Alternative fuels and green aviation - Biomass as Energy Source: Resources, Systems and Applications - page 177

At the same time, the availability of suitable energy sources to meet this demand will depend on
strategic and innovative actions. To date, economic growth in developed and developing nations
has been predicated on the availability of cheap oil. According to the International EnergyAgency
(IEA), the global peak of conventional oil reserves was reached in 2006 (IEA, 2010). Historical
data indicates that production in oil reservoirs have declined sharply after the peak is reached
(Hirsch, 2006), which is also predicted in the IEA report. The sharp decline in output can be at least
somewhat mitigated through development of new oil reservoirs, advanced techniques for recover-
ing oil from unconventional sources such as oil shale, and increased reliance on coal, natural gas
and alternative fuels. However, huge environmental impact could result without appropriate clean
coal technologies, safe recovery methods particularly for natural gas, and sustainable practices
in alternative fuel manufacture. There is a real sense of urgency, since there are consequences
associated with waiting too long to put mitigation strategies into place (Vaughan et al. , 2009).
The rapidly fluctuating price of oil puts pressure on the global economy that a stable source of
energy could help to alleviate. One thing that all sides should agree on is that it is crucial to make
informed public policy decisions that are based on high-quality, up-to-date science.
We are feverishly seeking a way to satisfy our thirst for energy in a way that respects our planet
and the life that depends on it. This will require the creative development of new energy sources,
and biofuels are widely considered to be the best, if not the only, solution. Aviation is responsible
for 10% of global transport energy consumption (Moavenzadeh et al. , 2011). Air transport

dumps hundreds of millions of tonnes of greenhouse gases (GHG) into the atmosphere annually,
currently accounting for

∼

3.5% of all GHG emissions. Legitimate concern over this contributor
to climate change has led to a deluge of environmental and economic analyses that attempt to
provide guidance as to a rational way forward at the global scale. The Life Cycle Assessment
(LCA) has emerged as a relatively new framework that is used to quantitatively evaluate local
and worldwide biofuel approaches in terms of their environmental and/or economic impact (see
section 11.5).
Until the biorefining industry becomes more established or another serious global oil crisis is
at hand, it is difficult to make a purely commercial case for biofuel manufacture. Public policy can
make all the difference in providing incentives. Despite a rocky beginning in 2005, the European
Union (EU) has been the leader in instituting carbon trading mechanisms in response to the Kyoto
Protocol (Gourlay et al. , 2011). To account for air traffic's contribution to climate change, the
European Union will include air travel in its comprehensive carbon trading system in January
2012 (Convery, 2009). All domestic and international flights that arrive or depart from the EU
will be covered by the EU Emissions Trading System. Airlines will receive carbon credits through
the use of biofuels; if their net output exceeds the specified targets, the airline must offset the
overproduction through carbon trading.
Other countries have also developed goals for reducing dependence on petroleum-based fuels
through the use of alternative fuels. China has set targets of reducing energy consumption by
16% and CO 2 emissions per unit of GDP by 17% in 2015 from its baseline in 2010 (Li et al. ,
2011). The US Energy Independence and Security Act of 2007 specifies a ramping-up of biofuel
production through 2012, which includes 36 billion gallons (136

∼

× 10 9 liters (L)) of renewable

10 9 L) of next-generation biofuels
that are not derived from corn ethanol. In addition, life cycle GHG emissions must be reduced by
at least 50% relative to 2005 output of petroleum-based transportation fuels (DOE, 2010). The US
Air Force has targeted that half of its aircraft will use blends of conventional and alternative fuels
by 2016 (Byron, 2011), and the US Navy plans to build the “Great Green Fleet” of carrier ships by
2016 powered entirely by non-fossil fuels (Karpovitch, 2011). The commitment to purchase large
quantities of biofuel will help bridge the gap between a product that is viable in the laboratory or
small-scale pilot plant and the establishment of large-scale biofuel production facilities that will
significantly bring down the cost of manufacture.
Although biofuels are an attractive solution, whether developed from feedstocks such as veg-
etable oils, agricultural waste or the much-anticipated algae, there are many issues that hinder
wide availability. Most studies agree that the cost of the feedstock is by far the largest contributor

fuels by 2022, which must include 21 billion gallons (79 . 5 ×