Scottish Government: Energy & Climate Change Directorate
Habitats Regulations Appraisal of the Implications of the proposed Forth Energy Grangemouth Biomass development
Firth of Forth SPA
07 December 2012
The following appraisal has been prepared by the Scottish Ministers as the Competent Authority for the above proposal.
Description
1
Brief description of the project
The development is for a biomass fuelled electricity and heat generating station at the Port
of Grangemouth, Falkirk with an electricity generating capacity of up to 120MW. The
biomass will be delivered to the plant mainly by ship (directly to Grangemouth port), with
some additional fuel arriving by road or rail.
The principal components of the development comprise of:
 Power plant area
 Fuel storage area
 An electrical switchyard
 A covered conveyor system for transferring fuel
The design of the plant will include:
 A 110m tall stack
 A boiler hall
 A turbine hall
 Main fuel and mixed fuel stores both 20m tall
 Ash silos (12m tall)
 Two auxiliary boilers with a single 55m stack containing two flues.
 A cooling water extraction pipe from within the docks.
 A cooling water discharge pipe into the River Carron.
The main generating station will be located within the existing docks, about 300m away
from the nearest intertidal area. Cooling water will be extracted from within the docks,
and the resulting warm water will be discharged into the River Avon, approx. 300m away
from the main plant.
The main development site is about 300m from the Firth of Forth SPA. The cooling water
discharge pipe in the River Carron is within the SPA.
2
Brief description of the designated Natura
site
Firth of Forth SPA is designated as an SPA for:

Wintering and migratory waders and waterfowl
The Firth of Forth SPA is a complex of estuarine and coastal habitats in south east
Scotland stretching east from Alloa to the coasts of Fife and East Lothian. The site includes
extensive invertebrate-rich intertidal mudflats (these are the habitats present at
Grangemeouth), rocky shores, saltmarsh, lagoons and sand dunes.
The Firth of Forth SPA supports wintering populations of European importance of the
Annex 1 species: red-throated diver, Slavonian grebe, golden plover and bar-tailed
godwit, and a post-breeding (passage) population of European importance of the Annex 1
species sandwich tern.
The SPA also supports wintering populations of both European and international
importance of the migratory species pink-footed goose, shelduck, knot, redshank and
turnstone, as well as a wintering waterfowl assemblage of European importance including
nationally important numbers of 15 migratory species: great crested grebe, cormorant,
scaup, eider, long-tailed duck, common scoter, velvet scoter, goldeneye, red-breasted
merganser, oystercatcher, ringed plover, grey plover, dunlin, and curlew. This assemblage
also includes large numbers of wigeon, mallard and lapwing.
3
Conservation objectives for Firth of Forth To avoid deterioration of the habitats of the qualifying species (listed below) or significant
disturbance to the qualifying species, thus ensuring that the integrity of the site is maintained; and
SPA
To ensure for the qualifying species that the following are maintained in the long term:
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Population of the species as a viable component of the site
Distribution of the species within site
Distribution and extent of habitats supporting the species
Structure, function and supporting processes of habitats supporting the species
No significant disturbance of the species.
Qualifying species of the site are:
 Bar-tailed godwit
 Common scoter
 Cormorant
 Curlew
 Dunlin
 Eider
 Golden plover
 Goldeneye
 Great crested grebe
 Grey plover
 Knot
 Lapwing
 Long-tailed duck
 Mallard
 Oystercatcher
 Pink-footed goose
 Red-breasted merganser
 Redshank
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Red-throated diver
Ringed plover
Sandwich tern
Scaup
Shelduck
Slavonian grebe
Turnstone
Velvet scoter
Wigeon
Waterfowl assemblage
Screening
4
Is the proposal directly connected with, or The proposal is not directly connected with, or necessary to, conservation management of
necessary to, conservation management of the Firth of Forth SPA and therefore, further consideration is needed.
the Natura site?
5
Is the plan /project likely to have a significant The proposed biomass plant could potentially affect the Firth of Forth SPA in a number of
effect on the Firth of Forth SPA either alone ways:
or in combination, with other plans or
 Construction of the cooling water discharge pipe could cause disturbance to
projects.
SPA bird species in the intertidal area along the River Avon.

The discharge of cooling water into the River Avon (thermal pollution) could
potentially affect the distribution and abundance of prey species in the
mudflat habitats in the intertidal areas on the river banks, which in turn could
affect the distribution and abundance of SPA bird species.

Atmospheric emissions from the proposals, specifically nitrogen and acid
depositions, could potentially affect the supporting habitats of the site.
The Environmental Statement and IIHRA identified the following qualifying species as
being present in significant numbers in the vicinity of the River Carron such that they
might be affected by construction disturbance or thermal pollution:
 Shelduck
 Knot
 Redshank
 Dunlin*
 Curlew*
The proposals is therefore likely to have a significant effect on the Firth of Forth SPA.
*Part of the waterfowl assemblage, not qualifying interests in their own right.
Appraisal
6
7
Identify the relevant conservation objectives
to consider for the Firth of Forth SPA
The relevant conservation objectives to consider of the Firth of Forth SPA:


Structure, function and supporting processes of habitats supporting the species.
No significant disturbance of the species.
Can it be ascertained that the proposal/plan Disturbance to bird species from construction of the cooling water discharge pipe
will not adversely affect the integrity of the Shelduck, knot, redshank, dunlin and curlew were the qualifying interests recorded in
Firth of Forth SPA
numbers feeding and roosting in the intertidal areas adjacent to the River Carron, within
distances where significant disturbance from construction activities might occur. These
birds are present outwith the breeding season, primarily over the winter months.
The ES and IIHRA propose that any construction works for the cooling water discharge
pipe in, or close to, the River Carron would be carried out from April to September to
avoid significant disturbance to these bird species. If this mitigation is carried out the
relevant conservation objective is addressed, and it can be concluded that there will be
no adverse effect on the qualifying interests of the Firth of Forth SPA from constructionrelated activities.
Thermal pollution effects on bird prey species
Discharging warm water into a river/intertidal habitat has the potential to change the
invertebrate fauna, which could have an effect on the prey availability for the bird species
identified above.
The River Carron, from the approximate point of discharge to the river mouth, is about
2km long, 200-400m wide at low/high tide and 2-4m deep at low/high tide. The cooling
water will be discharged over 4 hours per tidal cycle on the falling tide. The temperature
of the discharged water will be 8-12oC above ambient. At the point of discharge the water
will enter the river through diffusers to aid rapid mixing so avoiding a concentrated
thermal plume. The dispersion of the thermal plume will be speeded up, and it’s impact
therefore reduced, by discharge being restricted to the falling tide.
Modelling has shown that the thermal plume from the discharged water will be only 1 oC
above ambient at 140m from the point of discharge, affecting about 20m (10%) of the
width of the river. Therefore only a very small area of intertidal/benthic habitat and
invertebartes could potentially be affected (less than 0.25ha) and substantial habitat or
invertebrate changes would not be expected within the whole of this area, if at all. Of this
small area, most will be subtidal rather than intertidal, so the area affected that might be
used by birds for feeding (the intertidal bit) is very small indeed (<0.1ha). (By comparison,
the total area of intertidal habitat within the River Carron channel (downstream of the
discharge outfall) is approximately 40ha, with the adjacent mudflats (immediately to the
west) providing a further 400ha of feeding habitat.)
It is therefore concluded that the effect of the thermal pollution on the invertebrate fauna
along the River Carron is negligible. There will therefore be no significant decrease in the
food supply available to SPA bird species and there will be no adverse effect on the
qualifying interests of the Firth of Forth SPA, in view of the relevant conservation
objective from any thermal pollution.
Nitrogen and acid deposition
The ES and IIHRA identified that the process contributions to critical load for nitrogen and
acid deposition in the Firth of Forth from the Grangemouth Biomass Plant are <1% for
both. The one exception is at a single location, Bo’ness, where the acid deposition process
contribution was 1.9% (and 3.1% in combination with the other proposed biomass plants
at Rosyth, Leith* and Dundee). Excedence of the 1% threshold above which there could
potentially be an effect requires further consideration (Air Pollution Information System,
CEH).
The existing background level of acid deposition at the Bo’ness part of the Firth of Forth
SPA accounts for the vast majority of PEC (135%), i.e. the critical load (100%) is already
significantly exceeded by 35%. Adding the Grangemouth biomass plant’s emissions to this
background level will result in a PEC that is 136% of critical load (or 138% of critical load in
combination with the other proposed biomass plants).
A large salt water estuary is capable of a high level of chemical buffering against any
potential changes in acidity, such that the relatively small increase in this single site
attributable to the Grangemouth biomass plant, alone or in combination, would not cause
any change to the structure and function of the intertidal habitats of the Firth of Forth. No
effects from the current levels of nitrogen or acid deposition in the Firth of Forth have
been recorded. Therefore there would be no adverse effect on the qualifying bird species
in view of the relevant conservation objective.
Therefore, it can be ascertained that the increase in nitrogen or acid deposition
attributable to the Grangemouth biomass plant proposal, alone or in combination, will
not adversely affect the qualifying interests of the Firth of Forth SPA from acid or
nitrogen deposition.
*the Leith biomass plant has since been withdrawn.
8
Consider whether mitigation measures or Mitigation (enforced through conditions) is required to restrict any construction works in
conditions to be adopted to avoid impacts on the River Carron to the period April to September (inclusive).
site integrity.
Conclusion
9
Can impacts on site integrity be avoided
Subsequent to the application and enforcement of the specified mitigation, it can be
ascertained that the Grangemouth biomass application, on its own or in combination,
will not adversely affect the integrity of the Firth of Forth SPA.