Energy Audit: Cost-effective solutions for the industry in the era of energy crisis (part 2)

M. Masum Jujuly Nuvan

Featured Article: Received 7 July 2013; received in revised form 19 November 2013; accepted 11 December 2013; online published 9 January 2014.

Scenario in Bangladesh

Rapid growth of energy demand and insufficient public or private sector investment in the energy sector led to the initiation of the energy crisis in Bangladesh. Although the consumers or industries are taking remedial steps towards mitigating the power shortage, for instance by installing captive power plants in the industries, these remedies tend only to exacerbate the graver problem of insufficient gas production relative to the gas demand growth. The primary source of our fuel largely depends on gas (Figure 1) and the demand of energy is increasing (Figure 2). However, the major problem is the increasing gap between demand and supply due to inefficiencies in the generation, transmission/distribution, and end-use (demand) components of the electricity and gas sectors.

Energy Scenario in Bangladesh from 1972-2008

Figure 1.  Energy Scenario in Bangladesh from 1972-2008 (Orange: Biomass, Green: Gas, Blue: Oil) [2]

Energy efficiency can offer partial solutions to the issues arising from the energy crisis. Bangladesh is currently concentrating on improving energy efficiency on the demand side; this can lead to the improvement of energy security, increase competitiveness, reliability and reduce energy costs. In the past, the Government took a number of steps regarding energy efficiencies, but not much was achieved. Failure of all past energy efficiency efforts is accounted, principally, for low gas supply, high electricity prices and lack of patronage and commitment. These two facts have cumulatively worked as great disincentives to energy efficiency improvement in Bangladesh [1].

Growth of Electricity in Bangladesh 1972-2008

Figure 2. Growth of Electricity in Bangladesh 1972-2008 [OCED/IEA] (Blue: Hydro, Green: Gas, Sky blue: Oil) [2]

A number of international agencies and financial institutes have come forward to assist with identification of potential opportunities for energy efficiency improvement and demand-side management measures in Bangladesh, as well as with applications of renewable energy sources. Organizations like the World Bank (IFC-SEDF) and GIZ (previously GTZ) offer numerous opportunities for energy efficiency and demand side management in the energy sector.

By applying those opportunities, investors in the energy sector and the Government can take necessary steps in the future by increasing the use of renewable resources, including CFL (compact fluorescent lamp), solar power, bio-gas, wind-PV hybrid power, biomass gasifier according to the suitability for Bangladesh [2].

At present the use of renewable energy is limited to a small fraction of the society, i.e. for domestic purposes. However, the scenario in the industrial sector is different. Nearly all large industries are in the public sector, among them the fertilizer industry is the largest. After power sector, the second largest consumer of natural gas is the fertilizer sector. In 2007-08, the fertilizer sector consumed 12% of the natural gas (Figure 3); besides all the fertilizer factories in Bangladesh are more than 20 years old. Hence, routine maintenance and replacing the old plants with the modern efficient ones can increase the production from 1.5 to 2 times, and reduce the energy intensity of production [3].

Current Sector-wise Use of Gas in Bangladesh

Figure 3. Current Sector-wise Use of Gas in Bangladesh (Energy and Mineral Division) [9]

Other large industries with significant scopes for energy efficiency are sugar, pulp and paper, bricks and ceramic industry and need process improvement [e.g. Hoffman kiln process] and cement industry – Chattak Cement Factory needs to change from wet to dry process. Another potential sector for energy saving is the textiles knitwear industries in Bangladesh that consume a large amount of natural gas and electricity. Scopes for improvement lie in process development, insulation (e.g. boiler, stem pipelines and valves, boiler feed water tank), steam leakages, boiler blow-down rationale, heat recovery (Economizer for the boilers, EGB for generators, reformers), proper tuning of the boiler: boiler combustion analysis, compressed air leakage, requirement of earth leakage circuit breaker (ELCB), electrical power factor improvement, energy savings from rotating devices, usage of electronic ballast for tube lights, green architecture of the industries to save energy etc [4,5,6].

 

Case Study 1: Energy recovery from boiler plant system

Boilers are used to generate hot water and steam in a plant, as part of the process requirements. In most of the processing facilities, a substantial amount of fuel is consumed by the boiler alone, and it is also where most of the heat is lost from. Numerous energy losses take place from the boiler, the important ones of which are itemized in Table 1:

Table 1: Energy loss from boiler and steam distribution system [4]

Energy loss from boiler and steam distribution system

Sample calculation for the steam/hot water pipeline and insulation

To quantify the amount of heat loss resulting from uninsulated steam pipeline, a sample methodology will be demonstrated. Usually the temperature of a saturated steam pipeline (with 6-7 bar steam pressure) is around 150-160oC, capable of radiating a large amount of energy loss.  Surfaces of boilers, condensate return piping, and fittings, which have a temperature over 45°C, need to be insulated. Insulation of the surfaces will prevent radiation of heat and consequently save energy and improve process safety.

Pipe Heat Loss

Figure 4. Pipe Heat Loss [4]

From Figure 4, it is evident that heat is lost from the uninsulated bare surface of a steam/hot pipeline case. An estimation of the heat loss can be made by using Table 2.

Table 2: Total heat loss calculation from a bare pipe

Total heat loss calculation from a bare pipe

Case Study 2: Energy recovery from compressed air system

Compressed air is often referred to as the third utility, after heat and electricity, and it is accounted for the highest portion of the electric load. Compressed air leakage is one of the most common causes of energy wastage, typically accounting for up to 70% of the total wastage [4]. The overall efficiency of generating compressed air is very low (Figure 5) with high energy consumption.

Energy Flows and Losses in a Compressed Air System

Figure 5. Energy Flows and Losses in a Compressed Air System [4]

The losses in compressed air systems are categorized in Table 3.

Table 3: Losses from the generation of compressed air

Losses from the generation of compressed air

Besides the two case studies discussed, there are numerous other significant factors that are directly related to energy savings. Significant amount of energy may be saved from HVAC system, chiller& AHU, motor, pump, and other devices; power factor may be improved as well. Replacement of incandescent light and magnetic ballast of the fluorescent light with CFL and  industrial grade electronic ballast are ways in which substantial amount of electrical energy can be saved [7, 8].

It is now time for the industries to take the necessary steps involved in thermal and electrical energy monitoring and management system for efficient utilization of energy and business sustainability. Industrial sectors in Bangladesh emerged due to the core competences, which are low energy cost and cheap labor; but unfortunately these core competences are turning to core challenges, since power is no more longer cheap and gas has turned ‘not sufficient’ [10]. Energy audit is the foundation on which rests the entire energy management program, and is the way to optimum power usage. High energy costs, inadequate fuel supply, waste of money on ineffective action, and lack of proper allocation of funds for the action plan on energy conservation steps are only reflections of the deficiency of the current energy management. In Bangladesh, there is a common trend that vendors supply the instruments with a free energy audit but the energy auditor should have no conflict of interest. Energy audit is a continuous program and each cost saving activity is an independent project that requires its own knowledge, equipment, and people. Finally, there is always room for improvement and it is worth remembering that energy management never ends.

References:

1. Hossain, Ijaz, and M. Tamim., Energy and Sustainable Development in Bangladesh, Helio International, Sustainable Energy Watch, 2005.

2. IFC Sustainable Energy Finance Report: A Combined Advisory and Investment Services Approach to Help Reduce GHG Emissions, November 2009.

3. Danish Energy Management Report: Energy Auditor Training to Build Capacity of Service Providers (SPs) in Bangladesh and Nepal, February-April, 2011.

4. Energy Efficiency Planning and Management Guide, Natural Resources Canada, 2002.

5. Working Manual on Energy Auditing in Industries, Asian Productivity Organization, 2008. ISBN: 92-833-7069-4.

6. An Energy Audit Manual and Tool, Canadian Industry Program for Energy Conservation.

7. Cleaner Production – Energy Efficiency Manual for GERIAP, UNEP, Bangkok, National Productivity Council.

8. Turner, W. C., Steve, D., Energy management handbook, John Wiley and Sons, 7th Edition.

9. BP Statistical Review of World Energy, 2003 and 2007.

10. McKinsey Report ‘Bangladesh: The next hot spot in apparel sourcing?’ March, 2012.

Editor – Fauzia Sultana

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