ANSWERS TO GREEN PROBLEMS

By Michael Grey

The Sea – Issue 201-sep/oct 2009

The Copenhagen climate change conference is just a few months away, and already a hard look is being taken at the emissions from ships' funnels. If we are all to save the world (although it is pretty optimistic to think that any reductions of the three per cent of carbon attributable to human intervention will be even slightly meaningful), everyone, and that includes shipping, must bear the pain. Or so the environmental lobbies which are calling the shots tell us.

There is a great deal of commercial and government interest in carbon "trading" and in raising revenue through fuel taxes, but many in the shipping industry believe that there are far better ways of reducing harmful emissions which may, or may not, contribute to climate change or public health. Marine engines may seem to be efficient enough as they work night and day consuming heavy residual oils which nobody else would possibly use, but there is a lot of room for improvement.

The marine diesel, it has been said, is at about the same state of development as the car engine was in the late 1960s, and cars have become so much cleaner and more efficient over 40 years of intensive development. In the 1970s, so the diesel engine designer will tell us, the industry wanted light, compact, powerful engines that would operate economically with the worst possible quality of fuel. The diesel engine designers delivered exactly that specification, and everyone was happy.

Now environmental pressures are increasing, and there are different demands - for engines that will not belch out sulphur, nitrogen, particulates and CO₂. We will deliver this, say the engine designers, just give us a little time! And indeed, in engine works around the world, there are all sorts of exciting developments taking place that will make marine engines so much cleaner in their emissions.

There is a great deal we can do outside the engine room to make ships more efficient. There is still room for more "slippery" hulls that will offer reduced resistance to the water, for better coatings, perhaps, and for fresh consideration of hullforms and underwater design. What can we do to reduce the effects of a head-wind, which everyone knows slows the ship down dramatically?

There are already shipping companies experimenting with the use of solar panels, wind generators and even wind assistance, all with the aim of reducing fuel consumption and emissions. A ferry company discovered that the use of reflective foil over all the windows in their public rooms reduced the load on both air conditioning and heating systems by an appreciable amount. What a simple, clever idea.

Then there are operational efficiencies which can contribute much to the reduction of harmful emissions and, indeed, the consumption of expensive fuel. How many readers of this column have been on board ships which have rushed at full speed across an ocean, only to spend a frustrating fortnight at anchor waiting for a berth to become vacant? What a lot of wasted effort. Surely there must be a better way of organising things?

With a recession in place and a world surplus of ships, there is a renewed interest in slow steaming. If a 25 knot con- tainership is slowed down to 19 knots (which many will think quite fast) you save 40 per cent of the fuel, which is a massive financial saving, not to mention the reduction in emissions, which may make the greens smile. It is a balance, of course, as the shippers might be hostile to such an approach, or extra ships will be required to lift the cargo.

But at a time when half the container fleet is carrying around fresh air, or low value cargo, the need for speed is not quite so obvious. Slowing down the world liner fleet would also use up a lot of the surplus capacity, which is a serious conside-ration with an estimated 600 containerships currently idle. But there's nothing simple in today's world, and there is more to slow steaming than merely throttling back a few notches.

An engine which is designed to operate at 90 per cent of its full power objects strongly to running for extended periods at low revs. Things start overheating, and machinery like the turbocharger gets fouled up. Fuel valves get clogged, and there are even fire risks attendant in such economical running, which rather wrecks the economics.

Rotating machinery and bearings are turning too slowly for lubrication to properly take place and risk being damaged. Slow steaming may seem the answer for the struggling shipowner, but it means extra work for the hard-pressed engineers.

There is probably a further downside in that slow steaming risks the sanity of the crew, who suddenly see the voyage double in length, and possibly even risks the possibility of opportunist pirate attacks! But let us not be negative about this. Technology and operational efficiency can answer a lot of today's economic and environmental problems, given half a chance.