NOx sources in the UK: the story behind the figures

Why the UK continues to live up to its “Dirty man of Europe” reputation, despite being among the richer countries in Europe.

When data was published showing the EU-27’s largest point sources of NOx pollution, two aspects attracted particular attention.

The first was the domination of these tables by the UK: 8 of the EU-27’s top 20 NOx polluting plants were British. The second was that this domination of the tables occurred alongside countries with much lower GDP per capita incomes. Whilst the UK has an above-average GDP per capita income within the EU-27, others such as Poland, Bulgaria and Romania were much lower, with as little as 40 per cent of the average. So questions were asked as to why the UK continues to live up to its traditional ‘Dirty Man of Europe’ reputation in this way?

The issue of NOx control at UK large combustion plants goes back to the privatisation of the UK power sector back in the early 1990s, and the implementation of the UK’s Integrated Pollution Control (IPC) industrial management regime This was the UK’s very similar predecessor system to the EU’s Integrated Pollution Prevention and Control (IPPC) system.

Top 20 NOx producing point sources in EU-27.
Source: The Swedish NGO Secretariat on Acid Rain/European Environmental Bureau.

At this time, UK environmental groups presented evidence that advanced Selective Catalytic Reduction (SCR) NOx abatement technology should be employed at all UK power plants in addition to the much less effective but much cheaper low-NOx burners. However, this SCR evidence was rejected in favour of low-NOx burners only, given that all the UK power plant operators stated that they expected their coal-fired plants to close by 2010. Confidence in this decision was undermined by the fact that once this and a similar decision against the use of flue gas desulphurisation equipment (FGD) on any wider scale had been taken, it quickly became clear that the plants would remain open significantly beyond 2010.

Given this ‘new’ information, attention focused on revisiting the FGD decision. However, this was only resolved on any significant scale when the UK’s existing large combustion plants became subject to EU site-specific controls for the first time under the second EU directive regulating emissions from Large Combustion Plants (LCP), which came into force on 1 January 2008. In the negotiating process leading up to this directive, the UK had been instrumental in resisting a wider (then) EU-15 wish to see stronger controls on NOx emissions. As a result, existing coal-fired plants >500 MWth would not be required to fit SCR until 2016, when a NOx emission limit value of 200 mg/Nm³ came into force.

It was against this background that the UK’s coal-fired plants applied for their IPPC permits in March 2006. In these determinations, it was ironically the 2016 LCP directive NOx ELV that helped protect UK plants from having to fit SCR under IPPC. The expense of this technology could cause the UK’s ageing plants to close or opt for peak load operation, and it was successfully argued that uncertainty about their long-term future undermined any justification for an IPPC NOx Best Available Techniques (BAT) determination based on SCR. The BAT determinations therefore considered no period of possible operation beyond 2015, and were thus based on Boosted Over Fire Air (BOFA), a type of low-NOx burner. The UK BAT was set at 500 mg/Nm³, the LCP directive emission limit value (ELV) for plants of this size, despite evidence submitted to the regulator by NGOs that BOFA can achieve much greater emission reductions than this.

However, one plant, Aberthaw, is distinctive among UK coal-fired plants in that it has a different type of boiler technology, designed to enable it to burn a particularly low volatility local coal. It is not technically possible to retrofit Boosted Over Fire Air to this type of boiler, so the regulator had to decide whether to require a less or more strict NOx ELV.

Everything in the plant’s application suggested it should be stricter, and that Aberthaw should be required to fit SCR under IPPC. A key feature of this application that was of particular interest to environmental groups was the fact that it clearly stated that if Aberthaw was required to fit SCR, it would stay open beyond its 2018 deadline for meeting an LCP directive NOx ELV of 200 mg/Nm³.1 This meant that it would easily have enough operating time to amortise the debt of fitting SCR, and limited remaining plant life could not be used to evade a BAT determination based on SCR, which is the basis of the LCP BREF NOx BAT standard for existing plants of this size. Further, the cost per tonne of NOx abated if Aberthaw fitted SCR was well within cost data set out in the Economic and Cross Media BREF as having been judged to be reasonable in other EU member states.

However, despite all of this, Aberthaw managed to escape SCR, in part due to the UK’s BAT assessment methodology. This methodology determines BAT as being the point on the cost curve where costs start to increase more rapidly, but this is a relative measure that takes no account of whether the costs are still reasonable in absolute terms beyond this point.

Further, the calculations presented in the application amortised the debt of fitting SCR over only 10 years, thereby overemphasising those costs. Environmental groups made representations to the regulator (the UK Environment Agency) on this count, but the response was to benchmark a decision against SCR using a consultants’ study produced for the regulator that argued that even if the costs were amortised over 15 years, there was no economic case for fitting SCR to any UK power plant. But this study only reached its conclusion by using a methodology that is clearly stated as being inadequate in the Economic and Cross Media BREF and, as such, should never be used for BAT assessments.²

Friends of the Earth (FoE) in the UK looked to challenge the BAT determination legally, but was unable to do so because the BREFs are not legally binding and Member States are free to choose their own BAT assessment methodologies. This meant that any remaining case would amount to simply one technical opinion up against another, and FoE’s lawyers advised that the English courts do not like such cases. In addition, proceeding with such a case could prove very expensive as each side countered the other with additional technical experts. FoE therefore regretfully decided against proceeding with any legal challenge of the Aberthaw NOx BAT determination.

Despite the publication of the damning UK NOx data in the EU tables, the UK continues to seek derogations for its existing coal-fired plants in the current negotiations of the revision of the IPPC and LCP Directives into the new Industrial Emissions directive. Again, these are being justified in terms of a limited remaining life, albeit one that exceeds not only the initial 2010 ‘closure’ date, but also the later 2015 maximum time period taken into consideration in the determining of their IPPC permits.

In fact, since the UK plants started evading SCR, they have already had a continued life long enough to cover the 15 year period needed to amortise the debt of fitting SCR. But still they plead limited remaining life, poverty, prospective energy gaps etc, and the UK Government supports them in doing so.

And it is this that underlies the UK’s appalling performance in the EU-27’s tables of the largest point sources of NOx emissions.

Lesley James,
Friends of the Earth
(England, Wales & N. Ireland)

For more information see: ec.europa.eu/environment/air/pollutants/paints_directive.htm

[1] The very few plants burning low volatility coal within the EU have a derogation under the LCP Directive delaying the requirement to fit SCR until 31st December 2017.

[2] The study was based on a full cost benefit analysis. However, the Economic and Cross Media BREF states that this methodology should not be used for BAT assessments because of the problems of costing ecological damage – CBA studies therefore overemphasise the costs of fitting a technology. The ECM BREF states that instead, a simple cost effectiveness study should be undertaken, giving a cost/tonne of pollutant abated.