Air quality rules are getting tougher and so is budgeting for equipment upgrades, says Finning’s Kelly Cole. That’s where retrofitting can play a role.
While the Environment Agency is in the process of clarifying the legislation to support cleaner air throughout the UK, local authorities are already beginning to take an even stronger stance on enforcing lower nitrogen oxide emissions levels in their communities.
The Environment Agency is targeting nitrogen oxide emissions (NOx) of less than 2,000mg/Nm3 (5% O2). However, in local authorities working to tackle pollution hot spots, there have been examples where emissions targets have been set below that.
It is anticipated that in some areas – where air quality levels can be poor – future local targets may be set so low that Tier II engines, as well as existing generator sets, will need to be adapted further to achieve the levels set independently by councils.
With several factors to consider in maintaining operational capability, as well as supporting clean air initiatives, there is likely to be a considerable increase in the retrospective fitting of Selective Catalytic Reduction systems (SCRs) – which Finning, for example, has uccessfully used to drastically cut NOx emissions by over 90%.
New off-road/mobile generation engines are designed to meet emissions levels set by the EU and UK Government but these do not affect stationary power generation equipment. The rollout of regulations continues to bring existing gensets and machinery in line with these levels, with key deadlines set for 2025 and 2030.
Bringing into effect the European Medium Combustion Plant Directive (MCPD) in the UK, the Environmental Permitting (England and Wales) (Amendment) Regulations 2018, stated that all existing sites with aggregate machinery between 5MWth – 50MWth must achieve NOx levels of less than 200mg/Nm3 (15% O2) by 1 January 2025. Those below 5MWth have until January 2030 to meet the environmental requirements. Any sites above 50MWth are regulated under the Industrial Emissions Directive (IED) where it is typical for the authorities to apply the same level of emission restrictions.
While new engines already need to meet the Tier II emissions levels as a minimum, existing engines that were operational before the regulations were outlined and introduced may need to be adapted to meet the new level and secure an operating permit.
MCPD legislation often does not apply to generators used in back-up systems though, given there is a maximum allowance of 50 hours test per annum and no restriction on emergency use hours.
Existing engines that were operational before the regulations were outlined and introduced may need to be adapted to meet the new level and secure an operating permit
However, within the power of a local authority, where NOx emissions targets are driven down below that 2,000mg/Nm3 or Tier II threshold, regardless of hours of use, SCRs may need to meet the stricter controls to avoid fines or issues in securing environmental permits.
Many organisations will choose to retain proven engines that they can rely on for performance, that have been load tested and will reliably offer the back-up power needed. In this case, improving the emission readings while not affecting the generator performance through the application of SCRs can be a sound choice.
However, space can be a factor in making these changes. Generator sets with low usage are often stored in facilities that have a minimal amount of free space, especially where there are numerous engines. The addition of retrofitted SCRs requires a considerable amount of additional space alongside the existing units, which is something many firms may struggle with.
To meet targets below Environment Agency guidance levels, SCRs will certainly be needed achieve the standards demanded as this is the most effective way to dramatically reduce NOx emissions.
To meet demands for lower NOx emissions Finning has already tested the capability of SCRs in reducing NOx emissions on both existing and new gensets – as well as in bringing the levels below that set out in the latest government legislation. Whether space is at a premium or lower levels of NOx emissions are set by a local authority, there is the expertise available to provide power solutions that support operational requirements and meet the demands of legislation.
- Kelly Cole is general manager of electric power at Finning UK & Ireland
