A POWER BARGE LIFETIME ANALYSIS

Today, nearly every industry needs a continuous power supply, as data loss can be

more expensive than the capital expenditure for the backup power equipment. The

demand for ‘emergency’ capacity standby power and getting electricity to where it really

matters has been on the rise since the 1980s because of increasing industrialization.

The land-based resources and infrastructures needed to construct a power station may

not be available, and transport over water may be the only way to get large equipment

to the site, such as Power Barge or Power Ship.

A self-contained floating power plant can be the best and quickest solution when

electrical energy is needed on short notice in remote areas as backup in capacity or

as a sole power supply for a longer period. It can be built and installed relatively quickly,

supplying harbors, coastal regions, cities, coastal regions or sites near rivers.

We see over 40 power barges and power ships deployed worldwide and operating

worldwide. The utilization rate of power barges is around 95%, with only one or

two power barges and power ships available in the global market at any one time.

It is expected that a power barge or power ship could moor at one place for an average

duration of three to five years on a lease, or up to 20 years or more under a PPA

, depending on the lifetime of the power barge. For this reason, power ships or power

barges if constructed already, are a solution to bridge the gap for a certain time until a

local power plant is built or the high demand in electricity supply is over.

During the 1990s, power barges became a popular way of providing energy to

developing nations, with companies including equipment suppliers like GE,

Westinghouse, Wärtsilä, and MAN BW, by developers, which operate floating power

plants for customers located widely with a supply of energy across the continents and countries of Americas, Africa, the Middle East, and the Far East, such as New York City (US), Bangladesh, Bahamas, Dominican Republic, Jamaica, Panama, Guatemala, Venezuela, Martinique, Brazil, Ecuador, Angola, Nigeria, Kenya, Mozambique, Ghana, Iran, Iraq, Saudi Arabia, in the Philippines, Indonesia, Malaysia, Mauritius, and Thailand.

Design of power ships or power barges can be equipped with a single or multiple gas

turbines, reciprocating diesel and gas engines, in a combination of diesel engines and

turbines, boilers, or nuclear reactors for electricity generation. Classification Societies

like Bureau Veritas and ABS is an international certification agency with experience in

overseeing both shipbuilding and power plant development, classifies such floating

power plants as "special service power plants," where the hull is governed by the

Classification Society and Flagstate governed Safety and Environmental issues under

IMO (International Maritime Organization) rules and regulations.

Operation of the power barges was and has been entrusted mainly to companies with

expertise in this field since it requires dedicated training of personnel for sound and safe

operation and maintenance of a power barge or power ship and its influence on its lifetime.

The objective of this study is an assessment of a self-contained floating power barge

lifetime by contextual models for evaluation of operational lifetime, reliability, and risk where structural, machinery, and electrical equipment maintenance sets the standards for the lifetime of the power barge as per design specification.

This has been pursued by making an extensive literature survey from the Lloyds Coverholders London Power Barge Binder, IACS (Classification Society), and power barge Designers, where information concerning the relevant existing probabilistic degradation and risk analysis of various power barge-related claims has been

considered to assess the remaining lifetime and integrity of the structure, machinery, and

electrical systems/components of power barges.

In the following a power barge functionality and lifetime cycle will be introduced, and the

final conclusion will assess the lifetime range and which impacts are reducing lifetime before lifetime extension, as refurbishment projects are considered.

We have performed a study of a power barge and power ships portfolio of more than 60

units over a period of 20 years, from which we conclude a lifetime range set on

parameters related to parameters mentioned in this study, using several risk analysis methods, as well as some limitations and shortcomings concerning our professional

experience in this segment.

Keywords:

- Built to which standard (s).

- Technical operators’ quality standard and qualifications.

- Lifetime expectations and assessments.

- Sustainability.

- Maintenance philosophy.

- General condition and management standards.

- Embodied energy.

- Equipment and components end-of-life evaluation throughout the lifetime.

- Component life extension.

Power barges have unique characteristics when compared to other forms of Power

generation, in that the construction of the plant is undertaken in a completely different

environment to one in which the plant will operate.

Barges will be manufactured within a shipyard to a given standard by the barge owner

specification e.g. None – Industrial Standard – Marine/Offshore Standard and out fitted

and commissioned with full automation generating systems with ancillary equipment

before being transported to the location where they are to operate after a site

commissioning performance test.

This has implications for the ability to maintain and repair such plants and can pose

unique problems when major work is to be undertaken. The composition and operating

conditions will vary considerably from barge to barge, where power barges offer a quick

and economic solution to building power plants in remote parts of the world.

All-weather accessibility is a problem and consequently entails considerable extra

expense in transporting components to site as well as skilled construction labor which

need to be housed, and the availability of construction equipment on site.

In cases where equipment is damaged (generator set complete) or severely damaged to

the structural arrangement of a power barge, the repairs will have to be undertaken at a

shipyard.

Abstract: Lifetime, reliability, and risk analysis methods and applications for power barge

lifetime of structure, machinery and electrical systems with components of power barges

involve many fields of knowledge, such as structural design evaluation, mechanical

machinery i.e. diesel generator sets proven maker and type, breakdown of equipment

database awareness, knowledge of power barge owners' Quality Manual and technical

operator philosophy.

In practice, lifetime and risk analyses are usually performed by the power barge

technical operator with a suitable analysis tool, e.g. PMS (planned maintenance system)

as to equipment makers’ (OEM) recommendations and this to Classification Societies

systems and Flagstate rules and regulations cost controlled by owner with OPEX and

CAPEX long term budgets revealed the lifetime of the barge.

Ageing degradation in power barges should be managed by ensuring that the design

functions remain available throughout the service life of the plant. Example if

‘aftermarket’ parts, NON-OEM parts are used in machinery the lifetime of the equipment

becomes unknown and ‘high risks’ is build up for severe damage of vital equipment

and components causing PPA contract to call off-hire and activate the BI-plan by

Underwriters.

From the safety perspective, this implies that the ageing degradation of power barges

important to safety remain within acceptable limits, and that procedures and personnel

training remains adapted. Unchecked, ageing degradation has the potential to reduce

the safety of operating power plants why it is highly recommended to have third party

risk assessment of plant condition evaluated on yearly bases.

Mitigation of ageing effects should be made on the basis of identified degradation

mechanisms and their severity. The primary goal in this phase for the technical operator

of a power barge is to find suitable methods to prevent mitigate or restore the effects of

ageing. Thus, the basic management methods are controlling and slowing down ageing

as well as the replacement of components. The application of these methods is component-specific, depending on e.g., the expected ageing rate and mechanisms, the possibilities

of replacement, and early failure detection possibilities. In the case of repairable or

replaceable components that will age relatively fast compared to the plant lifetime, the

ageing management means following the efficiency of current maintenance procedures

and reviewing the manufacturer’s recommendations. In the case of components that are

difficult to replace, the efforts may be focused on the reduction of environmental stressors, re-evaluation of surveillance, and condition monitoring methods.

POWER BARGE OPERATION

Types of operating environment: floating static, where there is to a long-term demand

for a constant power supply or capacity provision, the barge will be permanently located

at one site or as a minimum of five to ten years.

TYPES OF OPERATION

Barges can be permanently moored alongside wharfs, jetties, quays, floating dolphin

arrangements and while still being a floating vessel will not move from this location.

Such barges are therefore exposed to wave movement and potentially impact from

other vessels.

Floating special mooring in some instances special moorings have been created where

the floating barge is protected from passing traffic. The site is dredged to create a

mooring off a river.

Another example of a special mooring is where a permanent “wet berth” is created with

a lock gate enabling the power barge to be floated into the mooring and then the water

level maintained to protect the barge form fluctuations in river level. This also provides

protection from impact from other vessels.

Grounded to achieve a more stable operating environment and eliminate perils of sea or

water, a dock is excavated, the barge is floated in and then sealed off from the water

course, water is pumped out and the dock is filled to create a permanent land based

generating station.

For all intents and purposes, this is now a land-based station, special considerations still

apply as the means by which the barge was transported, could not be utilized in the

event that spares or replacement parts needed to be delivered.

Moving barges can provide the temporary power supply when land-based generating plants undergo major overall for maintenance. In these circumstances, the

facility will have a PPA power purchase agreement, probably of less than five years

duration. Barge owners sometimes rely on the threat of moving their barges to another

country as a means of extracting payments from customers who are reluctant to pay.

LOCATION CONSIDERATIONS

Location considerations, remoteness, power barges are an attractive solution to the

provision of power to remote locations, providing of course that they have access to the

sea. Power barges being constructed away from the location where they will operate has the advantage that components do not have to be transported across hostile and difficult

terrain.

Labour costs are minimized as skilled staffs do not have to be transported to and

accommodated in remote locations avoiding the extra infrastructure costs and

allowances.

From five operational power barges known for inaccessible why the barge has been

sited at a location with navigational access to the sea, the location may be inaccessible

or not easily accessible over land. This becomes a major consideration when

maintenance or repairs are undertaken.

In many case it may not be possible for large cranes that would be required for lifting

machinery to access the site. Weight limits on roads and bridges, or height of tunnels

may prevent large replacement components from being transported to the site by road or rail.

Where it is not economically or physically possible to supply craneage and parts by

waterway, the option is to remove the barge to a dry dock or quayside, where the work

can be undertaken.

TYPES OF POWER GENERATION PLANTS

Types of power generation plant are fossil fuel / dual fuel diesel engines or gas turbines

on dual fuel, steam turbines and nuclear power units. Mostly of the power barges today

are either diesel engine or gas turbine units operating with daily fuel supply from supply

station. These systems are operating in isolation or in association with waste heat

boilers and steam turbines, which appear to be the most common method of generation

employed on barges.

The size of the diesel engine should not be underestimated and equally the craneage

needed for periodic lifetime maintenance scope of works such as lifting the engine block

or complete generator.

Marine Dieselsare robust and have a proven track record for operating in a marine

environment. They are not immune to catastrophic failure and an obstruction can

however cause destruction of the destruction of cylinders and crankshaft. Todays power

plants are with diesels operated on dual fuel i.e. LNG.

Gas Turbines became more common in the 2000s, operating with waste heat boilers

and steam turbines. More susceptible to damage from environmental perils are steam

turbines which are not very often seen on power barges but in shore plants operating on

waste heat from boilers.

Nuclear power barges are commonly in military use and at arctic locations, but new technology is moving towards worldwide commercial power barge designs.

IMPACT OF WAVE MOTION AND ENVIRONMENTAL CONDITIONS

The impact of wave motion and environmental conditions is not considered a problem during normal operation and with the anticipated sea conditions.

The mooring of the barge acts as a stabilizing factor to reduce the impact of wave

movement.

The atmosphere will have a high saline and moisture content, which causes corrosion

problems in electronics and monitoring systems if maintenance is inadequate. Air

purification will need to be capable of dealing with this to filter out excessive saline and

moisture.

Cooling water and feed water may well be drawn from the sea and purified through a

desalination plant on board, where chloride contents must be monitored and within the

tolerances of makers’ recommendations for cooling water of machinery. The systems

must be capable of taking out the salt content and coping with other pollutants that

might be discharged into the sea. The feed water is far more vulnerable to fluctuating

quality than land-based sites.

MAINTENANCE STATISTICS RISKS

Maintenance Static risks should be no more hazardous than a conventional power plant

or as to marine/offshore standards, subject to the ability to transport adequate spares to

site and the competence of the maintenance staff. Maintenance standards are however sometimes less than those for similar land based plant and marine/offshore standards, because barge operators tend to have less resources and competences where more remote locations are easily forgotten by management. Barges which are moved from site to site, pose an enhanced risk, as there is a tendency for maintenance to be neglected as responsibility moves from one location to another which is also noted on 2nd hand barges shifting owners one or two times in the barge lifetime.

MAINTENANCE MANAGEMENT OF RISKS

PMS (Planned maintenance system) considerations with diesel sets overspeeding or obstruction for same and poor system lube oil condition causes destruction of cylinders

and crankshaft and in some cases destruction of engine blocks and barge fire.

The cost to repair damage could easily exceed 50% of the unit value or from a fire 80 %

destruction of the barge.

Series loss through fuel contamination if all units on a barge are being fed the same

fuel, any impurities in the fuel quality will equally cause damage to all of the sets.

Waste heat boilers, distortion through dry firing. Steam / Gas Turbines, 100% damage

due to overspeeding/first stage blade failure downstream.

Construction compact nature of the barge may increase repair costs as to no access.

Other major non PMS losses are corrosion caused by poor feed water or cooling water

quality, fuel contamination, lube oil contamination, Non OEM parts, corrosion of hot gas

path components from exhausts, generator winding failures due to salt water ingress on

direct air cooled stators or build ups of dust and purities as well as corona hysteresis.

Main or auxiliary transformer destruction of phases due to poor oil quality, humidity in

the system / neglected maintenance

CONSEQUENCES OF A MAJOR FAILURE

Consequences of a Major failure unlike other power stations or marine/offshore units;

power barges are not built or assembled at the location where they operate.

If major damage occurs, it may not be possible to get a Jib crane either to the location

or the location may prevent the crane from operating alongside the barge. This could be

either due to the barge being moored away from the land or the ground not being solid

enough to support the weight of the crane for proposed component and equipment

lifting.

The implications of not being able to repair on site and the barge being taken to

the manufacturer/dry dock are that:

1. There is a loss of production for all units on the barge, not just the one that is

damaged, while the barge is away for repair.

2. The Barge is at risk during the Journey to dry dock, and if it sinks there, the Loss of

profit could be attributed to the original cause, till replaced and full production resumes,

with a replacement barge, subject to application of the indemnity period.

3. There is an increased risk of damage to machines during transit. Exposure to a

salt air and derangement due to rough weather could pose an increased breakdown risk

when the barge resumes operation.

4. There can be seasonal considerations, e.g. hurricane season, which would prevent

the barge from being moved at certain times of the year, resulting in a prolonged

interruption period.

5. Significantly increased repair costs.

6. Prolonged Interruption period and increased costs due to re-cabling between ship

and the Shore

UNDERWRITING CONSIDERATIONS CONFIRMATION

Underwriting considerations confirmation is needed when claims occur to severe

machinery or structure before repair or replacement of damage at the location of

operation and that the barge is static and will not be moved to any other locations

unless mutual agreed with Underwriters.

To avoid losses from perils of the sea and prolonged business interruption, from an

event occurring while the barge is removed for repairs, an exclusion needs to be applied

for any loss or damage or consequential loss while the barge is away from the location

irrespective of the reason for removal being due to an insured event or otherwise.

Series Loss clause would protect from common fault claims and could assist fuel

contamination, but would have no effect if the damage was caused simultaneously.

Warranties to ensure that units are serviced in accordance with OEM’s

recommendations would document an obligation for the Insured to ensure that

machinery is properly maintained.

Suitable equipment depreciation clauses can be considered; a suitable fuel quality

clause would be appropriate.

Barge cover would normally be subject to satisfactory survey or subject to the

recommendations from Underwriters survey being carried out on a yearly base.

LIFETIME ANALYSIS CONCLUSION

Our conclusion to Power barge lifetime before the lifetime extension is 25 to 30 years

where this range from 25 to 30 years is strictly dependent on proven barge

design as build and its lifetime maintenance history. Power barge lifetime above 30 years is dependable of its lifetime betterments before lifetime extension refurbish project is performed. In cases were a barge has had lifetime extension the lifetime is normally

prolonged with 10 to 15 years at its most with range 35 to 40 years lifetime from

new building.

LIFETIME RANGE

In general, ageing in power plants can be taken to mean the evolution of personnel and

procedure adequacy and evolution of material or equipment properties, which, after a

certain time may not be compatible with the required standard safety margins to what

is expected from a barge of its current age, or with the economic functioning of the plant.

Repair or replacement of components, as well as a change in service conditions for a

better compatibility with component reduced capacities are possible in the lifetime of a

barge to have a prolonged lifetime range. In the end, the lifetime period of the barge it is

seen that failures occur to the mechanical and electrical equipment, which is fading out

and structural material requires replacement in order to obtain a standard safety

margin and this is seen as a fixed maintenance cost in the barge lifetime and not as a lifetime

extension process.

As shown in the above figure, lifetime extension is not only obtainable through repair or

replacement of components, but also through a better use and a better evaluation of the

real evolution of component performance, for example, a better prediction of component

properties evolution, a better evaluation of existing defects, and the mechanical behaviour of

real defects, or a better knowledge of operating conditions.

Power plant structures and machinery generally have substantial standard safety

margins when properly designed and constructed. However, the available margins for

degraded maintenance are not generally well known. In addition, age-related degradation components and control systems may affect the dynamic properties, mechanical response, electrical resistance/capacity, failure mode, and location of failure initiation.

A lifetime difference of a barge can be influenced if the owner or technical operator has

set standards for the maintenance and operation performance of the barge, whereas

qualifies for and follows a number of quality control and improvement programmes by

being accredited to ISO standards and the structure/extent of the management system

with procedures based on international standards and consequently subjected to

external audits at regular intervals.

- ISO 9001-2010/15, Quality management

- ISO 14001- 2004, Environmental management

- OSHAS 18001- 1999, Occupational Health & Safety management

One principal concept in ageing and maintenance management is the concentration of

effort on the reduction of the failure probability of the most important components, and this

especially if OEM’s recommendations are not followed.

Reliability-centered maintenance (RCM) is a method for establishing a scheduled

preventive maintenance programme resulting in improved component reliability and

minimised costs (CAPEX or O&M costs). The RCM approach intends to optimise the use of maintenance resources by identifying the most critical components with respect to safety, availability, or maintenance costs, and selecting for these components the most appropriate maintenance procedures with the aid of decision logic.

EXAMPLES OF LIFETIME REDUCED BY COST SAVINGS

Below is an example 1 on how costs are squeezed during the aging process of a power barge

which will lead towards reduced lifetime or expensive lifetime extension

Example 1) Expected lifetime 25 years

Below is an example 2 on how costs have been maintained to obtain a standard safety margin. However, the O&M total costs are observed as squeezed during the past years of the barge, leading towards a low standard safety margin.

Example 2) Expected lifetime 25 to 30 years.

POWER BARGE / POWER SHIP RECYCLING

The barge is recycled after 25 – 30 years of service or when extension and retrofitting cannot be financially

justified. Normally, the owner sells the barge to a marine scrap

yard for demolition. At the yard, all the steel and some of the equipment are reused or sold

in the secondhand market.

The scrapping process's safety, health, and environmental issues must comply with the IMO rules established for it.

References:

"Bureau Veritas classes powerbarges&ships". Malta Maritime Directory. 29 June 2010.

Retrieved 22 August 2010.

LRS: Lloyd’s Register of Shipping. Life Cycle Cost per annum (AAC): Life Cycle cost divided by the number of years the PB/PS is expected to be in operation, calculated on the Average Annual

Cost (ACC) for the PB/PS operation

LEG Subcommittee Syndicates: Catlin - Norcliffe – Munich – Swiss Re – Zurich Re.

Lloyds Coverholders Binder for power Barges Worldwide; Condition and claims 1995-2016 covering portfolio study of +40 power barges and power ships.