** Shares of Fortescue FMG.AX fall 0.8% to A$15.98, in-line with 0.8% drop in mining sub-index .AXMM

** Stock set for fourth straight week of loss, is down nearly 3% this week

** FMG axes investment pact with U.S. hydrogen giant Plug Power in the latest blow for the clean energy power source, as per a media report

** Analysts at Morgan Stanley see risk to the book value of FMG's energy business if projects are abandoned

** Brokerage has a current book valuation of A$1.8 billion ($1.14 billion) for FMG's energy operations

** Plug Power was FMG’s preferred supplier for its Gibson Island project in Queensland

** Stock down 12.4% YTD

($1 = 1.5813 Australian dollars)

(Reporting by Rishav Chatterjee in Bengaluru)

((Rishav.Chatterjee@thomsonreuters.com;))