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• As an example for a plant producing a total of around 898,000 MWh the fuel savings alone by utilizing reciprocating diesel engines compared to combustion turbines amounts to USD 122 M per year (based on an LFO fuel price of USD 21 /MMBTU)
• The comparative savings using LNG/natural gas as a fuel will be aboutUSD 184 M per year!! (based on an LNG delivered price of USD 14/ MMBTU)
Annual Production : 898,818 MWh (based on 2008 energy sales data in Draft US Virgin Islands Comprehensive Strategy May 5, 2009 by SSEB)
New Recip plant: Assume average Heat Rate at 8500 Btu/kWh on LFO and 7866 Btu/kWh on gasTotal fuel (LFO) consumption: 7,639,953 MMBTUTotal fuel (Gas) consumption : 7,070,102 MMBTU
Main Driver: Environmental RegulationsStringent Emission limits (EPA Region 2 - NY)
“How that affects our study is that WAPA says they will never be able to get permits for diesels on the USVI; on the other hand our preliminary heat balance indicates there is a definite advantage from a plant heat rate standpoint to incorporate diesel engines.”
Carlos Rollan, P.E.Harris Group, Inc.Energy Services, Southeast
Excerpt from email to Rodney George August 10, 2004:
Emissions: NOx Reduction : Related to Generation Technology & BACT*
OTHER DRIVER: Water Production: from waste heat (steam production) – CT being less efficient produces more steam than diesel engine
Excerpt from an email to R.George Aug 10, 2004
“The installation of a SCR on a gas turbine is complicated and expensive, because there is no natural location for the SCR. After a diesel engine, the installation is less expensive and complicated….”
Jan TorrkullaSenior Development EngineerDevelopment & Technology, EnvironmentWartsila Finland Oy
*Source - from PSD Final Permit for North Shore, St. Croix Facility -November 27, 2000 - Page 3
Emission Rate Comparison – 66 MW Recip. Dual Fuel Plant and St. Croix Units 16,17 and 19 Combined
Recip. 66 MW Dual Fuel Plant equipped with SCR and Oxidation Catalyst (8,000 hrs/yr)
(63 MW)
Bottom Line: Lower annual emissions, higher efficiency for Recip. Plantand application of BACT for emission abatement - Should be able to get EPA to permit
WAPA
What are the solutions taking into account environmental realities ?
1) St. Thomas: New 66 MW (4 x16.5 MW) dual fuel reciprocating engine plant which will burn LFO initially until LNG becomes available. Existing gas turbines could be used for peaking. Approx. 12-14 months for commercial operation from permit approval
2) St. Croix: New 33 MW (2 x16.5 MW) dual fuel reciprocating engine plant which will burn LFO initially until LNG becomes available. Existing Simple cycle gas turbines could be used for peaking. Approx. 12-14 months for commercial operation from permit approval
To successfully permit a reciprocating engine plant (fired on natural gasor diesel) in the USVI, the use of a) SCR for NOx abatement and, b) Oxidation Catalyst for CO reduction HAS TO BE CONSIDERED
What are the solutions taking into account environmental realities ?
3) Phase out flash distillation system for water production and employ Reverse Osmosis(RO)Technology since older steam and gas turbine plant will be phased out for base load power generation
This is the strategy that Aruba and Curacao begun adapting in 2005
Aruba started installation of base load reciprocating diesel plants in 2006. Today a total of 98 MW installed – the last 44 MW was commissioned in last quarter of 2011 and are “gas prepared”.
All remaining oil fired steam plants will be eventually phased out
Advantages – Diesel Engines vs. Combustion Turbines
• High efficiency (43-45%) compared to latest combustion turbine (30-35%)
• Reliability – Recip Dual fuel plant will consist of four discrete units of approx 16.5 MW each – if one out of service , still have around 50 MW operational. With gas turbine more efficient units will be of a higher unit size - 30MW and above
• Ability to load follow (reduced output) without significant loss of efficiency
• Low operation and maintenance cost
• Negligible derating (output and efficiency) due to high ambient temperatures
• LNG is good quality natural gas• High methane content and free of impurities (cleaned during
liquefaction phase)• Non toxic and non corrosive• Lighter than air (good for safety) and not highly flammable (oxygen
ratio has to be between 5 and 15%) and too cold to ignite as liquid
• Transportation – well established activity• Transported and stored in low pressure insulated tanks at -164 °C• Occupies only 1/600th of the volume of gas• Phase change to gas relatively easy to accomplish
• Long term price outlook- by all accounts favourable vs. HFO/LFO
• Reality is that current power generation production in USVI is veryexpensive and does not need to be that way. Lower production cost will have a positive effect on overall retail electric rates
• Reciprocating Engine Dual Fuel Plant will generate tremendous savingswhen burning diesel fuel and confident that it can be permitted (with SCR and oxidation catalyst). Even greater savings will accrue coupled with even lower emissions when natural gas becomes available in the form of LNG (LFO always available as a back-up fuel). Existing CTs used for peaking • Environmental issues with reciprocating engine plant can easily be overcome by use of SCR (Global experience, good example: PG&E 167 MW Humboldt plant in California) • LNG is a real fuel option that should be considered for reasons of the long term outlook on price/price stability and environmental benefits • There are real players in the market who will step-up as an integrated LNG supplier