|Artist’s impression of the completed project|
A year-round need for cooling and less than perfect electricity grid supplies mean that buildings in many parts of the Middle East could benefit from on-site trigeneration schemes. One company is now installing the technology in a major development in Saudi Arabia, writes Angie Curran.
Headquarters Business Park (HQBP) is a development in Saudi Arabia by Adeem Al Wataniya about a 20-minute drive from King Abdul Aziz International airport, Jeddah, on the prestigious Corniche overlooking the Red Sea. The Jeddah Corniche area features recreation areas, pavilions and large-scale civic sculptures, as well as King Fahd’s Fountain, the world’s highest fountain. Currently undergoing renovation, the Corniche will be expanded with restaurants, play areas, entertainment and large developments like the HQBP.
The HQBP has three main sections: the 240-metre-tall West Tower, housing 52 floors with spectacular views over the city of Jeddah and the Corniche; the Podium, a parking and services section that is 11 floors high (nine above ground, two below ground) and caters for all supporting services including the energy generation facility; and the East Tower, a 70-metre-high structure on Prince Faisal Bin Fahad Street with 13 floors.
The building will house up to 250 flexible office units; 10 sky villas, each containing an 8-metre-high indoor garden; a health and fitness centre including an Olympic swimming pool and power napping rooms; 4000 m2 of restaurants and cafés, including one on level 52; a 17-storey, 300-bed hotel and a helipad atop the West Tower.
Developer Adeem Al Wataniya wanted to ensure the HQBP is not only iconic in quality, appearance, location and service, but also world class in energy efficiency. An efficient on-site trigeneration – heat, power and cooling – plant was determined to be the most appropriate solution.
TES, a joint venture between CES Energy and Al Aman, was selected in June 2011 to provide electricity, cooling, hot water and potable water to the HQBP project. The contract was signed under a 25-year build-own-operate (BOO) model, under which TES funds the trigeneration plant and sells the energy produced.
After visiting a trigeneration project developed by CES Energy in Sydney, Australia, Adeem was confident that CES Energy, in partnership with Al Aman, could deliver a similar trigeneration scheme for the HQBP project.
In 2006, CES Energy started a business in Australia that has led to the development of a trigeneration strategy for the City of Sydney aimed at delivering 360 MWe of decentralized power via a network of energy centres combined with district cooling. This strategy is now being implemented, helping Sydney meet its energy demand and carbon dioxide targets.
‘We selected a trigeneration BOO model as it delivered a significant carbon reduction for the Headquarters project, while reducing our capital spend and providing us with ongoing operational saving over a 25-year period,’ said Essam Fahiek, CEO of Adeem Al Wataniya Group. ‘There is very limited experience among companies with trigeneration within Saudi Arabia, so international co-operation was required. However, doing business in Saudi Arabia can be different – the combination of CES Energy and Al Aman gave us assurance regarding local delivery, international trigeneration experience while having an established local support and maintenance business.’
The benefits of a trigeneration solution to Adeem were:
- reduced energy cost,
- reduced capital outlay,
- reliable power available when required,
- future-proof and scalable,
- efficient and eco-friendly.
For TES, the first stage of the project was to determine the project’s demand for electricity, chilled water and hot water, based on the forecasted usage profile. The optimal solution was found through holding regular consultations with the client, as well as referring to industry norms, best practice guide and – most importantly – CES Energy’s experience in similar projects in Europe and Australia. Figure 1 shows the project’s expected annual energy use pattern.
Technically, the solution is designed to meet peak demands, baseloads and minimum loads through a combination of options, while constantly maintaining redundancy levels. Financial engineering assessed several options to ensure the most financially beneficial combination of equipment was selected. The solution was therefore designed around the following main plant items:
- eight 2 MW diesel generators;
- three electrical chillers, each of 1400 tonnes of refrigeration (TR);
- three absorption chillers, each of 700 TR;
- six cooling towers located on the 15th floor;
- a seawater reverse osmosis plant of 1300 m3 per day.
The project was designed by CES Energy in conjunction with Saudi Arabia-based joint venture company TES. It is designed to meet the peak building requirements with an ‘n+1’ scenario, allowing for redundancy and scheduled maintenance activities. The HQBP includes a 1.5 MVA connection to the grid network. The multiple engine layout of the HQBP plant room provides great flexibility in meeting the building’s actual demand by allowing individual engines to turn on and off as required, and therefore increases overall plant efficiency.
|Figure 1. The HQBP’s expected annual energy use pattern|
The energy centre is in the basement of the Podium, with its flue terminating at the 8th floor and the cooling towers on the 15th floor of the East Tower. The plant includes 180,000 litres of underground on-site diesel storage.
A custom-designed control system provides control and remote monitoring, allowing for autonomous operation of the entire plant. The plant’s operation is continuously monitored and measured to ensure optimum efficiency at all times.
Under the BOO contract, TES also provides the HQBP with potable water from a reverse osmosis plant combined with a system of intake and reject wells. Grey water is recycled within the building, treated and then re-used for cooling tower feedwater.
TES is installing eight CHP units each rated at 1825 kW prime power/2000 kW standby power for a total installed power of 14.6 MWe. This provides for security of operation, ensuring adequate standby generators are available at all times.
A digital control system will also be installed to control engine synchronizing, starting and stopping. The master control system will monitor the load and determine the number of engines required to satisfy the building and ancillary loads. The generator control system will also interface with a master SCADA system to enable data of critical system parameters to be collected and to allow the generation of automatic reports and alarms. In addition, the SCADA system will generate real-time reports providing data to assess and manage the efficiency of the overall installation. The system is fully metered to record fuel consumption, electricity generated and electricity used by the building tenants.
The waste heat from the engines will be used to generate chilled water. The system will include three electrical chillers, each rated at 1400 TR, and three absorption chillers, each of 700 TR. Installed capacity will therefore total 6300 TR. Dynamic balancing between the electrical and absorption chillers at different loads will match the heat capacity and allow for redundancy.
Waste heat recovered from the engine jacket and exhaust gases using shell and tube heat exchangers will be utilized in single-effect hot water absorption chillers. The chilled water is circulated in a common header to supply plate heat exchangers that provide the cooling energy to the landlord chilled water systems. Each circuit has an energy meter that records energy consumption by the tenant circuits. Redundancy is provided for all plate heat exchangers and circulating pumps to ensure availability at all times.
Controls and back office
The energy centre has a permanent on-site operations team and will be monitored 24-hour daily from the TES control centre. A dedicated dual internet connection allows for constant visibility, monitoring and management of the equipment and operating parameters.
A SCADA system will be implemented to include management, maintenance and operations. The system will also generate reports and store data for later retrieval at the request of the operator. This system ensures continuous monitoring of critical plant functions and allows preventative maintenance actions to be undertaken when required.
CARBON AND ENVIRONMENTAL BENEFITS
Under the currently expected usage model, the plant will reduce the HQBP’s imported electrical demand by more than 42 GWh per year, compared with conventional grid power.
The HQBP trigeneration plant, the largest in Saudi Arabia, can operate at 85% efficiency and avoid the emission of up to 15,000 tonnes of carbon dioxide per annum. HQBP’s efficient on-site power generation scheme ensures the facility will be iconic in MENA for energy efficiency, building quality, and environmental performance.
Other benefits of the trigeneration approach are:
- Trigeneration’s excellent potential for commercial and industrial applications due to the high year-round cooling demand of all buildings in Saudi Arabia.
- Favourable attitudes to the TES solution among building owners who wish to cut exposure to the relatively stable Saudi Arabian grid’s occasional outages.
- The relatively low cost of diesel fuel and the favourable electricity:diesel cost ratio, which leads to excellent financial viability for trigeneration solutions for a range of commercial and industrial applications.
- The industrial sector’s specific characteristics, which are ideal for trigeneration applications: 24-hour operation, leading to excellent use of trigeneration equipment; large and steady year-round energy consumption; high potential carbon and financial savings.
|Headquarters Business Park – the development will include 14.6 MW of trigeneration capacity|
FINANCIAL OVERVIEW AND CARBON CREDITS
The project is operated under a BOO model whereby TES funds the project’s capital cost and then sells the electricity, chilled water, hot water and potable water at pre-determined rates for a period of 25 years. A comprehensive power purchase agreement agreed between both parties covers all necessary aspects. All operational and plant replacement costs are the responsibility of TES.
The intention is to have the HQBP registered as a UN Clean Development Mechanism (CDM) project. The CDM allows Annex 1 countries to earn certified emission reduction credits from investing in emission reduction projects such as the HQBP in non-Annex 1 countries like Saudi Arabia. Each credit is equivalent to 1 tonne of carbon dioxide. Credits can be traded and sold, and used by industrialized countries to meet part of their emission reduction targets under the Kyoto protocol.
CES Energy Carbon Services currently has a multi-country cogeneration and trigeneration ‘programme of activities’ (POA) pending for Egypt, Saudi Arabia, the UAE, Qatar and Oman. Due to be registered by the end of 2012, the POA will be valid for 28 years. It will cover cogeneration and trigeneration projects within existing and new commercial buildings, and allow carbon credits to be available for projects in these five countries. Certified emission reduction credits are issued by the UNFCC and can be sold into the EU Emissions Trading Scheme for the duration of the crediting period.
THE SAUDI POWER MARKET
There seems to be no doubt that electricity demand in Saudi Arabia will continue to rise into the future. Demand for power across the region is expected to increase by 25% over the next five years, and demand in Saudi Arabia is currently rising by an almost steady 8% annually. However, massive industrial development in the Kingdom is expected to raise this percentage in the future, bringing the electricity demand in 2020 up to about 67 GW.
In parallel with this increasing demand, the Saudi government is raising its electricity production and distribution capacity. The country currently relies primarily on large-scale power production and desalination plants to meet its electricity needs, with some privately-owned power companies supplying the remaining portion. The total capacity of these three sources was about 45 GW in 2010 and is expected to reach 75 GW in the next five years.
The structural works for the HQBP are almost complete, with external cladding now being applied. Al Aman and TES are now building out the energy centre, with completion planned for the fourth quarter of this year. This project is expected to be one of many within Saudi Arabia as the country continues to grow and needs to meet its increased power demands.
Angie Curran is the marketing manager for TES, Jeddah, Saudi Arabia. Email: firstname.lastname@example.org