Cleaner and Greener

Sisson's pie charts show the burden of nitrogen oxide (N0x) and particulates (PM10) borne by cargo handling equipment on the terminal - roughly a quarter.

The PM10 (particles measuring 10 micrometers or less) standard was designed to identify those particles likely to be inhaled by humans, and PM10 has become the generally accepted measure of particulate material in the atmosphere in the UK and in Europe. The main sources of primary PM10 are road transport (all road transport emits PM10, but diesel vehicles emit a greater mass of particulate per vehicle kilometre).

When discussing strategies for reducing emissions, he singles out the following:

adaptation of newer cleaner diesel equipment use of alternative fuels electric yard cranes alternate layouts and systems that optimise use of equipment Modernising existing equipment is easy to do and involves no change to the surrounding infrastructure making it the most costeffective way of reducing emissions in the short term.

Alternative fuels excluding electricity but including LNG and LPG, can reduce air emissions but may not always be much cleaner than the cleanest standard diesel technology. Such fuels will typically add cost in terms of alternate engines and alternate fuel delivery systems.

Sisson also discusses electrified yard cranes as used in Oslo.

He goes on to point out the benefits of simulation in helping to evaluate different CY systems and lauds appointment systems that even out truck arrivals and reduce queuing at the gate. "Faster gate processes and faster CY service linked to appointments and automatic data transfer all help in the overall objective of reducing emissions." Finally he addresses the responsibility of the ship itself:

reducing speed in the vicinity of the port, alternative fuels and electric shore power or 'cold ironing'.

INCREASING SEVERITY But getting back to terminal handling equipment, just where do we stand today? Tim Davis, business manager, Industrial Engines, at Volvo Penta, says the primary changes are in the number and severity of regulations which have increased dramatically over recent years.

"This has meant we have had to pour a lot more resources into the design pot so that we can come up with solutions that meet and exceed the regulations." He hastens to add though that at Volvo (and its competitors too), there has always been a focus on environmental issues. "It is one of our core values and always has been."

The on-highway side of the industrial diesel engine business has been working with tougher emission laws much longer than the offhighway sector. "So we have used that technology, modified it and made it work for off-highway, " says Davis. "We are also strongly driven by things like fuel economy, reliability, durability, power density - all of those issues in the way of giving the customer more - a better product that lasts longer and does more for him. That's what we focus on."

Table 3 shows just where at least some of us are with regard to emission standards. Whilst the US started earlier, the EU, with its Non-Road Mobile Machinery (NRMM) Exhaust Emissions Directive*, has caught up. Hopefully by next year both will be synchronised.

Elsewhere, Korea has not announced any advance on Stage 2 whilst Japan plans to introduce Stage 2 next year and Stage 3 in 2010.

Aside from the original distinctions between on-highway and offhighway, and underpinning the current tranche of legislation are the divisions between mobile and constant speed, and between power bands, with the 130-560 kW band applying to most terminal handling equipment.

"The big change in the legislation for Stage 3 is that it combines hydrocarbons and nitrogen oxide into one level, " emphasises Davis. "In the past it has been measured at two individual levels. For example Stage 2 was 6grams per kW-hr of N0x and 1gram of hydrocarbons.

When we move to Stage 3 it reduces sharply to 4grams of N0x and hydrocarbons in total.

"With particulates, which are also a very important part of emission levels, at Stages 2 and 3A we are working at 0.2grams per kW-hr but when we move to Stage 3B the particulates reduce dramatically down to 0.025grams per kW-hr, and that's where different technologies will have to be employed to meet those requirements.

"Regarding constant speed machines such as generating sets, legislation will bring in the Stage 2 limits that we are running with today in January 2007 for Europe only. In 2011 Stage 3A limits for constant speed machines will apply - five years after it is introduced for mobile machines."

The conundrum in all this is that these regulations will not reduce fuel consumption but might even increase it. "The whole combustion process becomes that little bit more inefficient, " says Davis. There are still ways to reduce fuel consumption but this must be accomplished through clever control of the combustion process.

However exhaust gas regeneration and other such technologies are being developed throughout the market.

WHICH WORKS BEST?

So much for engines but what about the fuel that goes in them?

Kalmar, which has supplied both LNG and LPG terminal tractors to operators in California, is circumspect when it comes to evaluating alternative fuels. The company doesn't believe that diesel is dead or even dying as witnessed by the amount of research taking place aimed at reduced harmful emissions. "Given the size of the market and the investment in it, it would be naive to assume that major improvements won't be made. In its favour, diesel still packs more energy per litre than the green alternatives, and so less diesel needs to be burned to achieve the same amount of work, " says the company.

As to the liquefied options, Kalmar reckons LPG may continue as a popular industrial fuel source in California and elsewhere, but it is not as clean, in terms of emissions, as other fuels such as hydrogen or LNG. And in fact if continuing emission reductions occur with diesel, it may yet at some point be dirtier overall than even diesel.

That said, its current advantages include:

it is readily available the associated technology is well proven fuel station costs are very low fuelling and storage are perhaps a little less risky when compared to that of LNG LPG fuel is an abundant 'fraction' captured in the refinement of crude oil and as such is artificially commercially viable, at this point, due to a slightly lower cost.

However, says Kalmar, these advantages may be dissipating due to infrastructural and technological advances and increasing environmental restrictions. For example, when you factor in the increased consumption of LPG against diesel for the same work output, it is in fact more costly than diesel and this situation may worsen. If, for example, consumption of crude oil decreases in future, LPG could become much more costly to produce.

The key to the equation is that LPG produces greater carbon monoxide (CO) emissions than a diesel engine litre for litre and a diesel engine produces more work for that litre.

Meanwhile, in California there is a concerted effort to make LNG more widely available. LNG filling stations have become more plentiful despite the high cost. Compared to LPG, LNG offers lower emissions and greater run times. However, it is still not nearly as 'fuel dense' as diesel and run times and power outputs suffer as a result.

Although Kalmar is proceeding with the development of LNGpowered trucks and tractors, it admits to some caution. LNG is a cryogenic liquefied gas that is maintained at a temperature of -162infinity Celsius. The pressure in the vessel that contains this fuel is similar to LPG. The coldness presents certain risks: the fuelling is more difficult, more frequent and requires additional caution and training.

Another concern is that LNG is not odorised and a small leak could go undetected without the use of electronic detection sensors.

LNG technology is also quite expensive and without subsidies, it is unlikely that terminal operators would be considering its use. In California though, where cleaner air is a major issue and subsidies and grants are substantial, LNG is viable and is the fuel of choice for rapid transit buses, garbage collection services, etc. There are now thousands of vehicles operating on LNG just in California alone and by the end of this decade probably tens of thousands. LNG is the cleanest of the fossil fuels and only hydrogen, a non-fossil fuel unless extracted from fossil fuels, is cleaner.

* The purpose of this Directive is to harmonise the laws of EU member states relating to the emission of gaseous and particulate pollutant from internal combustion engines powering NRMM. It harmonises the type approvals of these engines and aims to reduce emissions by progressively tightening the allowable emissions and including more types of machinery.