Redmore Environmental was commissioned to undertake a Dispersion Modelling Assessment for a Short Term Operating Reserve (STOR) facility comprising three gas fired 2.5MW engines on land off Lower Dunton Road, Basildon.
Short Term Operating Reserve Background
The National Grid requires access to extra electricity in the form of either generation or demand reduction during certain periods of the day in order to manage situations where actual demand is greater than forecast demand and/or unforeseen generation unavailability. This eventuality is predicted to occur more frequently with the increase in renewables within the UK energy mix due to the unpredictable nature of some technologies, such as wind and solar.
In order to help meet this reserve requirement, the National Grid procures Short Term Operating Reserve.This is a contracted balancing service whereby individual facilities deliver a contracted level of power (within pre-agreed parameters) when instructed by National Grid. The requirement for STOR varies depending on the time of year, week and day, being a function of the system demand profile at that time.
The proposed development included three gas fired 2.5MW engines to provide 7.5MW of Short Term Operating Reserve power, as and when required. The operation of the facility had the potential to result in atmospheric emissions due to the combustion of natural gas. A Dispersion Modelling Assessment was therefore undertaken to quantify potential impacts associated with releases from the generators.
Dispersion Modelling Assessment for a Short Term Operating Reserve
The software package ADMS 5.2 was utilised to create a dispersion model to determine potential air quality impacts associated with the combustion of natural gas. Emissions from the generators were represented by three point sources. The emission rate, stack height and output temperatures from the manufacturer of the generator were used in order to accurately represent releases from the installation. The model was ran with five years of meteorological data recorded at Gravesend observation station and the year with the highest concentrations selected for use in the report in order to provide a worst case analysis.
Sensitive areas which may have been affected by changes in air quality were selected. These included both positions of human exposure, such as residential dwellings, schools and hospitals, and ecological receptors. Nearby sensitive habitats included several Local Wildlife Sites and the Landgdon Ridge Site of Special Scientific Interest (SSSI).
Outcome
The dispersion modelling results were compared against the relevant Environmental Quality Standards and the significance of the impacts determined using the Environment Agency guidance. This showed predicted nitrogen dioxide levels, as well as acid and nitrogen deposition rates, to be below the relevant standards at all locations in the vicinity of the site. Impacts at human and ecological receptors were also deemed to be not significant. The Dispersion Modelling Assessment for the Short Term Operating Reserve was subsequently submitted to the Environment Agency as part of the application for the Environmental Permit.
If you require a Dispersion Modelling Assessment for a Short Term Operating Reserve in support of a planning or permit application then please do not hesitate to get in touch with one of our specialist Air Quality Consultants today to find out more about how we can help you with your energy generation project.