Life cycle assessment (LCA) is a systematic approach to analyze and examine the impacts of products or services on the environment. Not only these impacts, but their whole life cycle (i. e., from resource extraction to end-of-life) is analyzed. LCA is based on the modeling of interconnections between the single processes of a product system, in order to identify the material and energy flows within the system. From this model, the so-called ‘elementary flows’ — i. e., material flows between the product system as a whole and the natural environment — can be derived. Finally, the impacts or damage to the environment can be assessed. The core methodology of LCA was developed during the 1990s, with the SETAC ‘Code of Practice’ as a first milestone (Consoli et al, 1993), and today is described in two international standards, ISO 14040 and 14044, which are part of the ISO 14000 family of standards on environmental management.

According to ISO 14040, a life cycle assessment study consists of four phases: goal and scope definition, inventory analysis, impact assessment, and finally interpretation (Fig. 3.2). The double arrows in Fig. 3.2 indicate that an LCA is seen as an iterative process; additional information gained during a study can require a backshift to a previous stage to include further aspects. The first phase of an LCA study, goal and scope definition, defines and specifies the objects and the research questions. It also defines the system

boundaries of the product system, e. g. as to space and time. A central task of LCA is the comparison of different products with the same function to extract particularly environmentally friendly goods or services. To fulfill this target, a clearly defined functional unit has to be determined. According to ISO 14040: ‘the functional unit defines the quantification of the identified functions of the product’, which means that the function has to be specified in terms of a quantity of a product or service, e. g. per kg of a product or per km of a transport service.

The second phase, life cycle inventory analysis (LCI), consists of three parts: creation of a flow model, data collection and calculation of the results. In a flow model, processes of the product system and their connections are described. The product system itself is defined by ISO 14040 as a ‘collection of unit processes with elementary and product flows, performing one or more defined functions and which models the life cycle of a product.’ For each unit process, data for input and output flows have to be gathered, together with other important information as to the process itself. The result of the LCI analysis is the quantification of the elementary flows resulting from the delivery of the functional unit, i. e. the product or service. The third step — the life cycle impact assessment, LCIA — transfers the results of the inventory analysis in a quantification of potential damage to the environment. To do so, the concept of impact categories is used. An impact category represents a certain environmental problem, e. g. climate change. It is quantified by a category indicator, which is based on an understanding of the underlying causes of an environmental problem as described in a respective scientific model (‘characterization model’). As the last phase of LCA, the interpretation transfers the results from the LCI analysis and LCIA to a clearly understandable message for the intended audience of an LCA study. The phase of interpretation also includes procedures of quality assurance and sensitivity analysis.

Details of the methodology of life cycle assessment can be found in textbooks as well as on internet platforms (Baumann and Tillmann, 2004).

Given the widespread distribution of bio-feedstocks such as dedicated non­food crops or food supply chain residues, the development of small localized biorefineries compared to traditional mega-scale refineries is attractive. This will ensure that biomass is valorized as closely as possible to its production site, avoiding high transport costs for lower value feedstocks and increasing the sustainability of the process, as well as making sure as little as possible biomass is imported to meet targets. Such an approach will also prove the feasibility and the scalability of novel clean and green technologies while requiring a lower primary investment. This will encourage further industry sectors to support biomass and food supply chain residue conversion to bio-chemicals, bio-materials and bio-fuels. Important steps in this direction include the use of continuous processing and of feedstock agnostic technologies to allow maximum biomass conversion efficiency and flexibility in operation to suit places with multiple resources (e. g., an area growing or processing fruit and vegetables). Biofuels alone are likely to become insufficient as green products as wind, solar and other clean energies develop; but the combination of bio-fuels and the higher value bio-chemicals can make biorefineries the sustainable production chain for the twenty-first century, just as petroleum refineries dominated the twentieth century.

1.2 Sources of further information and advice

• EU COST Action TD1203 ‘Food Waste Valorisation for Sustainable Chemicals, Materials & Fuels’, http://costeubis. org/

• S. K. C. Lin et al., Energy Environ. Sci., 2013, 6, 426-464.

• L. Pfaltzgraff et al., Green Chem., 2013, 15, 307-314.

• Green Chemistry Network: http://www. greenchemistrynetwork. org/ index. htm

• Handbook of Green Chemistry and Technology, edited by James Clark & Duncan Macquarrie, Blackwell Publishing, Oxford, 2002.

• Renewable Raw Materials — New Feedstocks for the Chemical Industry, edited by R. Ulber, D. Sell and T. Hirth, Wiley-VCH, Weinheim, 2011.

• Feedstocks for the Future — Renewables for the Production of Chemicals and Materials, edited by J. J. Bozell and M. K. Patel, American Chemical Society, Washington, DC, 2006.

Biomass supply chains span from local collection efforts to international networks. National and regional biorefineries can thus be classified by the extent of their supply networks and product distribution. Most biorefineries are small-scale, regional facilities that collect feedstock from within a state or region. On the other hand, large-scale, national biorefineries would transport biomass across state borders to meet demand.

A majority of US ethanol biorefineries generate less than 80 million gallons (303 million liters) per year as shown in Fig. 2.2 (Anon., 2009b). At this capacity, biorefineries can collect enough corn from surrounding counties. In Iowa, for example, corn ethanol biorefineries receive their feedstock from an average distance of 28 miles (45 kilometers) (Anon., 2008). Nearly half of corn suppliers use tractor-pulled wagons while others employ straight trucks, fifth wheels or semi-trucks. Although short transport distances characterize corn supply, corn ethanol travels much farther. Corn biorefineries employ rail, trucks, and barges to ship ethanol to demand centers both within the county and across multiple state borders.

National, and international, biorefineries are defined here as facilities that receive feedstock by multiple transportation modes and from regions hundreds of miles from the facility. The large supply networks required to feed these types of biorefineries pose key economic challenges that differ from those faced by the fossil fuel industry. The biomass industry is still trying to understand the nature of these challenges and develop ways of addressing them.

Green chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances (Anastas et al., 2000). The concept emerged 20 years ago with the introduction by Paul T. Anastas and J. C. Warner of the 12 principles of green chemistry (see Table 1.1). The subject continues to develop strongly around these principles (Anastas and Warner, 1998). Green chemistry aims to achieve (Clark and Macquarrie, 2002):

• maximum conversion of reactants into a determined product,

• minimum waste production through enhanced reaction design,

© 2014 Woodhead Publishing Limited

Table 1.1 The 12 green chemistry principles

1. Prevention

It is better to prevent waste than to treat or clean up waste after it has been created.

2. Atom economy

Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.

3. Less hazardous chemical syntheses

Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to human health and the environment.

4. Designing safer chemicals

Chemical products should be designed to effect their desired function while minimizing their toxicity.

5. Safer solvents and auxiliaries

The use of auxiliary substances (e. g., solvents, separation agents, etc.) should be made unnecessary wherever possible and innocuous when used.

6. Design for energy efficiency

Energy requirements of chemical processes should be recognized for their environmental and economic impacts and should be minimized.

If possible, synthetic methods should be conducted at ambient temperature and pressure.

7. Use of renewable feedstocks

A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.

8. Reduce derivatives

Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.

9. Catalysis

Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.

10. Design for degradation

Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.

11. Real-time analysis for pollution prevention

Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.

12. Inherently safer chemistry for accident prevention

Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions and fires.

• the use and production of non-hazardous raw materials and products,

• safer and more energy efficient processes, and

• the use of renewable feedstocks.

Efficiency is the key, and green chemistry has continued developing around the principles, which guide both academia and industry in their pursuit of more sustainable processes. In an ideal case, according to these principles, a reaction would only produce useful material. Waste and pollutants would be prevented, improving the reaction yield and reducing losses, thus improving the overall economics of a process. Since our society and industries are governed by increasing efficiency and profit, green chemistry therefore theoretically fits the agendas of most manufacturing companies these days, not only appealing to chemical producers.

Today, 20 years after their publication, the 12 principles of green chemistry are as meaningful as ever in the light of the increasing interest the area attracts due to concerns over sustainability (Anastas and Kirchoff, 2002). Misunderstandings have arisen due to the attractiveness of the area to sectors dealing directly with public demands for ‘greener and more environmentally friendly’ products. It is therefore of vital importance that the message is not distorted by common misconceptions over what is or is not ‘green’, thus altering their original goal: to aim towards safer and cleaner chemistry.

The implementation of REACH (Registration, Evaluation, Authori­zation and Restriction of Chemicals), or Directive (EC 1907/2006), ROHS (Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment) or Directive 2003/108/EC, and other initiatives highlighting the hazardous character of some chemicals used in day-to-day consumer products, such as the SIN list (n. d.), are pushing hard for their replacement to avoid further risks to human and/or environmental health. However, we should make sure the substitutes used are genuinely safer across the whole life cycle and as effective as what they are replacing. Investing in R&D focused on finding truly greener alternatives, thus eliminating rushed and weak substitutions that can even increase the number of components present in formulations when ingredients are added to compensate for a lack of performance in the ‘greener’ formulation, is important. The same applies to the substitution of fossil-derived chemi­cals with more sustainable bio-derived chemicals: when using renewable feedstocks such as biomass, we have to use clean and efficient synthetic routes, minimizing the amount of unwanted by-products and the use of scarce resources (i. e., scarce metals).

Scarce metals are increasingly used in clean alternative energy-producing technologies. Their reserves are sometimes only estimated to last another 50 years, or even less for key elements such as indium (a key component in solar panels) (Dodson et al., 2012) and we must take this into account when modifying our energy and manufacturing infrastructure, taking advantage of the whole periodic table. This is especially relevant to the area of catalysis: re-usable catalytic metals are seen as better reagents than hazardous reagents such as AlCl3. But many of the most interesting catalytic metals are also becoming scarce and their production process can be resource intensive and wasteful, making their recovery and reuse essential. Water is increasingly seen as a scarce resource too in certain areas of our planet, but its use as a green solvent is increasingly envisaged due to its non-toxicity compared to hydrocarbon-based solvents (Simon and Li, 2012). Nevertheless, contaminated water is difficult and expensive to treat and re-use. Another alternative to VOC solvents are involatile solvents such as ionic liquids designed to eliminate air-borne emissions. Ionic liquids are used in phase transfer catalysis for example (Welton, 2004), but their non-emissions are counteracted by their toxicity and their environmental impact when prepared, used and separated for end-use.

Biodegradability is an important sought-after characteristic for ‘greener’ products, but increasing the life-time of a molecule to promote its re-use could be another strategy. Heavily halogenated compounds are poorly degradable and there are some large volume halogenated compounds that need to be phased out (e. g., the solvent dichloromethane). But we must not bundle all halogenated compounds in the same ‘red’ basket. Nature turns over enormous quantities of organohalogen compounds and we need to learn from nature and avoid, as much as possible, those compounds that it cannot deal with (e. g., perhalogenated compounds).

Food waste is a feedstock rich in functionalized molecules, and although it is biodegradable, it should be valorized for new applications as a raw material for renewable chemicals, materials and bio-fuels, leading us towards waste minimization and waste valorization. Wasting resources should be avoided in any optimized process. However, waste can also represent an opportunity as we can no longer afford the luxury of waste.

This past paragraph shows you how tightly knit these issues are, illustrating how important it is to assess the greenness of a process through each of its steps, from the use of raw materials to end-use through manufacturing and use. One change can affect several steps and it is important to assess a process through its full life cycle even though it is time-consuming and its quality is dependent on the data used. Such a tool can help us assess the use of bio-processes versus chemo-processes, for example. Many believe bio-processes are preferable to chemo-processes as they are superior in terms of environmental impact, since they use non-toxic components to selectively yield the targeted product. But as they are time-consuming and expensive, it is unrealistic to believe that chemo-processes will be entirely replaced by natural organism catalysed processes in the foreseeable future.

The assessment of biorefineries generally encounters as a difficulty, that so far there is no unified classification system. The most widely quoted definition of ‘biorefinery’ has been published by the International Energy Agency (IEA) Task 42. ‘Biorefinery is sustainable processing of biomass into a spectrum of marketable products (food, feed, materials, and chemicals) and energy (fuels, power, heat).’ In the same report, a generic classification of biorefinery systems is proposed based on four main features: platforms, products, feedstocks, and conversion processes. Most LCA studies on biorefineries consider or compare products or feedstocks, thus the other classification features such as platform and process appear only in the background. Information about platform and process only gets a closer look when systems are optimized, e. g. to use the same platform for multiple products, to optimize and reduce processing steps, or to avoid energy­intensive processes. The focus of LCA studies is on the products of biorefineries, which is not surprising, as LCA is always focused along the life cycle of its functional unit. This is an advantage on one hand, as it makes comparisons with other process routes for the same product quite easy. On the other hand, it is a shortcoming because the possible specific advantage of a biorefinery as a networking production system is difficult to account for. Still, in the following section a structure following specific products of biorefineries will be applied, while possible shortcomings by the holistic approaches of biorefineries will be discussed later.

T. R. BROWN, Iowa State University, USA, M. M. WRIGHT and Y. ROMAN-LESHKOV, Massachusetts

Institute of Technology, USA and R. C. BROWN, Iowa State University, USA

DOI: 10.1533/9780857097385.1.34

Abstract: This chapter covers techno-economic assessments (TEA) of advanced biochemical and thermochemical biorefineries. We discuss how governments, companies, and academic institutions are affecting the economic prospects of advanced biorefineries. The text describes their economic challenges and the various strategies being pursued to increase commercial adoption of advanced biorefineries: government incentives, facility scale-up, and technological innovation. Finally, we present an overall view of emerging trends in biorefinery TEAs with the intent of identifying key opportunities for improvement.

Key words: biorefinery techno-economic analysis (TEA), advanced biofuel incentives, biomass costs and logistics, thermochemical and biochemical conversion.

2.1 Introduction

The pace of biorefinery technology research and development is increas­ing, fueled by concerns over energy security and environmental impacts. Academic institutions and national laboratories are leading the assessment of promising biorefinery concepts. These assessments investigate concepts at various development stages — from laboratory research to plant-scale commercialization. In this chapter we summarize recent techno-economic analysis findings, discuss how policy influences biomass trade and industry subsidies, and describe the differences between national and regional biorefineries. Our concluding section contemplates the impacts of current challenges and emerging trends.

The term biorefinery encompasses different types of facilities that can convert biomass into valuable products (Brown, 2003). We define a biorefinery as an integrated facility capable of producing fuel, electricity, chemicals, and other types of bioproducts. This concept allows for the full

© 2014 Woodhead Publishing Limited

utilization of biomass compounds and the versatility to vary the product distribution. This concept builds upon the desire to replace every product derived from a barrel of crude oil. In addition to the main industrial building blocks, researchers envision biorefineries that could produce novel types of chemicals and polymers.

There are several biorefinery concepts at various stages of development and commercialization. Their future prospects depend on technological innovation and market conditions. Given the multiple steps required to convert biomass into marketable products, research breakthroughs along any of the conversion steps could accelerate the adoption of a given pathway. Similarly, market conditions could turn formerly unprofitable schemes into commercial successes. More than likely it will be a combination of technological and economic changes that lead the way to commercially — viable biorefineries. Thus, techno-economic assessments provide a unique perspective on current and future biorefinery technologies.

The United States and European governments have established guidelines and incentives to develop renewable fuels. Biorefineries that meet specific government conditions are eligible to receive financial incentives in the form of subsidies. Biorefinery subsidies are projected to increase from US$66 billion today to almost US$250 billion by 2035 (Anon., 2011).

Some biorefinery subsidies have expired in recent years without major impacts to industry growth, signaling the maturity of the biofuel market. However, government subsidy programs have begun to set strict requirements relating to direct and indirect lifecycle greenhouse gas emissions (GHG) on advanced biorefineries as a condition of participation. In order to meet these requirements, renewable energy companies are seeking novel approaches to convert a wider range of biomass into cleaner, cheaper bioproducts. This search requires the assessment of the technical and economic prospects of novel pathways. Therefore, governments are collaborating with academic institutions, national laboratories, and commercial enterprises.

The diffuse nature of biomass availability means that biorefinery scale-up will have wide area impacts on local, regional, and national scales. Although most biorefineries today are limited to capacities of about 100 million gallons (379 million liters) per year, process development and improved biomass logistics could lead to larger biorefineries that gather biomass from hundreds of square kilometers via truck, rail, or barge transport. These biorefineries will present novel, international case scenarios. Thus, there is interest in studying the challenges and opportunities for biorefineries in the global market from a TEA perspective.

The biomass industry presents a rapidly changing landscape with challenges and opportunities. Three recent trends have emerged as the result of faltering government support, sustained high petroleum prices, and changing public opinions on biorenewables: the replacement of starch feedstocks with lignocellulosic biomass, interest in thermochemical pathways, and public and private investment in high-risk, high-reward alternatives.

Lignocellulosic biomass has historically proven difficult to convert into bioproducts with traditional biochemical approaches due to the biological recalcitrance of cellulose and antimicrobial properties of lignin. Develop­ments in genetic and metabolic engineering have opened new pathways to convert hemicellulose into valuable products. These avenues range from enhancing biomass growth to developing bacteria strains capable of digesting formerly discarded or toxic parts of biomass crops.

Thermochemical research pathways have attracted recent attention due to their ability to inexpensively convert lignocellulosic feedstocks to energy — dense gases and liquids. Most of the recent development in the field has been on adapting conventional commercial processes (such as those employed by petroleum refineries) to handle biomass feedstocks and biobased intermediate products. However, there are growing efforts in the search for novel catalysts that can optimize the selectivity and yield of desired bioproducts. Finally, researchers have also proposed hybrid approaches that combine the strengths of the biochemical and thermochemical platforms (Brown, 2005).

There is growing commercial and political support for the develop­ment of high-risk, high-reward platforms such as microalgae-to-fuels, furan synthesis, and sugar-based hydrocarbons. Government-funded algae research was eliminated in the 1990s in favor of ethanol but has recently staged a resurgence due to concerns over land availability and GHG emissions.

Biomass is a diffuse resource that requires significant investment to collect and transport to a biorefinery. There are numerous studies on biomass logistics. Recent developments in geographic information systems (GIS) and operations research (OR) allow for increasing level of detail in logistic studies. In general, logistic studies attempt to estimate the costs for biomass collection, storage, and transportation.

Researchers at Iowa State developed estimates for feedstock suppliers’ willingness to accept (WTA) selling price based on the following equation (Miranowski and Rosburg, 2010):

where CES stands for establishment and seeding costs, COpp represents land and biomass opportunity costs, YB is the biomass yield, CHM are harvest and crop maintenance costs, SF are stumpage fees, CNR are nutrient replacement costs, Cs is storage, DFC and DVC are the fixed and variable transportation costs, respectively, D is the distance to the biorefinery, and G are governmental incentives.

Biomass production incurs sunk costs in the form of establishment, opportunity, and nutrient replacement costs. Establishment costs can be ignored for biomass residue, but they are important for dedicated energy
crops. Biomass land and opportunity account for the loss revenue from growing alternative crops and land rental value. The removal of significant quantities of waste material would require nutrient addition in order to maintain soil quality.

Biomass collection varies between different types of feedstock. The corn, and sugarcane, industry has developed specialized machinery that collects grain at low cost: harvesting costs account for less than 15% of corn costs (Duffy, 2012). Collection costs for other types of feedstock have higher contributions to the overall cost. Harvesting cost estimates for corn stover, switchgrass, and miscanthus range between $14 and $84 per dry ton ($15 and $93 per dry ton) (Committee on Economic and Environmental Impacts of Increasing Biofuels Production, 2011), which could represent between 10 and over 80% of the delivered feedstock cost.

Cost estimates for biomass transport vary widely. They vary due to a lack of consistent data and because of the different methods employed. Transportation costs are typically reported as a total delivered cost or with fixed and variable components. DVC costs range between $0.09 and $0.60 per dry ton per mile ($0.06 and $0.41 per dry ton per km). DFC costs range between $4.80 and $9.80 per dry ton ($5.30 and $10.8 per dry ton).

Location is a major factor in the overall costs of delivering biomass to a facility. Land productivity, transportation networks, and storage facilities are a few of the parameters that vary significantly across various locations. GIS software provides display and analytical capabilities to investigate biomass supply chains. The US government provides a wealth of data in the form of GIS maps and dataset through their centralized portal www. data. gov. An example is shown in Fig. 2.3, which illustrates the distribution of total biomass resources in the US. There are high concentrations of biomass in the Midwest (stover), Pacific, Atlantic, and Gulf Coast (wood) regions, and around large metropolitan areas (MSW). This study estimates the biomass resources currently available in the United States by country. It includes the following feedstock categories: crop residues (5 year average; 2003­2007), forest and primary mill residues (2007), secondary mill and urban wood waste (2002), methane emissions from landfills (2008), domestic wastewater treatment (2007), and animal manure (2002). For more informa­tion on the data development, please refer to http://www. nrel. gov/docs/ fy06ostiZ39181.pdf. Although, the document contains the methodology for the development of an older assessment, the information is applicable to this assessment as well. The difference is only in the data’s time period.

The operations research field has developed mathematical formulas that evaluate biomass logistics within a geographical context. These formulas can estimate costs for a given region (city, municipality, county, state, agricultural district, nation, international) with improved relevance. Biomass supply formulations typically involve an objective function, several variables

2.3 US total biomass (grain, waste, wood) county-level supply (Milbrandt 2005, produced by the National Renewable Energy Laboratory for the US Department of Energy).

or parameters, and multiple constraints. For example, we could reduce

where i and j are subscripts representing biomass supply and biorefinery locations respectively, F is the amount of biomass shipped from i to j, n is the set of biomass supply counties, and m is the set of biorefinery locations. The Biomass constraint ensures that no more than the available amount of biomass gets shipped from a supply count, and the Demand constraint requires that the biorefinery receive enough biomass to satisfy their full capacity. This simple formulation can be expanded to include dynamic or temporal considerations, multi-level supply chains, and social and environmental parameters.

Our society faces a new challenge: as the current consumption model dominated by market demand is running out of breath, our society needs to adopt a more realistic and sustainable model based on the efficient and sustainable use of natural resources in order to sustain emerging economies at the standard established in the West over the last century.

Current manufacturing practices are strained by the increasing price of feedstocks such as oil and consequently of energy and petrochemicals, increasing waste cost (treatment or disposal) together with the increasing impact of legislation affecting almost all aspects of its operations (e. g., supply of raw material, manufacturing, end-use and disposal).

Legislation has had a dramatic impact on product manufacturing since human and environmental safety have attracted increased concern follow­ing publications of traces of chemicals in animal and human tissue in the 1970s and 1980s (e. g., dioxins) (Schecter, 1998). Legislation now has an influence on the type of process, process steps, emissions, end treatment of waste, illustrating how every stage of the supply chain of a chemical product has to be the least polluting possible (i. e., Integrated Pollution Prevention and Control legislation, IPPC) (Lancaster, 2010). With new regulations such as REACH and ROHS (Restriction of Hazardous Substances), an important number of chemicals will have to be replaced by less harmful substitutes, shaking to the core industrial sectors like home and personal care products, the pharmaceutical industry and the agricultural sector.

Resource is a stage in the product life cycle where green chemistry can have a major impact in the future. The use of renewable, typically biomass for carbon, instead of finite resources is becoming more economically and environmentally sound, being one of the main areas of research in green chemistry along with clean synthesis, greener solvents and renewable materials. Biomass is also a resource which can be renewed within a time interval relevant to our resource consumption (see Fig. 1.1), biomass being a ‘biological material derived from living, or recently living organisms’.

The emergence of EU standards for bio-based products (Mandate M/429; see Section 1.3.1) will, in the near future, embrace life cycle considerations and introduce specifications along the whole supply chain for new and existing products on biomass content, and will further discourage the use of fossil resources in favour of renewable feedstocks such as biomass including bio-wastes.

The public and consequently the retail sector have been increasingly aware of the dangers of some unsafe practices in industry and unsafe chemicals in consumer product formulations. They are now asking manu­facturers to produce bio-derived chemicals and question the environmental impact of their production, driving the market towards green and

1.1

Comparison of production cycles of chemicals derived from biomass and oil.

renewable alternatives in many sectors, especially in home and personal care products.

In line with the EU’s innovation strategy and following the initiation of a new policy in 2006 aiming to support the development of high economic and societal value markets, the European Commission proposed further steps for the creation of lead markets. Bio-based products are the subject of one of the identified lead markets and fall into this category for several reasons (European Commission, 2007, 2009):

• use of renewable and expendable resources

• less dependency on limited and increasingly expensive fossil resources

• the potential to reduce greenhouse gas emissions (carbon neutral/low carbon impact)

• the potential for sustainable industrial production

• potentially improved community health

• support to rural development

• increased industrial competitiveness through innovative eco-efficient products

• potential for transfer to other regions of the world including the transfer of appropriate technologies discovered and proven in the EU.

A recent study estimates that, by 2025, over 15% of the US$3 trillion global chemical market will be derived from bio-derived sources (Vijayendran, 2010). Yet another study highlights the technical feasibility of over 90% of the annual global plastic production of 270 Mt being substituted by bioplastics. In 2005, bio-based products already accounted for 7% of global sales and around €77 billion in value in the chemical sector. EU industry accounted for approximately 30% of this value. Estimates of the ad hoc advisory group for bio-based products have identified active pharmaceutical ingredients, polymers, cosmetics, lubricants and solvents as the most important sub-segments (Commission, 2009). Active pharmaceutical ingredients in particular, with 33.7% of global chemical sales, are expected to be the chemical segment with the highest percentage sales of products produced using biotechnological processes. It is predicted that Europe will be strong in sales in the following sub-segments: active pharmaceutical ingredients, polymers and fibres, cosmetics, solvents and synthetic organic compounds.

Given the current policy interest in biofuels, a large number of studies are available. The term biofuels denotes plant oils, biodiesel, bioethanol and biogas. Generally, LCA studies compare biofuels with the respective petrochemical fuels, which are gasoline, diesel and natural gas. An additional interest is to compare different biofuels, which are specified as so-called feedstock-technology combinations, i. e. process chains using a specific feedstock and a specific technology, where one technology may be feasible for different feedstocks and vice versa.

100% Rape ME CH 100% Rape ME RER 100% Palm oil ME MY 100% Soy ME US 100% Soy ME BR 100% Recycled plant oil ME CH 100% Recycled plant oil ME FR Methanol fixed bed CH Methanol fluidized bed CH Ethanol grass CH Ethanol potatoes CH Ethanol sugar beets CH Ethanol whey CH Ethanol wood CH Ethanol sweet sorghum CN Ethanol rye RER Ethanol corn US Ethanol sugarcane BR Methane grass biorefinery

> Methane manure

і Methane manure+cosubstrate

> Methane manure, optimized Methane manure+cosubstrate, optimized

Methane biowaste Methane sewage sludge Methane wood

3.3 GHG emissions for several biofuels per km for biofuels and fossil fuels (Zah et al., 2007).

One comprehensive survey including the biofuels ethanol, methanol, biodiesel and biogas has been carried out in a study commissioned in 2007 by the Swiss federal administration (Zah et al., 2007). It covered several technologies as well as biomass from domestic and from main production regions worldwide. The main results are presented in Fig. 3.3.

As Fig. 3.3 shows, the environmental performance as to global warming potential (GWP) is dependent on the type of fuel, the species and the regional origin of the feedstock. The lowest GHG emissions can be found for biofuels based on waste materials. Among agricultural feedstocks, those with high yield due to the species and the climatic conditions of agriculture show better performance; this is true, for example, for sugar cane from Brazil. The other way round, low yields per hectare and high use of nitrogen fertilizer along with the emissions of N2O (nitrous oxide) for
certain agricultural techniques, e. g. for corn from the US, lead to comparably high values of GHG emissions. The assessment of biofuels is different for other impact categories, notably eutrophication. Here, fertilizer use gener­ally causes a higher impact compared to fossil fuels but also shifts environ­mental performance between different feedstock-technology combinations. In addition, specific contributions to other impact categories exist, for example by the use of chemicals in agriculture, toxicity impacts appear.

These general findings are confirmed by the majority of studies, although controversial debates on single issues are encountered in the literature. One of these debates emerged as to the net energy ratio of starchy crops, specifically on bioethanol production from corn in the US, where some authors reported negative results and stated that more fossil fuel is consumed by production than gained as bioethanol (Pimentel and Patzek, 2005). These findings, however, were not confirmed by others (Hill et al., 2006; von Blottnitz and Curran, 2007). In contrast, all studies agree that net energy ratio as well as GWP are far better for sugar cane compared to corn, and that crop yields have a major impact on the overall results, as shown in Fig. 3.4 for GHG savings per acre depending on crop yields.

The large contribution of agriculture is also confirmed for other impact categories. This is shown, for example, for sugarcane by Cavalett et al. (2011) (Fig. 3.5). Due to the use of agrochemicals, agriculture is generally seen as the main contributor to the impact categories of human toxicity and ecotoxicity (Bai et al., 2010; Cherubini and Jungmeier, 2010).

During recent years, an additional aspect of agriculture has been recog­nized as a crucial issue for assessment of biofuels, which is the concern of land use changes (LUC) due to the rising demand for biomass. Land use change implies the direct or indirect change of not-cultivated land for agricultural use. Depending on former use, actual crop and agricultural techniques, carbon contained in the soil and plants can be released to the atmosphere, which in the worst case can jeopardize all GHG savings of biofuels. There are controversial statements regarding this topic since the first publication, but all studies agree that additional contributions to GHG must be expected from the conversion of very carbon-rich areas like peatland. This is confirmed, for example, for the case of palm oil diesel by a recent meta-analytic review of LCA (Manik and Halog, 2013).

The other important issue as to environmental performance of biofuels is the conversion technology itself. Here, several aspects have to be taken into account, primarily the efficiency of the technology. So-called second generation biofuels that make use of the full plant (and not only part of it, like seeds) are expected to show better performance, but this is also controversial. Von Blottnitz considered 47 publications that compare bioethanol production systems using LCA. Some of the LCA studies show a better environmental performance for second generation biofuels than first generation biofuels (Stoglehner and Narodoslawsky, 2009; Cherubini and Jungmeier, 2010). In addition to this, conversion technologies may provide by-products, e. g. glycerin from biodiesel production. In LCA, these are accounted for as to their substitution of fossil-based products. The way this is done on the methodological level may also be decisive for the outcome of an LCA study (see Cherubini and Str0mman, 2011).

LCA results for bio-based chemicals

Bio-based basic chemicals, often called platform chemicals, are industrially produced chemicals that are used as raw material for many industrial products. Here, only few LCA studies are available (excluding ethanol, which was included above as part of the biofuels section). In 2006 a study of biotechnological production of 21 bulk chemicals from renewable resources was carried out on behalf of the EU (Patel et al., 2006). All bio­based products were compared with the respective petrochemical product using the categories of non-renewable energy use (NREU), GWP, land use in the form of land occupations and other environmental impacts. From this, significant reductions have been identified for all bio-based products. Limited availability of data and uncertainty concerning novel processes were identified as a main drawback of the assessment. Mainly based on this study, Hermann et al. presented results for the assessment of ten bio-based bulk chemicals produced by biotechnological processes (Hermann et al., 2007): 1,3-propanediol (PDO), acetic acid, acrylic acid, adipic acid, butanol, ethanol, lysine, lactic acid, polyhydroxyalkanoates (PHA), and succinic acid. In addition to that, five products produced from the aforementioned products are included: caprolactam, ethyl lactate, ethylene, polylactic acid (PLA), and polytrimethylene terephthalate (PTT). The assessment covers waste management within the system boundary and takes into account the impact categories NREU, GWP, and land use. Results show savings as to GHG and NREU for most bio-based chemicals, already for current technologies. For future technology, it is estimated that due to learning effects the savings will be 25-35% higher. This can be explained by the relatively high energy requirement for the production of petrochemical polymers.

There are some studies focusing on individual bio-based basic chemicals. Ekman and Borjesson show that propionic acid produced from by-products of agriculture leads to significant reduction of GHG emissions compared to fossil fuel alternatives. However, the contribution of propionic acid to eutrophication is higher (Ekman and Borjesson, 2011). Glutamic acid is an important component of waste from biofuel production and an interesting starting material for the synthesis of bio-based chemicals. Lammens et al. compare the environmental impacts of four bio-based chemicals from glutamic acid with their petrochemical equivalents: N-methylpyrrolidone (NMP), N-vinylpyrrolidone (NVP), acrylonitrile (ACN), and succinonitrile (SCN). The bio-based NMP and NVP show less impact on the environment, while for the ACN and SCN the petrol-based chemicals have less impact. Further optimizations indicate that the production of bio-based SCN can be improved to a level that can compete with the petrochemical process (Lammens et al., 2011).

Uihlein and Schebek (2009) compare the environmental impact of a lignocellulose biorefinery system with conventional production alternatives. The biorefinery delivers three products (lignin, ethanol, xylite), which are compared to their fossil counterparts (see Fig. 3.6). It was found that the biorefinery has the largest environmental impacts in the three categories fossil fuel use, respiratory effects and carcinogenics. The environmental impacts mainly arise from the provision of hydrochloric acid and to a lesser extent also from the provision of process heat. The optimal variant (acid and heat recovery) provides better results than the fossil alternatives, whereas the overall environmental impact is approximately 41% lower compared to the fossil alternatives (Uihlein and Schebek, 2009).

Polymers are a main product group of the chemical industry as to the amount produced. This is why bio-based polymers are also the most interesting for biorefinery systems. Vinka et al. have compared the polylactic acid (PLA) production with the production of conventional petrochemical polymers of various kinds for 1 kg product as functional unit by means of LCA. The investigated impact categories are fossil fuel use, GWP and water demand. Fossil fuel use and GWP show significant benefits for PLA. In contrast, water demand shows a much smaller difference between the compared products (Vinka et al., 2003).

Kim and Dale have tried to estimate the ‘cradle to gate’ environmental impact of bio-based polyhydroxyalkanoates (PHA) packaging film made from crop residues (a mixture of corn grain and corn stover). The PHA production from corn grain was defined as the reference system. Compared to PHA from corn grains only, the PHA made from corn husks and corn grains shows negative GHG emissions by -0.28 to -1.9 kg CO2-eq. per kg depending on the technology used. The significant reduction can be explained by the surplus energy from lignin-rich corn stover. Photochemical smog and eutrophication are related to nitrogen-induced soil pollution. PHA fermentation technology is still immature and in the development phase. The trend shows further improvements, thus reducing the environmental impact (Kim and Dale, 2005).

A cradle-to-gate LCA for PHB production was carried out by Harding et al. For the life cycle impact assessment (LCIA) GWP and ten other impact categories were selected. The LCA results were compared with the production of polypropylene (PP) and polyethylene (PE). They show that, on one hand, the energy required for the PHB production is significantly lower than for the polyolefin production, on the other hand, the acidification and eutrophication effects are lower for PE than for PHB (Harding et al., 2007).

Roes and Patel (2007) have developed an approach, which is based on classical risk assessment methods (largely based on toxicology), as developed by the life cycle assessment (LCA) community, with statistics on techno­logical disasters, accidents, and work-related illnesses. The approach has been applied to ethanol and four polymers from cradle to grave: polytrimethylene (PTT), polyhydroxyalkanoates (PHA), polyethylene terephthalate (PET) and polyethylene (PE). The results show lower risks for bio-based polymers compared to petrochemical equivalents. However, the uncertainties in the data need to be reduced (Roes and Patel, 2007).

Alvarenga et al. investigate PVC production from bioethanol as a substitute for ethylene. Two scenarios for bioethanol-based PVC for 2010 and 2018 are compared with fossil-based PVC, using several indicators for impact assessment. As to non-renewable resource use and GWP, bio-based PVC performed better; as to other impact categories, for some assumptions it performed worse for the state of 2010. As to 2018, better results turned out due to gains in efficiency and technological

oxidation processes. This causes a general increase of costs along with increasing the oxygen content in the production (see Fig. 3.7) (Lange, 2007).

The generic advantage of renewable resources is that they are often rich in oxygen functionalities. This is why renewable resources can be used best when highly functional intermediates and polymer need to be obtained. Other authors point out that the selective deoxygenation of carbohydrates is more effective and therefore cheaper than the selective oxygenation of hydrocarbonates (Alles and Jenkins, 2010).

Luo et al. dealt with the economic and environmental analysis as well as with technical design of a lignocellulosic biorefinery (LCF), which produces ethanol, succinic acid, acetic acid and electricity. The economic analysis shows that the designed biorefinery has great potential in comparison with a sole ethanol biorefinery even if the price of succinic acid drops or the investment costs double (Luo et al., 2010).

Various studies address the costs of production across the value chain. One important aspect here is transport. Several studies use mathematical models to assess the complete costs of energy use of biomass while considering the whole supply chain (biomass production, harvest, farm and road transport and conversion plant). On the basis of the assessment results, strategies have been proposed to reduce costs. In general the transport of biomass is an important aspect, so processing biomass in the vicinity of agricultural production areas has economic advantages (Yu and Tao, 2009; Akgul et al., 2012; Giarola et al., 2011).

Economic assessments are becoming important in the analysis of biorefinery concepts (Wright and Brown, 2011). This is due in part to the lack of commercial experience in establishing novel technologies that can convert alternative feedstock into products not commonly derived from renewable sources. Another factor is the recent volatility in oil prices yielding to the possibility of long-term financial viability of biorefinery projects. Finally, strong governmental support ensures that attractive processes receive financial support during development. These factors have resulted in an increase in the publication rates of biorefinery techno-economic studies.

Recent biorefinery techno-economic papers have focused on advanced biorefineries based on the thermochemical and biochemical platforms. These papers assess the technical and economic viability of technologies ranging from the development phase up to demonstration stage. Some assessments benefit from the data available for established commercial technologies employed in other industries. However, many of the advanced biorefinery technologies are first-of-a-kind facilities, which present a major engineering challenge. In this section, we discuss how insights provided by techno-economic analysis have contributed to our understanding of advanced thermochemical and biochemical biorefinery concepts.