As Gail states.

You may get some mileage from this:

-- Extract this chunk of your query separately

--------------------------------------------------------------------

JOIN OSS_BENCHMARK_PRICE_REFERENCE PR

ON L.DAILY_BENCHMARK_LOCAL_SEQ=PR.DAILY_BENCHMARK_LOCAL_SEQ

JOIN RD_MARKET_PRICE MP

ON MP.MARKET_PRICE_SEQ=PR.MARKET_PRICE_SEQ

OR MP.MARKET_PRICE_SEQ=PR.FUEL_MARKET_PRICE_SEQ

OR MP.MARKET_PRICE_SEQ=PR.GAS_MARKET_PRICE_SEQ

LEFT JOIN OSS_MARKET_PRICE_DAILY FPD

ON MP.MARKET_PRICE_SEQ=FPD.MARKET_PRICE_SEQ

AND MP.PRICE_TYPE_CD ='FREIGHT'

AND FPD.OPTIMISATION_JOB_SEQ= @JOB_ID

AND CONVERT(VARCHAR(8), FPD.APPLICABLE_DT, 112)= CONVERT(VARCHAR(8), G.price_dt, 112)

LEFT JOIN OSS_MARKET_PRICE_DAILY FOPD

ON MP.MARKET_PRICE_SEQ=FOPD.MARKET_PRICE_SEQ

AND MP.PRICE_TYPE_CD ='FUEL OIL'

AND FOPD.OPTIMISATION_JOB_SEQ= @JOB_ID

AND CONVERT(VARCHAR(8), FOPD.APPLICABLE_DT, 112)= CONVERT(VARCHAR(8), G.price_dt, 112)

LEFT JOIN OSS_MARKET_PRICE_DAILY GOPD

ON MP.MARKET_PRICE_SEQ=GOPD.MARKET_PRICE_SEQ

AND MP.PRICE_TYPE_CD ='GAS OIL'

AND GOPD.OPTIMISATION_JOB_SEQ = @JOB_ID

AND CONVERT(VARCHAR(8), GOPD.APPLICABLE_DT, 112)= CONVERT(VARCHAR(8), G.price_dt, 112)

-------------------------------------------------------------------

-- something like this. Set it up either as a CTE, a derived table,

-- or (probably faster) a #temporary table

SELECT

PR.DAILY_BENCHMARK_LOCAL_SEQ,

APPLICABLE_DT = CONVERT(VARCHAR(8), FPD.APPLICABLE_DT, 112),

FREIGHT_RATE = CASE WHEN MP.PRICE_TYPE_CD ='FREIGHT' THEN FPD.QUOTE_VAL ELSE 0 END,

BUNKER_RATE = CASE WHEN MP.PRICE_TYPE_CD ='FUEL OIL' THEN FPD.QUOTE_VAL ELSE 0 END,

DIESEL_RATE = CASE WHEN MP.PRICE_TYPE_CD ='GAS OIL' THEN FPD.QUOTE_VAL ELSE 0 END

FROM OSS_BENCHMARK_PRICE_REFERENCE PR

INNER JOIN RD_MARKET_PRICE MP

ON MP.MARKET_PRICE_SEQ IN (PR.MARKET_PRICE_SEQ, PR.FUEL_MARKET_PRICE_SEQ, PR.GAS_MARKET_PRICE_SEQ)

LEFT JOIN OSS_MARKET_PRICE_DAILY FPD

ON MP.MARKET_PRICE_SEQ = FPD.MARKET_PRICE_SEQ

--AND MP.PRICE_TYPE_CD ='FREIGHT'

AND FPD.OPTIMISATION_JOB_SEQ = @JOB_ID

--AND CONVERT(VARCHAR(8), FPD.APPLICABLE_DT, 112)= CONVERT(VARCHAR(8), G.price_dt, 112)

GROUP BY

PR.DAILY_BENCHMARK_LOCAL_SEQ,

CONVERT(VARCHAR(8), FPD.APPLICABLE_DT, 112)

-- note that functions in JOINs and the WHERE clause are likely to render the search non-SARGable