Diesel generators powered by fossil fuels have traditionally been the technology of choice for powering off-grid telephone network infrastructure as well as providing backup power generation in unreliable grid supply scenarios.
In terms of operating efficiency and reliability, the diesel generator continues to provide a low capital expenditure solution for the provision of both continuous and/or standby electricity supplies. However, with mobile network operators (MNOs) experiencing increasing Opex as the price of fossil diesel fuel continues to escalate, much attention is being focused on development of power generation systems using sustainable energy resources.
According to latest figures issued by the GSM Association, around 640 000 off-grid base stations will be rolled out across emerging markets by 2012. The target is for 118 000 of these to be powered by renewable energy.
It is perhaps naive to assume that some 500 000 diesel gensets will therefore be installed over the next two years. But it is clear that rising fuel prices, environmental considerations such as emission control, noise, carbon footprint and environmental impact are all issues that will be influencing decisions over specifications.
Globally, there are now more than 5bn mobile phone subscribers and this could increase by 50 per cent over the next five years. The magnitude of the task set for MNOs planning further expansion into remote areas and for providers of off-grid power generation systems cannot be understated.
It is estimated that 1.6bn people live off-grid, and an additional 1bn people reside in unreliable grid regions. South Asia has the largest off-grid population in the world: some 614m people – 40 per cent of the region’s population.
Lack of a stable grid drives the deployment of vast numbers of diesel generators for primary and backup power. And with the cost of conventional mineral diesel fuel escalating, alternatives such as biodiesel, diesel hybrid wind turbines and solar power arrays, are receiving much attention.
In traditional GSM networks, an off-grid cellular base station requires a 5-10 kW power generation source. In more remote areas, the power requirements for “last mile” mobile services provision may be substantially reduced together with the number of subscribers and service offerings.
In 1912, Rudolf Diesel is quoted as saying that the use of vegetable oils for engine fuels “may seem insignificant today, but such oils may become, in the course of time, as important as petroleum and the products of the present time”. Prophetic words which now, a century later and with the development of advanced diesel engines, have found new resonance in the form of modern biodiesel fuels.
In terms of operational reliability, many modern diesel engines will run from 16 000 to 18 000 hours before requiring servicing other than routine maintenance, and are increasingly installed in tandem with wind and/or solar powered generators.
Operating for four hours a day as an integral part of a hybrid solution, 18 000 running hours translates to, potentially, 12 years between major servicing. Advanced remote monitoring techniques also ensure that fuel efficiency and power output continuity is maintained.
Biodiesel is a sustainable fuel that offers clean burning characteristics. Produced from nut oils, such as coconut, palm, castor or jatropha and other vegetable oils, including rapeseed and soya, research into methods of prolonging storage life is ongoing, since it is prone to microbiological degradation over long periods.
Biodiesel and biodiesel/fossil fuel mixes (from B10 to B100) can be utilized in many existing diesel gensets, although some modification may be required to maximize the efficiency and reliability of older gensets, as biofuels are not compatible with certain plastics and rubbers.
Emission benefits are also gained, even on low blends. If the biodiesel can be sourced locally, transportation costs may be reduced and a degree of insulation against the price fluctuations of fossil fuels attained.
However, in many countries the use of biodiesel as a primary fuel attracts excise duty, albeit to a lesser degree, in the same way as fossil fuels. Fortunately, increasing global awareness of green issues has resulted in some governments, especially in emerging markets, providing biofuel subsidies in a bid to encourage industry to reduce both its carbon footprint and reliance on fossil fuels, as well as encouraging its production to provide sustainable economic development in some remote regions.
MNOs will undoubtedly be looking closely at any “sunset” clauses incorporated in fuel subsidy agreements since the cost of refining biodiesel to a level whereby it can be reliably used in a genset can prove to be more costly than commercial diesel fuel – even at current prices.
For MNOs, the task of specifying the right technology that can provide a reliable, long-term, cost-effective solution to powering off-grid cell towers and base stations, plants based on green solutions call for a multi-disciplined approach.
The introduction of power systems that use wind and/or solar energy as the prime fuel source in addition to diesel gensets will add significantly to the number of variables that need to be considered.
Green power solutions such as solar panels, wind turbines or hybrids using both technologies are totally dependent on both the availability and variability of the renewable resource: energy derived from wind or the sun.
Obviously, the terrain, local metrological conditions and seasonal changes need to be considered together with battery capacity requirements to support site autonomy when no power is produced (such as at night or on still days). Additional switch and control gear will also be required to monitor power flow and charge capacity.
Alstom, Shaanxi Diesel Heavy Industry to supply emergency gensets to Chinese nuclear power plant
Alstom, partnering with Shaanxi Diesel Heavy Industry, has won a contract to supply emergency diesel generators (EDGs) for China’s Tianwan nuclear power plant, and at the same time secured contracts to supply gas stripping and evaporation unit equipments to the Ningde, Fangchenggang, Yangjiang, Fuqing and Tianwan nuclear power plants.
Worth €40m ($58m) in total, the contracts were signed with CNPE, the EPC contracting arm of the China National Nuclear Corporation (CNNC) and with CNPEC, the EPC contracting arm of China Guangdong Nuclear Power Corporation (CGNPC), respectively.
Under the agreements, Alstom will supply five EDGs to Tianwan in Jiangsu, as well as liquid purification equipments (LPE) by evaporation-stripping for five nuclear plants: Ningde, Fangchenggang, Yangjiang, Fuqing and Tianwan. It will all be used on the CPR 1000 range of modified pressurized reactors.
As a leading supplier for China’s nuclear industry, Alstom has been supporting the development of China’s nuclear power industry ever since its involvement in the construction of Daya Bay, China’s first major nuclear power plant, 20 years ago. Partnering with Dongfang, Alstom has been involved in most of China’s major nuclear projects such as Taishan, Ling Ao I and II, Hongyanhe and many others by supplying key nuclear equipment, including Alstom’s Arabelle turbine-generator package featuring the world’s most powerful steam turbine.
The projects’ equipment will mostly be manufactured in China by the Alstom Wuhan Engineering and Technology Company, which has a proven record in high standard engineering, project management and procurement. In order to meet the stringent requirements of the nuclear industry, the company has set up high standard sourcing and logistics processes as well as for project and quality management.
Caterpillar delivers greater control, more power and reduced operating costs with extended-duty genset
Caterpillar has released a series of performance enhancements for 50Hz Cat G3512E and G3520E gas generator sets, as well as a new 60Hz option now available for the G3520E.
These improvements reduce total owning and operating costs for customers through higher power density, improved fuel efficiency and extended preventive maintenance intervals. Designed for extended-duty distributed generation and combined heat and power (CHP) applications, G3512E and G3520E generator sets have been updated with enhancements to the engine and generator systems and include a next generation engine control system.
As a result, they provide optimized performance to customers via increased electrical and thermal efficiency, enhanced altitude capability, improved transient performance capability, reduced oil consumption and extended intervals between oil changes.
Available now, the upgraded 50 Hz Cat G3512E gas generator set features a 20 per cent improvement in power density over the previous model with a new output rating of 1200 ekW at 0.8 pf (1211 ekW at 1.0 pf). The full-load electrical efficiency has improved to 42.3 per cent.
The enhanced 50 Hz Cat G3520E offers an uprate to 2022 ekW at 0.8 pf (2043 ekW at 1.0 pf) with an increase in full-load electrical efficiency to 42.6 per cent, while the 60 Hz version provides 2009 ekW at 0.8 pf (2026 ekW at 1.0 pf) with a full-load electrical efficiency of 42.2 per cent.
“As global access to gas pipeline infrastructure increases, market demand for advanced, low-emission gas generator sets that offer reduced total owning and operating costs is also rapidly rising,” said Willy Schumacher, electric power gas general manager for Caterpillar.
“By enhancing the G3512E and G3520E generator sets with a comprehensive suite of technological improvements, Caterpillar has further strengthened its market-leading line of products for distributed generation and CHP applications.”
Customers recovering engine heat for use in CHP applications can enjoy best-in-class thermal efficiencies for the G3512E and G3520E that result in total system efficiencies of up to 85 per cent and 87.9 per cent, respectively.
The latest engine design improvements have reduced average oil consumption of the G3512E and G3520E by 57 per cent. Further, recommended oil change intervals have doubled from 1000 hours to 2000 hours. This delivers substantial savings in maintenance and repair costs over the life of the engine.
The greater precision offered by the updated gas engine control module allows these enhanced generator sets to meet NOx emission levels of 500 and 250 mg/Nm3 (1.0 and 0.5 g/bhp per hour).
New software mapping in the engine controller extends Caterpillar’s industry-leading transient performance in applications isolated from the utility grid, while newly developed air and fuel controls improve the altitude capability to deliver a unique combination of efficiency and performance.
Greater Cairo Water Authority relies on G-Drive engines
The flash floods occurring in Egypt last year killed at least a dozen people and forced hundreds of others to abandon their homes.
Along the Sinai Peninsula, Upper Egypt and Aswan, where the rain-induced flooding reached record levels, more than 1100 homes were washed away and the authorities estimated damages amounting to $75 million.
This year, the Greater Cairo Water Authority has been preparing for any further emergencies thanks to a fleet of four mobile response units that carry water pumps powered by Cummins G-Drive engines.
These pumps are mounted onto trucks for mobility, and after successfully completing a rigorous testing programme, they are standing by to be deployed to critical areas in an emergency.
Whenever heavy rains are forecast from now on, the Egyptian water authority can move the vehicles to whichever designated area it requires, so they are ready to tackle any flooding before it reaches dangerous levels.
The engineers at Al Mohandes, a Cairo-based original equipment manufacturer, chose Cummins G-Drive model 6CTA8.3-G2 and 12V DC engines.
Designed for fuel-efficiency, these high-performance diesel engines were found to provide the best solution for the specific requirements of this project.
“We know this particular Cummins engine series extremely well,” said Aly Khamis of Al Mohandes. “As testament to the quality and durability of its products, we have forged and maintained an excellent relationship with Cummins and have enjoyed a good experience with their products during the 25 years that we have been working with them.”
The Cairo Water Authority did not specify its actual power requirement for the pumps. Therefore the Al Mohandes team of engineers based its calculations on the average level of efficiency it would require, before specifying the engines that would exceed the project’s likely power requirements by a 20 per cent margin of safety.
Khamis added: “The Greater Cairo Water Authority is so pleased with the success of the project that they are already talking to us about their next pump installation project, which will involve four mobile response units in Northern Egypt and Delta area and a further four in the South of Egypt.”
The Cummins G-Drive engines are renowned for delivering vital prime, standby or continuous power to help keep the world on the move. Its reliable diesel engines range from the small but powerful X1.3 to the QSK78, considered best in its class for power density and emissions.
Aggreko load testing paves way for Brazilian thermal plant commissioning to go ahead in Campina Grande
Aggreko has performed a series of load tests for the 169 MW thermal power plant in Campina Grande, in the state of Paraiba, Brazil.
The power station, which is owned by the utility company Borborema Energetica, operates on heavy fuel oil and generates output using 20 generators.
The load tests performed by Aggreko were a critical step in the final commissioning of the power station.
Load testing is a specialist service provided by Aggreko, which enables customers to test their power generation equipment in a variety of ways, ensuring that the commissioned equipment is operating to accepted standards.
“The tests helped to identify and solve some problems in the system, ensuring that the generators were ready to operate once the connection to the national grid system was available,” said Diogenes Paoli Neto, managing director, Aggreko South America.
In addition to the equipment provided for the load tests, which included loadbanks, transformers and auxiliary generators, Aggreko also provided four teams, each consisting of one engineer and two technicians.
These teams worked alternating shifts 24 hours a day to keep the project running and to ensure a safe and successful commissioning.
In recent years, Aggreko has provided numerous solutions for the commissioning of power generation systems in Brazil.
MWM to supply gas gensets for British water suppliers
Edina UK, distribution partner of MWM in the UK, has had a year of major successes in supplying gas powered generators from Mannheim-based MWM GmbH to the UK Water Utility industry, concluding a multi-year contract with Anglian Water and numerous projects for Welsh Water, two important UK water suppliers.
The order for Welsh Water comprises the delivery of complete container gensets for four large Advanced Thermal Digestion projects at Eign, Wrexham, Cardiff, and Afan, with a total generator output of more than 10.2 MW.
Edina UK received the second order for power generation from sewage gas from Anglian Water under the AMPS5 programme.
The contract provides for the supply of container gensets over a period of five years. The first six were commissioned in early 2011.
MWM is the world’s oldest manufacturer of gas powered generators whose innovative gas engines are noted for their high-efficiency, proven reliability and low maintenance, two features that combine to make them a highly profitable solution.
The Edina Group has an enviable track record in the design, construction, and long-term operation of gas engines powered by various types of gas, including sewage gas.
The company plays a key role in the development of renewable and sustainable energy sources to reduce dependence on fossil fuels.
Aggreko mobilizes 200 MW emergency power for Japan
Tokyo Electric Power Company (Tepco) has signed a letter of intent with Aggreko stating that it intends, subject to negotiation of definitive terms, to award Aggreko a contract for the rental of 200 MW of emergency power.
The contract would be for 100 MW of gas fired and 100 MW of diesel fired generation, and would be for a minimum one-year term.
In view of the challenges facing the Japanese power supply following a powerful earthquake and tsunami on 11 March this year that damaged the Fukushima Dai-ichi nuclear power plant and much other public infrastructure, Aggreko has started mobilization of the equipment immediately.
It is intended that the power plants units will be installed at sites in the Tokyo Bay area, and will help to sustain the supply of electricity to consumers and industry which has been seriously affected by the earthquake and tsunami.
The Aggreko plant is expected to start delivering power to the grid in June.
Rupert Soames, chief executive officer of Aggreko, said: “Within a few days of the disaster, Aggreko entered into discussions with Tepco to bring additional power to the grid.
“Tepco has moved extremely fast and with great professionalism to define an engineering solution which will bring additional generating capacity to Japan.
“Aggreko is pleased it is able to be of assistance to the country at this very difficult time.”
Aggreko provides power and temperature control solutions to customers who need them either very quickly, or for a short or indeterminate length of time.
Examples would be the supply of power to an industrial site which needs to service its permanent power supply, supplying a whole city in times of power shortage, or providing a major sporting event with power and cooling systems.
The company serves its customers either through our 148 service centres, which it calls the local business, or globally through its international power projects business.
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