The Hague’s century-old power plant, now owned by E.ON, provides electricity to the local grid and thermal energy for the city’s district heating system. Poor performance from the plant’s 25-year-old equipment and The Hague’s wish to become a carbon-neutral city by 2010 gave birth to the idea of repowering the existing plant. For protecting a historic building while investing in low-emissions electricity generation, achieving improved plant efficiency and reliability, and accelerating the project so the plant could be back online for the next heating season, The Hague Repowering Project is the winner of POWER’s 2009 Marmaduke Award for excellence in O&M. The award is named for Marmaduke Surfaceblow, the fictional marine engineer and plant troubleshooter par excellence.
Den Haag (The Hague), Netherlands, known as the "International City of Peace and Justice," hosts about 150 international legal organizations, including the International Court of Justice, the primary judicial arm of the United Nations. The world’s first peace conference, which convened in The Hague in 1899, eventually led to establishment of the Permanent Court of Arbitration, the world’s first court for settling international disputes, and the predecessor of the International Court of Justice.
Much of the grand architecture in the historic areas of The Hague dates from the latter half of the 19th century and the early 20th century, when the city was modernized and prosperous. The grandeur of The Hague continued to grow with each passing year until the destruction brought on by the deportation of its citizens, occupation, and later liberation of the city caused by World War II. Today, Monumentenzorg (The Bureau for Monuments and Historical Sites) requires owners of historic buildings constructed prior to 1945 to preserve their façades and the buildings’ other cultural-historical qualities. The Hague’s original power plant, located in the center of the city, is one such building. The exterior looks the same today as when the plant first entered commercial service in 1906 (Figure 1). Since 1978 it has also provided district heating to many homes, businesses, and government offices, including the World Court.
1. In the prime of life. The Hague Repowering Project removed two old gas turbines and generators and replaced them with state-of-the-art aeroderivative gas turbines to improve the plant’s efficiency and power output—all within the confines of the plant’s historic 1906 building near the city center. Courtesy: E.ON
Heat and Power Provider
The Hague’s Electriciteitsfabriek or Electricity Factory, located on De Constant Rebecque Square in the city center, is owned by E.ON Benelux and is one of the oldest still-operating combined heat and power (CHP) plants in the Netherlands. The building that houses this plant remains attractive. However, its beauty is more than skin deep.
The generating plant originally consisted of five steam engines and multiple boilers and generators. A number of changes were made over the years. In 1983, Unit 15 — consisting of two combustion turbines, two heat-recovery steam generators (HRSGs), and a single condensing steam turbine with extraction steam — was added. It was the only unit operating prior to the latest repowering. The nameplate capacity of this plant was 75 MW electric with 80 MW thermal, although actual production over the past decade was much lower.
The extraction steam is used to produce hot water that is circulated through the district heating system to large buildings such as those housing the government building department and the Dutch parliamentary complex. By 2005, operating inefficiencies and the expiration of its heat supply contract meant the time had arrived for the power station to enter the digital age.
At the end of 2006, E.ON, as purchaser and distributor of heat to The Hague; ENECO Energie, a leading Dutch energy company with the contract to distribute the heat to customers; and the city of The Hague reached an agreement that ensured the supply of district heat to the city through 2023. The new agreement also supports the municipal leadership’s goal of making The Hague a climate-neutral city by 2010. According to Joost van Dijk, chairman of the Board of E.ON Benelux, "We were able to take on this responsibility to society because the city council has given district heating an important place in its policy around CO2. This is an excellent example of shared, lateral thinking whereby all parties work together to enable this sort of massive investment." E.ON Benelux invested some €70 million ($97.9 million in mid-June) to complete the repowering project.
With a new district heat agreement in hand in November 2006, The Hague Repowering Project was soon under way. Energy Services Inc. (ESI) of Farmington, Conn., a subsidiary of United Technologies Corp., was selected as the turnkey contractor for the project based on its successful commissioning of a similar repowering project in late 2005 in Leiden, only 10 miles from The Hague. In the Leiden Repowering Project, two older combustion turbines were replaced with new-technology General Electric (GE) LM-2500+ turbines; the two existing generators and other process equipment were in serviceable condition and were reused. The Leiden Repowering Project, also located in a historic building, was successfully completed within a very tight three-month schedule, and E.ON predicted a three-year payback on its investment.
One of the first major challenges encountered by The Hague’s project team was timing the construction phase. Electricity supplies can be replaced by market purchases, but district heat supplies are another matter. "Although an investment of €70 million in the recently liberalised energy market entails major risk, stopping heat deliveries just wasn’t an option," said van Dijk. Much of the construction work to follow was scheduled to ensure that there would be no disruption to the district heating system during the next heating season, beginning in October 2007 (Table 1).
Table 1. Compressed project schedule. The repowering project had to be executed between winter heating seasons to ensure heat deliveries to The Hague’s district heating grid. The timeline for the gas turbine replacements was the project’s critical path. Source: ESI
Another major challenge was the very tight budget for the renovation. In fact, early feasibility studies in 2004 and 2005 were not optimistic that the project was economically feasible. Other options were investigated until a clear technical option that could be constructed within the project’s financial constraints was identified: replace the aging and unreliable combustion turbines with high-efficiency turbines, but reuse the existing HRSGs, steam turbine, and district heating equipment because these components were in good, serviceable condition.
One of the pivotal moments in this decision-making process was when the HRSGs were found to be capable of handling up to 25% more exhaust mass flow. The higher exhaust mass flow limit allowed ESI to specify larger and more efficient combustion turbines than was originally thought possible. Turbine specs were limited only by the space and volume available in the building and the existing location of the HRSG inlet flanges.
Major contractors and suppliers to the project are listed in Table 2.
Table 2. Major suppliers to The Hague Repowering Project. Source: ESI
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