Pollution police: How are ship emissions monitored?

Pollution police: How are ship emissions monitored?

In an era of ever-tightening regulations for the shipping industry and increased concern for the environment, keeping close tabs on what vessels are emitting has become more important than ever. But monitoring the 50,000 ships that are on the seas is no easy feat. Here's a look at how it's done.

Text: Steve Roman Photo: 123RF

Carbon dioxide, nitrogen oxides, particulate matter, oil, ballast water, bilge water, sewage. There's a long list of ship emissions that merit scrutiny. Among the most harmful, and hence heavily regulated, is sulphur oxide (SOx). It is here that Port State Control authorities, those responsible for policing ships that dock in their countries, focus the bulk of their monitoring efforts. 

Though engine exhaust is how SOx is emitted, the traditional way to monitor it in any given ship doesn't involve testing the exhaust at all. SOx emissions are directly dependent on the Sulphur content of the fuel. In the absence of emission reduction technologies, the emissions can be derived from a fuel sample. Checking is done at the port, with inspectors boarding a ship, usually chosen at random or because of suspicious indicators, and manually extracting a sample from the fuel tank. 

“It's an easy way of monitoring emissions because anything that goes into the ship as fuel, which is eventually burned in the engine, is coming out as exhaust,” explains Teus van Beek, General Manager for Open Innovation at Wärtsilä. 

A certified lab then tests the fuel's Sulphurpercentage to see whether it complies with regulated limits – 0.1% in the case of special Sulphur Emissions Control Areas (SECAs) and, starting 1 January, 2020, 0.5% everywhere else. The challenge, as seen by the marine industry, is to use cleaner, more expensive fuels or alternatively exhaust gas treatment systems. Shipowners are struggling to finance the extra costs linked to these solutions. 

Given the complexity and hit-and-miss nature of onboard spot checks, PSC officers have been looking for better ways to zero in on violators. New technologies introduced over the past decade have come to the rescue.

High-tech help


Johan Mellqvist, a professor at Chalmers University of Technology in Sweden, specialises in remote emissions monitoring. The systems his team have developed and put into use in the EU rely on optical measurement of the ship's exhaust plume. “We have a passive measurement system. Solar light is reflected on the ocean, and it's reflecting up into sensors in telescopes that we have on an aircraft. From this, we can see the ratio of SO2 to CO2.” 

The more close-up tools for checking ships are 'sniffers', sensors that come into contact with the exhaust itself. These sensors can be mounted on aircraft or, as they are in Denmark and Germany, placed under bridges. Authorities in the EU and ports such as Hong Kong have recently begun flying sensor-equipped drones into ships' plumes, though Mellqvist points out that the drones can carry only the lighter, simpler, types of sensors. 

The one drawback of all these high-tech solutions is that they are a few years ahead of the law. Courts in the EU and elsewhere won't yet accept their findings as proof on their own, so the systems are mainly used as indicators, showing PSC officers where to target their onboard fuel checks.  

Port inspection is one thing but keeping an eye on what ships do in international waters, where enforcement responsibility falls to the ship's flag state, is another matter. Luckily for regulators, the International Marine Organization's lower worldwide sulphur limits for 2020 will come with a ban on carrying the old, high-sulphur standby, HFO (Heavy Fuel Oil) without a scrubber. When a ship comes into port, PSC authorities will be able to check the fuel tanks for signs of the prohibited HFO or, for ships using scrubbers, check the data from the scrubber's mandatory, tamper-proof sensors. This way, any foul play on the high seas can be reported back to the flag state. 

For the other highly-regulated types of emissions, nitrogen oxides (NOx), policing is more complicated. Though technically speaking, optical and sensor monitoring of NOxcan be done in the same way as with SOx, NOx emissions allowances for each ship depends on the engine type, year of build and other factors. For this reason, NOx controls typically happen at the stage of engine installation.

What about liquids? Scrubber wash water release, along with several properties of the water, is recorded by the scrubber's sensors and available for spot inspection. But to monitor other regulated liquid emissions like oil, grey and black water, etc, authorities have to look through a ship's logbooks. Though theoretically there's an opportunity for cheating here, insiders say that the stringent record-keeping requirements would make doing so very difficult. 

Tending the greenhouse


Regulatory enforcement is certainly the main driver for ship emissions monitoring, but there are also significant efforts being put into tracking emissions that aren't regulated at all, namely CO2.

Awareness and concern about the impact of greenhouse gasses, of which CO2 is the prime culprit, have reached all levels of the industry. Shippers such as Kuehne + Nagel and DHL now offer calculators on their websites that let customers estimate how much the transport will add to the carbon footprint of their goods. The IMO, for its part, has set a goal of reducing GHG emissions in shipping by at least 50% by 2050 compared to 2008.

Monitoring the combined carbon output of the global fleet has thus far been done using a bottom-up approach, with owners and operators of vessels larger than 5,000 gross tonnages required to file carbon reports to both the IMO and the EU. The numbers can be compiled and crunched to approximate how much CO2 is being pumped out over a certain time period. For instance, the EU has monitoring, reporting and verification of fuel consumption (MRV reporting) for vessels larger the 5000 GT calling at EU and EFTA (Norway and Iceland) port. The regulation requires shipowners to annually monitor the amount of CO2. The first publication by the European Commission is expected by 30 June 2019.

While the investments and time required to monitor these emissions might sound challenging, it is minor in comparison to the benefits that clean shipping can bring in for the industry as a whole. With regulations getting ever more stringent, stakeholders across the board recognise the need for the maritime sector to reduce emissions and decarbonise in order to sustain itself as a business in the future. 

The good news is that smart technologies are making the process easier and more thorough for both shipowners and regulators. UK-based Ricardo Energy & Environment, for example, has developed a novel way to use data from the Automatic Identification System (AIS) trackers that all ships carry. Coupling ships' locations and speed with parameters like engine power and fuel consumption rate, the company can create a composite view of carbon emissions in a given area. 

Soon satellites might join the monitoring effort as well. The European Space Agency's Sentinel 5 satellite has already proven its ability to measure the amount of NOx in shipping lanes. Now the EU has asked the agency to design a satellite specifically for the macro-monitoring of CO₂. The hope is that the new, carbon-tracking bird will be in orbit sometime in the 2020s, proving yet another tool for checking the health of the planet. 

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