1. Klarifikasi perbedaan calorific value 4200 kcal/kg LHV (Contract specification) dan 4120 kcal/kg LHV (bidder proposal)

Berdasarkan tabel perbandingan batubara seperti dibawah ini (dengan acuan PLTU Labuan), dapat disimpulkan bahwa Net Plant Heat Rate (NPHR) dengan batubara 4200 kcal/kg lebih baik dari pada 4120 kcal/kg. Oleh sebab itu performance guarantee berdasarkan perhitungan yang disimulasikan terhadap 4200 kcal/kg LHV akan lebih baik dari pada 4120 kcal/kg. Meskipun demikian dalam penulisan performance guarantee kontraktor akan menuliskan angka-angka yang sesuai dengan batubara sebagai berikut:

a) Jika 4120 kcal/kg LHV maka guarantee Net Plant heat rate 2246.7 kcal/kWh

b) Jika 4200 kcal/kg LHV maka guarantee Net Plant heat rate 2246 kcal/kWh

NO DESCRIPTION UNIT CALCULATED 1 CALCULATED 2 1 Coal Calorific Value HHV of Coal kcal/kg 4356 4545 LHV of Coal kcal/kg 4120 4200 2 Boiler Efficiency HHV base % 85.78 86 LHV base % 92.96 93 3 Power Gross Power Output MW 300 300 Net Power Output MW 283.4 283.4 4 Turbine Heat Rate kcal/kWh 1973 1973 5 Gross Plant Heat Rate HHV base kcal/kWh 2300 2294 LHV base kcal/kWh 2122.4 2122 6 Net Plant Heat rate HHV base kcal/kWh 2435 2429 LHV base kcal/kWh 2246.7 2246

2. Justifikasi nilai Gross Calorific Value 4200 kcal/kg dari data yang tercantum dalam surat Dirkit No 00877/121/DITKIT/2006 per tanggal 31 Juli 2006 terhadap 4200 LHV sebagai dasar desain boiler dengan range 3900 – 4500 kcal/kg.

Berdasarkan hasil perhitungan chemical content dari batubara dalam surat Dirkit tersebut maka dapat disimpulkan bahwa nilai kalorific value batu bara tersebut adalah LHV.

Proximate analysis (%)

As Received (ar)

Air Dried Basis (adb)

Dry Basis (db) Dry Ash Free (daf)

Total Moisture 30.00 Inherent Moisture 20.00 Volatile Matter 35.00 40.17 50.21 52.85Fixed Carbon 30.00 34.12 42.65 47.15Ash 5.00 5.71 7.14 Total (%) 100.00 100.00 100.00 100.00

Ultimate Analysis (%)As Received

(ar)Air Dried

Basis (adb)Dry Basis (db) Dry Ash Free

(daf)C 47.649 54.46 68.07 71.65H 3.36 3.84 4.80 5.05N 0.77 0.88 1.10 1.16S 0.231 0.26 0.33 0.35O 14.21 16.24 20.30 21.37Ash 3.5 4 5 0Total (%) 99.72 99.68 99.60 99.58

Design Institute (kCal/kg) ar HHV 4504.1Design Institute (kCal/kg) ar LHV 4142.7

delta 361.4Francis & Lloyd Formula (kCal/kg) ar HHV 4500.7

World coal Institute LHV 4152.5 delta 348.2

Dulong Formula HHV 4355.6 LHV 4011.0 delta 344.6

Bechtel Formula HHV 4355.6 LHV 4184.0 delta 171.6

Berdasarkan hasil perhitungan apabila perbandingan antara batubara yang datang mempunyai nilai kalor 4200 kcal/kg HHV dan 4200 kcal/kg LHV adalah sebagai berikut:

NO DESCRIPTION UNIT BATUBARA 1 BATUBARA 2 1 Coal Calorivic Value HHV of Coal kcal/kg 4545 4200 LHV of Coal kcal/kg 4200 3836 2 Boiler Efficiency HHV base % 86 84,93 LHV base % 93 92,89 3 Coal Feed Rate t/h 153 167

Apabila batubara yang datang mempunyai nilai kalor 4200 kcal/kg LHV maka bisa diperoleh penghematan sekitar 14 ton/jam batubara dibandingkan jika batubaranya 4200 kcal/kg HHV.

3. Garansi 1 tahun apa harus kontinu beroperasi 300 MW

Berdasarkan Contract Document Book II, Part 4.3B clause 4.3B.4 General Operating Condition dan Book I, Part 2 General Condition clause 2.34 Warranty dibawah ini, maka tidak ada ketentuan dalam kontrak yang menyatakan bahwa Power Plant akan beroperasi 300 MW secara terus menerus selama satu tahun (periode masa garansi).

Contract Document Book II, Part 4.3B clause 4.3B.4 General Operating Condition:

The principal purpose of the plant generation is to provide the base load for all type of consumers. The average plant load factor is assumed to be about 70%. However, the plant shall also be capable of alternate operating patterns including two (2) shift operations. For these reasons, the Plant shall be highly efficient and reliable. Unit startup generator, normal operation and control shall be executed from the central control room.

Contract Document Book I, Part 2 General Condition clause 2.34 Warranty:

a. The warranty period shall starts from the date stated in the Taking-Over Certificate for each Unit and shall expire after twelve (12) months from that date. If the issue of the Taking-Over Certificate is delayed for reasons beyond the control of the Owner and/or the Contractor, then the matter shall be discussed by both parties to fix the date of commencement of the warranty period.

b. In case a failure of the equipment due to Contractor's fault (mechanical or electrical) occurs

- The causes of which are in the equipment supplied

- during the original warranty period leading to a stoppage of the generating set for more than one (1) calendar month from the date the Contractor has been informed, the following consequences shall take place :

- The Contractor shall replace defective parts and to effect a repair as fast as possible.

- A new warranty period equal to one (1) year shall be applied to the replaced parts of major components, starting from the date the generating set is ready to run.

- The original warranty period on the concerned generating set which is interrupted by this procedure shall be extended by a period equal to the period during which the generating set is out of order as a result of the defect.

- The performance Bond/Bank Guarantee shall be extended accordingly and submitted to the Owner.

The Contractor shall not have any liability regarding defects beyond the obligation to repair and/or replace the defective part(s) at its own cost.

Catatan: Capacity Factor = Load Factor x Availability Factor

Jika Load Factor 70% dan Availability Factor 90% (Contract Specification) maka Capacity Factor-nya adalah 63%.