Continuous emissions monitoring: A powerful tool in managing environmental transition

Tony Bowers, Marine CEMS Specialist at Kittiwake Procal, explains how the accuracy of in-situ continuous emissions monitoring in ensuring ‘real time’ environmental data for marine applications can be a powerful tool in managing transition within a rapidly changing world

Reducing shipping emissions will be the major driver of change in the maritime industry for decades to come. In the near term, the sulphur limit for fuels burnt in emission control areas (ECAs) will drop from 1.0% to 0.1% in 2015. And since 2010, vessels also need to comply with EC Regulation 2005/33/EC when in EU ports, which, apart from a few exceptions, requires the use of 0.1% sulphur fuel or equivalent emissions. Moreover, legislation pertaining to Nitrogen Oxide (NOx) has already been implemented, whilst beyond the horizon, legislation around Greenhouse Gases, from either the International Marine Organization (IMO) or the European Union, or both, is imminent.

So ship owners and operators have serious decisions to make and data sets to provide; ultimately based on a complex set of circumstances and a fluid regulatory background. However, there are only three choices enabling vessels to comply with SOx emissions regulations; burn marine distillates, switch to liquefied natural gas; or install a scrubber system.

To monitor emissions, continuous emissions monitoring systems (CEMS) have an important role to play, and ‘in situ’ tools are the most accurate yet. The IMO regulation allows for abatement technology to achieve sulphur emission reductions and Wärtsilä’s recent acquisition of Hamworthy Krystallon, coupled with increasing industry uptake, illustrates the ongoing development of the scrubber market. Systems capable of measuring down to the equivalent of 0.1% sulphur fuel are key for confirming compliance with SOx regulations when after treatment is used. Similarly, if fuel switching is the chosen option, monitoring provides assurance that fuels have been changed in a timely manner before entry into an ECA. That compliance is ongoing with more ECAs likely to be implemented soon. With the approval of a US-Caribbean ECA and the proposed Pearl River Delta and Japanese ECAs gathering momentum; the proliferation of regulation seems inescapable.

However, innovative ship owners and operators are not waiting for regulators to tell them what to do. The emergence of emissions benchmarking and vessel efficiency tools – such as from the Carbon War Room, the Environmental Ship Index (ESI) from the World Ports Climate Initiative (WPCI) or the Swedish-led Clean Shipping Index – shows that shipping innovators are aware that charterers see a value in vessel efficiency. The likes of Caterpillar, Volvo and Wal-Mart are now asking for emissions data and Maersk Line has become the first shipping line to publish independently verified CO2 emissions data, vessel by vessel. However, this needs to be accurately assessed, and the days of measuring CO2 through a ‘back of the envelope’ calculation based on the amount of bunker fuel purchased will not meet international standards for CO2 data collection in the medium to long term.

Shipping emissions monitoring is already a fact of life for the shipping industry. IMO MARPOL Annex VI’s now well-established regulations for the prevention of air pollution from ships have made emissions monitoring an essential data tool to monitor and report emissions in order to demonstrate compliance. This means that both the commercial incentives and regulatory requirement to manage emissions are here today, and the commercial and operational benefits of getting it right are substantial. Moreover, there is no doubt that, in time, emissions monitoring from the stack will become mandatory.

When it comes to meeting emissions limits through lower sulphur bunker fuel, a testing agency simply takes a sample of the fuel as it is pumped onto a vessel. Compliance with ECA regulations is therefore straightforward. However, accurately assessing SOx or NOx levels when a vessel is fitted with a scrubber or a Selective Catalytic Reduction (SCR) unit is not.

The most effective method for measuring emissions is through in-situ monitoring using CEMS. In contrast to extractive sampling where an exhaust gas sample needs to be physically extracted from the system and then analysed, ‘in-situ’ emissions monitoring provides a continuous, real time measurement of the content of your exhaust gases – with data provided instantaneously on a screen that can be installed in the engine and on the bridge.

The unique nature of infra-red in-situ systems are sensitive enough to confirm compliance, even when emission limits are very low. Emissions that are the equivalent of 0.1% sulphur fuel are around 22ppm of SOx in the exhaust gas. Any instrument with a range over 0-100 ppm will not be accurate enough to measure this and an inappropriate choice for operational scrubber monitoring. For example, Kittiwake’s Procal 2000 – an infra-red (IR), duct or stack-mounted system, designed to provide in-stack analysis – has an SO2 monitoring range of 0-100 ppm but can automatically switch ranges to 0-500/1000 ppm for monitoring operations outside of an ECA on high sulphur fuels.

Such systems are also versatile enough to measure several gases and from several onboard locations. Kittiwake’s Procal 2000 can analyse up to six different exhaust gases from multiple engines and boilers, including SO2, CO2 and NOx. It comprises up to six exhaust-mounted analysers, each with automatic verification facilities, which makes it ideal for a crew lacking experience in emissions analysis. The Procal 2000 analyser has an in-situ sample cell that sits inside the exhaust, avoiding the need to manually extract gas using costly, high maintenance sample handling systems, and enabling analysis of an unmodified, representative gas sample. Kittiwake’s Procal 2000 can also measure H2O or water vapour, which means that measurements can be reported in as ‘dry’ or ‘wet’, another key advantage over many extractive alternatives.

As well as meeting regulatory standards, continuous emissions monitoring performs a valuable operational and commercial role. Armed with accurate data about the emissions of its vessels, an owner/operator can optimise operational efficiency within those regulatory limits. Accurate emissions data will also allow an owner/operator to baseline the existing combustion systems on its vessels and then benchmark the performance and value for money of emission reduction tools techniques and technologies.

The better information you have, the better decisions you can take, not just in ensuring regulatory compliance and avoiding the costs of emission breaches, but also in maximising operational efficiency and making the right strategic calls on new technology investments. When it comes to controlling your emissions, knowledge coupled with accuracy and transparency becomes a powerful tool to mange transition within a rapidly changing world.

Nautilus International, February 2012