1. Non-technical summary
1.4 Assessment of impact and environmental risks
Figure 1-2, Figure 1-3 and Figure 1-4 provide overviews of operations and conditions that potentially may affect organisms and other environmental features that have been assessed in the EIA during the three phases:
construction, production and decommissioning.
Figure 1-2 Overview of operations during construction and the receptors that may primarily be affected by the different operations which has been assessed in the EIA.
Figure 1-3 Overview of operations during production and the receptors that may primarily be affected by the different operations which has been assessed in the EIA.
Figure 1-4 Overview of operations during decommissioning and the receptors that may primarily be affected by the different operations which has been assessed in the EIA.
1.4.2 Severity and risk of impacts
Environmental severity and risks of different project activities and incidences have been assessed. Environ-mental risk is defined as the combination of the severity of and impact of an activity/incidence and the proba-bility that the impact will occur.
The severity of an impact has been defined by combining criteria for:
• The nature of the impact (Positive or negative)
• Extension of the impact (Local, regional, national, or international)
• Duration of the impact (Short-term, medium-term, or long-term)
• Magnitude of the impact (Small, medium, or large).
By combining these criteria in a predefined manner, the following severity categories have been used: Positive impact, no impact, minor impact, moderate impact or major impact.
The probability that an impact will occur has been defined as very low, low, probable, highly probable or defi-nite.
1.4.3 Impacts during construction phase 1.4.3.1 Discharge from drilling
Discharges leading to potential impact distances of more than 500 metres can occur in connection with the short-term activities completion and rig washing (durations of 1-4 hours/event), which, based on PNEC values for long term effects, imply a risk of effects up to 4,700 m away from the discharge point (completion, use of bactericide). However, the duration of these activities is very short (few hours per event), and, in the case of completion, will occur only once during the lifetime of the field.
It is therefore assessed that toxic effects on any eggs or larvae of fish that may be spawning in the area (such as, cod, plaice, dab, long rough dab, lemon sole, mackerel, sandeel and probably also for whiting are encoun-tered) and other plankton organisms around Solsort and SA-WHPN will be local, marginal and without meas-urable impacts on the stocks.
1.4.3.2 Impact of underwater noise
Possible ramming of well conductor and noise from machinery, propellers and thrusters of ships will generate underwater noise. The impact of noise producing activities are temporary and local. Based on this, it is as-sessed that underwater noise will have negligible impacts on marine life such as cetaceans and fish.
1.4.3.3 Impacts of artificial light
As the drilling rig operates 24 hours per day, it will be illuminated during the dark hours. Artificial light may affect seabirds and migrating land birds both positively and negatively. Light may improve foraging during night for seabirds, but there may also be an increased risk of bird collision, since they may be attracted by the light.
The risk of bird collision due to light attraction is considered to be minor and the negative impact on bird population due to light is negligible.
1.4.3.4 Emissions during construction
In relations to the site survey, construction of the wells, emissions to air will be generated from the fuel gas and diesel combustion for power generation, machinery and transport of supplies, equipment and crew. The emissions relation to site survey and drilling are expected to be approx. 21,800 ton CO₂-eq and 250 ton NOX/year.
1.4.3.5 Impacts of waste during the construction phase
All waste from South Arne and Solsort will be transported to Esbjerg by vessel. The waste will be sorted and sent to approved waste treatment plants. The environmental risk is assessed to be negligible.
1.4.3.6 Impacts of drilling on cultural heritage
Drilling and discharge of cuttings during drilling may potentially burry and damage ship and plane wrecks.
There are no registered findings of wrecks in the vicinity of the project area and the environmental risk is assessed to be negligible. Potential findings of wrecks or other historical artifacts will be reported to Slots- og Kulturstyrelsen.
1.4.3.7 Impacts on hydrography
The substructure of the rig will be temporary located in the water column. The structure consists of 3 legs with a total cross section area of 2013 m². The legs are placed in an open structure and are considered too small to have any impact on the hydrography of the North Sea. In addition to that the rig will placed in the location temporary.
1.4.4 Impacts during production phase
1.4.4.1 Impacts of planned discharges during the production phase
Produced water will be discharged from the host platform after pre-treatment with the primary objective of keeping the content of oil in the produced water below the OSPAR requirement of 30 mg/l. The content of natural occurring substances is available through water samples of the produced water.
Impacts during the production phase from tie-in of the Solsort West Lobe wells will be limited and is expected to result in no additional impacts compared to the impacts from planned activities at the South Arne installations already covered by existing EIA.
1.4.4.2 Emissions during production
In comparison with the overall national emissions of CO2 from the oil and gas industry, the production of oil originated from Solsort West Lobe wells will equal 5.7% of the CO2 emissions of 2013 (Danmarks olie- og gasproduction, 2013).
The emissions to air related to production and maintenance of the two Solsort West Lobe wells are covered within the emissions to air from planned production and maintenance for the South Arne field as the well are utilising the most appropriate slots on the SA-WHPN platform already covered by the South Arne EIA.
1.4.5 Impacts during decommissioning
The expected lifetime of the wells is approximately 25 years. Decommissioning of the project include pull out of production strings as well as plug and abandonment of wells. It is assessed that the environmental risk of the decommissioning of the production and water injection wells will be negligible and included in the decom-missioning activities related to the South Arne field.
1.4.6 Impacts of accidental spills
Blowout is an extremely rare event and extensive preventative/control measures are implemented to reduce the likelihood of such events.
Experience from previous blowouts and oil spills at sea have shown that it is mainly birds, marine mammals, fish and coastal ecosystems that may be affected by large oil spills.
The assessment of the environmental impacts of accidental blowout is based on modelling results represent-ing a worst-case scenario in which no mitigatrepresent-ing oil spill response measures are taken.
The modelling shows that the risk of oil stranding on coasts is negligible, even in case of a blowout. How-ever, Norwegian SVOs may be hit by oil in case of an unmitigated blowout.
Impacts on the conservation status of the nearest Natura 2000 areas (German and Dutch Natura 2000 areas 45 km south of Solsort) is assessed to be limited. There may however be a risk of sedimentation of oil on the habitat type 1110 Sandbanks, especially in the German area, thereby affecting the benthic infauna commu-nity at Dogger Bank.
Harbour porpoises, harbour seals and grey seals may be affected by oil, but it is assessed that only a tiny fraction of the populations is likely to be affected.
The risk of environmental impacts during a blowout is generally assessed to be low. This is mainly due to the risk that a blowout is extremely low since all safety systems and measures are in place on the platform or during drilling.
In case of a blowout, the South Arne oil spill contingency plan will be activated, and oil spill combat will be carried out, which will reduce the spreading of oil and mitigate impacts of any spill.
1.4.7 Summary of environmental impacts
The tables below summarize the assessed environmental severities and risks of planned activities during the construction (Table 1-1), production, decommissioning and accidental spills (Table 1-2).
Table 1-1 Environmental severity and risk of planned activities during the construction phase.
Impact Severity of
Impacts of discharges from the drilling rig
Impacts of the discharge of cuttings and drilling mud (WBM)
Minor Impact Definite Low risk
Impacts of underwater noise during site survey
Insignificant impact
Probable Negligible risk Impacts of underwater noise during
ramming of well conductor casing
Insignificant impact
Probable Negligible risk Impacts of drilling noise from rig Insignificant
impact
Improvement of night foraging op-portunities for seabirds
- Probable Positive
effect Risk of bird collision due to light
at-traction
Impacts of air emissions (VOC) Insignificant impact
Low Negligible
risk Impacts of air emissions (NOX, SOX) Minor impact Low Negligible
risk Impacts of air emissions (CO₂-eq) Minor impact Low Negligible
risk Impacts from waste
Impacts of waste Minor impact Low Negligible
risk
Impact Severity of
Risk of damage of wrecks Minor impact Very low Negligible risk Impact on hydrography
Impacts on seabed Insignificant
impact
Low Negligible
risk Impacts on water column Insignificant
impact
Low Negligible
risk Impacts on benthic fauna Insignificant
impact Impacts of gas release during
blow-out
Moderate im-pact
Very low Negligible risk Impacts of accidental spills of
chem-icals
Insignificant impact
Low Negligible
risk
Table 1-2 Environmental severity and risk of impacts of planned activities during the operation phase, of accidental spills and decommissioning.
Impacts of planned discharges and emissions from host platform
Discharge of produced water Insignificant impact
Probable Negligible risk Impacts of air emissions Insignificant
impact Impacts of gas release during
blow-out
Moderate im-pact
Very low Negligible risk Impacts of accidental spills of
chem-icals
Insignificant impact
Low Negligible
risk Impacts of decommissioning of production wells
Impacts from leaving cutting piles Insignificant impact
Highly proba-ble
Negligible risk
Emissions to air Insignificant
impact
Low Negligible risk