Efficiency of over 60% for the Irsching gas and steam power plant

• Optimisation of plant integration with regard to efficiency, availability and economic viability
• New cooling concept for turbine blades (effusion cooling)
• Materials with high temperature-resistance (fibre-reinforced ceramics, surface coatings)
• Production of surface coatings using nanotechnology
• Development of new manufacturing and production processes

The range of requirements that will apply to the innovative combined gas power plants of the future will become increasingly more complex. On the one hand, the power plant must be able to adapt to fluctuating electricity requirements in the grid, i.e. the changing load. It should be able to meet peak demands, but also be able to operate efficiently close to the base load. In addition, it must have good partial-load efficiency – for example, to balance out short-term fluctuations in electricity generated from wind or photovoltaic power.

On the other hand, the following factors are also important: high availability with competitive investment costs; low maintenance costs; and high fuel flexibility with as low a fuel consumption as possible – all of these considerations represent engineering and economic constraints.

The improvement of efficiencies is of central importance to the success of COORETEC. Every increase in efficiency is accompanied by a reduction in the specific CO₂ emissions. Moreover, reduced CO₂ emissions lead to significantly reduced costs for CO₂ capture, which also can be considerable for gas-fired power plants from an engineering viewpoint.

The total net installed capacity of gas-fired power plants in Germany was around 23.4 GW in 2008. This represented approximately 15.9% of the total installed power plant capacity. Natural gas power plants accounted for around 83 TWh of power generation in 2007, which corresponded to around 14% of total power generation.

Current gas turbines achieve efficiencies of between 38% and over 40%, depending on their size. The highest efficiencies can be achieved by coupling a gas turbine and a steam cycle. Gas and steam turbine plants in operation today achieve net efficiencies of over 58%.

An efficiency of over 60% has been reached in the gas and steam turbine plant that is connected to the grid in Irsching since summer 2011. The construction of new power plant capacity in Germany since 2000 has mainly been the result of new gas and steam turbine plants (around 8 GW to date). Natural gas power plants currently represent around 25% of the world's installed power plant capacity. In the long term, the International Energy Agency (IEA) estimates that installed capacity will increase by 50% by 2030.

Due to the low capital costs relative to coal-fired power plants, the cost of generating electricity from gas-fired plants will mainly be determined by fuel prices. For this reason, the future development of natural gas plant capacity needs to be considered in the context of future price trends for natural gas in particular. This gives further emphasis to the importance of continued improvements in efficiencies.

Prototype trials at the Irsching 4 prototype power plant to test and refine the new highly efficient Siemens (SGT5-8000H) gas turbine, the largest in the world

Organisation carrying out research: Siemens Aktiengesellschaft - Power Generation - Dep. P312

Project number: 0327776B

At E.ON's Irsching power plant site on the river Danube (Pfaffenhofen administrative district, Bavaria), Siemens has tested what is currently the largest gas turbine in the world. This turbine has the largest single-shaft turbogenerator in the world. It is rated at 340 megawatts (MW), which means that its output is 20% above that of conventional systems. It is 13 metres long, has a diameter of 5 metres and weighs over 440 tonnes.

The newly developed SGT5-8000H gas turbine represents a world first in terms of the block output of over 530 MW for a gas and steam turbine single-shaft power plant and the overall efficiency of over 60%. Trials with the prototype of the new gas turbine have been conducted at the gas turbine test power plant in Irsching. This plant was constructed and financed by Siemens, and the company has also directed operation of the plant during the "start-up" and "partial-load" test phases. The tests included cold-start tests, load-free runs at low rotational speeds and tests in the partial-load range. Conversions and tests on the ongoing development of the gas turbine for the next generation of turbines have also been carried out. The test results were used to verify the planned design and service-life data and to further refine the prototype, the next generation of gas turbines and the components on the existing range of gas turbines.

The energy supplier E.ON has constructed the Irsching 4 und 5 power plant blocks in Irsching since 2006. These are gas and steam turbine plants fuelled by natural gas and have a high efficiency. Block 4 represents the construction of a gas and steam turbine plant with the highest efficiency possible anywhere in the world of over 60 percent, as described above. This will result in savings of over 100,000 tonnes of CO₂ per annum compared to the standard technology currently in use.

Construction has been taking place in two stages. Phase I involved intensive testing by Siemens of its new SGT5 8000 H gas turbine up to 2009. Siemens' engineers investigated the performance of the new turbine using over 3,000 measurement points, thus developing the turbine to a stage where it was ready for series production. Since 2009, a waste-heat steam boiler and a steam turbine have been added to the gas and steam turbine plant as part of Phase II; the plant was commissioned by E.ON Kraftwerke in 2011.