Moorburg Power Plant will be put into operation in October. Photo: © Sven Petersen - Fotolia.com
The city of Hamburg’s climate ambitions are overshadowed by a new Vattenfall coal power plant, which will emit 8.7 million tons of CO2 annually when it comes into operation.
Visitors to the city of Hamburg may be surprised to learn that this “European Green Capital of 2011” now hosts Germany’s second largest hard coal power station. The 1,640 megawatt (MW) Moorburg plant on the Elbe River will be commissioned in autumn 2014 by Vattenfall Europe to generate 12 billion kilowatt-hours (12 TWh) of electricity per year, nearly equivalent to the city’s total power demand.
Although renewable energies presently account for almost one fourth of grid power in Germany, coal-fired generation is holding its own. After the Fukushima catastrophe of March 2011, a nuclear phase-out programme was agreed by German parliament with the aim of retiring the country’s 17 reactors by the year 2022. The resulting 22 per cent loss in base load power is not being fully replaced by wind and solar generation within the same time frame, leaving fossil fuels to fill the gap.
As renewable energy usage continues to rise, however, the output capacity of the Moorburg plant can be reduced by up to two thirds to avoid exceeding total electricity demand. Natural gas and decentralized motor generators respond even more effectively to the increasing availability of wind and solar power on the grid. However, imported gas is priced at six times the cost of domestic lignite and four times seaboard coal per unit of thermal energy. Wind, solar and biogas generation are cost-competitive and unaffected by fuel market trends. The contribution of natural gas to German power production consequently fell from 12.1 to 10.5 per cent last year due to the proliferation of lower-cost alternatives.
The United States is increasing coal exports to Europe, although most shipments consist of Appalachian metallurgical grades used for steelmaking. The 12,000 tonnes of steam coal required each day by Moorburg may be imported from Poland, Indonesia, South Africa, and Australia according to the Vattenfall website. Local environmental advocates suspect Columbia instead, where working conditions may be irreconcilable with German mining standards.
The new power station is intended to remain in operation past 2050, when Hamburg has committed to reducing carbon dioxide emissions to four million tonnes (Mt). Moorburg will release twice that amount of CO2 – up to 8.7 Mt annually. Hamburg’s total greenhouse gas inventory by mid-century could therefore reach three times the level originally targeted.
That prospect was not taken into consideration when the city was selected for the 2011 Green Capital Award. There was no mention of Moorburg in the Expert Panel evaluation report, while the city’s Municipal Climate Act was specifically commended.
Industrial-scale installations may justifiably qualify as phantom facilities when municipal policies are compared, but Hamburg once had far greater climate ambitions. In Germany’s Upper House of parliament, its government voted in support of carbon capture and storage (CCS) under EU Directive 2009/31/EC. At that time, Moorburg neatly meshed with prevailing aspirations for a trans-European CO2 pipeline network.
At the beginning of 2010, the regional newspaper Hamburger Abendblatt reported that the plant would be equipped for carbon capture after completion of CCS pilot testing in eastern Germany. While an implementation date was not set, Vattenfall declared that 60 million tonnes of CO2 emissions from fossil fuel generation would be reduced by half within twenty years, and eliminated entirely by 2050. Moorburg had clearly been intended as a capture-ready plant under EU “decarbonisation” objectives. It was later determined, however, that no adjacent land had been reserved for an installation as large as an airplane hanger, which is needed to extract and compress flue gas CO2.
It has been necessary to replace 10 per cent of the T24 boiler steel at Moorburg to avoid disruptive thermal stresses from highly pressurised steam. Repeated scheduling delays and cost overruns are now compounded by environmental restrictions.
Dissipating the heat of combustion imposes immense cooling water demands. Original planning called for sluicing 64 cubic metres of water per second through the Moorburg plant, constituting about half the flow of the Elbe River. To avoid overheating aquatic ecosystems, restricted water withdrawal hours were imposed. Vattenfall ultimately redesigned the plant to use self-contained cooling towers. These closed-cycle evaporation systems diminish net plant power by only about one per cent compared with flow-through cooling.
A CCS retrofit could boost cooling requirements by another 25 per cent, however. The grid output capacity would be diminished by nearly a third due to the power demands of CO2 capture and pipeline compression.
Elbe water withdrawal by the plant was prohibited altogether by court order at the beginning of 2013. The increased temperatures of cooling system discharges would have diminished the survival rates of microscopic organisms within aquatic food chains.
Additional revenues had originally been expected from dedicating 650 MW of thermal capacity at Moorburg for heating 180,000 dwellings in the city of Hamburg. Deploying dissipated thermal energy would have raised coal utilisation from 46.5 per cent, solely for power generation, to 61 per cent for combined heat and power. Since the Moorburg site is on the southern Elbe shore, however, a 4.4 kilometre tunnel beneath the river – extolled by the chamber of commerce as the “artery” of the plant – would have been required to connect with the borough of Altona. Excavation could have necessitated uprooting 300 trees in greenway parks. Public opposition to the loss of city landscapes motivated Vattenfall to cancel the project, substituting a new gas-fired plant in Wedel, to the west of Altona.
However, a city referendum in September 2013 revoked Vattenfall’s power grid concession, restoring municipal ownership for about half a billion euro. The heat distribution network may also be taken over by the Hamburg Senate as late as 2019 for an additional 1.15 billion euro charge.
In all cases, Moorburg will be superfluous to the municipal heating infrastructure. Decentralised power and heating plants could hypothetically be situated throughout the city to eliminate the plant entirely. However, this concept would only be cost-effective if heating services from Wedel could also be precluded. Under present circumstances, by contrast, additional greenhouse gases will be emitted from the second plant to the detriment of climate strategies. From that perspective, the city referendum has been a Pyrrhic victory.
When first proposed, the Moorburg power station represented an advanced technological realisation. The necessary substitution of Elbe water withdrawal by hybrid cooling towers has since lowered plant efficiency. Water vaporisation from these structures now raises the danger of airborne Legionella microbes being wafted over nearby residential areas.
The abandonment of heat production has reduced coal utilisation and contradicted the environmental arguments originally made for constructing the plant. A similar 533 MW power station in the Baltic city of Rostock achieves a coal utilisation figure of 62 per cent using combined heat and power.
A study commissioned by Friends of the Earth (BUND) Hamburg predicted in 2007 that the Moorburg project would not be competitive under the EU Emissions Trading Scheme. Vattenfall has relinquished the two essential options – CCS and district heat – capable of lowering the climate risks of coal generation. If carbon emissions are heavily taxed in the future, and if renewable energies continue to diminish the market share remaining for conventional generation, the economic viability of Hamburg’s Moorburg power station will be seriously degraded. For the present, however, the plant endures as a monument to the incompatibility of coal power with municipal climate strategies.
Jeffrey H. Michel