In Spain, ACCIONA Energía, the energy division of the global infrastructure engineering group ACCIONA SA has held a groundbreaking ceremony in Logrosán, Cáceres, Extremadura marking the start of construction for a 49.9 MWe biomass power plant in Extremadura.
First announced in October 2022, the Logrosán project was the successful bidder in the third auction round for renewable power held by the Spanish Ministry for the Ecological Transition and the Demographic Challenge.
This build, own, operate, and maintain power-purchase agreement (PPA) guarantees a sale price for the renewable electricity to be produced by the plant for a twenty-year period.
Held in March this year, the ground-breaking ceremony also marked the start of construction for the Logrosán plant which is scheduled to begin supplying renewable electricity to the grid in the latter half of 2025.
The second biomass power plant in Cáceres
The Logrosán project also marks the second biomass power plant for ACCIONA Energía in Cáceres. Commissioned in 2010, the 15 MWe Miajadas biomass plant was the first one in Europe to use two types of biomass fuel – agricultural and forestry residues.
This flexibility enables a diversified fuel supply. Still operational, the first-of-its-kind plant was developed as a European R&D project in collaboration with other companies and technology centers from Spain, Finland, and Denmark, under the EU’s Seventh Framework Programme (FP7).
The new Logrosán plant is an example of the advantages of biomass, which the region of Extremadura already had the opportunity to experience through ACCIONA Energía’s plant in Miajadas, said Rafael Mateo, CEO of ACCIONA Energía.
Triple benefits
The biomass power plant is being built 10 kilometers from Logrosán urban center, and it will cover a total area of 200,000 square meters, of which over half will be dedicated to biomass storage. The Logrosán plant will use agricultural and forestry biomass as fuel.
On an annual basis, the plant will require an estimated 261,000 tonnes of biomass fuel the majority of which will be sourced from the surrounding area.
The annual power production of the Logrosán plant is estimated to be 376 GWh and is anticipated to lead to an avoidance of around 165,000 tonnes of carbon dioxide (CO2) annually.
Furthermore, it is estimated to generate around 1,400 direct, indirect, and induced jobs during its life cycle.
Biomass helps to reduce emissions and, in addition, it has proven to be the technology that creates the most jobs, reactivating rural areas thanks to the direct, indirect, and induced employment generated by the collection and handling of biogenic waste that is used as fuel, said Rafael Mateo.
The plant will also boost the regional economy by promoting activities for the use of agricultural and forestry waste and, at the same time, it will help prevent wildfires by encouraging the cleaning and vegetation maintenance of the forests and pasture lands in the area.
The use of brush and other agricultural and forestry waste is also a way of preventing fires, as it takes away highly combustible material that contributes to the spread of fire and converts it into a valuable raw material that helps to reduce energy dependence, Rafael Mateo added.
The project includes support plans to monitor the preservation and regeneration of the area’s flora and fauna, as well as social action programmes to promote local development and employment.
进行的一些活动包括training programme to promote the hiring of local personnel, advice and qualification for the agricultural and livestock sector in the area, and an entrepreneurship project aimed at supplying material for the plant.
Berkes-BWE boiler island
Berkes-BWE has been selected by ACCIONA Energía to design, manufacture, supply, and supervise the installation, and commission of the biomass boiler island including the fuel feeding system, bottom ash, and auxiliary systems.
This is a milestone project for us, said Steven Bimson, Commercial Manager Energy, at Berkes-BWE.
The BWE boiler is of the drum type with natural circulation and reheat. The woodchip feeding system and patented spreader developed by BWE are optimized for woodchip particle size distribution (PSD) according to EN/ISO 17225-1.
The woodchips are conveyed through four parallel sets of dosing silos and spreaders to the boiler, capable of running full load on three sets. With a heat input of up to 123 MJ/s, the boiler is also designed and optimized to operate with corrosive ash caused by woodchip combustion.
The water-cooled vibrating grate (WCVG) designed by BWE will ensure homogeneous and stable combustion of untreated biomass and can handle a range of biomass fuels such as cereal straw, rice paddy, sugarcane trash, woodchips, cotton residuals, palm fronds, and olive cake.
The WCVG is a BWE in-house design available from 30 to 150 MWth. A key feature is that the design can be tailored to customer requirements and optimized for specific fuels and fuel combinations. The specific fuel-feeding systems are adapted depending on the type. Low-density fuels typically require a double screw stoker, whereas high-density fuels, such as for this project, typically require spreaders, said Steven Bimson.
The water-cooled vibrating grate also makes up part of the evaporator system of the boiler.
Primary Air is introduced through a hole pattern and takes up only 30 percent of the total air. The remaining 70 percent is introduced as Ignition Air, Secondary Air, and Overfire Air through injection nozzles placed above the grate, staging the combustion into the furnace for superior NOx formation control. This proprietary design also ensures the optimal utilization of the fuel with a minimum of maintenance, Steven Bimson explained.
This article was first published inBioenergy International no. 3-2023. Note that as a magazine subscriber, you get access to the e-magazine and articles like this before the print edition reaches your desk!
