Foire au questions

This section is dedicated to "Most aked questions" on the PROFORBIOMED theme.

Question 1: What is biomass?

The Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources (OJ L 140/16 5.6.2009) defines biomass as “the biodegradable fraction of products, waste and residues from biological origin from agriculture (including vegetal and animal substances), forestry and related industries including fisheries and aquaculture, as well as the biodegradable fraction of industrial and municipal waste”.

Biomass is short form of ‘biological mass’. The term is used for any organic material derived from plant and animal tissue. The Forest Resource Assessment of the UN Food and Agriculture Organization (FAO 2010) defines biomass as organic material both above-ground and below-ground, and both living and dead, e.g., trees, crops, grasses, tree litter, roots etc. The IPCC 2006 Guidelines consider biomass the living plant and animal material, both above-ground and below-ground, usually expressed as dry weight.

Question 2: What is bioenergy?

Bioenergy is the energy created from biomass like wood, forestry wood residues (branches, twigs, roots, bark, wood-shavings and sawdust), sugarcane, corn or algae as well as a multitude of agricultural residues (maize cobs, coconut shells, coconut husks, cereal straws, rice husks, etc.) and peat, and excluding material embedded in geological formations and transformed to fossil.
Bioenergy production systems generally involve the farming of biomass dedicated specifically to the purpose of supplying fuel energy.

Biomass can be used to produce heat or converted into electricity or liquid fuels. The principal categories of biomass conversion technologies for power and heat production are direct-fired and gasification systems. Anaerobic digesters are also considered a biomass conversion technology.

Question 3: What species / vegetal structures to be considered as potential producers of forest biomass?

The adopted methodology will tend to estimate the production of forest biomass produced under conducive to regular silvicultural management of forest stands. This will be considered the following tree species: Eucalyptus globulus, Pinus pinaster and Pinus pinea. The cork oak (Quercus suber), despite their territorial expression will not be considered as a species producing residual forest biomass as this could conflict with their status as protected species.

Given the fact that it has great relevance in territorial Algarve will also be made ​​an approach to estimating the potential production of biomass from areas with a predominance of weeds.

Question 4: What are the benefits of wood energy ?

1°) a green power :

  • The wood burning presents a neutral impact on the carbon cycle. The carbon released into the atmosphere is set again in the growing forests.
  • The modern wood heating is respectful of Air Quality. It emits very little sulfur and heavy metals compared to other energy fossil sources.
  • The wood energy allow to improve forest management, timber production values. It allows also to find a way to use low value wood. Furthermore, in France for example, the forest area is increasing.

2°) an economic power:

  • The wood energy price is highly competitive and less fluctuating compared to others energy fossil sources.
  • In addition, a package of aid (grants, tax credit…) is available in France. This reduces the cost of a wood burning installation and this allows to faster return on investment.

3°) a local energy :

  • In France, the wood resource is widely available.
  • The wood energy gives value to the wood obtained by managing the local forest.
  • It promotes also local job creation.

Question 5: Which are the pros of bioenergy? And the cons?

There are many potential advantages to using biomass for energy instead of fossil fuels and other alternative sources of energy. Specific benefits depend upon the intended use and fuel source, but often include: greenhouse gas (particularly CO2) and other air pollutant reductions (NOx, SO2, etc.), energy cost savings, local economic development, waste reduction, and the security of a domestic fuel supply. In addition, biomass is more flexible, as it can generate both power and heat and reliable (as a non-intermittent resource) as an energy option than many other sources of renewable energy.

Main drawbacks of conventional biomass compared to coal, oil or gas and other fuel alternatives, are low energy density, high moisture content and heterogeneity.

A large-scale harvesting of energy biomass will raise the question how sustainable the energy systems based on biomass are and what are  the climatic and management effects on energy biomass production and utilisation. In addition, the production of energy biomass needs fossil energy and enhances the emissions of greenhouse gases, thus sinking or negating the benefits of the production.

Question 6:  Would an increase in management for bioenergy production have an impact on biodiversity or other environmental characteristics?

Changing land use can have positive or negative impacts on ecosystem services and biodiversity, which is the prerequisite underpinning each of them: soil quality, landscape pattern, water quantity and quality, pollution of rivers and lakes, production of toxic emissions and so on.

Significant bioenergy development will come at the expense of natural forests, either directly, through conversion of forests to non-forestland, or indirectly, through competition between land uses. Bioenergy development may increase the demand for agricultural land; if such land is sourced from tropical forests, the net carbon balance would be highly negative.

There may also be social and cultural impacts. These are complex and site-specific issues that are beyond the scope of this report, but some general observations can be made, taking the example of biodiversity. In the case of new forest energy plantations, biodiversity increases, at ecosystem, species, genetic level, when they occur on degraded lands or on agricultural lands.  However, forests and energy crops can only increase diversity where they replace land cover which is species-poor, while in some places their introduction may threaten valued species and habitats. Trade-offs between fuel/fibre production and carbon sinks, and maintaining biodiversity, can also occur when creating large areas of productive crops or managed forest, especially monocultures of exotic species managed on short rotations. There are management options available to address the trade-offs between production and biodiversity. These include using of sustainable planting stock (native species, eventually produced by seed ), creating a patchwork of crops and multi-aged forest stands, generating hedgerows plantations aimed at connecting fragmented habitats, altering field and felling unit sizes, selection of edge lengths, minimizing chemical inputs, encouraging ground vegetation, and using species and age mixtures. With clear goals in terms of conservation of biodiversity, optimal compromises can be chosen between maximizing carbon sinks or biomass productivity and maintaining biodiversity.

Literature: Danielsen F, et al. (2009) Biofuel Plantations on Forested Lands: Double Jeopardy for Biodiversity and Climate. Conversation Biology 23

Question 7: How much is the potential of bio-energy to contribute to securing future global energy supply?

Biomass as a renewable energy source provided about 10.2% (50.3 EJ) of world's total primary energy supply in 2008. Within the renewable energy sector (13% of global energy supply), bioenergy is the dominant source followed by hydropower and to a smaller extent wind power, geothermal energy and solar energy. (Nuclear energy represents almost 6%.)

Traditional use of wood, straws, charcoal, dung and other manures for cooking, space heating and lighting by generally poorer populations in developing countries accounts for about 30.7 EJ, and another 20 to 40% occurs in unaccounted informal sectors including charcoal production and distribution. World's total primary energy supply from biomass for electricity, heat, combined heat and power, and transport fuels was 11.3 EJ in 2008 compared to 9.6 EJ in 2005 and the share of modern bioenergy with high conversion efficiency was 22% compared to 20.6%.

Bioenergy has great potentials of increased utilization. According to a IPCC report the potential deployment levels of biomass for energy in 2050 could be in the range of 100 to 300 EJ per year, 20-30 times the current use. However, there are large uncertainties in this potential such as market and policy conditions, and it strongly depends on the rate of improvement in the efficiency of existing biomass use as well as increasing the availability of biomass.  The upper bound of the technical potential of biomass for energy may be as large as 500 EJ/yr by 2050. Reaching a substantial fraction of the technical potential will require sophisticated land and water management, large worldwide plant productivity increases, land optimization and other measures. For comparison, the equivalent heat content of the total biomass harvested worldwide for food, fodder and fibre is about 219 EJ/yr today.

Question 8: What is the target of Renewable Energy that Partner's coutries has to achieve by 2020 (example of Italy)?

The Directive 2009/28/CE on the promotion of renewable sources includes a goal of national growth in all sectors, leaving Member States the declination of sectorial measures for its achievement. Countries aim to redress the balance of its energy mix, which is currently too dependent on imported fossil fuels.


Objectifs globaux des Etats membres (extraits de la Directive 2009/28/CE)
Country % energy produced from renewable energy sources in the gross final energy consumption in 2005 % energy produced from renewable energy sources in the gross final energy consumption in 2020
Greece 6,9 18
France 10,3 23
Italy 5,2 17
Portugal 20,5 31
Slovenia 16,0 25
Spain 8,7 20

The needs to tackle the issue of environmental sustainability within a coherent framework, where security of supply and system adequacy can be assessed, as well as GHG emissions is therefore strong. However, a comprehensive set of measures to reach the targets and to guarantee security of supply is still missing.

Question 9: What is the difference between CO2 emissions from bioenergy and from fossil fuels and How big is the potential to reduce greenhouse gas emissions by using more bioenergy?

There is a substantial difference between energy production from fossil fuels and from purpose-grown biomass.  Burning fossil fuels releases into the atmosphere geological CO2 that has been locked up for millions of years, contributing to the man-made green-house effect. By contrast, burning biomass simply returns to the atmosphere the CO2 that was absorbed as the plants grew and, once harvested, the plants can grow again quite quickly, so there is no net release of CO2.

For some authors, this is too simplicistic.  Producing bioenergy requires fossil energy (and water) consumption, however research shows that usually the energy used is a small fraction of the energy produced. How little is ‘small’ is a question of debate. Typical energy balances for relevant forestry and agriculture systems indicate that roughly 25 to 50 units of bioenergy are produced for every 1 unit of fossil energy consumed in production. Producing liquid bioenergy requires more input energy, but still reduces fossil fuel consumption overall. But –including the net effect of the land use change shows that corn ethanol, for example, releases 93 percent more greenhouse gases over a 30 year period. It would take a 169 year period for ethanol to offset this amount. In the case of forest conversion for palm seeds, it has been predicted that it would take between 75 and 93 years. On degraded grassland, it would take only 10 years. Still, the primary point is that land use change releases a massive amount of greenhouse gases into the atmosphere that would take years to offset.

Carbon emissions from generation of a unit of electricity from bioenergy are approximately between one twentieth and one tenth of emissions from fossil fuel-based electricity generation.

Some studies suggest that the potential global contribution of bioenergy to reduce green-house emissions is between 1.4 and 4.2 GtC per year (based on the current global energy mix). In 2010, about 30 GtC were released into the atmosphere because of combustion of fossil fuels.  This land-based climate change mitigation potential might be achieved in parallel with achieving carbon sequestration through newly created forests or adapted agricultural systems.

Question 10:  How much forestland is needed to supply bioenergy to a power station?

Consider an example of a power station using only forest biomass to generate and supply electricity rated at 3 MW.  Suppose that it operates at full loading for 6000 hours a year, with the remaining time taken up by maintenance or repairs. This means that the power station generates 3 • 6000 = 18,000 MWh of electrical energy every year. Considering that the power station operates with an efficiency of 40%, so to produce 18,000 MWh of electrical energy as output, every year the power station must need 18,000 / 0.4 = 45,000 MWh of bioenergy to burn as input energy. Here it is assumed that the biomass of the forests has an energy value of approximately 4 MWh per dry tonne, after allowing for the influence of moisture content on energy value. Suppose that the power station is to be supplied from dedicated wood energy crops that produce on average 10 dry tonnes of biomass per hectare per year. For this example, the area of land required would be 45,000 / (4 • 10) = 1,250 hectares. If much of the biomass produced will be used for industrial timber, with only a fraction of the harvested biomass – say 10% – available directly as a supply of bioenergy the areas of forest and bioenergy crops may be estimated at between 12,500 hectares.

Question 11: What are the main constraints to develop wood energy market?

Land ownership fragmentation, the lack in horizontal integration among the forest owners and the limited entrepreneurship of the forest managers are the main factors affecting the competitiveness of forest – wood / non-wood / services – consumer chain in many of Mediterranean countries.

The barriers to entrepreneurship are connected with the limited profit arising from wood-related economic activities and the social profile of many land owners.

The low profitability depends from the prevailing location of Mediterranean forests: most of them are located in mountain areas, characterized by many environmental and infrastructural constraints. The low level of international timber prices in the last years and the de-localisation of many wood-working industries to foreign countries is reducing the internal demand for industrial roundwood from mountain areas.

The social profile of many forest owners is characterised by the presence of many aged managers, working part-time in the sector, with a low attitude to introduce innovations, scarcely to participate to associations and any other business activities carried out in cooperation with other economic operators.

The main problems and research questions for enterprise development in the forest sector are connected with the need to overcome the above-mentioned barriers; therefore, the problems seem more related to the need of a social change than to the lack of technologies.

Question 12: What is the Forest certification? What are the main existing Forest Certifications?

Forest certification is a voluntary, market-based tool that supports responsible forest management to ensure that social, economic, ecological, cultural and spiritual needs of present and future generations are met. Certification provides forest owners,  managers, families, communities and companies with access to the global marketplace for certified products. Forest managers or owners who want to prove that their forest operation are socially beneficial and managed in an environmentally appropriate and economically viable manner can apply for forest management (FM) certification.

Dominant certification schemes for certified forest products are the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification (PEFC) schemes. Both, FSC and PEFC, are independent, non-governmental, nonprofit organizations. They promote sustainable forest management through independent third party certification and provide an assurance mechanism to purchasers of wood and paper products that they are promoting the sustainable management of forests.

FSC was established in 1993 as a multi-stakeholder organization aiming to promote the responsible management of the world’s forests. PEFC was established few years later, in 1999, under the name of Pan European Forest Certification (therefore limited to the European context) and then in 2003 became international and adopted the current denomination. Despite sharing the same general aim, the two schemes remain strongly different with regard to (among others) their governance systems, involved actors, standard setting procedures, standard contents, and certification/accreditation mechanisms. The rate of increase of certified forest areas has slowed down during the past decade. Since 2009 PEFC and FSC have been dominant certification schemes. This is partly due to the fact that a large amount of national/regional schemes have been mutually endorsed by PEFC. Link: and

A forest manager and all companies through the supply chain must also achieve Chain of Custody certification (CoC). The CoC can be defined as the “process of handling of information on the origin of forest based products which allows the organization to make accurate and verifiable claims on the content of certified material” (PEFC, 2010). More into detail it is an information trail about the path taken by products from the forest or, in the case of recycled materials, from the reclamation site to the consumer including each stage of processing, transformation, manufacturing, and distribution where progress to the next stage of the supply chain involves a change of ownership (FSC, 2007). CoC certification is applicable for companies that manufacture, process or trade in timber or non-timber forest products and want to demonstrate to their customers that they use responsibly produced raw materials. The forest certification schemes labels ensure customers and buyers of certified wood products they are from responsibly harvested and verified sources.

Question 13: A biomass plant can make use of Green Certificate?

Yes, because the biomass is a renewable energy source. The Italian regulations provides for all plants that use removable source can make use of Green Certificate. Green Certificate are a system to provide incentives electric energy production from renewable source.

Question 14: What is National Renewable Energy Action Plans?

Article 4 of the renewable energy Directive (2009/28/EC) requires Member States to submit national renewable energy action plans by 30 June 2010. These plans, to be prepared in accordance with the template published by the Commission, provide detailed roadmaps of how each Member State expects to reach its legally binding 2020 target for the share of renewable energy in their final energy consumption.

Link to NREAP:

Question 15: How many forest biomass technologies for the energetic use exists on the market?

The most used technology nowadays is local, micro or district heating systems on the wood chips. The boiler house contains boiler, heat tank, wood chips storage with the transport system, armatures and control system.  In the boiler one can produce hot water only or hot water and steam. In this case we have CHP plant (combined heat and power). Steam is used in the steam turbine for electricity production. The newest technology is biomass gasification technology. The main product of the gasification technology is gas which is burned in the co-generator where electricity and heat are produced.

Question 16: What is the cost ratio between biomass and heating oil?

The heating costs depend in the prices of the biomass and heating oil on the market. In Slovenia, for example, the prices of the biomass is  21 EUR/MWh and of the oil is 99 EUR/MWh. The price of the heationg oil is 0,988 EUR/L, the wood chips price is max. 18 EUR/m3.

Question 17: What are the end uses, in suits of energy production, which will be considered under the project for recovery of residual forest biomass?

Despite the end uses to be considered are directly related to the preliminary results of the regional estimate (available quantities and typology of materials), we will analyse the potential of using biomass for energy production in small centers, production of pellets, "district heating ", and local exploitations(municipal swimming pool heating, nursing homes, schools, etc.).