Faced with fast-growing demand, the Long Island Power Authority balanced high-efficiency combined cycle generation, on a power purchase and merchant basis, with renewables to provide diversity and reliability.
New York’s independent system operator found in 2003 that the state would need at least 5000 MW of additional capacity over the following five years, and most of that would be required in the downstate and Long Island areas.
More than a million consumers in the Long Island area are served by the Long Island Power Authority (Lipa) and the utility agrees that more power will be required. It has developed an energy plan that relies partly on energy efficiency and new investment in renewables, and partly on new cable interconnections. But for large scale new capacity it is investing in high-efficiency combined cycle generation, maintaining a diversity of suppliers by offering long term contracts and a unique deal that includes dedicated merchant capacity.
The need for additional generating capacity on Long Island became very evident in 2002. During a July heatwave, Lipa’s power demand record was broken twice, reaching 5059 MW. In the following year, during the summer peak period, Lipa delivered nearly ten per cent more power than it did in 2001. In fact, Lipa’s summer demand has been increasing at an average of five per cent per year. Additionally, Lipa experienced new winter peaks in 2004.
The company said in announcing its energy plans that given this level of growth, the loss of a large generating unit or major transmission interconnection could be devastating to Lipa’s electrical system.
The situation has been made more difficult by a Department of Energy decision blocking the operation of the Cross Sound Cable, which has increased the need for capacity on Long Island itself.
Figure 1: Long Island’s limited links with the New York system mean on-island sites like Pinelawn are needed.
Referring to the Cross Sound decision, Lipa said, “In essence, Long Island has already experienced its second largest contingency. The failure of the largest contingency, or two of the next largest contingencies, could easily put Lipa in the position of interrupting load to customers in order to preserve the bulk power system reliability.” Long Island’s transmission and capacity constraints are also aggravated by the fact that the generating infrastructure in Lipa’s electrical system is relatively old. The majority of the generating resource capacity comes from facilities that are more than 30 years old, and a significant portion of the generating capacity is derived from facilities that are more than 40 years old.
The amount of capacity required is determined by New York’s Independent System Operator (NYISO), which requires Lipa to either own, or have contracts for, generating capacity and other resources to meet peak summer demand plus a reserve of 18 per cent. But the area has additional constraints. NYISO also requires Lipa to maintain a certain per cent of its generating resources within its own service area. This is due to the limited transmission capacity to this area as a result of Long Island’s geographical separation from the major transmission infrastructure in New York State’s electric grid. NYISO had set the locational requirement at 95 per cent of the expected summer peak demand in 2003. However, it updated the requirement to 99 per cent in February 2004
Responding to the need
Lipa’s comprehensive energy resource plan contains five key elements.
First is an Energy Efficiency and Demand Reduction Plan expected to achieve up to 75 MW of energy and capacity savings through long-term energy efficiency initiatives. Second is an offshore wind farm rated at between 100 MW and 140 MW. The third element was for long-term baseload capacity, and Lipa issued a Request for Proposals for 250 MW to 600 MW of on-island generation assets or off-island sources linked to Long Island via a new cable.
Lipa’s evaluation team reviewed a total of 14 responses and selected a combination of two projects. The Caithness Bellport proposal, which will be capable of generating 326 MW, emerged as the favoured on-island generation proposal. Lipa will seek a Power Purchase Agreement (PPA) for 277 MW of the plant’s output, while for the first time on Long Island, the remaining 49 MW will be dedicated as a merchant power component.
The second baseload project was a 67 mile long cable known as the Neptune project, which can link Long Island to a diverse source of supply from markets southwest of the region
The Neptune cable will be capable of transmitting 660 MW of supply, which Lipa says will open up an “energy corridor” from the Mid-Atlantic states through Long Island on into New England and Canada. Selecting the Neptune project allowed Lipa to issue another request for proposals for 600 MW to be imported over the Neptune cable from summer 2007.
These energy purchase contracts would meet Lipa’s fourth key element, diversity of supply.
The Authority’s fifth key element was a plan to add new capacity using high-efficiency combined cycle power plants, capable of quick construction, in order to meet immediate needs.
Combined cycle for summer
In its planning for generation for summer 2005 Lipa wanted a commercial operation date of early summer 2005 with a contract length of up to 20 years, fuelling by either natural gas or liquid fuel; and compliance with all permitting requirements and use of Best Available Control Technology for air emissions.
On 23 February 2004, Lipa sought proposals for new combined cycle generation to be in operation by early summer 2005. Fifteen proposals were received. Based on a selection committee’s evaluation, Calpine’s Bethpage project and Pinelawn Power’s Babylon project, which will each be capable of producing a maximum of 79.9 MW of electricity, were chosen to go into operation in summer this year.
Pinelawn Power Project would provide energy to the Lipa grid via connection to Lipa’s existing Pinelawn Power Substation. Lipa would purchase the power via a 20-year Power Purchase Agreement with Pinelawn Power.
Figure 2: Location map of the Pinelawn Project, Babylon, New York State.
The project includes the construction and operation of a General Electric LM 6000 SPRINT combustion turbine generator, a once-through steam generator with duct burners, a steam turbine generator, and a two-cell evaporative cooling tower. The project would be fired primarily with natural gas, with liquid fuel as a back-up. The proposed schedule calls for the project to achieve simple-cycle commercial operation by May 2005 and combined-cycle commercial operation in June 2005.
The Bethpage combined cycle project will be adjacent to existing Calpine power generation facilities in Hicksville, Nassau County, New York. Calpine would build, own and operate the plant on land owned or leased by a subsidiary company. Lipa would acquire, either by direct purchase, condemnation or transfer of jurisdiction, the 1.7-acre project site and then would lease the site back to Calpine. Electricity generated by the proposed project would be purchased by Lipa under a long term contract.
The project schedule calls for the new combustion turbine to be in commercial operation during June 2005. The major equipment includes a General Electric LM6000 SPRINT combustion turbine generator, an IST once through steam generator (OTSG) equipped with duct burners, a Siemens Westinghouse steam turbine generator, and a five-cell cooling tower. The turbine would use natural gas from KeySpan as its fuel.
Caithness Bellport Energy Center
Lipa’s largest new generating facility will be sited on Long Island, and is described by the Authority as a critical ingredient of its strategy for ensuring sufficient and reliable electric power to the Island’s consumers.
This project is nominally rated at 300 MW and is a dual-fuel, combined-cycle facility that would be located in the town of Brookhaven, Long Island, New York, and known as Caithness Bellport Energy Center. The proposed facility’s maximum electrical output would be 350 MW when operating the facility’s gas-fired duct burner.
The proposed facility would utilize a Siemens Westinghouse 501F steam turbine and would be permitted for full-year operation (24 hours per day, 365 days per year). Natural gas would be utilized as the primary fuel with provisions to use low sulphur distillate fuel oil for up to 30 days as the back-up fuel for the combustion turbine only. The facility would be constructed in a one on one configuration with one combustion turbine, a heat recovery steam generator (HRSG), and a single steam turbine. The HRSG would be equipped with natural gas fired duct burners.
The project would interconnect to the 138 kV Lipa system within the 96-acre site via a new 138 kV substation to be constructed on site and adjacent to the existing Lipa 138 kV Holbrook to Brookhaven transmission line right-of-way. Natural gas supply would be provided by a new spur.
Lipa said the the Caithness Bellport proposal was the on-island generation proposal with the greatest long-term benefits for Long Island. Lipa will seek a PPA for 277 MW of the plant’s output, which will make 49 MW available for merchant transactions. This will be the first power plant on Long Island with a dedicated merchant power component.