Planning Application for Construction of an anaerobic digestion
plant at Lords Meadow Industrial Estate
Application reference 16/00825/MFUL
Sustainable Crediton Energy Group supports anaerobic digestion
to treat and recycle farm wastes and in the process to provide a
source of renewable energy either as electricity or biogas. However
we do have some concerns, conditions and questions about this
particular planning application asset out below. If the Applicant
can respond satisfactorily , we can certainly support in principle
the planning application at Lords Meadow Industrial Estate.
Stated Benefit from Annual Biogas Gas Production Incorrect
The Applicant stated at the February presentation to the
Crediton Town Council that the amount of biogas injected into the
gas grid would be enough to continuously supply about 5000 homes.
Using data provided by the applicant, we estimate the plant is
actually capable of producing gas for fewer than 3500 homes. By
taking account of the fossil fuels used in the transportation and
production of the purpose grown crops to feed the Anaerobic
Digestion Plant, the net benefit is the production of renewable gas
for 2100 homes. This is still a worthwhile benefit. This benefit
could be significantly improved by changing the balance of
feedstocks and by choice of agricultural practices for the purpose
We also note that there is no other alternative form of
renewable gas currently on the market.. Gas is the only source of
renewable power that is easily stored, transported and produced all
year round under all weather conditions. This is base load power
that would compete directly with traditional fossil fuels , nuclear
and fracked gas.
Crops as Feedstock
At a presentation given to the Crediton Town Council in February
the applicant made statements to the effect that the feedstock for
the anaerobic digester would be a mixture of farm wastes and
"break" crops. We were told that the "break" crops would be crops
that were planted to give fields an annual rotational break and
that would improve the fertility of the soil. We have been advised
by the applicant that the annual feedstock will be 15,000 tonnes of
farm wastes comprising 3000 tonnes of farm yard manure, 6000 tonnes
of chicken litter and 6000 tonnes of straw. This will be
supplemented by 26,600 tonnes per annum of locally grown crops
comprising 3500 tonnes of hybrid rye, 5000 tonnes of fresh grass,
15000 tonnes of fresh maize and 3100 tonnes of oats. We do not
consider these crops to be "break" crops. These crops could be used
for animal or human consumption. We also have a concern that the
growing of maize for anaerobic digestors is having a detrimental
effect on soil fertility and soil run-off.
We would prefer that the feedstock was 100% farm wastes and that
the maize/grass/oats/rye silage proposed for the digester feedstock
was used as animal feed, that is good agricultural land is used for
food production rather than energy production. However we do
recognise that adding a modest amount of crop material can increase
the energy yield from anaerobic digestion dramatically compared
with using farm waste only. We also recognise that although the
proposed proportions of farm waste and crops is not ideal from a
sustainability perspective and that the Government is consulting on
the introduction of feedstock restrictions to minimise the use of
crops in anaerobic digestion plants, we believe that having the
facility in place then allows the business/farming community and
other community stakeholders to be creative in the future in
finding / supplying alternative genuinely high calorific value
waste feed stocks. If that waste was free or at low cost to the
Anaerobic Digestor Operator then why wouldn't they use that instead
of purpose grown crops?
We therefore propose two conditions for our support for this
That the Applicant works with the local business/ farming
community and other community stakeholders such as Sustainable
Crediton to find high calorific waste feedstocks to eventually
replace the energy crops feedstock.
That the Applicant in the interim for the benefit of
biodiversity grows the energy crops without the use of pesticides
and herbicides and intersperse the rows of crops with nitrogenous
plants such as clover to increase the fertility of the soils.
Fossil fuel fertilisers should not be used in the production of
such crops, but digestate from the Anaerobic Digestion Plant could
Questions concerning the on-site processes
1. The off-gas from the digester will not be pure methane. It
will be wet and will include a significant proportion of carbon
dioxide, typically about 40% by vol. It may also contain some
A. How is it proposed to treat the off-gas ?
B. What is it intended to do with the separation products?
C. What method will be used to compress the methane to a
pressure at which it can be introduced into the gas main?
2. How are the raw feed materials to be stored on site ? In
particular can it be guaranteed that no odours will escape the site
either from feed material or other operations on site?
3. How can the proposers justify the statement in their
submission that no hazard is associated with methane on site?
We attach a link to a report undertaken to
determine the frequency and causes of accidents in AD plants. A
large number of incidents were identified, many resulting in
serious injury and in some cases fatalities. The majority involved
either biogas explosions or hydrogen sulpide poisonings. The number
of incidents appears to result from an industry previously lacking
a formal safety culture handling materials for which a more
rigorous chemical engineering approach and procedures are required.
Lessons learned and put into effect apply to all stages of an
industrial scale AD project, from design, documentation and process
review through project management to commissioning, operation and
4. As the digestate is to be spread on fields. Will it be
The number of vehicle movements in the Transport Statement
appears to be consistent with the tonnages to be moved.
It is not made clear in the Application due to the general
assumptions of 60% material originating from the south of Crediton
and 40% from the north what the precise geographical locations of
the feed material are likely to be. Without more information about
the sources of feed materials it is impossible to predict the
extent to which the vehicle movements may increase congestion at
critical points, for example along Fordton, which already has
serious congestion at harvest times. Where are the sources of the
raw materials for digestion?
We expect that the process will be designed so that noise
and odours from the site are limited and do not affect householders
on the Bramble Lane estate.