At Riviera Maritime Media’s webinar Compressors: squeezing out energy savings, panellists discussed the challenges of balancing compressor costs with shipowner needs
Typically, shipowners ordering newbuildings look for the best price for the vessel and as a result, the selected shipyard looks to reduce purchase prices for the required equipment on the new ship.
Compressor manufacturer represtatives Kaeser Kompressoren business development manager Oscar de Groen and Sauer Compressors head of business development projects Stephan Behrens said a different way of doing business would give shipowners more return on investment.
Mr de Groen mooted shifting the focus from lower-priced compressors to opting for systems with the highest energy efficiency. He believes the low-price policy is not as beneficial for the opex shipowners will incur in the long term, while the shipyard will not be affected by the operational expenses of the purchased air compressors.
Instead, priority ought to be given to energy expenses, which represent over 50% of the lifecycle cost of a compressor, in his view. While predictive maintenance will give low-cost providers some advantages, he believes these will be limited to early detection, but give no guarantee of reliability.
Only 44% of audience members reported monitoring the lifecycle costs of the shipboard air compressors currently on their fleet.
The relation between the shipboard compressed air application and the required capacity of the compressor is key.
He said “The golden rule is to select an air compressor with a rated capacity at the discharge pressure as close as possible to the specified maximum air consumption of the marine application.”
“Over capacity and higher discharge pressures than required will increase energy consumption. After-treatment systems are required for control air and for feed air conditioning of nitrogen generators, especially when pressure-swing adsorption or PSA air-separation technology is used.”
For audience members, service and control air remained the most important compressed air application in terms of capex, with 46% voting this way.
Sauer Compressors’ strategy focuses on a three-stage compression design. Mr Behrens said three-stage compression has shown energy savings of up to 8% compared with a two-stage water-cooled compression.
Sauer also operates EasyCare, an advanced maintenance concept, which prioritises using a new kit after a set number of operating hours to improve the lifecycle of the compressor. The company expects to save up to 36% in energy costs throughout the lifecycle of a compressor.
On the cost-cutting measures, Mr Behrens agreed with Mr de Groen, and said Sauer receives many requests from yards to compromise on costs. But neither panellist was enthusiastic about skimping on capex costs.
Mr Behrens noted that cost cutting sometimes extends to compressor overhauling, often conducted by ship staff using low-quality spares which can reduce a compressor’s lifecycle.
To counter this, Sauer tries to establish a close working relationship with shipowners, technical and commercial teams to ensure owners have a more rounded knowledge of purchase options and ensure greater availability of quality spare parts for smooth fleet operations. The manufacturer has over 8,000 compressors under fixed budget and company data shows that when owners use original spares, structural damage is reduced to “close to zero”.
Both panellists also believe a lack of practical compressor installations is a problem. Mr de Groen said Kaeser sees the documentation for the installation is often carelessly read and leads to installation and operational issues down the line.
Mr Behrens concluded that owners will be better served by investing in the existing compressor plant and choosing the right compressor plant to save operational costs on the existing fleet in the long term, rather than eyeing capital expenditure. Most owners (86%) felt they saw returns on investment between five and eight years after installation.
Mr de Groen reiterated the importance of energy expenses for air compressors regardless of size. “We need a new way to do business. We are focused on sale price and maintenance expenses, but conservative calculations have shown these are not the dominant concerns in the lifecycle of a compressor: That is energy. It is more important than you think.”
It seems owners will still need more persuading: 41% of respondents were open to accepting higher capex costs to reduce both lifecycle costs and the environmental footprint but an equal number remained unconvinced, while 18% disagreed.