SIEMENS

According to Dr. Oliver Geden, an expert for EU climate policy at the German Institute for International and Security Affairs in Berlin, effective climate protection begins when "many people consume in an environmentally sustainable way, without having to think twice about what they’re doing." For this to happen, says Geden, it will take huge structural changes in how we generate and consume electricity, including expanded use of renewable energy, and more efficient conventional power plants.
Significant progress has already been made in the construction of new power plants. Over the period from 1992 to the present, the efficiency of the latest coal-fired power plants in the industrialized West has risen from 42 to 47 %. This amounts to a huge advance in climate protection. For instance, for a 700-MW generating unit, an increase in efficiency of five percentage points translates into a reduction in annual CO₂ emissions of around 500,000 t. This is particularly important for China, where, according to the International Energy Agency, one new coal-fired power plant with an efficiency of over 44 % enters commercial service every month.
When it comes to upgrading existing power plants, however, there is still massive untapped potential, both in economic and environmental terms. The average efficiency of Europe’s coal-fired power plants is a mere 37 to 38 %. Only about one in 10 plants tops the 40 % mark. That’s hardly surprising, given that steam turbines in Europe are, on average, almost 29 years old. Gas turbines, on the other hand, are usually of a more recent vintage, with an average age of just under 12 years. Nevertheless, the German Association of Energy and Water Industries (BDEW) estimates that around one-quarter of Germany’s power plants will need to be modernized in the immediate future.
As Ralf Hendricks from Siemens Energy explains, the increasing exploitation of alternative energy sources is also accelerating the pace of modernization. "In Europe, power companies have to convert a lot of older combined-cycle power plants from base- to peak-load operation," says Hendricks, who is responsible for so-called lifetime management and thus for power plant upgrades.
The reason for the conversions is that Europe is ramping up use of land-based and offshore wind farms. When winds are strong, these farms generate lots of electricity, which means conventional plants can scale back output. But when winds die down, the latter have to be able to reach peak load rapidly to compensate for load fluctuations. The ability to react rapidly not only secures a power company high prices on the power market; an upgraded power plant also reaches its operating point more quickly, which cuts CO₂ emissions.
Siemens is a specialist in upgrading steam turbines, a job that primarily involves replacing the rotor and the inner casing. The latest in turbine blade technology and enlarged flow areas boost the efficiency and performance of the turbine. In addition, the use of new seals in high- and intermediate-pressure turbines reduces clearance losses, which likewise increases efficiency. These measures lengthen the service life of the turbine, allowing it to remain in operation for an additional 15 to 20 years. As a rule, Siemens also renews the control system for the turbine set or the power plant as a whole (see Pictures of the Future, Spring 2009, "Oh what a Tune-Up!"). According to Dr. Norbert Henkel, responsible at Siemens for the modernization of fossil-fuel and nuclear power plants, it costs between €20 million and €60 million to comprehensively upgrade a steam turbine system for a medium-sized power plant. "By modernizing the turbine, we can tease an extra 30 to 40 MW out of the plant. As a result, the initial capital expenditure is amortized within just a few years," he explains.
Power generator Energie Baden-Württemberg (EnBW), for example, has invested around €30 million on upgrading its cogeneration plant in Altbach, near Stuttgart, a measure that will keep it in action for the next 30 years. Siemens renewed the plant’s control systems and upgraded its steam turbine, replacing the blades and seals, which has made it more efficient and boosted its output by 11 MW. The entire outer casing could be retained. With around 4,000 operating hours at full load per year, the plant has benefitted from the upgrade with a reduction in its annual CO₂ emissions of 50,000 t. As a result, the plant is now classified as one of EnBW’s "green" facilities and may, if required, rack up additional operating hours.
North America’s power plants are even older than Europe’s, with an average of 34 years for steam turbines in the U.S. and Canada, and 17 years for gas turbines. Siemens is involved in a number of major upgrades in this area. Some of these cover more than just the turbines, with the company currently contracted to renew the complete control system for a number of plants, including a coal-fired facility in Carneys Point, New Jersey, a combined-cycle plant in Redding, California, and combined-cycle installations in Syracuse and Beaver-Falls, New York, all of which are being fitted with the SPPA-T3000 web-based instrumentation and control system. This system integrates the power plant and turbine control functions in a common, easy-to-use platform. For the operators of Carneys Point, for example, this will provide greater flexibility to tailor operation of the individual generating units to actual demand, along with greater reliability and reduced maintenance costs.

Boosting Output by 100 MW. In contrast to fossil-fired power plants, many of which were commissioned over the last few decades, most of the world’s nuclear plants date from the 1970s and 1980s. "The conventional components of these plants, including the turbines, all need upgrading at around the same time," Henkel explains. Whereas most of the nuclear facilities in Germany have been almost completely updated over the past 10 to 15 years, many of the plants in France, the U.S., and Japan are still in need of modernization. In 2008, Siemens was awarded the Asian Power Award for its upgrading of the Sendai nuclear power plant in Japan. Following modernization of the control systems and the three turbines, the output of the plant rose by 40.5 MW to 942 MW. At present, in a contract awarded by Florida Power and Light (FPL), Siemens is overhauling the generator and renewing a high-pressure turbine and two low-pressure turbines at the St. Lucie nuclear plant in Florida. This will increase the output of each of the two reactors by 100 MW. In addition, Siemens is installing new high-pressure turbines and modernizing the generator at FPL’s Turkey Point nuclear plant, which will boost its output by around 100 MW. Both projects are scheduled for completion by 2012.
With the exception of France, which generates the lion’s share of its power using nuclear plants, the energy mix in Europe still includes a major share of coal. This applies particularly to Central European countries, including Poland, which meets over 90 % of its power needs from coal.
At the same time, these countries have the least-efficient power plants. In Europe, there are over 500 steam turbine plants that are older than 25 years and in urgent need of modernization. This figure includes all the aging plants in Central Europe and is unrivaled anywhere else in the world. In India, for example, where industrialization came much later, there are fewer than 50 plants of a similar vintage. China, on the other hand, still has a lot of coal-fired power plants rated at efficiency levels of between 26 and 30 %. To cover the rapidly-growing demand for electricity from industry and households, China is currently building a raft of new power plants, 60 % of which are ultramodern facilities. According to the IEA, China has been able to radically reduce construction costs for such plants, which feature extremely heat-resistant steam turbines, by building a large number of them at the same time and thus exploiting the effects of standardization. China, which tends to close unprofitable power plants rather than upgrade them, has been decommissioning around 50 GW of older fossil generating capacity since 1997 — a process that is due to be completed by 2010.

Rewarding Efficiency. Back in Europe, power companies in the western member states are rapidly upgrading their facilities. In this sector, climate protection is still largely a corporate affair. Unlike its stance on the automobile industry, the European Union is prepared to let market forces, rather than regulation, bring about power plant modernization. That said, climate expert Geden foresees a major upheaval in the power plant market from 2013 onward, when CO₂ emission certificates in this sector will all be auctioned.
Power companies will therefore have to pay for a percentage of their CO₂ emissions through the purchase of emission certificates. An exception, however, has been made for many Central and Eastern European countries, giving them until 2020 to catch up. During this time, the most efficient power plants will set the benchmark there too. Power plants meeting this standard will receive emission permits free of charge. Emissions trading will thus ensure that old power plants become increasingly unprofitable. And once the last inefficient plant has been decommissioned, each electricity consumer will have become a little bit easier on the environment — without even thinking about it.