emissions into the atmosphere at levels below 1 tonne per megawatt hour produced.
Future Plan
In parallel to the request for closure, Endesa voluntarily presented a Future Plan designed to compensate for the effects of the closure by means of a number of specific measures to promote the development of economic activities and job creation in the area around the plant.
The Future Plan includes the relocation of the plant's employees, as well as giving absolute priority to the recruitment of workers from auxiliary companies for the performance of the plant closure and dismantling activities and at the renewable parks that Endesa intends on opening in the area.
Endesa's Futur-e Plan foresees an investment of more than 1.4 billion euros and its ultimate aim is the construction of 1,830 MW of photovoltaic and wind power plants.
The creation of these facilities will generate 4,000 jobs during the construction stage and 300 jobs for more than 25 years as part of the plant operation and maintenance activities.