Sustainable biomass and the italian case-Andrea Greti
MSc in sustainable energy and environment
Sustainable biomass and the italian case
Case study for the Energy Studies module
This study is done with the purpose to look at biomass and its market in Europe. After an introduction of what is biomass and why it is important to find alternative energy sources to face with the environmental and oil based fuel problems, will be made a point of the European production of biomass. After it will be covered the different aspects of biomass as energy source.
At the end will be taken in consideration a national case study, Italian energy production strongly based on fuel import, oil and gas, for instance, biomass could be a good resource to limit this reliance.
Annual total GHG emission has been continuously increasing since the beginning of the last century, combustion of fossil fuel is highly dominant in the market of energy production, more than 1100 GT of CO2 have been released in atmosphere from the mid-19th century, 70% of this and all the other pollutant emission have been released during energy process mainly based on fossil fuels. Energy demand is highly unequal distributed across the globe most of the demand pro capita is concentrated in the occidental countries but the fast growth of developing countries will strongly increase the global demand of energy. For instance, not only the problem of sustainable energy systems but the possibility to have access to energy is becoming a key issue in the society. Three factor can be highlighted energy should be seen as affordable, supply reliable and with low environment impact(R.E.H. Sims et all 2007).
In this scenario of energy demand the follow issues have to be faced in the nearly future:
Oil peak, it is uncertain exactly when it is going to happen or if it has been already reached but it is certain that the easy reserve of oil are finishing and oil prices are likely to increase in the futures decades.
Gas peak, same as the oil even if the peak it will occur in a further off future, other issue related: sources are even less distributed than oil.
Coal is still remain abundant but strict environmental regulation require the development of CCS technologies.
Nuclear energy could be a contributor to a carbon free energy production but still there are major barriers as the long term availability, safety and waste management.
Renewable energy are nowadays playing a small role in the energy sector, cost effectiveness and efficiency are barriers to the development in large scale.
In this context the biomass play a major role as renewable energy, this mostly because in developing countries it always has been used to produce heat.
A development of biomass could help to reduce world dependences on fossil fuels, even if there are some sustainable problems in the production of biomass and even if there would be a net saving in most of the processes using biofuels instead of fossil based fuels still CO2 will be emitted in the atmosphere. The Zero global CO2 cycle is not always applicable for biomass production.
What is Biomass
Biomass is defined as different biological materials that can be used as a primary source in order to obtain energy. Producing energy from crops waste, woody material and specifically energy crops has became more and more important for mainly two reasons: the dependence from fossil fuels which are running out and the possibility to decrease emissions respect to the old traditional fuels(Sims 2002).
Biomass has been the first source of energy for the human being as a way to produce warmth. During the eighteenth century it is estimated that two-thirds of the wood removed in America was used for energy purposes. Nowadays there are developed countries that use wood directly in combustion to cover a percentage of their energy demand. In a wider view we can see that in developing countries biomass it is the primary source in the private residential sector, arriving to cover in some of them the 80% of primary energy consumption(Lee 1996).
Renewable energy sources accounted for 12% (59 EJ) of the world's total primary energy demand in 2005. Because of its widespread noncommercial use in developing countries, biomass is by far the greatest source of renewable energy (48 EJ). Approximately two-thirds of biomass is used for cooking and heating in developing countries(Heinimo 2009).
Different type and common uses
Biomass can be obtained from residues or from specifically crops. As residues it can comes from waste after harvesting of different kind of crops or wood process, as specifically crops they can be divided in woody crops which are normally perennial and herbaceous crops which can enter in an agricultural rotation(Lee 1996).
Different approaches are used to convert biomass in energy: direct combustion & co-firing, gasification, pyrolysis and liquefaction are the main processes.
Direct combustion: First form to produce heat has been seen in the past as a potential source of toxic gases and pollution, specially in developing countries where indoor uses had caused real health problems. Nowadays well vented combustion permit to produce energy from 100% biomass or mixed with other fossil fuel(mainly coal).Has been tested that emissions are lower than normal fossil fuel particularly in SOx and efficiency can reach good standards, if electricity and heat production are coupled it is possible to have efficiency of about 80%.(Rajvanshi 1986)
Gasification: Biomass gasification means incomplete combustion of biomass resulting in production of combustible gases consisting of Carbon monoxide (CO), Hydrogen (H2) and traces of Methane (CH4). This mixture is called producer gas. Producer gas can be used to run internal combustion engines (both compression and spark ignition), can be used as substitute for furnace oil in direct heat applications and can be used to produce, in an economically viable way, methanol which is useful both as fuel for heat engines as well as chemical feedstock for industries. Since any biomass material can undergo gasification, this process is much more attractive than ethanol production or biogas where only selected biomass materials can produce the fuel(Rajvanshi 1986).
Pyrolysis & Liquefaction: Both are thermal process in which biomass in converted in biofuels. During the liquefaction process macro-molecule of substance are decomposed into light reactive molecules, in presence of a catalyst and water at high pressure, which stabilizing form oily products. On the other hand, during pyrolysis process normally is not used any catalyst and light molecules are converted in oil chain through a homogeneous reaction in the gas phase(Demirba 2000).
From the Biomass UE action plan(2005):"that increased use of renewable energy is essential for "environmental and competitiveness reasons", while the European Parliament recently noted "that biomass has many advantages over conventional energy sources, as well as over some other renewable energies, in particular, relatively low costs, less dependence on short-term weather changes, promotion of regional economic structures and provision of alternative sources of income for farmers".
UE aims to reach the limits post from the Kyoto protocol and from the 20-20-20 thanks to a vivid increase in biomass consumption, in 2005 it was estimated that bioenergy was accounting for a 4% of the total energy production, in the UE reports the projections are to double this value before 2010.
From the figures of the IEA in 2008 it comes that biomass has grown from the 1990 to the 2006 doubling his market and arriving, regarding the net energy production the 4% is coming from different biomass processes this number has to be added to the biomass used for heating(more than 55% of the renewable heating production) and transport.
First, second generation
After 2000 has been seen a rapid increase of biofuels of first generation as bioethanol and biodiesel, coming respectively from sugar/starch plants or oil plants, after 2007 this trend has decreased mostly for the raising of costs, for an increasingly concern from international associations as FAO about the reliability of this products and the issue of the competition with land used for food production.
More attention is now over the second generation processes which account the gasification process, hydrolysis, biodiesel and bioetanhol produced by algae(called even third gen.). These processes are not in competition with the agricultural production even if they can subtract arable land. These solutions require more steps to arrive to the final product but are able to produce sub-product useful for example in the chemical area(ENEA 2008)
CO2 and Economical impacts.
Biomass has seen as one of the major key option to reduce CO2 emission specially looking at the transport sector.
Today oil derivate used by vehicles are accounting for almost 20 % of the global CO2 emissions biofuels in this case,biomass would help to reduce between a 50-70% of these emissions, and a 30% of emissions would be saved substituting even gas car engine.
Other impact this time negative could be produced by the use of arable lands for the purpose of energy crops production, although not primary important in developed countries has been assessed as a real problem in developing countries(Demirbas et all 2009).
Economical benefits are in several areas of interest to governments, including agricultural production, greenhouse gas emissions, energy security, trade balances, rural development and economic opportunities for developing countries(Demibras 2009).
The specific nature of biomass sources for energy supply requires significant component of agricultural land, these areas are normally characterized by a slow economy and high unemployment. Biomass power could be a driver for a most vivid economy, creating new jobs and rising the medium wages.(Morris 1999)
The CO2 life cycle in the biomass energy has received particular attention in the last years. From the last studies reported from ITABIA(2008), in the UE the policies of sustainability for biomass are changing and special attention is focused on the biofuel process(ITABIA 2008).
It has been set up from the European union that it will have to be considered as renewable energy only those fuels that produce at least 35% less of the CO2 produced with fossil fuels, special attention has been post on the risk of biodiversity, for instance in Italy has been it is required that crops will maintain intact the local biodiversity(ITABIA 2008).
Biomass in the past biomass has been considered a renewable energy without any constraint now it has been argued that biomass can have some limits and it can not be considered always sustainable.
Considering the CO2 cycle in different scenarios the results may vary, for instance if we use forest land to produce energy has been viewed that the net CO2 is arising, as the wood is burned to produce energy the CO2 normally stocked in the plants is released in atmosphere(Reijnders 2006). On the other hand the use of arable land to grow forest crops can lead to a net carbon sequestration.
Finally there is the last opportunity to capture and storage CO2 during the energy production, this vision has been seen in the last years as a big opportunity to have a net gain of CO2 savings during in the biomass sector(Uddin 2007).
Soil, nutrients and water
An important factor in maintaining high productivity, in energy crops, is the maintenance of high levels of organic matter in the soil. Soil organic matter is an important reserve for plant nutrients, such as N (nitrogen) and P (phosphate), improves soil structure and water holding capacity, limiting erosion factor. This may lead to restrictions on burning of harvest residues.
Another factor important in sustainable productivity is the indefinite availability of sufficient mineral nutrients, such as N, P, S (sulphur), K (potassium), Ca (calcium) and Mg (magnesium). Sustainability, as defined here, requires that nutrient levels are maintained and can be maintained indefinitely by the practices used.
Overall, as rates of biomass harvesting also tend to be much higher on plantations than in forests, large deficits in nutrients are to be expected if no fertilization is used. Sustainable enhancement of biomass production can be achieved if there are ways to increase nutrient availability indefinitely(Reijnders 2006).
Fresh water is an important resource in order to have a high productivity. For meeting the criterion of sustainability usage of fresh water resources should not exceed addition to stocks. The potential for biomass production on suitable soils is strongly influenced by water availability.
Use of fossil fuel in biomass process
The increased availability of nitrogen compounds to be used as fertilizer, if compared with the situation before the industrial revolution, is mainly based on the Haber synthesis, which converts fossil methane into ammonia. Based on the Haber synthesis on fossil fuels
cannot be maintained indefinitely as fossil carbon is virtually non-renewable. In this case one may circumvent inputs of virtually non-renewables. For instance hydrogen necessary for converting nitrogen present in air into N-fertilizers can also be generated by 'siphoning' H (hydrogen) from biomass or by hydrolysis powered by solar energy, ways of production that in principle may be maintained indefinitely(Reijnders 2006).
Other application of non renewable resources during the process of energy as transport and powering machinery could theoretically be circumvent by using other renewable fuels.
Three different main chain can be discussed in energy from biomass: bio-oil chain, ethanol chain and ligno-cellulose chain.
1) In Europe the only three cultivations economically growth are rapeseed, sunflower and soybean, rape and sunflower can be grown on set-aside land all over the EU following established procedures and are the two most promising species for further development in Europe.
For these three different species (Venturi 2003)it has been found the energy ratio.
Adopting this criteria, it can be said that ratio and net gain are both always favorable only for rape, this would only be possible for the other species where there was greater use of technical factors and greater production.
2)Ethanol can be obtained through fermentation processes, from crops with high carbohydrate content (cereals, sugar beet, sweet sorghum). Among cereals, wheat, barley, corn and grain sorghum must be considered the best(Venturi 2003).
Criterias to choose any of these different species are not only related to the yield production or the energy ratio but obviously are dictated from external condition such as weather, kind of agriculture, technical know-how fig.4 shows the different variables that have to be take in account during to choose the best crop."From these tables, the choice factors show a clear predominance of cereals that can be assigned to energy production only with the change of final use of product."
The table shows that besides the higher amount of energy required by the sweet sorghum(growing in summer condition), this crop maintain the higher energy ratio. In Europe the major producers are Italy, France, Albany but the percentage of arable land addressed is highly lower than other cereal crops(Venturi 2003). Regarding this species it has to be highlighted the correlation between food and energy production.
3)Among the many species tested in different conditions, those reported in fig.6 are of the greatest interest. Fiber sorghum seems to prevail among annual crops; Arundo donax among perennial crops even though Miscanthus giganteus must be taken into consideration and Cynara cardunculus could be preferred when water is a limiting factor. Other species, mainly switchgrass (Panicum virgatum), seem to be of interest because ecotypes for different needs are available so they can be grown in a wide range of environmental conditions. Biomass ligno-cellulose crops are still at an experimental stage, growing techniques must be developed for them and some hurdles must be overcome, mainly with respect to harvest mechanization and transportation logistics(Venturi 2003).
Another issue to be faced in the biomass energy is the competition with food. Food issue is to ensure in the future availability and access to anybody, from the last review of FAO (FAO 2008), almost 850 million of people are suffering of undernourishment and this number it could growth as the population in the future(FAO ,2008). Biomass growing in arable land has an intrinsic connection with the food market. Energy market has become in the last years really powerful and with now has this strong link with the food market. Consequence of this is that the price of food could now be regulated not only from the human demand but even from the energy supply demand. This will bring instability and will be possible to see fluctuation in the future following the gas and oil prices. In this point rely one of the major ethical problems of biomass. It is important in this section concentrate especially in poorest countries as they are the most sensitive.
They are living in a period of growing import in food and energy sector, this is crucial as an arise of the prices will not favorite in any way the potential of the developing countries. Short term analysis studied in (FAO ,2008) show that during the first period negative effects are predominant, particularly in poor urban and rural area, but in the long term view a development could bring some benefits. Higher prices could promote agriculture in developing countries, some of them have a good climate in order to become from buyers to producer of their own energy, this require a strong government commitment in public investment. Small farmer realities will have to be active part of this growth gaining improved efficiency techniques and therefore an easier access to the market. In some case there could be external private investor trying to develop biofuel, this will bring more funds but at the same time will have to be regulated in order to do not cut off local producers.
Some best practices in order to maintain a social sustainability of biomass are:
- Growing without needs of extra-stock of water
- Use of marginal lands
- develop second generation ligno-cellulose biomass having no competition with food
- Preserve small scale realities especially in poor countries, this will help to increase the local economies rather than the profit of some multinational.
Italian biomass production and potential
Italian energy outlook
From the eurostat statistics of energy in Italy, the scenario of the energy sector it can be drawn for the last years in this country. Italy is highly dependent on primary resource import, the general electrical system is highly based on fossil fuels since there is no production of nuclear power, in 2007 85% of the electrical demand has been covered with thermal processes, the 65% of it has been produced by natural gas(Eurostat 2009).
There is almost a ratio of 7.5 between the import and the import and the national production with 60^3*100toe imported(Eurostat 2 2009). Moreover the capacity of the italian generation system is not sufficient to cover the entire demand and as it is possible to see from the graph below in the last 20 years there has been a continuous rise of the electricity imported primary from France.
In the last years the amount of energy imported is accounted for more than 10-12% of the total electricity used.
In this frame the renewable energies are still a small player. If it is considered only the electrical production, Italy can account a high potential in hydro power but it is mostly remarked in literature that probably there will not be any other big development in this field, other component is the geothermic energy, Italy has been one of the first countries to use underground heat to produce energy, today it accounts for a small 1.5% of the electrical consumption[Enel SPA]
Arriving to the renewable italian mix from the 2007 stats it is composed as follow.
If it is considered the whole energy consumption renewable sources they account for a 6.9% of the gross consumption, mostly are used to produce heat and electricity. The renewables with the most potential in Italy include geothermal, biomass, solar thermal and solar PV, whereas the hydro potential is nearly fully utilized. The development of the gross consumption of renewable energy in Italy this accounts not only the electricity production but any demand of energy in the country as heating and transport as well, even if is notable the continuous growth still the shares of renewable energies respect the total supply are relatively low, last year they were attested at the 6.5%. The total renewable energy available in Italy is still mostly based on the variation of hydro power available in any year. As it is possible to see from the graph below the total supply follow the peak and trough of the available amount of hydro each year. Regarding the electricity production Italy have the 18.2% produced by renewable resources this is formed mostly from the hydro systems.
Biomass in Italy
The use of biomass in Italy has grown in the last 10 years from a potential of 89 MW in 1997 is today arrived to have a plants power of 449 MW with 45 plants active, as shown in the next table. Between these years the number of plants processing biomass has grown around 10% per year, the average increase of power is attested to be a 15.8% per year. In this period there has been an evolution of the plants, passing from small plants with an average power of 5.6 MW in 1997 to plants with a mean of 10 in 2008. In the last year Italy produced more than 2.5*10^3 GWh from the 45 plants with an average increase of 27% per year in the last 10 years, a rocketing peak had been during 2001 and 2004 when energy produced increased of 240% in three years. In the UE 15 the energy form biomass represent the 9.7% of the renewable energy shares. First contributor with more than 21% is Germany followed by Finland and Sweden, Italy has only the 5.6% of the total production(GSE 2008).
The total amount of available land to produce biomass has been assessed by Cotana (2009).
The amount of forest that could be available for biomass production is 10 Mha, if the productivity is set up as between 60 and 100t/ha year with a life cycle of 20 years, it is possible to hypothesize a total production of 36Mt of biomass to which has to be subtract the amount of wood for different processes(wood for furnitures, wood for private heating, wood to expensive to bring outside,ecc), so that at the end the net amount would be 17Mt.
Taking in consideration the set a side crops it would be possible have an average productivity of 15Mt/ha*y and 8Mt/ha*y in those zones were there is no irrigation thanks to species as the robinia. It is estimated that 0.8Mha could be available for crop energy uses without competition with the food production and 3Mha are available of marginal lands that could be used to produce biomass even if with a low yielding factor. If it is accounted a possible competition between food crops and biomass production there could be a possibility to gain 1Mha more from the 8Mha of fertilized land available for agriculture, it is possible to have a 1.8Mha for energy corps. In 2003 The "Ministero dell'ambiente e della tutela del territorio" has published a report(ITABIA 2003) where it is highlighted that the possible annual supply of biomass from agricultural residues could be about 7.9 Mt/year this taking in account that part of these are not cost effective. In fact one of the major problem of this basket of potential energy is laying in the difficulty to have a high organized harvesting process, this appears particularly difficult if applied to small realities, for instance only in the last few years have been introduced a mechanical harvesting of the pruning. In the report has been viewed as a possibility to increase this process the creation of co-operative companies specialized and organized in this process. Moreover it has to be counted that part of the waste in some process as the straw it is normally leaved in order to maintain a quantity of organic matters. Another source of organic matter for biomass it could arrive from the so called agri-industry(oil, wine, furniture, paper, rice, conserve,dried fruit), ITABIA (italian biomass association) estimated in 2003 that another 7.3Mt of potential biomass could be obtained from this industry. This means that there is a 15.2 potential in the organic residues. With these scenarios it is possible to obtain a total mass of organic substance available of 67.55Mt/year and it should be added a 14Mt more if it would be used some of the arable land.
A qualitative estimation of the energy that could be produced by this biomass 6.76*10^3 GWh/year.
In conclusion there is still available a potential to triplicate the actual production of energy by biomass from 2.5GWh/y to more than 7GWh/y if it is accounted a low competition with food production. The last national report from the government and ITABIA2008 besides the importance of biomass specially the one from the residues of the different sector, emphasize the importance of control along all the process in order to maintain sustainability standards.
In this work it has been touched three main arguments. First, it has been highlighted the energy and environmental issues, bases for the entrance of biomass in the energy mix. Where biomass is coming from (crops, wood, waste), and the process involving biomass in order to produce energy or fuels. In the second part various benefit and problems have been highlighted.
Economical growth in some rural areas.
The environmental problems and the focus on the importance of reduce CO2 in the life cycle assessment. The sustainability dilemma in the secondary process with the use of oil and the problem at an organic level relate with the soil. At the end of this section has been focused the problem to face a growing food demand with the strong competition created between food and energy. In the third part it has been carried out an overview of the italian energy status, which are the main renewable sources used in Italy. The importance of biomass how this sector is growing and some future potential mainly thanks to the use of industrial waste.
In conclusion the main points coming out from this study are: the importance of biomass to face the problem of energy supply, the necessity to switch to a generation not in competition with food, regulation in order to safeguard sustainability, the potential in Italy of industrial waste and the importance of biomass in order to reduce energy dependence.
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See appendix 1