Document:

Amendment I-A dated Jan 3, 2005 to Electric Power Purchase and Sales Agreement

 Exhibit 4.17 
  
 AMENDMENT TO THE ELECTRIC POWER PURCHASE AND SALE AGREEMENT 
  
 AMENDMENT I-A TO THE ELECTRIC POWER PURCHASE AND SALE AGREEMENT, CELEBRATED BETWEEN
COMPANHIA HIDRO ELÉTRICA DO SÃO FRANCISCO – CHESF AND BRASKEM S.A.- UNIB-BA, DATED AS OF 10/20/2004. 
  
 By this deed, the Parties  
  
 COMPANHIA HIDRO ELÉTRICA DO SÃO FRANCISCO – CHESF, a public services concessionaire engaged in the supply of electric power, with headquarters
in the city of Recife, in the state of Pernambuco, at Rua Delmiro Gouveia, n° 333, Bairro do Bongi, enrolled before the CNPJ of the Ministry of Finance under no 33.541.368/0001-16, and enrolled before the state tax office under no 18.1.001.0005584-6, hereinafter simply referred to as “CHESF” and represented herein pursuant to its Bylaws by its Directors, described and undersigned at the end of the agreement; and 
  
 BRASKEM S.A. – UNIB-BA, with headquarters in the city of Camaçari, in the
state of Bahia, at Rua Eteno, n° 1561, Camaçari Petrochemical Complex, enrolled before the CNPJ of the Ministry of Finance under no 42.150.391/0001-70, and enrolled before the state tax office under no 01.027.389-NO,
hereinafter referred to simply as “CONSUMER”, and represented herein pursuant to its Bylaws by its Directors, described and undersigned at the end of the agreement. 
  
 WHEREAS: 
  

	 	•	 	on October 20, 2004, pursuant to the provisions of Article 25 of Law no 10.848, dated March 15, 2004, and pursuant to paragraph 2 of Article 54 of Decree no
5.163, dated July 30, 2004, the PARTIES celebrated the Electric Power Purchase and Sale Agreement for the supply of electric power by CHESF to the CONSUMER’s industrial installations, located within the City of
Camaçari, in the state of Bahia, governed by the binomial hourly-seasonal tariff structure; 

  

	 	•	 	in respect to the peculiarities of its contractual ties, the continuity of the entire supply set forth between CHESF and its industrial consumers have been bound to the
definition of the tariff methodology to be applied to the electric power agreements, of use of the transmission and connection system resulting from the segmentation process established by the Electric Power Industry Institutional Model in force;

  

	 	•	 	the inexistence of a typical distribution concession agreement entered into between CHESF and the Granting Authority turned out to be a theme of particular relevance as to
the discussion about the treatment to be given to the tariff adjustment of this power generation concessionaire as of 2004, as regards its industrial markets and the transfer of the Item Variation Amounts Offsetting Account for Installment
“A” – (“CVA”); 

  

	 	•	 	pursuant to the Homologation Resolution no 268, dated November 24, 2004, ANEEL set for the year 2005 the corresponding electric power tariffs used by CHESF;

  

	 	•	 	 While ANEEL’s Resolution no 268, dated November 24, 2004, homologated the electric power tariffs charged by CHESF, it also set forth in its
Annex V the amount of the CVA to be 

  

 1 

	 	 
retrieved as regards the financial tariff component other than the annual adjustment; 

  

	 	•	 	CHESF, jointly with its Industrial Consumers, agreed to determine the total CVA amount for the period between November 2002 and October 2004, pursuant to the data obtained
from the Technical Note no 274/2004-SRE-ANEEL, dated November 05, 2004; 

  

	 	•	 	Pursuant to the Proceeding no 48500.003597/04-18, discrepancies were detected regarding the determination of the tariff indexes applied as result of the calculation methodology
elected to determine the adjustment of tariffs from the years 2000 to 2002, so as to justify the determination to offset its financial effects on behalf of the consumers, pursuant to the sole paragraph of art. 6 of said Homologation Resolution
no 268/04; 

  

	 	•	 	The installments of the CVA amounts, calculated pursuant to Technical Note no 274/2004-SRE-ANEEL, dated November 5, 2004, and its offsetting using CONSUMER credits,
resulted in the net amounts to be undertaken individually by the latter do not characterize any waiver of revenues by CHESF;  

  

	 	•	 	The negotiation complies with the principle of isonomy and of economic-financial balance between the PARTIES, to the extent that CHESF transfers the amounts
acknowledged by ANEEL as deriving from the CVA, taking into account the negotiations accomplished so far to maintain its contractual ties, 

  
 have decided to celebrate this Amendment to the above mentioned Electric Power Purchase and Sale Agreement, pursuant to the following clauses and conditions: 

 
 CLAUSE 1 – The following ANNEXES are integral
parts of this AMENDMENT: 
  

	 	(a)	ANNEX I – CVA AMOUNTS PERTAINING TO THE PERIOD FROM THE YEARS 2002 TO 2004, ITEMIZED BY CONSUMER UNIT OF CHESF’s FINAL CONSUMERS. 

	 	(b)	ANNEX II – AMOUNTS OF CREDITS PERTAINING TO THE PERIOD BETWEEN NOVEMBER 2000 TO NOVEMBER 2002, ITEMIZED BY CONSUMER UNIT OF CHESF’s FINAL CONSUMERS.

	 	(c)	ANNEX III – CVA AMOUNTS AND SETOFF CREDITS ITEMIZED BY CONSUMER UNIT OF THE CONSUMER AND THE PAYMENT FLOW METHODOLOGY. 

  
 CHAPTER I 
  
 OBJECT AND TERM OF EFFECTIVENESS 
  
 CLAUSE 2 – The purpose of this AMENDMENT is to amend the Electric Power Purchase and Sale Agreement-(“EPPSA”),
celebrated by the PARTIES on October 20, 2004 to set forth the terms and conditions corresponding to the CVA installment and its compensation with the financial effects arising from the revision of the procedures used to calculate supply
tariffs pertaining to the period between December 2000 and November 2003, overpaid by the CONSUMER, in pursuance with the amounts and periods itemized in the tables included in ANNEXES I to III. 
  

 2 

 CLAUSE 3 – This AMENDMENT is effective on the date of its execution and shall go into effect for the period
of 72 months counted as of January 2005, or until the effective compliance of all obligations established herein. 
  
 First Paragraph – This AMENDMENT shall be extinguished with the formalization of the term of dissolution of the agreement, in which the terms and
conditions for advance maturity of the remaining amounts shall be dealt with, the payment whereof shall be made in conjunction with the execution of the respective term of dissolution. 
  
 Second Paragraph – The CONSUMER shall be allowed to acquit its due balance as itemized in ANNEX III of this term at any
time. To that effect, said CONSUMER shall request CHESF to provide an updated position as to his/her due balance, pursuant to clause 4, third paragraph, computed up to the time chosen for the payment. 
  
 CHAPTER II 
  
 CRITERIA USED FOR THE INSTALLMENT AND OFFSETTING OF CVA AMOUNTS

  
 CLAUSE 4 – For the purposes established in clause 2 of this
AMENDMENT, the CONSUMER shall assure CHESF the payment of the amount corresponding to the difference between the CONSUMER credits, calculated as result of the discrepancies that arose at the time of the calculation of
tariff indexes computed by ANEEL regarding the tariff adjustments for the years 2000, 2001 and 2002, and the amounts calculated in the Item Amount Variation Offset Account for Installment “A” – CVA. 
  
 First Paragraph – The amounts contained in ANNEX I represent the amount of the
CVA for the period between November 2002 and October 2004, acknowledged by ANEEL in its Technical Note no 274/2004-SRE/ANEEL, dated November 5, 2004, and they correspond to the cost attributed to the CONSUMER regarding its CONSUMER
UNIT(S), taking into account their apportionment among CHESF’s final consumers, and taking into account the criteria used to compute the effective power used up by said consumers, which took place during the same period acknowledged by
CVA. These amounts refer back to December 31, 2004. 
  
 Second Paragraph
– The amounts listed on ANNEX II represent CONSUMER credits pertaining to its CONSUMER UNIT(S), and pertaining to the amounts due to said consumer by CHESF, as arising from the revision of the procedures used on calculating
supply tariffs for the periods between December 2000 and November 2003, pursuant to the terms of Proceeding no 48500.003597/04-18, ongoing before ANEEL’s Superintendence of Economic Regulation – SRE. These amounts refer back to
December 31, 2004. 
  
 Third Paragraph – The difference between
the amounts calculated according to the explanations contained in the first and second paragraphs of this clause, amount to R$8.281.002,45 (eight million, two hundred and eighty-one thousand and two reais and forty-five centavos), representing a
liability owed by the CONSUMER to CHESF, which shall be settled in seventy-two (72) monthly installments, according to the payment flow methodology contained in ANNEX III, concomitantly with the payment of electric power bills by
EPPSA as of the billing in January 2005, abiding by the following computation methodology: 
  

 3 

 (a) – The balance due, as defined in the previous paragraph, shall be adjusted on a monthly basis as of the date of
its consolidation on December 31, 2004, based on ninety-nine percent (99%) of the variation of the average adjusted index for the daily financing of federal instruments of indebtedness, determined by the Special Settlement and Custody
System (SELIC), disclosed by the Central Bank of Brazil (BACEN); 
  
 (b) –
Payments referring to the period between January and December 2005, shall be constant, and they shall be calculated taking into account the amount of the obligation, as defined in the previous paragraph, divided by the term of the contract, which is
of 72 months; 
  
 (c) – The following installments shall be computed dividing
the balance due of the obligation, adjusted for inflation pursuant to sub-item “e” infra, by the number of remaining installments, said installments to remain fixed for a period of 12 months; 
  
 (d) – The adjusted due balance shall be made-up by the due balance adjusted pursuant to
item “a” supra, subtracted from the payments that have been effected pursuant to items “b” and “c” of this paragraph. 
  
 (e) – The balance due of the obligation, calculated on December 31 of each year, shall be projected over the following twelve (12) months, taking into
account ninety-nine percent (99%) of the forecast for the variation of the SELIC rate, based on the average SELIC rate for the last twelve (12) months; 
  
 (f) – The payment of the last installment shall correspond to the balance due of the CONSUMER’s obligation. 
  
 (g) – In case the SELIC rate forecast for the last period is much higher than the
monthly SELIC rate, the consumer’s due balance may be settled before the payment of the last installment, in which case the procedure envisaged in the previous item “f” shall be adopted. 
  
 CLAUSE 5 – The CONSUMER shall pay monthly to CHESF the amount of
each installment, computed pursuant to the third paragraph of the previous clause, and which has been included in the electric power bill corresponding to each period of the BILLING CYCLE. 
  
 CLAUSE 6 – The billing of the installments referred to in the previous clause
shall be accomplished according the same conditions established in the EPPSA, and its amounts shall be minimal for the purposes of billing, even if there is no consumption to be billed by CHESF. 
  
 CHAPTER III 
  
 GENERAL PROVISIONS 
  
 CLAUSE 7 – The amounts listed in ANNEXES I to III may be revised and/or changed
by the PARTIES as arising from the agreement or as arising from the revision accomplished by ANEEL or by an APPROPRIATE AUTHORITY, for the CVA amount listed on Technical Note no 274/2004-SRE/ANEEL, dated November 05, 2004.

  
 Sole Paragraph – A possible revision of the CVA amounts itemized
in ANNEXES I to III must necessarily become the object of a new contractual amendment, used to recompose the Balance Due. 
  

 4 

 CLAUSE 8a – By means of a previous and explicit written consent from the CONSUMER, this
AMENDMENT and/or the credits generated by it may be assigned by CHESF as a guarantee for possible financing to be obtained by it or by an affiliated, associated, controlled, controlling, conjoined or subsidiary company, which is under
common control with CHESF, or in which CHESF may have an equity, there being maintained the responsibilities of the PARTIES in case the concessionaire defaults. The CONSUMER shall only be allowed to assign this AMENDMENT
by means of a prior and explicit written consent by CHESF. 
  

 5 

 AND, IN WITNESS WHEREOF, THE PARTIES HAVE EXECUTED THIS INSTRUMENT IN THREE (03) COUNTERPARTS, EACH CONSIDERED TO BE
AN ORIGINAL, IN THE PRESENCE OF THE TWO UNDERSIGNED WITNESSES. 
  
 Recife,
January 03, 2005. 
  

	
	Companhia Hidro Elétrica do São Francisco – CHESF
	
	 /s/ Dilton da Conti Oliveira

	Dilton da Conti Oliveira
	Director-President
	CPF: 018.205.404-72

  

	
	 /s/ Mozart Bandeira Arnaud

	Mozart Bandeira Arnaud
	Operations Director
	CPF: 137.474.444-15

  

	
	BRASKEM S.A. – UNIB-BA
	
	 /s/ Bernardo Afonso de Almeida Gradin

	Bernardo Afonso de Almeida Gradin
	Director
	CPF: 316.183.245-00

  

	
	 /s/ Ricardo de Maya Gomes Simões

	Ricardo de Maya Gomes Simões
	Power Manager/Attorney in Fact
	CPF: 382.605.654-04

  

	
	Witnesses:
	
	 /s/ Manoel Carnaúba Cortez

	Name: Manoel Carnaúba Cortez
	CPF: 209049084-53

  

	
	 /s/ Murilo Carrilho Mattos

	Name: Murilo Carrilho Mattos
	RG: 1.823.105-PE
	CPF: 435.173.664-04

  

 6 

 ANNEX I 
  
 PURSUANT TO TECHNICAL NOTE 254/2004-SRE-ANEEL, THE CVA AMOUNTS PERTAINING TO THE PERIOD BETWEEN 2002 AND 2004 FOR THE CONSUMER BRASKEM
S.A.-UNIB-BA, HAVE BEEN ADJUSTED UP UNTIL DECEMBER 31, 2004, AND THEY AMOUNT TO [R$ 9.145.548,52 (nine million, one hundred and forty-five thousand, five hundred and forty-eight reais and fifty-two centavos)]. 
  
 ANNEX II 
  
 PURSUANT TO TECHNICAL NOTE 274/2003-SRE-ANEEL, THE CREDIT AMOUNTS PERTAINING TO THE PERIOD
BETWEEN DECEMBER, 2000, AND NOVEMBER, 2003, FOR CONSUMER BRASKEM S.A.-UNIB-BA BEFORE CHESF, HAVE BEEN ADJUSTED UP UNTIL DECEMBER 31, 2004, AND THEY AMOUNT TO [R$ 864.546,07 (eight hundred and sixty-four thousand, five hundred and forty-six
reais and seven centavos)]. 
  
 ANNEX III

  
 THE CVA AMOUNTS AND THE CREDITS THAT HAVE BEEN OFFSET, ITEMIZED BY
CONSUMER UNIT OF THE CONSUMER, AND THE METHODOLOGY USED FOR THE PAYMENT FLOWS 
  

							
	 ANNEX III

	 INITIAL BALANCE DUE

	  	 R$ xxxxxxxxxxxxx

	  	 	  	 
	 MONTHS

	  	 BALANCE DUE

	  	FINANCIAL COST

	  	MONTHLY PAYMENT

				
	 Jan/05
	  	 SD = SDI + CF - PGTO
	  	CF = SDI x CFM	  	PGTO = SDI / 72
				
	 Feb/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Mar/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Apr/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 May/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Jun/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Jul/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Aug/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Sep/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Oct/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Nov/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Dec/05
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SDI / 72
				
	 Jan/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Feb/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Mar/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Apr/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 May/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Jun/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Jul/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Aug/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Sep/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Oct/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
				
	 Nov/06
	  	 SD = SDA + CF-PGTO
	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60

  

 7 

							
	 ANNEX III

	 INITIAL BALANCE DUE

	  	 R$ xxxxxxxxxxxxx

	  	 	  	 
	 MONTHS

	  	 BALANCE DUE

	  	FINANCIAL COST

	  	MONTHLY PAYMENT

	 Dec/06
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 06/60
	 Jan/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Feb/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Mar/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Apr/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 May/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Jun/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Jul/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Aug/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Sep/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Oct/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Nov/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Dec/07
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 07/48
	 Jan/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Feb/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Mar/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Apr/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 May/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Jun/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Jul/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Aug/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Sep/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Oct/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Nov/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Dec/08
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 08/36
	 Jan/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Feb/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Mar/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Apr/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 May/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Jun/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Jul/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Aug/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Sep/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Oct/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Nov/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Dec/09
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 09/24
	 Jan/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Feb/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Mar/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Apr/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 May/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Jun/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Jul/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Aug/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Sep/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Oct/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Nov/10
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Dec/10 (A)
	  	SD = SDA + CF-PGTO	  	CF = SDA x CFM	  	PGTO = SD Dec. 10/12
	 Dec/10 (B)
	  	FINAL DUE	  	 	  	PGTO = FINAL DUE

  

 8 

 SDI = starting balance due 
  
 SD = balance due 
  
 SDA = previous balance due 
  
 CF = financial cost

  
 CFM = rate corresponding to... 
 PGTO = monthly payment 
  

 9Second Amendment, dated 12-05-05 to Electric Power Purchase and Sale Agreement

 Exhibit 4.18 
  
 SECOND AMENDMENT TO THE ELECTRIC POWER PURCHASE AND SALE AGREEMENT — EPPSA-011/2004, CELEBRATED BETWEEN COMPANHIA HIDRO
ELÉTRICA DO SÃO FRANCISCO-CHESF AND BRASKEM S.A.-UNIB-BA, DATED AS OF 10/20/2004. 
  
 By this instrument, the PARTIES  
  
 COMPANHIA HIDRO ELÉTRICA DO SÃO FRANCISCO — CHESF, a public services concessionaire engaged in the supply of electric power, with headquartered in the city of Recife, in the state of Pernambuco, at Rua Delmiro
Gouveia, n° 333, Bairro do Bongi, enrolled before the CNPJ of the Ministry of Finance under no
33.541.368/0001-16, and enrolled before the state tax office under no 18.1.001.0005584-6, hereinafter simply
referred to as “CHESF” and represented herein pursuant to its Bylaws by its Directors, described and undersigned at the end of the agreement; and 
  
 BRASKEM S.A. – UNIB-BA, with headquarters in the city of Camaçari, in the state of Bahia, at Rua Eteno, n° 1561,
Camaçari Petrochemical Complex, enrolled before the CNPJ of the Ministry of Finance under no
42.150.391/0001-70, and enrolled before the state tax office under no 01.027.389-NO, hereinafter referred to simply
as “CONSUMER”, represented herein pursuant to its Bylaws by its Directors, described and undersigned at the end of the agreement. 
  
 WHEREAS 
  

	 	•	 	pursuant to the Electric Power Purchase and Sale Agreement – EPPSA–011/2004, hereinafter referred to as AGREEMENT celebrated between the PARTIES on
October 20, 2004, which sets forth that, each year, the electric power reserve will be updated to be effective as of January of the subsequent year, 

  
 have decided to celebrate the 2nd Amendment to the AGREEMENT pursuant to the following clauses and conditions: 
  
 FIRST CLAUSE – This Amendment (“AMENDMENT”) purports to update the ELECTRIC POWER RESERVE CHART of the Annex I
of the First Amendment to the AGREEMENT. 
  
 SECOND CLAUSE — The
amounts corresponding to the period between January 2006 and December 2010, referred to in the ELECTRIC POWER RESERVE CHART of the Annex I of the First Amendment to the AGREEMENT are replaced herein by the amounts referred to in the ELECTRIC POWER
RESERVE CHART of the Annex I of this Amendment. 
  
 THIRD CLAUSE — All
the remaining conditions set forth in the AGREEMENT as well as its Amendment remain unchanged and fully valid as regards everything that do not conflict, explicitly or implicitly, with this document. 
  

 1 

 And, in witness whereof, the PARTIES have celebrated this AMENDMENT in two (2) counterparts, each considered to be
an original, in the presence of the undersigned witnesses. 
  
 Recife,
December 30, 2005. 
  

	
	Companhia Hidro Elétrica do São Francisco – CHESF
	
	/s/ Dilton da Conti Oliveira
	 Dilton da Conti Oliveira
 Director-President
 CPF: 018.205.404-72

  

	
	
	/s/ Mozart Bandeira Arnaud
	 Mozart Bandeira Arnaud
 Operations Director

CPF: 137.474.444-15

  

	
	Consumer: Braskem S.A. – UNIB-BA
	
	/s/ Bernardo Afonso de Almeida Gradin
	 Bernardo Afonso de Almeida Gradin
 Director

CPF: 316.183.245-00

  

	
	
	/s/ Ricardo de Maya Gomes Simões
	 Ricardo de Maya Gomes Simões
 Power
Manager/Attorney in Fact
 CPF: 382.605.654-04

  
 Witnesses: 
  
 Name: 
 CPF: 
  

	
	/s/ Ana Carla Gomes Petti Queiroga
	 Name: Ana Carla Gomes Petti Queiroga
 CPF:
071.040.877-37

  

 2 

 ELECTRIC POWER RESERVE CHART – ANNEX I 
  
 Annex to the Second Amendment of the Electric Power Purchase and Sale Agreement,
EPPSA-011/2004, celebrated between CHESF and BRASKEM – UNIB-BA, on 10/20/2004. 
  

									
	period of supply

	  	 period
 of the
 year

	  	 ELECTRIC POWER RESERVE
 (AMOUNTS IN kW)

	item

	  	 month/year

	  	  	peak

	  	off Peak

	1	  	Jan to Apr/2006	  	Wet	  	69,000	  	125,000
	2	  	May to Nov/2006	  	Dry	  	69,000	  	125,000
	3	  	Dec/2006	  	Wet	  	69,000	  	125,000
	4	  	Jan to Apr/2007	  	Wet	  	85,000	  	150,000
	5	  	May to Nov/2007	  	Dry	  	85,000	  	150,000
	6	  	Dec/2007	  	Wet	  	85,000	  	150,000
	7	  	Jan to Apr/2008	  	Wet	  	85,000	  	150,000
	8	  	May to Nov/2008	  	Dry	  	85,000	  	150,000
	9	  	Dec/2008	  	Wet	  	85,000	  	150,000
	10	  	Jan to Apr/2009	  	Wet	  	85,000	  	150,000
	11	  	May to Nov/2009	  	Dry	  	85,000	  	150,000
	12	  	Dec/2009	  	Wet	  	85,000	  	150,000
	13	  	Jan to Apr/2010	  	Wet	  	85,000	  	150,000
	14	  	May to Nov/2010	  	Dry	  	85,000	  	150,000
	15	  	Dec/2010	  	Wet	  	85,000	  	150,000

  

 3

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00105-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00105-of-00352.parquet"}]]