Perennials, willows better for biofuels
July 5, 2013 - A report from the European
Environment Agency (EEA) says that bioenergy production should follow European
Union (EU) resource efficiency principles.
The report, EU bioenergy from a resource efficiency perspective,
looks at the potential for energy from agricultural land, including forest and
In 2010, bioenergy was the source of approximately
7.5 per cent of energy used in the EU and is predicted to rise to around 10 per
cent by 2020.
Bioenergy should be produced in line with EU objectives to use resources more efficiently,
the report says. This means reducing the land and other resources needed to
produce each unit of bioenergy and avoiding environmental harm from bioenergy
production. According to the EEA analysis, the most efficient energy use of
biomass is for heating and electricity as well as advanced biofuels, also
called ‘second generation' biofuels.
First generation transport biofuels, for example,
biodiesel based on oilseed rape or ethanol from wheat, are shown to be a far
less efficient use of resources.
Building on previous analysis, the report shows that
the current energy crop mix is not favourable to the environment. The report
recommends a broader mix of crops to reduce environmental impacts. Specifically,
this should include perennial crops, which are not harvested annually - for
example energy grasses or short rotation willow plantations. This would
enhance, rather than harm, ‘ecosystem services' provided by farmland - such as
flood prevention and water filtration.
Bioenergy is often considered ‘carbon neutral', as
the carbon dioxide released in combustion is assumed to be compensated by the
CO2 absorbed during plant growth. However, as shown in this report, indirect
land use change can negate any greenhouse gas savings from biofuel production
based on energy crops. This is due to the displacement of crop production onto
previously unused land, which can lead to the conversion of forests and
savannah to agriculture. Such land use change harms biodiversity and increases
greenhouse gas emissions.
"Bioenergy is an important component of our renewable
energy mix, helping to ensure a stable energy supply," said Hans Bruyninckx,
EEA Executive Director. "But this study highlights the fact that forest biomass
and productive land are limited resources, and part of Europe's ‘natural
capital'. So it is essential that we consider how we can use existing resources
efficiently before we impose additional demands on land for energy production."
Bioenergy in 2020 - exploring different options
The report develops three different ‘storylines' with
varying technological, economic and policy assumptions. This helps explore
different future options, illustrating which bioenergy types are most
resource-efficient and which have the lowest environmental impact. The main
conclusions of this analysis are below:
EEA has revised its estimate of potential bioenergy production in the EU
first published in 2006, reducing the estimate by approximately 40 per
cent. The estimate was revised due to changes in scientific understanding,
the changed EU policy framework and accounting for economic factors.
biomass-to-energy conversion technologies vary significantly in their
efficiency. For example, generating electricity by burning pure biomass is
only approximately 30 to 35 per cent efficient, while burning the same
material to produce heat is usually more than 85 per cent efficient. In
general, using bioenergy for heat and power is a considerably more
efficient way of reducing greenhouse gas emissions, compared to using
bioenergy for transport fuel.
energy cropping systems can vary hugely in their productivity, as well as
in environmental impacts. High-yielding systems with efficient conversion
can deliver more than 20 times more energy compared to low-yielding
inefficient systems using the same land area.
EU bioenergy policy only partially accounts for potentially adverse
environmental effects connected to direct land‑use effects, including
changes in land management. Additional policies could help reduce these
environmental impacts, particularly regarding water resources and farmland
countries with the largest estimated agricultural bioenergy potential in
2020 are France, Germany, Spain, Italy, Poland and Romania, the report
using mature trees for energy purposes may have a negative effect on the
climate, due to the long time it takes for the trees to regrow and
re-capture the CO2 that is released when wood is used for energy. This
‘carbon debt' does not arise if bioenergy uses other forest biomass
instead, for example branches left over from forest harvesting by-products
or waste products from timber and paper production.
organic waste and agricultural or forestry residues as feedstock is more
resource efficient than many other types of feedstock, as it does not add
pressure on land and water resources and offers very high greenhouse gas