Competition between Fossil and Renewable Feedstocks

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There is a widespread belief that with rising fossil fuel prices, renewable raw materials will, in principle, become economically viable. But, as can be shown, price linkages to fossil-based raw materials do exist - 12] (see also Section 12.2.2). Furthermore, 'Peak Oil' is often used as an argument to shift the focus of renewable feedstocks as the only - natural- carbon source. It is true that, in the global chemical industry, 15-20% of the total fossil fuel energy resources are used as feedstocks and process energy (IEA, 2007 [1]). Yet, in the light of this aspect and by taking into account the high added value provided by the chemical industry compared with any other fossil fuel energy intense sector, it should be clear that the chemical industry will be one of the last sectors to 'run out of oil'. Furthermore, as opposed to feedstock use, the main driver of competition is as an energy source, since both fossil fuels and biomass can and are used for heat and power generation, as well as mobility. To understand the principles it is helpful to compare the mass-based and dry energy content of different raw materials (see Table 12.1):

For energy purposes, raw materials can only be compared if they are in the same aggregate state. This means that most of the renewable feedstocks must be compared against the price of coal, oils and fats and crude oil, as shown for example in Table 12.2.

Simply exchanging fossil fuels with biomass is hampered by some additional yet simple economic constraints. Logistics plays a key role since there are no

Table 12.1 Energy content of different raw materials.

Fossil Renewable

Energy content (lower calorific value) in MJkg -

Hard coal

30

Wood

15

3

Hard coal briquette

31

Sugar

16

o on

Lignite (50-60% water)

9

Starch

15

Lignite briquette

20

Fat

39

Gasoline

43

Vegetable oil

37

'3 a

Diesel

43

Biodiesel

37

3

Naphtha

44

Bioethanol

27

m rt

Natural gas

38

Biogas

27

u

Ethylene

47

12.2 Renewable Feedstocks | 427 Table 12.2 Mass-based price comparison, triggered by fossil-based prices.

Fossil Renewable

Price in $/ton and in $/ton C respectively; Average production in mio ton/a

2007

2009

Prod.

2007

2009

Prod.

$/ton

$/ton C

$/ton

$/ton C

mio ton/a

$/ton

$/ton C

$/ton

$/ton C

on

Hard coal

87

87

76

76

2950a)

Sugar

218

519

402

957

150

T3 '!

Naphtha

676

786

490

570

362

Rapeseed oil

943

1232

826

1079

20

J

Bioethanol

509

976

467

896

68

m rt

Natural gas

370

493

216

288

2490a)

Biogas

N.A.

N.A.

453

604

N.A.

o

Ethylene

1240

1442

988

1149

130

a) Oil equivalent tons.

a) Oil equivalent tons.

concentrated 'oil wells' within the realm of bio-based feedstocks. On average 10 ton and at best 20 ton dry weight biomass can be harvested per hectare of arable land respectively. Thus harvesting and transport costs and the indirect CO2 emissions (even for a single large -scale plant with a multimillion ton production capacity) must be taken into account for an overall balance.

One trigger for increasing the overall proportion of renewable raw materials in the chemical industry is the possibility of using simplified process parameters. High pressures and temperatures could be avoided, a decreased number of processing steps could be realized, etc. The overall production costs could be reduced despite of high raw materials prices. Investment costs for processes requiring extreme conditions, can be decreased analogously (see also Section 12.4.3). The other trigger is exclusivity, when a product with specific properties can only be produced via a biotechnological process. These basic economic considerations could be completely overruled, if legislation creates mandates for the incorporation of renewable raw materials (such as with existing biofuel policies). The CO2 certificate prices could also be artificially elevated thereby emphasizing a greater role for the biomass- based processes, especially if one considers the general viewpoint that they are more sustainable, that is, the overall CO2 emissions are substantially lower than a fossil-based process (see also Sections 12.3.2.3 and 12.5).

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