A project structure aiming at demonstration
The project is structured in two preparatory actions A1-A2 and seven implementation actions B1-B7, containing an important effort of demonstration activities as explained in the technical part. The project already has an ambitious dissemination program that is being implemented through five blocks of actions D1-D5.
Four sites with different biomass applications and capacities for stable biofuel supply and use have been defined for the demonstration purposes (Figure 1): a pellet factory in As Pontes (A Coruña-Galicia) with 70,000 t / year capacity, a bioelectricity plant in Garray (Soria, Castilla y León) of 15 MWe nominal power, a two district heating networks in Fabero and Las Navas del Marqués (both in the region of Castilla y León).
Figure 1: Selected locations for demonstrative activities
Preparatory actions performed to evaluate the natural and socioeconomic environment
The preparatory action A1 and its finished deliverable include the results about the natural and socio-economic environment of the areas covered by the project. Initially, the preparatory study was planned for four zones which were extended to five, by indication of the Commission after the evaluation of the inception report as it was decided to include scrub clearing zones in an additional area that was not initially foreseen. The new zone is located in the province of Zamora and will complement the actions in the area of Fabero due to the difficult terrain in the area.
Preparatory action A2 (Selection of areas for demonstrative clearings) is almost finished, results can be found in deliverable A2. Field sites necessary to carry out biomass harvesting tasks have been selected. Only one site is still pending to be selected, in As Pontes location (A Coruña), where the selection procedure is currently on-going. For the selected sites, permissions were obtained from land owners (public and/or private), thematic maps were made and technical guidelines for harvesting and data acquisition were prepared.
Clearing and harvesting works started in November 2014 and finished in February 2017
Once the sites were selected and the permissions obtained, Action B1 consisting of demonstrative field works started: clearing and harvesting scrub biomass started in November 2014. These works have advanced considerably so far. Harvesting is being performed using two different systems: (1) a “harvester-baler” system, Biobaler WB-55 (Photo 1) and (2) a “harvester-mulcher” system, RETRABIO prototype (Photo 2).
Photo 1: Harvester-baler system (Biobaler WB-55) working in a pasture land invaded by rockrose in Navalcaballo (Soria)
Photo 2: Retrabio working on a mixture of broom, heater and rockrose in Figueruela de Arriba (Zamora)
Up to now, clearing and harvesting is concluded. Following a chronologic order, demonstrative clearing and biomass harvesting works progressed as follows:
- In Las Navas del Marqués (Ávila), 11 hectares were harvested between December 2014 and January 2015, using the “harvester-baler” system. 137 tonnes of round bales containing shrubs biomass (fresh material) were obtained.
- In Fabero (León) and Figueruela (Zamora) 11 hectares were harvested between April and May 2015, using the “harvester-mulcher” system. 241 tonnes of shrubs chips (fresh material) were obtained.
- In As Pontes (A Coruña), 14 hectares were harvested between June and August 2015, using the “harvester-mulcher” system. 478 tonnes of shrubs chips (fresh material) were obtained.
- In Garray (Soria), 86 hectares were harvested between November 2015 and March 2016, using the “harvester-baler” system. 376 tonnes of round bales containing shrubs biomass (fresh material) were obtained.
- In Fabero (León), 8 hectares were cleared in April 2016, using the “harvester-baler” system.
- In Valdoviño (la Coruña) and Palas de Rey (Lugo) the clearing works has been performed in November 2016 and February 2017 affecting 3,8 ha.
In summary a total 137 ha have been cleared and 1,629 t of green biomass have been collected.
Action B1: 137 ha cleared and 1,629 t biomass collected
In conclusion, about the key action B1, we can say that the actions carried out have demonstrated the technical feasibility of using mechanized means for clearing, harvesting and logistics of biomass scrub, however, in the coming months of the project, where all data are available, it is necessary to conduct a thorough evaluation of the results, focusing on the points that have been proven more complicated as the stony ground, the influence of the weather and the state of development of machinery, which allow to reach conclusions about the technical and economical feasibility of the clearing-harvesting-logistic process and write a reliable good practice manual.
Action B2: Successful transformation of shrub biomass into solid biofuels (pellets).
In action B2, the methodology used for evaluating the pre-treatment and combustion of just harvested shrub biomass has been successful. No significant problem has been identified. At the moment, for all studied localizations, all results have been obtained with regard to just harvested shrub biomass. Process of stored biomass is still on progress and will be concluded, at the end of the project in december 2017.
As example, the preparation process followed with broom is shown in figure 2.
Figure 2: Chart of the process followed to obtain pellets of broom collected in Las Navas del Marqués (Ávila).
It's necessary to adapt the equipment in order to reduce emissions from the combustion of shrub fuels in small boilers.s necesario adaptar el equipo para reducir las emisiones de la combustión de los combustibles de matorral en calderas pequeñas.
Drying is the most critical step to take into account in the energy consumption of a facility that manufactures wood pellets. With the scrub biomass obtained in the project, it has been verified that the moisture of the baled biomass drops rapidly after collection, which is an advantage as very little or no energy consumption is required in drying.
In general, scrub biomass combustion in domestic commercial boilers or stoves, when compared to the combustion of commercial wood grade A1 pellets, generates higher particulate and NOx emissions, and for the gorse, in particular, the recommended limits of SO2 and HCl can be exceeded. It is therefore necessary to have equipment adapted to these fuels when it comes to using them in small boilers and or stoves.
The rockrose biomass has been tested twice in the power installation (15 mWe) of Garray . The behavior in the boiler is similar as other woody fuels.
Concerning the pelletizing and combustion demonstrative tests corresponding to the action B3, in spite of minor changes in the working program, they have been, in general, satisfactory during the first campaign but it was concluded that some modifications and improvements was necessary in the boilers of Fabero and las Navas del Marqués. New measurements will be performed at the end of 2017.
Due to the difficulties to feed milled biomass initially foreseen in the boiler of Las Navas, it was decided to transport the biomass to CEDER-CIEMAT in order to produce pellets to be tested in that boiler. In addition, in order to test milled broom biomass it was decided to transport milled biomasss to the municipality of Cuéllar (Segovia) and test it in a bigger boiler able to feed milled biomass. Demonstration activities have been also carried out in BIOMASA FORESTAL pellet mill in As Pontes, pellets production from gorse biomass (photo 3) and combustion testing of rockrose biomass in the 15 MWe power plant in Garray, owned by GESTAMP BIOMASS (Photo 4 )
The B3 demonstrations activities will continue in 2017 with a second campaign:
In May 2017 an assay using 150 tons of rockrose biomass stored during one year and milled in CEDER- has been performed in Garray power plant. The biomass has been ground to a smaller particle size than in the previous test in order to avoid feeding disturbances at the boiler inlet.
In autumn 2017 new assays will be carried out in the boilers of Fabero and Las Navas del Marqués. As concluded in the previous assays these boilers needed some adjustments in order to optimize the combustion performance. These adjustments are programed to be done during summer 2017.
Photo 3: Production and combustion of gorse pellets in BIOMASA FORESTAL facilities (first campaign).
Photo 4: CIEMAT scientists at the Garray Power Plant in May 2016. Sampling emissions at the chimney.
Action B4. Shrub inventories. Both LiDAR and satellite information can be used to generate biomass prediction models.
The objective of action B4 is the demonstration of the utilisation of LiDAR technology for inventorying shrub areas present in the selected demonstration areas (Las Navas, Garray, Fabero and As Pontes).
This action, now concluded, suffered a bit delay due to some technical difficulties: the bad results obtained after the application of LiDAR technology in some areas forced to look for other remote sensing technics such as the use of satellite imagery interpretation. Such technology has been added to the action as a tool for obtaining shrub cartography in some locations. The activities developed so far in action B4 consisted in obtaining and processing LiDAR information, field work (data collection in 120 sampling points, 120 biomass samples, 266 shrub sections), parametric model fitting for the estimation of dry biomass from LiDAR information for Cistus laurifolius, Genista cinerascens and Ulex europaeus, gathering and processing of satellite information for the areas of Garray, Fabero and As Pontes, and non-parametric model fitting for the estimation of dry biomass from satellite information for Cistus laurifolius, Erica arborea y Ulex europaeus.
One conclusion from the action B4 is that the non-parametric models based on remote sensing with LANDSAT gave worse adjustments than those obtained with LiDAR, however, they allow to obtain a first evaluation of the scrub resources with much shorter processing times. They also provide an alternative when the scrub masses have undergone changes after the LiDAR flight. The implementation of specific LiDAR flights for large areas of bush together with the processing of data imply very high costs taking into account the low value of the scrub resource.
The information of available scrub surfaces in the study areas has permitted the integration of the information in the BIORAISE tool as was initially foreseen. Now the information on potential biomass in the studded areas has been processed and incorporated to the tool (figure 3).
Figure 3: BIORAISE window shows the potential resources in the studied areas
Concerning the results of the characterization of the 120 biomass samples, it can be concluded that the quality of the shrub biomass collected in the areas considered in this study is worse than pure wood, particularly in terms of ash content and troublesome elements such as N, S, and Cl, but very similar to virgin wood materials from short rotation coppice like poplar, eucalyptus or willow. Nevertheless, it can be considered that the quality of this shrub biomass is far better than the one typically recorded for herbaceous biomass or for woody biomass from pruning, not only regarding ash content and troublesome elements, but also from the perspective of the fusibility behavior of their ashes (table1).
Table1: Shrub biomass characteristics and comparison with other typical biomasses.
The evaluation of the environmental impacts of clearing indicates a low impact of the machinery on the ground. Monitoring is still ongoing.
In action B5, the environmental impacts of the mechanized clearance carried out on shrubs formations within different ecosystems are being evaluated. In particular, the impacts on biodiversity (composition and shrub structure), physical and chemical properties of the soil, and on erosion and forest fire risks are being monitored. For that purpose, the impact is evaluated considering the situation of the shrub stands prior to shrub clearance (year 2015), and performing a two-year monitoring after the clearance. All the vegetation and soil samplings regarding the first two years have been finished and processed, so biodiversity indexes and soil and litter variables were calculated for all studied sites. These values will be compared with the ones obtained during the following years in order to evaluate the evolution. Moreover, the percentage of bare soil was calculated on each studied area, as well as a visual estimation of erosive processes, which will be also compared to the future situation. Furthermore, other complementary activities as photointerpretation of shrubs formations though the analysis of historical and currently ortophotos, dendrochronological analysis of the main shrub species or calculation of the available biomass within the stands are being performed, thus facilitating the attainment of the objectives within this action.
The assessment of the environmental impacts is limited to the short-term follow-up after the clearing activities carried out in action B1 of the project, which began in December 2014 in Las Navas del Marqués (Ávila) and were concluded in February 2017 in Palas de Rei (Lugo) with one-year delay from the foreseen schedule. It is therefore not possible to draw yet conclusions about the positive / negative impacts of clearing without having a sufficient monitoring period to allow an assessment of the trend of the mass and its main variables (soil, biodiversity, fire risk)
As possible negative impacts in the first and second year after the clearing, as a consequence of the strong mineralization of the organic matter after the opening to sunlight, there is a slight acidification and migration of fine and organic matter in some locations from the upper horizon. These parameters must be followed in the next years to know their evolution in parallel with the regeneration of the masses. Regarding the risk of fire, there is a significant decrease after the clearing and two years later in the studied locations.
The machines used in the clearing have had a very small erosive impact in the soil, with mainly superficial rolling and affecting a small surface. No sheet erosion, rill erosion or gully erosion has been detected in any of the zones. Previous studies, which have used forestry machinery for managing scrubland, have generally shown a greater erosive impact.
Actions B6 and B7. An adequate diagnosis and evaluation of non-technical barriers. Promote guidelines and policies for scrub management.
These two actions are relevant in the sense that will serve to translate technical conclusions to action proposals and guidance pathways for the involved stakeholders.
B6 action has allowed evaluating non-technical aspects that influence or may influence the feasibility of making clearings and energy recovery from biomass scrub. In the first half of the project the land ownership regime of studied has been characterized and lessons have been learned about some interesting aspects to be debated with stakeholders. One of the main conclusions is that, except in the area of Fabero, scrubs are extended much more in private owned land than in public. This fact highlights the lack of silvicultural management on private forestry lands due in most cases to a lack of resources and profitability. This lack of profitability, coupled with the lack of public support for the realization of silvicultural activities and treatments, favors the development of bushes on private land. (ej pastures, abandoned arable land, young afforested areas etc.).
Another lesson learned and is subject to discussion and proposal is the legal consideration that should be given to the scrub clearings. Should be considered as a conventional forest harvesting issue? Or should it be considered as a silvicultural treatment being the biomass collection a secondary collateral and recommended issue? Legal and / or regulatory consequences of each choice are relevant because the first option (biomass harvesting) is subject to administrative authorization and even a payment of a tax, while the second option only generally requires a prior notification. The position of ENERBIOSCRUB project, once analyzed the information on the profitability of the realization of the clearings, is to recommend that the regulations focus on the second option, since, according to the results, very high percentage of the cleared, is not harvest by machinery and the amounts harvested don’t cover the costs of clearing as biomass yields are usually low. On the other hand, even if the yields were high, a previous thorough evaluation of the places that can be considered for harvesting or silvicultural treatment should be required. Up to date, what we have observed is that clearings are not carried out because owners have to pay them, which reaffirm us in the position that, clearing technics have to become more efficient, and/or biomass collected have to be better payed (now there are seldom stakeholders demanding) so that these tasks can be shelf-financed by biomass income. Meanwhile, clearings should continue to be considered only as silvicultural activity.
Another aspect to put under discussion is the possible constraints to the management of harvested biomass. During the first phase of the project we have observed some obstacles or reticence by the forest administration with regard to the possibility of leaving biomass storages several months near places of clearing, in theory, arguing the risk of fire as impediment. In this sense, we understand that the mere fact of banning the storages is not the best option to achieve the viability of the use of biomass in the future and therefore profitability / self-financing of clearings. We understand that is necessary to regulate this type of logistics operations and in this regard we have identified some interesting cases to study such as the Law 7/2012, of June 28, Montes de Galicia in which the figure of "forest biomass manager" is defined and "collection and treatment points” can be established. These points are places or land in which managers deals with storage, handling for at least one year, to facilitate further transport and/or commercialization.
Dissemination actions. Towards a better understanding of the possibilities of the scrubland.
The dissemination actions of the project have been important and have served to make contact with different sectors, from the forest owners, forest administration, bioenergy market actors, to engineering students and general public. As an example can be cited the event held in November 2016, which was attended by more than 40 people from different sectors of activity in which a demonstration was carried out at INVIED, Valdoviño (La Coruña), where two different machines could be seen carrying out the clearing and harvesting of gorse bush and the technical meeting held afterwards in As Pontes at the INTACTA facilities, completed with a visit to the BIOMASA FORESTAL pellet plant (photo 5).
Photo 5: Above, demonstrative harvesting activities at INVIED (La Coruña). Below, visiting the BIOMASA FORESTAL installations.
The technical seminars such as those held in Soria (April 27, 2017) and Madrid (May 23, 2017), both in a university environment, have served as a forum for the debate on the results obtained in the project, allowing to draw some conclusions that Are discussed below.
Photo 6: Seminar celebrated in the University of Valladolid in Soria