UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 1

Sustainable Energy Options

UAU212F

BIO FUELS

Throstur Thorsteinsson ThrosturTh@hi.is

Biomass share in TPES

⇨ Provided about 10.2% (50.3 EJ) of global

(TPES) in 2008. ⇨ 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,

⇨ 20 to 40% occurs in unaccounted informal sectors

including charcoal production and distribution.

⇨ TPES from biomass for electricity, heat, combined

heat and power (CHP), and transport fuels was 11.3 EJ

in 2008 and the share of modern bioenergy was 22%

Biomass

sources for energy

⇨ Roundwood products are

saw logs and veneer logs

for the forest products

industry and wood chips

that are used for making

pulpwood used in paper,

newsprint and Kraft paper. ⇨ In 2009, reflecting the downturn

in the economy, there was a

decline to 3.25 (total) and 1.25

(industrial) billion m3

Feedstock – Conversion – Heat / Power

Commercial (solid lines) and developing (dashed lines).

Lignocellulosic biomass Biomass energy conversion

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 2

Gasifier

⇨ The biomass in the gasifier undergoes

four processes; ⇨ drying,

⇨ pyrolysis, ⇨ Pyrolysis is the thermal decomposition of the dry

biomass in the absence of oxygen.

⇨ oxidation

⇨ reduction.

⇨ The products are bio-char (charcoal),

liquids (oils) and gaseous products. ⇨ The products of pyrolysis are then subjected to

oxidation the end result of which is a

combination of carbon, water and carbon

dioxide.

Gasifier outcome

⇨ The final products are a gas the combustible

part of which is ⇨ hydrogen (10-20% by volume),

⇨ carbon monoxide (15-30%) and

⇨ methane (2-4%);

⇨ the remainder is nitrogen and non-reacted carbon

dioxide

Biofuel

production

and trade

2009

Biofuel production

Global biofuel production Uncertain size of source

⇨ Important factors include ⇨ Population and economic/technology development

⇨ how these translate into fibre, fodder and food demand

(especially share and type of animal food products in

diets) and development in agriculture and forestry.

⇨ climate change impacts on future land use including its

adaptation capability;

⇨ considerations set by biodiversity and nature

conservation requirements; and

⇨ consequences of land degradation and water scarcity.

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 3

Technical potential

Must know:

⇨ The amount of land available for biomass

plantations.

⇨ Regional distribution of the land and distances

to consumption centers.

⇨ Productivity of the land.

⇨ Water Availability.

⇨ Environmental implications.

⇨ Technical and economic performance of

conversion technologies.

Biomass technical potential

Global technical potential

Biofuel vs. fossil fuel

GHG CO2 mitigation potential

Source: OECD, 2007; Biofuels: Is the cure worse than the disease?

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 4

Lifecycle GHG emissions

Sustainability …

2050 projections

2050 deployment scenarios

Env & soc/eco impacts of bioenergy Social aspect

⇨ Land conflicts

⇨ Indecent work ⇨ http://www.birdlife.org/eu/EU_policy/Biofuels/eu_biofuels2b.html

⇨ The Social Costs and Benefits of Biofuels:

The Intersection of Environmental, Energy

and Agricultural Policy ⇨ http://aepp.oxfordjournals.org/content/32/1/4.full

⇨ Local social and environmental impact of

biofuels ⇨ http://www.ecologyandsociety.org/issues/view.php?sf=68

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 5

Efficiency

⇨ Corn ethanol production requires 1.29 gallons

of fossil fuels per gallon of ethanol produced,

and soy biodiesel production requires 1.27

gallons of fossil energy per gallon of diesel

produced. In addition, approximately three

gallons of ethanol are needed to displace two

gallons of gasoline. ⇨ http://www.foodfirst.org/node/1662

Environmental issues

⇨ Land, Water, and Nutrient Consumption

⇨ Pollution from Growing & Harvesting

⇨ Effluents from Thermal Conversion Processes

⇨ Combustion Emissions ⇨ Centralized Steam, Electricity Generation Refuse Based Fuels:

⇨ Trace Hydrocarbons (PAH), Dioxins, Furans

⇨ Metals

⇨ HCl

⇨ Wood Stoves & Fireplaces ⇨ PAH

⇨ Other Complex Organics

⇨ Particulates

⇨ CO2 Management

⇨ If Fossil and Biomass Consumption Offset by New Biomass

Growth

Environment and biomass power Environment

⇨ Soil erosion and deforestation

⇨ Impact on water resources

⇨ Loss of biodiversity

⇨ Pollution

Fossil fuel

⇨ Fossil fuel is material which has been formed

by natural processes such as the anaerobic

decomposition of organic remains (plants or

animals), usually over a long period of time

⇨ Fossil fuels include petroleum, coal, peat and

natural gas

⇨ Fossil fuels are rich in carbon

Fossil fuels in transport

⇨ Petroleum based fuels dominate transport

fuels and have for almost a century ⇨ High energy content

⇨ Infrastructure in place

⇨ Familiar

⇨ Cheap

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 6

Biomass attributes

⇨ Renewable

⇨ Connected to farming - economics

⇨ Multiuse – food, shelter, energy, materials

⇨ Environmental concerns include land and water use,

fertilizer and other nutrient requirements

Vegetation

Photosynthesis:

energy (sunlight) + 6CO2 +

H2O => C6H12O6 + 6O2

Respiration:

C6H12O6 (organic matter) +

6O2 => 6CO2 + 6 H2O +

energy

26126

22

6

6(sunlight)Energy

OOHC

OHCO

Energy66

6

22

26126

OHCO

OOHC

Bioethanol from grain corn feedstock

Starch from corn

Opportunities for Biotechnology

⇨ Fermentation ⇨ Yeasts that can:

⇨ Use a broader substrate spectrum

⇨ Have higher yields

⇨ Are resistant to ethanol or pretreated substrates

⇨ Production of more valuable co-products

⇨ Improved catalysts - enzyme production

⇨ Genetic engineering of plant feedstocks

Biofuels

⇨ Ethanol (alcohols)

⇨ Biodiesel

⇨ Methane

⇨ Biogasoline

⇨ Hydrogen

Biofuels - production

⇨ Ethanol ⇨ Fermentation (sugars,

starch and cellulose)

⇨ Hydration

⇨ Anaerobic bacteria

⇨ Biodiesel

⇨ Transesterification ⇨ Vegetable oil refining

⇨ F-T (any carbon

source) http://en.wikipedia.org/wiki/Fischer-

Tropsch_process

⇨ Methane ⇨ Gasification

⇨ Fermentation

⇨ Pyrolysis

⇨ Biogasoline ⇨ Aqueous Phase

Reforming (sugars)

⇨ Hydrogen ⇨ Gasification, pyrolysis

⇨ Bacteria

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 7

Biofuels - history

⇨ First generation ⇨ Biodiesel from energy crops and animal fat

⇨ Ethanol from sugars and starch

⇨ Second generation ⇨ Ethanol from cellulose (cheaply!)

⇨ Third generation ⇨ Anaerobic bacteria

⇨ Algae

Biofuels today

Ethanol

PROS

⇨ Carbon neutral (?)

⇨ Can utilize existing

infrastructure - mix

in gasoline

⇨ Less pollution

⇨ Can use waste

⇨ Well known tech (!)

⇨ Energy source, not

energy carrier

CONS

⇨ Food vs. fuel

⇨ Pollutes (CO2)

⇨ Land use

⇨ Upper limit on

production

⇨ Production can

depend on weather

⇨ Energy balance not

great sometimes

Biodiesel

PROS

⇨ Carbon neutral

⇨ Can utilize existing

infrastructure - mix in

regular diesel

⇨ Less pollution and good

for engine

⇨ Can use waste

⇨ Well known tech

⇨ Energy source, not

energy carrier

CONS

⇨ Food vs. fuel

⇨ Pollutes

⇨ Land use

⇨ Upper limit on

production

⇨ Production can depend

on weather

⇨ Energy balance not

great sometimes

methyl linoleate

Methane

PROS

⇨ Carbon neutral

⇨ Less pollution

⇨ Can use waste

⇨ Produced in landfills

⇨ Well known tech

⇨ Energy source, not

energy carrier

CONS

⇨ Pollutes (a little)

⇨ Needs new

infrastructure

⇨ Upper limit on

production

Biogasoline

PROS

⇨ Carbon neutral (?)

⇨ Can utilize existing

infrastructure - is

gasoline

⇨ Less pollution

⇨ Can use waste

⇨ Energy source, not

energy carrier

CONS

⇨ Food vs. fuel

⇨ Pollutes

⇨ Land use

⇨ Upper limit on

production

⇨ Production can

depend on weather

⇨ New tech

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 8

Biomass

⇨ 11% of total world energy consumption.

⇨ In developing countries on average 35%

comes from biomass (19% in China) but in

very poor countries such as e.g. Bangladesh

biomass account for up to 90% of energy

supply.

Biomass classification

A)Plant Biomass a) Woody biomass: Trees and shrubs, bamboo, palms…

b) Non-woody biomass: sugarcane, cotton, stems and

roots, grass etc…

c) Processed waste: Corn husks, nut shells, sawmill

waste, industrial wood waste, black liquor from pulp

mills, municipal waste.

d) Processed fuels: charcoal, wood alcohol (ethanol),

plant oil, biogas…

B)Animal Biomass: Manure

Issues

Biomass is often perceived as a fuel of the past because

of:

⇨ Low efficiency ⇨ Energy density low, EROI low - implications for: land use

⇨ Water use -water already is scarce

⇨ Water quality

⇨ Soil fertility – thus management practices MUST be

sustainable

⇨ Biodiversity impacts

⇨ Pollution and unpredictable quality ⇨ Particulate pollution, water quantity in biomass

⇨ Association with poverty ⇨ Poor mans fuel

Biofuel by feedstock used

Drop in global grain stocks Factors

Short term

⇨ Extreme weather conditions

(cereals, milk)

⇨ Some production decline in

important exporting countries

(Argentina: milk; EU: milk)

⇨ Low stocks

Long term

⇨ Growing food demand in

emerging economies

⇨ Higher production costs: oil

price

⇨ Demand for biofuels

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 9

Consumption gains

Whole Milk

Powder

Feedstock requirements for bio fuels

become a major new source of demand

Food security and biofuels

⇨ Hunger, malnutrition have economic causes: ⇨ income, food prices

⇨ Bioefuels affect food security in developing

countries through ⇨ income generated in domestic biofuel production

⇨ world price impact of biofuel production in OECD

countries

⇨ Rising world price of food benefits producers,

harms consumer

Poor countries import

⇨ Poor urban consumers are negatively affected

⇨ by rising food prices

⇨ Many poor farmers in developing countries

are net food consumers

⇨ Overall, developing countries are net

importers of food, in particular cereals (in

2016: 143 mill tonnes, excl. rice)

⇨ Africa in particular is a net importer (SSA in

2016: 18 mill tonnes, excl. rice

Country size ‒ cereal net exports

Country size in proportion to cereal net exports

Policies

⇨ Biofuel demand in OECD countries is largely

driven by policies (subsidies, tax breaks,

blending requirements, …)

⇨ These policies raise demand for agricultural

products and world prices of food

⇨ … and harm food consumers

⇨ OECD tariffs harm biofuels producers in

developing countries

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 10

OECD Policies benefits

⇨ Energy security?

⇨ Fighting climate change?

⇨ Improving the environment?

⇨ Supporting rural development?

⇨ Creating economic benefits?

⇨ Superior to improving energy efficiency?

OECD summary

⇨ Current hike of world food prices is in part

result of production shortfalls, transitory

• … but also reflects growth of biofuel use

• … which is expected to accelerate

• … largely as result of rich country policies

• … with questionable benefits

• … and negative impacts on food security

Barrier to biomass use

⇨ Uncompetitive costs – unless the input – the biomass

is free – not yet competitive with oil, gas or coal as

of yet. This can be fixed via technological

development.

⇨ Relatively inefficient (low EROI)

⇨ Has socioeconomic implications

⇨ Low public acceptability

⇨ Potentially large environmental impacts

⇨ Competition for land use – w/ agriculture e.g.

⇨ Water use

Biomass to electricity (USA)

Source: Adapted From Table 5-2 T.C. Schweizer,

et al., EPRI Report No. TR-111893 (1998).

Type of Biomass # Installations Capacity (MW)

Wood 259 5 332

Pulping liquor 6 443

Bagasse and other agricultural residue

39 669

Digester Gas 61 112

Landfill Gas 174 583

Tires 3 69

Total (+ other) 678 10 006

Challenges

⇨ Low heat to power efficiency of combustion steam

turbines ⇨ 18-24% (14,000-19,000 Btu/kWh)

⇨ Supply stability and economics

⇨ Alkali and other trace metal deposits and emissions

⇨ Particulate Deposits and Emissions

⇨ NOx Emissions

⇨ Cost of Electricity ⇨ $0.065 – 0.08/kWh

⇨ Lower Energy Density ⇨ Oxygen = 30-45 wt % dry basis

⇨ Use of Land, Water, Nutrients

⇨ Displacement of Higher Value Crops

Biogas

⇨ ~ ½ CH4, ½ CO2

⇨ From Anaerobic Digestion of wet Biomass ⇨ Animal, Human Wastes

⇨ Sewage Sludge

⇨ Crop Residues

⇨ NOT Lignin

⇨ By-Products: Nitrogen-rich Sludge (Fertilizer) and

Fewer Pathogens

⇨ Extensive Use in India and China (Millions of

Digesters); Industrialized Countries (Stockyards,

Municipal Sewage, ~5000 Digestors)

⇨ Major Goals ⇨ Environmental Neutralization of Waste

⇨ Fertilizer From Waste

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 11

Opportunities for biomass

⇨ Reducing Greenhouse Gas CO2

⇨ Restoring Forest Resources

⇨ Renewable Carbon Source for Energy Future

Dominated by Non-Carbon Based Electricity,

e.g. Nuclear, Geothermal, and Solar. Biomass

Becomes Significant Raw Material for: ⇨ Liquid Hydrocarbon Fuels

⇨ Chemicals

⇨ Other High Value Products

Summary

⇨ Biomass to electricity and fuels: R&D Opportunities and challenges ⇨ Increasing Conversion Efficiency

⇨ Better catalysts

⇨ Lower land and water use impacts

⇨ Harvesting and processing

⇨ Municipal and food processing residuals provide opportunities ⇨ Scarcity of landfills

⇨ Concerns about disease vectors and toxins

⇨ Environmental effects of biomass utilization warrant careful scrutiny

→ needs LCA approaches

⇨ Advantages ⇨ Countermeasure to Global Climate Forcing by Fossil CO2

⇨ Renewable Carbon Source for Premium Products

⇨ Ecosystem Management: Forests, Water

⇨ Facilitate Transition to Lower Fossil Contribution

⇨ Genetically Tailored Crops: “Sunshine-to-Gasoline”

⇨ Economics still is a Major Challenge

Iceland

⇨ Þorvaldseyri - repjurækt

PROCESSES Thermochemical, chemical, …

Thermochemical processes

⇨ Biomass combustion ⇨ Process where carbon and hydrogen in the fuel react with excess

oxygen to form CO2 and water and release heat.

⇨ Direct burning of biomass is popular in rural areas for cooking.

⇨ Wood and charcoal are also used as a fuel in the industry.

⇨ Combustion processes are well understood and a wide range of

existing commercial technologies are tailored to the

characteristics of the biomass and the scale of their applications.

⇨ Biomass can also be co-combusted with coal in coal-fi red plants

(van Loo and Koppejan, 2002; Faaij, 2006; Egsgaard et al.,

2009).

Thermochemical processes ..

⇨ Pyrolysis ⇨ The thermal decomposition of biomass occurring in the

absence of oxygen that produces a solid (charcoal), a

liquid (pyrolysis oil or bio-oil) and a gas product. ⇨ The relative amounts of the three co-products depend on the

operating temperature and the residence time used in the

process. ⇨ High heating rates of the biomass feedstocks at moderate temperatures

(450°C to 550°C) result in oxygenated oils as the major products (70 to

80%), with the remainder split between a biochar and gases.

⇨ Slow pyrolysis (also known as carbonization) is practiced throughout

the world, for example, in traditional stoves in developing countries, in

barbecues in Western countries, and in the Brazilian steel industry

(Bridgwater et al., 2003; Laird et al., 2009).

UAU212F Spring 2012

Throstur Thorsteinsson (ThrosturTh@hi.is) 12

Thermochemical processes …

⇨ Biomass Gasification ⇨ Occurs when a partial oxidation of biomass happens

upon heating.

⇨ This produces a combustible gas mixture rich in CO

and hydrogen (H2) that has an energy content of 5 to

20 MJ/Nm3

⇨ This energy content is roughly 10 to 45% of the

heating value of natural gas.

⇨ Fuel gas can then be upgraded to a higher-quality gas

mixture called biomass synthesis gas or syngas (Faaij,

2006).

Chemical processes

⇨ Transesterification ⇨ The process through which alcohols (often methanol) react in the

presence of a catalyst (acid or base) with triglycerides contained in

vegetable oils or animal fats to form an alkyl ester of fatty acids and a

glycerine by-product.

⇨ The hydrogenation ⇨ of vegetable oil, animal fats or recycled oils in the presence of a catalyst

yields a renewable diesel fuel-hydrocarbons that can be blended in any

proportion with petroleum-based diesel and propane as products. This

process involves reacting vegetable oil or animal fats with H2 (typically

sourced from an oil refinery) in the presence of a catalyst (Bauen et al.,

2009a).