The New Face Of Efficiency

The New Face Of Efficiency
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Efficiency in power plants is very important for minimising waste and maximising available resources, which is especially important in countries such as Singapore. One German example will be presented. By Sebastian Webel, Pictures of the Future

Electricity is the lifeblood of today’s cities. Everything from a city’s infrastructure and transport systems to its offices and factories rely on the constant supply of electricity in order to function effectively. As such, cities need power plants that are efficient, to minimise wastage and maximise output.

In growing cities such as Singapore, this is especially important. It is projected that by 2016, with a population of about six million, the electricity consumption in Singapore will amount to about 50,000 gWh . In order to provide enough electricity for a growing city’s residential, infrastructural, industrial and commercial purposes, it is important to adopt advanced technologies that allow for highly efficient power generation.

Doing so will not only help to protect the environment, it will also help to ensure the sustainable growth of these cities. Thankfully, new technologies are available that allow cities to do just that. One such example is already in place at Düsseldorf, Germany. To cater to its growing population, a highly efficient power plant is getting constructed there, a plant that many are calling the new face of efficiency.

Designing For Efficiency

At Lausward, part of the Düsseldorf harbour area, a landmark is taking shape. “The building will be visible from many places in the city, so it deserves a special design; one that creates a distinctive identity,” commented Gerhard Wittfeld, MD of kadawittfeldarchitektur, the architecture firm responsible for the project. “And that led to the idea of giving the building a sort of rhythm, which is generated by its steel frames and the gaps between them.”

If this sounds like one of those faceless office towers that cities are famous for, it is not. Instead of carpeted offices or lofts, this one-of-a-kind structure will house a Combined Cycle Gas Turbine (CCGT) power plant. To be more precise, it will be home to the world’s most efficient and as such most environmentally-friendly power plant of its kind; and it is being built by Siemens.

The plant’s glass-enclosed power source will open up to the city. “We want our architecture to make people aware of the sources of energy that are driving our city,” said Mr Wittfeld. The client is the utility company Stadtwerke Düsseldorf (SWD), which wants to use the plant as a reliable energy source for the city and, considering its prominent location in the middle of Düsseldorf, to also create a new urban statement.

“In contrast to many other regions in Germany, the population here is continuing to grow,” said Rainer Tröger, Lead Project Manager, SWD. “Together with the high demand for power and heat from the regional economy, that means a growing need in the future, and the new power plant addresses that demand. At the same time, we want to get the most out of our fuel.” The power plant is designed with precisely that goal in mind. Due to begin supplying electricity and heat in 2016, the plant will be outfitted with a combination of a gas turbine, a steam turbine, and additional waste heat recovery — and it will try to break three world records at once.

Here is how:

At the heart of the plant will be the latest Siemens turbine generation: the SGT5-8000H. Its output is equivalent to that of 22 jumbo jet engines, and it weighs as much as an Airbus A380 with full fuel tanks. In combination with a downstream steam turbine (Siemens SST5-5000), the Düsseldorf power plant will provide an electrical output of approximately 595 megawatts (MW) in a single block, which is a first.

In another first, the electrical efficiency of the power plant will be over 61 percent — exceeding the previous record of 60.75 percent attained by the Siemens-built “Ulrich Hartmann” CCGT plant in the Bavarian town of Irsching.

In an additional process, the plant’s waste heat energy will be used to supply district heating for the city of Düsseldorf. The 300 MW of thermal energy that will be extracted for this purpose will set a worldwide record for the amount of power harvested by a single gas turbine generating unit.

Full-Load Output In 30 Minutes

When it goes on line, the ‘Block Fortuna’ plant, as it has been christened by Stadtwerke Düsseldorf, will burn its natural gas fuel with an overall efficiency rate of 85 percent. Every year, the plant will therefore emit approximately 700,000 fewer metric tonnes of CO2 than the worldwide average for electricity generation plants. That corresponds to the amount of CO2 produced by approximately 350,000 passenger cars, each driving 15,000 kilometres a year.

However, by themselves, these achievements will not be enough for the plant to operate cost-effectively. In order to supply energy profitably, it will have to operate at full capacity. To understand why, it is important to bear the following in mind: From a technical point of view, efficient gas-fired power plants like this one represent the ideal technology for an economy that is using a steadily growing share of renewables to meet its energy needs, which is what Germany plans to do while shifting to a sustainable energy supply. After all, fluctuations in power generation as a result of changing winds or cloud cover must be quickly compensated for, and the Block Fortuna power plant will be a true champion in this department. It will be able to reach full generating capacity within just 30 minutes of starting up.

Unfortunately, however, electricity from CCGT plants is hardly cost-effective in Germany, because of current market conditions. At the moment, in fact, despite Germany’s plans for greener energy production, because of low raw material costs and the extremely low prices for CO2 emission certificates, coal, rather than natural gas, is the most common fuel now being used to generate electricity. “In Germany, many gas-fired power plants therefore produce electricity only 1,000 to 2,000 hours per year. But to operate cost-effectively, at least 3,000 hours are normally needed,” explained Olaf Kreyenberg, head of European power plant sales at Siemens Energy, who is responsible for sales activities at the Lausward project.

How can the Lausward power plant escape the fate of other similar plants? “To operate a CCGT plant profitably in Germany, you currently need more than just electricity production,” Mr Kreyenberg continued. “You need guaranteed purchases of the process heat to boost the operating hours into an economical range. And that is precisely what you have in Düsseldorf, thanks to one of the largest district heating systems in Germany. As a result, the plant is expected to reach a utilisation rate of approximately 5,000 hours per year.”

Mr Tröger added: “We have the perfect conditions here. The plant is being built on a site that has been used for power generation since the 1950s — so a large part of the infrastructure we need is already present, such as the district heating system and a direct connection to a 110-kilovolt grid owned by SWD. Heat supply in particular will continue to play an important role here in the future.”

District Heating Makes The Difference

Despite the economic efficiency that is expected to drive Block Fortuna’s success, the plant is by no means a blueprint for the CCGT market in Germany as a whole. “A power plant of this kind with reliable customers for both heat and electricity, with a large installed district heating system, is possible at only a few locations in Germany,” said Mr Kreyenberg.

Nevertheless, the Lausward example illustrates that CCGT power plants can, under certain conditions, be operated profitably even in the current regulatory environment. And to ensure that the plant will deliver profitable and leading performance for as long as possible, Siemens and Stadtwerke Düsseldorf have decided to continue their partnership after SWD takes charge of the plant. “In years to come, we want to help our partners in Düsseldorf always get the best out of their plant — for example, by raising its efficiency even further through innovations,” says Kreyenberg.

The Lausward plant will as such be a system that can respond flexibly to the requirements of the energy market in the future. And that is a characteristic that architect Mr Wittfeld and his firm keep coming back to. “Regardless of the angle from which people will look at this building, they will always have a sense of flexibility; of the rhythm of the power plant,” he said. But despite the plant’s name, the architect, the plant operator, and Siemens are not leaving fortuna’s success to Lady Luck. Thanks to the technology, they expect it to be a showpiece of a power plant — in more ways than one.

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