MarkWest Energy Partners Announces Major Expansion Projects and Reports Record Financial and Operational Results for Second

  MarkWest Energy Partners Announces Major Expansion Projects and Reports
  Record Financial and Operational Results for Second Quarter 2014

  *Second quarter DCF of $161.7 million and increased quarterly distribution
    of 88 cents per common unit with 104 percent distribution coverage
  *Placed into service five major infrastructure projects, consisting of two
    processing plants with 320 MMcf/d of capacity in the Marcellus Shale, a
    200 MMcf/d processing plant in the Utica Shale, 20,000 Bbl/d of ethane and
    heavier fractionation in the Marcellus Shale, and a 40,000 Bbl/d
    de-ethanization facility in the Utica Shale
  *Announced 7 major infrastructure projects adding 720 MMcf/d of processing
    capacity and 110,000 Bbl/d of fractionation capacity
  *19 major processing and fractionation facilities under construction and
    maintains capital forecast of $2.0 to $2.3 billion in 2014 and
    approximately $2.0 billion in 2015
  *Achieved investment grade rating on the $1.3 billion Senior Secured Credit
    Facility
  *Increased fee-based net operating margin to 71 percent from 61 percent
    when compared to the second quarter of 2013
  *Narrowed 2014 DCF forecast to $630 to $670 million, which increases
    midpoint to $650 million
  *Achieved the number one ranking in the 2014 Oil & Natural Gas Midstream
    Services Customer Satisfaction Survey conducted by EnergyPoint Research.
    The Partnership has achieved the highest ranking for total customer
    satisfaction in four out of five surveys that EnergyPoint has conducted
    since 2006

Business Wire

DENVER -- August 6, 2014

MarkWest Energy Partners, L.P. (NYSE: MWE) (“the Partnership”) today reported
quarterly cash available for distribution to common unitholders, or
distributable cash flow (DCF), of $161.7 million for the three months ended
June 30, 2014, and $310.2 million for the six months ended June 30, 2014. DCF
for the three months ended June 30, 2014 represents distribution coverage of
104 percent. The second quarter distribution of $155.8 million, or $0.88 per
common unit, will be paid to unitholders on August 14, 2014. The second
quarter 2014 distribution represents an increase of $0.01 per common unit or
1.2 percent over the first quarter 2014 distribution and an increase of $0.04
per common unit or 4.8 percent compared to the second quarter 2013
distribution. As a Master Limited Partnership, cash distributions to common
unitholders are largely determined based on DCF. A reconciliation of DCF to
net income, the most directly comparable GAAP financial measure, is provided
within the financial tables of this press release.

The Partnership reported Adjusted EBITDA for the three and six months ended
June 30, 2014, of $208.2 million and $395.8 million, respectively, compared to
$155.7 million and $296.5 million for the respective three and six months
ended June 30, 2013. The Partnership believes the presentation of Adjusted
EBITDA provides useful information because it is commonly used by investors in
Master Limited Partnerships to assess financial performance and operating
results of ongoing business operations. A reconciliation of Adjusted EBITDA to
net income, the most directly comparable GAAP financial measure, is provided
within the financial tables of this press release.

The Partnership reported income before provision for income tax for the three
and six months ended June 30, 2014 of $10.1 million and $38.6 million,
respectively. Income before provision for income tax includes non-cash losses
associated with the change in fair value of derivative instruments of $18.8
million and $7.0 million for the respective three and six months ended June
30, 2014. Excluding these items, income before provision for income tax for
the three and six months ended June 30, 2014 would have been $28.9 million and
$45.6 million, respectively.

“We are excited to announce major capacity expansions and record financial and
operational performance for the second quarter of 2014,” stated Frank Semple,
Chairman, President, and Chief Executive Officer. “The completion of five
major infrastructure projects in the Marcellus and Utica Shales over the past
three months has provided our producer customers the ability to continue
expanding their rich-gas development programs. Due to their ongoing success,
we expect overall system volumes to continue to rapidly expand and provide us
with unique opportunities to significantly grow cash flow and achieve future
distribution growth targets.”

BUSINESS HIGHLIGHTS

Marcellus:

  *In May, the Partnership announced that it will increase total processing
    capacity at the Mobley complex in Wetzel County, West Virginia to 920
    million cubic feet per day (MMcf/d) with the construction of an additional
    200 MMcf/d processing plant. The new plant is anchored by a long-term,
    fee-based contract with EQT Corporation (NYSE: EQT) and is expected to be
    in service by the second quarter of 2015. The Mobley complex currently
    consists of three plants with 520 MMcf/d of total processing capacity and
    during the fourth quarter of this year, the Partnership will begin
    operations of a fourth plant at the complex, increasing capacity to 720
    MMcf/d. The Mobley complex supports growing Marcellus rich-gas production
    from EQT Corporation, Magnum Hunter Resources Corporation (NYSE: MHR),
    Stone Energy Corporation (NYSE: SGY), CONSOL Energy Inc. (NYSE: CNX), and
    Noble Energy, Inc. (NYSE: NBL).
  *In May, the Partnership commenced operations of a fifth 200 MMcf/d
    Majorsville processing plant at the Majorsville complex in Marshall
    County, West Virginia. The new plant is anchored by Range Resources
    Corporation (NYSE: RRC) (Range Resources) and has increased the total
    capacity of the Majorsville Complex to 870 MMcf/d.
  *In May, the Partnership completed the 120 MMcf/d Bluestone II processing
    plant in Butler County, Pennsylvania. The new plant is anchored by a long
    term, fee-based contract with Rex Energy Corporation (NASDAQ: REXX). In
    conjunction with new processing, the Partnership began operations of an
    additional 20,000 barrels per day (Bbl/d) of ethane and heavier
    fractionation infrastructure to support growing NGL production from the
    rich-gas areas of the northeast Marcellus Shale and Upper Devonian
    formation. To facilitate the production of ethane at the Bluestone
    complex, the Partnership has also completed a 32-mile purity ethane
    pipeline connecting to the Mariner West project.

  *Today, the Partnership is announcing that it will construct a seventh 200
    MMcf/d processing plant at the Sherwood complex in Doddridge County, West
    Virginia, at the request of Antero Resources Corporation (NYSE: AR)
    (Antero Resources). The new plant is anchored by long-term, fee-based
    agreements and will expand total capacity at the Sherwood complex to 1.4
    billion cubic feet per day (Bcf/d) by the third quarter of 2015. Later
    this month, the Partnership will begin operations of the Sherwood IV
    plant. Antero Resources is the anchor producer supporting the Sherwood
    complex and continues to develop its prolific rich-gas acreage position in
    northern West Virginia.
  *Today, the Partnership is announcing that it will construct a sixth
    processing complex in the Marcellus Shale. The new Hillman complex will be
    located in Washington County, Pennsylvania and will support Range
    Resources’ rapidly growing rich-gas production. The Hillman complex will
    initially consist of Hillman I, a 200 MMcf/d processing plant, and an
    associated de-ethanization facility. The Hillman complex is scheduled to
    become operational during the first quarter of 2016. Propane and heavier
    natural gas liquids recovered at the Hillman complex will be transported
    by a new pipeline to the Houston complex for fractionation.

Utica:

  *In June, the Partnership and The Energy & Minerals Group (EMG) announced
    an expansion of the Hopedale fractionation and marketing complex (Hopedale
    complex) in Harrison County, Ohio to support growing NGL production from
    the Marcellus and Utica Shales. The expansion will double the propane and
    heavier fractionation capacity at the Hopedale complex to 120,000 Bbl/d
    and is expected to be operational in the first quarter of 2015.
  *In June, Summit Midstream Partners, LLC (Summit), the privately held
    company that owns and controls the general partner of Summit Midstream
    Partners, LP (NYSE: SMLP), exercised the option it acquired from a
    subsidiary of Gulfport Energy Corporation (NASDAQ: GPOR) (Gulfport Energy)
    to purchase a 40% equity interest in two of the Partnership’s and EMG’s
    unconsolidated affiliates, Ohio Gathering Company, L.L.C. and Ohio
    Condensate Company, L.L.C., through a cash investment of approximately
    $324.7 million and $7.3 million, respectively, that was received in May
    2014 and true-up payments of $16.5 million and $1.3 million, respectively,
    that were received in July 2014.
  *In July, MarkWest Utica EMG completed the 200 MMcf/d Seneca III processing
    plant in Noble County, Ohio. The new plant is anchored by Antero Resources
    under a long-term, fee-based contract and has expanded the total
    processing capacity of the Seneca complex to 600 MMcf/d. In order to
    support the continued growth of Antero Resources and other producers, the
    Partnership expects to complete a fourth 200 MMcf/d processing plant in
    the second quarter of 2015.

  *In July, MarkWest Utica EMG completed a 40,000 Bbl/d de-ethanization
    facility at the Cadiz complex in Harrison County, Ohio. This new
    fractionation facility will provide MarkWest Utica EMG’s producer
    customers with the ability to meet residue gas quality specifications and
    downstream ethane pipeline commitments. Purity ethane produced at the new
    Cadiz facility will be delivered to the ATEX pipeline.
  *Today, MarkWest Utica EMG is announcing the development of Cadiz III, a
    200 MMcf/d processing plant at the Cadiz complex in Harrison County, Ohio.
    The new facility is expected to begin operations during the first quarter
    of 2015 and will increase total processing capacity of the Cadiz complex
    to 525 MMcf/d. The Cadiz complex currently consists of a 125 MMcf/d
    cryogenic processing plant and during September 2014, MarkWest Utica EMG
    will begin operations of the 200 MMcf/d Cadiz II plant to support rich-gas
    production from Gulfport Energy and other producers.

Southwest:

  *In April, the Partnership’s Centrahoma Joint Venture (Centrahoma)
    commenced operations of the Stonewall processing facility, a 120 MMcf/d
    plant in the Woodford Shale in Southwest Oklahoma. The completion of the
    Stonewall plant increases Centrahoma’s total processing capacity to 220
    MMcf/d.
  *Today, the Partnership is announcing that it will construct a fourth
    processing plant at its Carthage facilities in Panola County, Texas to
    support growing rich-gas production from the Haynesville Shale and Cotton
    Valley formation. The new plant will have an initial capacity of 120
    MMcf/d and is scheduled to begin operations in the first quarter of 2015.
    Once completed, total processing capacity at the Partnership’s East Texas
    operations will increase to 520 MMcf/d.

Capital Markets

  *Year-to-date, the Partnership has issued 15.1 million new units and
    received net proceeds of approximately $976.9 million.
  *Achieved investment grade rating by Standard & Poor’s on the Partnership’s
    Senior Secured Credit Facility.

FINANCIAL RESULTS

Balance Sheet

  *As of June 30, 2014, the Partnership had $74.0 million of cash and cash
    equivalents in wholly owned subsidiaries and $847.5 million of remaining
    capacity under its $1.3 billion Senior Secured Credit Facility after
    consideration of $11.3 million of outstanding letters of credit and $441.2
    million of outstanding borrowings.

Operating Results

  *Operating income before items not allocated to segments for the three
    months ended June 30, 2014, was $220.1 million, an increase of $42.6
    million when compared to $177.5 million over the same period in 2013. This
    increase was primarily attributable to higher processing volumes.
    Processed volumes continued to increase in the second quarter of 2014,
    growing approximately 53 percent when compared to the second quarter of
    2013, primarily due to the Partnership’s Marcellus and Utica segments.

    A reconciliation of operating income before items not allocated to
    segments to income before provision for income tax, the most directly
    comparable GAAP financial measure, is provided within the financial tables
    of this press release.

  *Operating income before items not allocated to segments does not include
    (losses) gains on commodity derivative instruments. Realized (losses)
    gains on commodity derivative instruments were ($1.9) million in the
    second quarter of 2014 and $2.0 million in the second quarter of 2013.

Capital Expenditures

  *For the three months ended June 30, 2014, the Partnership’s portion of
    capital expenditures was $608.1 million.

ADJUSTED EBITDA, DCF AND CAPITAL EXPENDITURE FORECAST

The Partnership forecasts its 2014 Adjusted EBITDA in a range of $810 million
to $870 million and has narrowed its 2014 DCF forecast to a range of $630
million to $670 million based on its current forecast. The Partnership has
become less sensitive to changes in commodity prices as a result of
significant increases in fee-based income. An updated sensitivity analysis for
forecasted 2014 DCF based on changes in composite NGL prices and changes in
volume assumptions is provided within the tables of this press release.

The Partnership’s portion of growth capital expenditures for 2014 is
forecasted in a range of $2.0 billion to $2.3 billion and for 2015 is
forecasted at approximately $2.0 billion. Maintenance capital for 2014 is
forecasted at approximately $25 million.

CONFERENCE CALL

The Partnership will host a conference call and webcast on Thursday, August 7,
2014, at 12:00 p.m. Eastern Time to review its second quarter 2014 financial
results. Interested parties can participate in the call by dialing (800)
475-0218 (passcode “MarkWest”) approximately ten minutes prior to the
scheduled start time. To access the webcast and associated second quarter 2014
earnings call presentation, please visit the Investor Relations section of the
Partnership’s website at www.markwest.com. A replay of the conference call
will be available on the Partnership’s website or by dialing (800) 839-1248
(no passcode required).

MarkWest Energy Partners, L.P. is a master limited partnership engaged in the
gathering, processing and transportation of natural gas; the gathering,
transportation, fractionation, storage and marketing of natural gas liquids;
and the gathering and transportation of crude oil. MarkWest has a leading
presence in many unconventional gas plays including the Marcellus Shale, Utica
Shale, Huron/Berea Shale, Haynesville Shale, Woodford Shale and Granite Wash
formation.

This press release includes “forward-looking statements.” All statements other
than statements of historical facts included or incorporated herein may
constitute forward-looking statements. Actual results could vary significantly
from those expressed or implied in such statements and are subject to a number
of risks and uncertainties. Although MarkWest believes that the expectations
reflected in the forward-looking statements are reasonable, MarkWest can give
no assurance that such expectations will prove to be correct. The
forward-looking statements involve risks and uncertainties that affect
operations, financial performance, and other factors as discussed in filings
with the Securities and Exchange Commission (SEC). Among the factors that
could cause results to differ materially are those risks discussed in the
periodic reports filed with the SEC, including MarkWest’s Annual Report on
Form 10-K for the year ended December 31, 2013. You are urged to carefully
review and consider the cautionary statements and other disclosures made in
those filings, specifically those under the heading “Risk Factors.” MarkWest
does not undertake any duty to update any forward-looking statement except as
required by law.

                
MarkWest Energy Partners, L.P.
Financial Statistics
(unaudited, in thousands, except per unit data)
                                                               
                  Three months ended June 30,      Six months ended June 30,
Statement of       2014           2013          2014           2013       
Operations Data
Revenue:
Revenue           $ 525,119        $ 395,421       $ 1,041,562      $ 768,879
Derivative         (6,753     )    19,699        (10,720    )    19,514     
(loss) gain
Total revenue      518,366        415,120       1,030,842      788,393    
                                                                    
Operating
expenses:
Purchased           215,824          155,359         427,388          307,916
product costs
Derivative loss
(gain) related      11,964           (20,432   )     4,166            (31,136    )
to purchased
product costs
Facility            83,545           62,797          167,250          122,307
expenses
Derivative loss
related to          2,045            800             1,777            468
facility
expenses
Selling,
general and         27,701           25,499          62,991           50,741
administrative
expenses
Depreciation        104,078          71,562          206,007          139,579
Amortization of
intangible          15,965           17,092          31,943           31,922
assets
Loss (gain) on
sale or
disposal of         1,450            (37,736   )     1,357            (37,598    )
property, plant
and equipment
Accretion of
asset              168            157           336            509        
retirement
obligations
Total operating    462,740        275,098       903,215        584,708    
expenses
                                                                    
Income from         55,626           140,022         127,627          203,685
operations
                                                                    
Other (expense)
income:
Equity in
(loss) earnings
from                (721       )     430             (471       )     665
unconsolidated
affiliates
Interest income     10               62              19               211
Interest            (43,391    )     (36,955   )     (84,375    )     (75,291    )
expense
Amortization of
deferred
financing costs
and debt            (1,449     )     (1,784    )     (4,273     )     (3,614     )
discount (a
component of
interest
expense)
Loss on
redemption of       -                -               -                (38,455    )
debt
Miscellaneous      33             6             43             6          
income, net
Income before
provision for       10,108           101,781         38,570           87,207
income tax
                                                                    
Provision for
income tax
(benefit)
expense:
Current             (19        )     (2,745    )     326              (8,159     )
Deferred           (2,921     )    19,028        9,280          30,999     
Total provision    (2,940     )    16,283        9,606          22,840     
for income tax
                                                                    
Net income          13,048           85,498          28,964           64,367
                                                                    
Net (income)
loss
attributable to    (4,071     )    (1,799    )    (7,495     )    3,874      
non-controlling
interest
                                                                    
Net income
attributable to
the               $ 8,977         $ 83,699       $ 21,469        $ 68,241     
Partnership's
unitholders
                                                                    
Net income
attributable to
the
Partnership's
common
unitholders per
common unit:
Basic             $ 0.05          $ 0.63         $ 0.13          $ 0.52       
Diluted           $ 0.05          $ 0.55         $ 0.12          $ 0.45       
                                                                    
Weighted
average number
of outstanding
common units:
Basic              164,613        131,227       161,727        129,928    
Diluted            181,237        151,866       178,378        150,580    
                                                                    
Cash Flow Data
Net cash flow
provided by
(used in):
Operating         $ 244,450        $ 93,838        $ 356,823        $ 177,596
activities
Investing         $ (429,684   )   $ (825,660  )   $ (1,005,158 )   $ (1,435,021 )
activities
Financing         $ 361,165        $ 434,867       $ 862,442        $ 1,266,223
activities
                                                                    
Other Financial
Data
Distributable     $ 161,734        $ 128,391       $ 310,180        $ 238,216
cash flow
Adjusted EBITDA   $ 208,231        $ 155,741       $ 395,798        $ 296,542
                                                                    
                                                                    
Balance Sheet     June 30, 2014    December 31,
Data                               2013
Total assets      $ 10,183,390     $ 9,396,423
Total debt        $ 3,464,637      $ 3,023,071
Total equity      $ 5,401,550      $ 4,798,133
                                                                    

MarkWest Energy Partners, L.P.
Operating Statistics
                                                                
                          Three months ended June 30,   Six months ended June
                                                        30,
                          2014            2013          2014          2013
Marcellus
Gathering system          599,500         544,000       600,500       526,700
throughput (Mcf/d) (1)
Natural gas processed     1,823,200       1,033,700     1,732,500     931,400
(Mcf/d)
                                                                      
C2 (purity ethane)        45,900          -             47,400        -
produced (Bbl/d)
C3+ fractionated          82,200          48,900        76,200        43,000
(Bbl/d) (2)
Total NGLs fractionated   128,100         48,900        123,600       43,000
(Bbl/d)
                                                                      
Utica
Gathering system          188,700         46,300        184,700       27,800
throughput (Mcf/d)
Natural gas processed     293,800         46,300        272,700       27,200
(Mcf/d) (3)
C3+ fractionated          13,500          -             12,900        -
(Bbl/d) (2)
                                                                      
Northeast
Natural gas processed     281,500         296,400       268,600       299,500
(Mcf/d)
NGLs fractionated         17,500          18,100        17,500        17,600
(Bbl/d) (4)
                                                                      
Keep-whole sales          24,800          27,100        57,000        64,500
(gallons, in thousands)
Percent-of-proceeds
sales (gallons, in        29,900          32,200        56,000        67,100
thousands)
Total NGL sales
(gallons, in thousands)   54,700          59,300        113,000       131,600
(5)
                                                                      
Crude oil transported     10,600          9,700         10,200        10,000
for a fee (Bbl/d)
                                                                      
Southwest
East Texas gathering
systems throughput        549,500         521,700       522,800       510,500
(Mcf/d)
East Texas natural gas    398,500         377,600       383,400       358,600
processed (Mcf/d)
East Texas NGL sales
(gallons, in thousands)   109,500         86,200        203,400       158,400
(6)
                                                                      
Western Oklahoma
gathering system          348,200         220,000       322,700       211,400
throughput (Mcf/d) (7)
Western Oklahoma
natural gas processed     296,300         189,900       269,800       188,100
(Mcf/d)
Western Oklahoma NGL
sales (gallons, in        56,900          42,900        111,300       97,700
thousands) (8)
                                                                      
Southeast Oklahoma
gathering system          414,500         473,300       398,200       467,300
throughput (Mcf/d)
Southeast Oklahoma
natural gas processed     186,600         160,400       167,000       155,800
(Mcf/d) (9)
Southeast Oklahoma NGL
sales (gallons, in        29,200          54,000        50,200        93,300
thousands)
                                                                      
Other Southwest
gathering system          48,900          39,900        47,900        30,300
throughput (Mcf/d) (10)
                                                                      
Gulf Coast refinery
off-gas processed         112,000         117,700       111,300       106,600
(Mcf/d)
Gulf Coast liquids
fractionated (Bbl/d)      21,000          22,100        20,200        19,700
(11)
Gulf Coast NGL sales
(gallons, in thousands)   80,300          84,600        153,300       149,700
(11)
                                                                      

(1)   The 2013 volumes exclude Sherwood gathering for comparability as this
       system was sold to Summit in June 2013.
       The Marcellus segment includes both the Houston Fractionation Facility
       and Marcellus’ portion utilized of the jointly owned Hopedale
       Fractionation Facility. Hopedale is currently jointly owned 60% and 40%
(2)    by MarkWest Liberty Midstream and MarkWest Utica EMG, respectively. The
       Utica segment includes only the portion it utilized of the jointly
       owned Hopedale Fractionation Facility. Operations began in January
       2014. The volumes reported for 2014 are the average daily rate for the
       days of operation.
(3)    Utica operations began in August 2013.
(4)    Includes NGLs fractionated for Utica and Marcellus segments.
       Represents sales at the Siloam fractionator. The total sales exclude
       approximately 8,757,000 gallons and 6,611,000 gallons sold by the
       Northeast on behalf of Marcellus for the three months ended June 30,
(5)    2014 and 2013, respectively. The total sales exclude approximately
       22,010,000 gallons and 6,818,000 gallons sold by the Northeast on
       behalf of Marcellus for the six months ended June 30, 2014 and 2013,
       respectively.
       Excludes zero and 318,000 gallons processed in conjunction with take in
       kind contracts for the respective three and six months ended June 30,
(6)    2014 and 3,989,000 and 12,351,000 gallons processed in conjunction with
       take in kind contracts for the respective three and six months ended
       June 30, 2013.
       Includes natural gas gathered in Western Oklahoma and from the Granite
(7)    Wash formation in the Texas Panhandle as management considers this one
       integrated area of operations.
       Excludes 41,969,000 and 53,685,000 gallons processed in conjunction
(8)    with take in kind contracts for the respective three and six months
       ended June 30, 2014.
(9)    The natural gas processing in Southeast Oklahoma is outsourced to our
       joint venture Centrahoma or other third-party processors.
(10)   Excludes lateral pipelines where revenue is not based on throughput.
(11)   Excludes Hydrogen volumes.
       

MarkWest Energy Partners, L.P.
Reconciliation of GAAP Financial Measure to Non-GAAP Financial Measure
Operating Income before Items not Allocated to Segments
(unaudited, in thousands)
                                                                                 
Three months                                                             Eliminations
ended June 30,      Marcellus      Utica         Northeast   Southwest   (1)            Total
2014
Segment revenue     $ 183,734      $ 30,826      $  43,777   $ 271,140   $  (900    )   $ 528,577
                                                                                        
Operating
expenses:
Purchased product     39,710         7,353          15,169     153,628      -             215,860
costs
Facility expenses    33,755       12,174       8,509     34,354      (900    )    87,892
Total operating
expenses before
items not             73,465         19,527         23,678     187,982      (900    )     303,752
allocated to
segments
                                                                                        
Portion of
operating income
attributable to      -            4,687        -         6           -           4,693
non-controlling
interests
Operating income
before items not    $ 110,269     $ 6,612      $  20,099   $ 83,152    $  -          $ 220,132
allocated to
segments
                                                                                        
                                                                                        
Three months
ended June 30,      Marcellus      Utica         Northeast   Southwest   Total
2013
Segment revenue     $ 120,057      $ 3,594       $  45,365   $ 227,842   $  396,858
                                                                                        
Operating
expenses:
Purchased product     16,993         -              15,126     123,240      155,359
costs
Facility expenses    22,272       6,412        6,655     29,778      65,117  
Total operating
expenses before
items not             39,265         6,412          21,781     153,018      220,476
allocated to
segments
                                                                                        
Portion of
operating (loss)
income               -            (1,143  )     -         53          (1,090  )
attributable to
non-controlling
interests
Operating income
(loss) before
items not           $ 80,792      $ (1,675  )   $  23,584   $ 74,771    $  177,472 
allocated to
segments
                                                                                        
(1) Amounts represent revenues and expenses associated with the Northeast segment fractionation
completed on behalf of the Marcellus segment, which occurs when NGL volumes in the Marcellus
exceed its fractionation capacity.
                                                                                        
                    Three months ended June
                    30,
                     2014         2013    
                                                                                        
Operating income
before items not    $ 220,132      $ 177,472
allocated to
segments
Portion of
operating income
(loss)                4,184          (1,090  )
attributable to
non-controlling
interests
Derivative (loss)
gain not              (20,762  )     39,331
allocated to
segments
Revenue
adjustment for        (3,833   )     -
unconsolidated
affiliate
Revenue deferral
adjustment and        375            (1,437  )
other
Compensation
expense included
in facility           (903     )     (368    )
expenses not
allocated to
segments
Facility expense
and purchase
product cost          2,598          -
adjustments for
unconsolidated
affiliate
Portion of
operating loss
attributable to
non-controlling       509            -
interests of an
unconsolidated
affiliate
Facility expenses     2,688          2,688
adjustments
Selling, general
and                   (27,701  )     (25,499 )
administrative
expenses
Depreciation          (104,078 )     (71,562 )
Amortization of       (15,965  )     (17,092 )
intangible assets
(Loss) gain on
disposal of           (1,450   )     37,736
property, plant
and equipment
Accretion of
asset retirement     (168     )    (157    )
obligations
Income from           55,626         140,022
operations
Other
(expense)income:
Equity in (loss)
earnings from         (721     )     430
unconsolidated
affiliates
Interest income       10             62
Interest expense      (43,391  )     (36,955 )
Amortization of
deferred
financing costs
and debt discount     (1,449   )     (1,784  )
(a component of
interest
expense)
Miscellaneous        33           6       
income, net
Income before
provision for       $ 10,108      $ 101,781 
income tax
                                                                                        

                                                                                
MarkWest Energy Partners, L.P.
Reconciliation of GAAP Financial Measure to Non-GAAP Financial Measure
Operating Income before Items not Allocated to Segments
(unaudited, in thousands)
                                                                                       
Six months                                                              Eliminations
ended June 30,    Marcellus      Utica          Northeast   Southwest   (1)            Total
2014
Segment revenue   $ 358,893      $ 54,592       $ 105,030   $ 530,470   $  (2,471  )   $ 1,046,514
                                                                                       
Operating
expenses:
Purchased           74,000         11,488         35,624      306,312      -             427,424
product costs
Facility           69,228       24,026       15,623     66,876      (2,471  )    173,282
expenses
Total operating
expenses before
items not           143,228        35,514         51,247      373,188      (2,471  )     600,706
allocated to
segments
                                                                                       
Portion of
operating
income             -            7,823        -          5           -           7,828
attributable to
non-controlling
interests
Operating
income before
items not         $ 215,665     $ 11,255      $ 53,783    $ 157,277   $  -          $ 437,980
allocated to
segments
                                                                                       
                                                                                       
Six months
ended June 30,    Marcellus      Utica          Northeast   Southwest   Total
2013
Segment revenue   $ 228,554      $ 4,217        $ 102,701   $ 436,208   $  771,680
                                                                                       
Operating
expenses:
Purchased           35,786         -              34,788      237,342      307,916
product costs
Facility           44,908       10,374       13,179     58,468      126,929 
expenses
Total operating
expenses before
items not           80,694         10,374         47,967      295,810      434,845
allocated to
segments
                                                                                       
Portion of
operating
(loss) income      -            (2,482   )    -          117         (2,365  )
attributable to
non-controlling
interests
Operating
income (loss)
before items      $ 147,860     $ (3,675   )   $ 54,734    $ 140,281   $  339,200 
not allocated
to segments
                                                                                       
(1) Amounts represent revenues and expenses associated with the Northeast segment fractionation
completed on behalf of the Marcellus segment, which occurs when NGL volumes in the Marcellus
exceed its fractionation capacity.
                                                                                       
                  Six months ended June 30,
                   2014         2013     
                                                                                       
Operating
income before
items not         $ 437,980      $ 339,200
allocated to
segments
Portion of
operating
income (loss)       7,319          (2,365   )
attributable to
non-controlling
interests
Derivative
(loss) gain not     (16,663  )     50,182
allocated to
segments
Revenue
adjustment for      (3,833   )     -
unconsolidated
affiliate
Revenue
deferral            (1,119   )     (2,801   )
adjustment and
other
Compensation
expense
included in
facility            (1,906   )     (754     )
expenses not
allocated to
segments
Facility
expense and
purchase
product cost        2,598          -
adjustments for
unconsolidated
affiliate
Portion of
operating loss
attributable to
non-controlling     509            -
interests of an
unconsolidated
affiliate
Facility
expenses            5,376          5,376
adjustments
Selling,
general and         (62,991  )     (50,741  )
administrative
expenses
Depreciation        (206,007 )     (139,579 )
Amortization of
intangible          (31,943  )     (31,922  )
assets
(Loss) gain on
disposal of         (1,357   )     37,598
property, plant
and equipment
Accretion of
asset              (336     )    (509     )
retirement
obligations
Income from         127,627        203,685
operations
Other (expense)
income:
Equity in
(loss) earnings
from                (471     )     665
unconsolidated
affiliates
Interest income     19             211
Interest            (84,375  )     (75,291  )
expense
Amortization of
deferred
financing costs
and debt            (4,273   )     (3,614   )
discount (a
component of
interest
expense)
Loss on
redemption of       -              (38,455  )
debt
Miscellaneous      43           6        
income, net
Income before
provision for     $ 38,570      $ 87,207   
income tax
                                                                                       

                                                           
Reconciliation of GAAP Financial Measure to Non-GAAP Financial Measure
Distributable Cash Flow
(unaudited, in thousands)
                                                                 
                  Three months ended June 30,    Six months ended June 30,
                   2014         2013          2014          2013      
                                                                 
Net income        $ 13,048       $ 85,498        $ 28,964        $ 64,367
Depreciation,
amortization
and other           120,361        88,889          239,311         172,166
non-cash
operating
expenses
Loss (gain) on
sale or
disposal of         1,450          (34,689   )     1,357           (34,551   )
property, plant
and equipment
Loss on
redemption of       -              -               -               36,178
debt, net of
tax benefit
Amortization of
deferred
financing costs     1,449          1,784           4,273           3,614
and debt
discount
Equity in loss
(earnings) from     721            (430      )     471             (665      )
unconsolidated
affiliates
Distributions
from                2,541          1,962           3,910           2,728
unconsolidated
affiliates
Non-cash
compensation        1,835          1,157           5,802           3,541
expense
Unrealized loss
(gain) on           18,844         (37,287   )     7,024           (46,320   )
derivative
instruments
Deferred income
tax (benefit)       (2,921   )     19,028          9,280           30,999
expense
Cash adjustment
for
non-controlling     (3,178   )     1,720           (5,296    )     3,489
interest of
consolidated
subsidiaries
Revenue
deferral            1,722          1,645           3,813           3,410
adjustment
Other (1)           12,867         3,318           21,022          5,355
Maintenance
capital            (7,005   )    (4,204    )    (9,751    )    (6,095    )
expenditures
(2)
Distributable     $ 161,734     $ 128,391      $ 310,180      $ 238,216   
cash flow
                                                                 
Maintenance
capital           $ 7,005        $ 4,204         $ 9,751         $ 6,095
expenditures
(2)
Growth capital
expenditures of     681,198        799,322         1,265,572       1,428,989
consolidated
subsidiaries
Growth capital
expenditures of
unconsolidated     40,013      -             40,013        -         
subsidiaries
(3)
Total capital       728,216        803,526         1,315,336       1,435,084
expenditures
Acquisitions,
net of cash        -            225,210       -             225,210   
acquired
Total capital
expenditures        728,216        1,028,736       1,315,336       1,660,294
and
acquisitions
Joint venture
partner            (120,106 )    (360,499  )    (120,106  )    (625,819  )
contributions
Total capital
expenditures
and               $ 608,110     $ 668,237      $ 1,195,230    $ 1,034,475 
acquisitions,
net
                                                                 
Distributable     $ 161,734      $ 128,391       $ 310,180       $ 238,216
cash flow
Maintenance
capital             7,005          4,204           9,751           6,095
expenditures
(2)
Changes in
receivables,        (35,710  )     (68,767   )     (42,763   )     (67,501   )
inventories and
other assets
Changes in
accounts
payable,
accrued             120,755        37,601          95,041          10,053
liabilities and
other long-term
liabilities
Cash adjustment
for
non-controlling     3,178          (1,720    )     5,296           (3,489    )
interest of
consolidated
subsidiaries
Other              (12,512  )    (5,871    )    (20,682   )    (5,778    )
Net cash
provided by       $ 244,450     $ 93,838       $ 356,823      $ 177,596   
operating
activities
                                                                             

      Other includes amounts related to capitalized interest associated with
(1)  joint venture capital expenditures and fees earned related to
      development of joint venture capital projects.
(2)   Net of joint venture partner contributions.
(3)   Growth capital expenditures for Ohio Gathering, L.L.C.
      

MarkWest Energy Partners, L.P.
Reconciliation of GAAP Financial Measure to Non-GAAP Financial Measure
Adjusted EBITDA
(unaudited, in thousands)
                                                              
                       Three months ended June 30,   Six months ended June 30,
                         2014         2013         2014        2013    
                                                                   
Net income             $  13,048       $ 85,498      $  28,964     $ 64,367
Non-cash                  1,835          1,157          5,802        3,541
compensation expense
Unrealized loss
(gain) on derivative      18,844         (37,287 )      7,024        (46,320 )
instruments
Interest expense (1)      42,765         36,610         84,483       74,632
Depreciation,
amortization and          120,361        88,889         239,311      172,166
other non-cash
operating expenses
Loss (gain) on sale
or disposal of            1,450          (37,736 )      1,357        (37,598 )
property, plant and
equipment
Loss on redemption        -              -              -            38,455
of debt
Provision for income
tax (benefit)             (2,940   )     16,283         9,606        22,840
expense
Adjustment for cash
flow from                 3,262          1,532          4,381        2,063
unconsolidated
affiliates
Other (2)                9,606        795          14,870      2,396   
Adjusted EBITDA        $  208,231     $ 155,741    $  395,798    $ 296,542 
                                                                             

(1)  Includes amortization of deferred financing costs and debt discount, and
      excludes interest expense related to the Steam Methane Reformer.
      For the three and six months ended June 30, 2014, Other includes amounts
(2)   related to capitalized interest associated with joint venture capital
      expenditures and fees earned related to development of joint venture
      capital projects.
      

                        MarkWest Energy Partners, L.P.
                 Distributable Cash Flow Sensitivity Analysis
                           (unaudited, in millions)

The Partnership periodically estimates the effect on DCF resulting from
changes in its volume forecast and NGL prices. The Partnership has become less
sensitive to changes in commodity prices as a result of significant increases
in fee-based income. For the full year 2014, the Partnership estimates that
net operating margin will be over 70 percent fee-based. In addition, the
Partnership has hedged approximately 60 percent of its forecasted 2014 NGL
exposure on a volumetric basis, over 90 percent of these with direct product
hedges.

The analysis further assumes derivative instruments outstanding as of August
6, 2014, and production volumes estimated through December31, 2014. The range
of stated hypothetical changes in commodity prices considers current and
historic market performance.

Estimated Range of 2014 DCF
                                         
                        Volume Forecast (1)
                  Low Case   Base Case   High Case
              $1.05     $   635    $   659     $   680
NGL $/Gal     $1.00     $   631    $   654     $   676
(2) (3)       $0.95     $   627    $   650     $   671
              $0.90     $   623    $   646     $   667
            $0.85   $   619    $   641     $   662
                                              

(1)  Volume Forecast is increased/decreased by 10% in the Marcellus and Utica
      segments for the High and Low Cases.
      The composition is based on the Partnership’s projected barrel of
(2)   approximately: Ethane: 35%, Propane: 35%, Iso-Butane: 6%, Normal Butane:
      12%, Natural Gasoline: 12%.
(3)   Composite NGL prices are based on the Partnership’s average forecasted
      price.

The table is based on current information, expectations, and beliefs
concerning future developments and their potential effects, and does not
consider actions the Partnership’s management may take to mitigate exposure to
changes. Further, the table does not consider the effects that such
hypothetical adverse changes may have on overall economic activity. Historical
volumes, prices and correlations do not guarantee future results.

Although the Partnership believes the expectations reflected in this analysis
are reasonable, the Partnership can give no assurance that such expectations
will prove to be correct and readers are cautioned that projected performance,
results, or distributions may not be achieved. Actual changes in market
prices, market conditions and constraints, production, NGL composition,
infrastructure availability, market participants, and ratios between product
prices may differ from the assumptions utilized in the analysis. Actual
results, performance, distributions, volumes, events, or transactions could
vary significantly from those expressed, considered or implied in this
analysis. All results, performance, distributions, volumes, events or
transactions are subject to a number of uncertainties and risks. Those
uncertainties and risks may not be factored into or accounted for in this
analysis. Readers are urged to carefully review and consider the cautionary
statements and disclosures made in the Partnership’s periodic reports filed
with the SEC, specifically those under the heading “Risk Factors.”

Contact:

MarkWest Energy Partners, L.P.
Frank Semple, Chairman, President & CEO
Nancy Buese, Executive VP and CFO
Josh Hallenbeck, VP of Finance & Treasurer
866-858-0482
investorrelations@markwest.com
 
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