Annex 1
Memorandum from the Biotechnology &
Biological Sciences Research Council
BBSRC's interests in developing sources
of renewable energy are focused upon the exploitation of biological
systems. Essentially, this currently means fundamental plant science
research geared towards understanding the biology of biomass crops
and their development for the efficient generation of electricity.
Current examples of biomass crops under study are poplar trees,
coppiced willow trees and elephant grass (Miscanthus).
The following comments have been elicited
from BBSRC's research community and are therefore focused on biomass
energy crops. It is apparent that, at present, no bioenergy system
can compete with fossil fuels in any market at any scale. With
further research, however, this situation will change for the
better.
1. What are the cost-effective technologies
available now for the generation of renewable energy, and those
that are likely to become available in the next 10 years or so?
The commercial exploitation of biomass
for electricity generation is likely to become feasible within
the next 10 years or so. Biomass fuels and residues can be converted
to energy via thermal, biological and physical processes. Thermal
processing currently attracts the most interest, of which gasification
receives the most RD&D support as it offers higher efficiencies
compared to combustion and fast pyrolysis is still at a relatively
early stage of development. Both of these thermochemical conversion
processes offer high conversion efficiencies, potentially competitive
costs and considerable flexibility in scale of operation and range
of products. Combustion, biological conversion processes (fermentation
and digestion) and mechanical processing (eg vegetable oils) are
well established and are commercially offered with performance
guarantees.
There are a few genetic markers already
available in poplar and willow trees which identify traits that
make a good biomass crop, though none as yet in the energy grasses.
More of these markers will be identified as a better understanding
is gained on what makes a good biomass crop, though the UK research
effort is fairly modest at present. At Rothamsted Research (RRes),
there are a number of interesting candidate traits which can be
worked on very quickly with the necessary research support. The
National Willow collection has been successfully transferred to
RRes and there is a complete DNA fingerprint of all clones to
ensure each is unique. This provides the basis for fundamental
studies which will impact on biomass crop breeding and selection
over the next 10 years. The genetic transformation of poplar is
now established, though only limited work in this respect has
been completed on willow. The challenges facing biotechnology
in terms of biomass crops relate to improving the productivity
and final energy density of the crop harvest, together with facilitating
harvesting, processing, combustion and fermentation. There are
a number of viable scientific options currently being tested,
although many of them involve GM technologies. As with any crop,
there are thermodynamic limits to yield set by total annual light
interception and conversion. These limits can already be incorporated
into economic models and used to estimate how significant breeding
and management advances could be in the overall cycle of production.
It is very important that these analyses are carried out as part
of any strategy which seeks to generate viable biomass-based energy
production systems.
Further research is required on biomass
crop pest and disease resistance, and also on economic management.
The complete bioenergy system needs to be considered from biomass
in the field or forest through to an energy product delivered
to the consumer, rather than as discrete elements for research.
Insufficient attention is currently paid to the interfaces between
biomass production and its conversion.
2. What is the number of sites potentially
available for such technologies, and the obstacles to taking these
up in terms of (a) planning and other consents, (b) manufacturing
and installation capacity, and (c) providing the supporting infrastructure,
such as access roads and extensions to the electricity network?
Given the breadth of biomass crops under
development—Miscanthus, Phalaris, poplar and
willow, to name a few—and their differing growth requirements
and harvesting times, there are few grassland or arable sites
which could not support biomass energy crops. Work remains to
be done on agronomy and farming system impact across all locations
in the UK. For example, there may be some conflict with other
non-agricultural or food uses of water in places such as East
Anglia. The equipment for harvesting biomass crops is mostly available
(though imported) and farmers would feel comfortable using it.
The existing agricultural infrastructure for arable farming could
be adapted fairly easily for biomass crops.
Changes in farming subsidies under the
Common Agricultural Policy would go a long way to persuading farmers
to take up the cultivation of biomass energy crops. The necessary
farm land would therefore become available. In a densely populated
country like the UK with scarce land resources, it is important
that the amount of useful energy delivered per hectare is optimised.
Planning permission for power stations
is problematic because of stack emissions and the environmental
nuisance caused by traffic, though emissions from the combustion
of biomass energy crops have been shown to be minimal. Local power
stations with minimal transport distances remain crucial to the
successful commercial exploitation of biomass crops in electricity
generation. All the current biomass products have dry-matter heat
contents of around 50 per cent of that of coal, therefore stations
will require large storage facilities.
Technical barriers to electricity production
from biomass crops remain, but are generally soluble in the medium
term. Non-technical barriers (logistical problems) are poorly
appreciated and often more significant than expected.
It is important to appreciate that biomass
is a diffuse resource, arising over very large areas and thus
requiring large land areas with substantial logistical problems
in collection and transport as well as high costs. Typically a
sustainable crop of 10 dry t/ha/y of woody biomass can be produced
in Northern Europe rising to perhaps 15 or maybe 20 dry t/ha/y
for energy crops in Southern Europe. Thus an area of 1 sq km or
100 ha will produce 1,000 dry t/y enough for a power output 150
kWe at low conversion efficiencies or 300 kWe at high conversion
efficiencies. It is therefore difficult to visualise power generation
plants much bigger than around 30-40 MWe anywhere in Europe and
even these will require a planted area of around 100 sq km. A
further complication with almost all forms of biomass is their
seasonality—forestry and coppiced crops can only be harvested
during the winter months and energy crops and agricultural residues
are even more seasonal, typically only being produced for a few
months a year. Extensive storage provision thus has to be made.
One solution to this problem is a multi-fuel system and increasing
efforts are underway to develop such processes that can accept
a number of different fuels either mixed or separately. The current
view is that even these plant sizes are limited in number with
a more typical plant size of 5-15 MWe likely to dominate the market
in the short term. However, in locations with extensive forest
products industrial operations it is technically feasible and
economically attractive to have large scale bioenergy Combined
Heat and Power (CHP) plants where the process residues are utilised
as fuel for the energy requirements of the local industry. For
example the Alhomens boiler in Finland (commissioned in 2001)
has a design capacity of 500 MWth and is designed to operate up
to 100 per cent biomass or mixtures of biomass and peat. Biomass
and agricultural wastes are very similar in their arisings, with
most European industries individually producing comparable quantities
of material, although overall regional and national totals may
be substantial.
3. What are the logistics of providing
stand-by capacity for times when intermittent sources are not
available?
For biomass crops, this relies on being
able to co-fire a range of energy crop species which can be harvested
at different times throughout the year. Co-firing of willow/poplar
and grasses has been developed. The drying of wood (and especially
grasses) for medium to long-term storage is a problem given power
consumption, though it is possible and just economic.
4. What are the intermediate milestones
that should be set on the way to achieving the White Paper's aims?
A realistic milestone for the contribution
of biomass energy crops to the total renewables target would be
15 per cent by 2020. To achieve this would require some additional
research investment and incentives to farmers above the
45 per hectare (on set-aside) currently being discussed
at the European Commission. It is important that targets should
be set to reflect the potential contribution of biomass crops
to energy production in different portions of the country. These
should emphasise local production and utilisation, and should
be complemented by targets for larger, more centralised electricity
generation from biomass crops.
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