Other energy emissions
In 2006 Nuon took further measures to reduce emission of acidifying substances. This has a direct impact on the air quality in the area around the power stations.
Sulphur dioxide (SO2)
Nitrogen oxides (NOx)
Cooling water
Waste water
Sulphur dioxide (SO2)
As a member of the European Union the Netherlands aims to reduce SO2 emissions to a maximum of 50 kilotons by 2010. Nuon is also making a contribution towards this target. Nuon produces about 2,000 tons of SO2 emissions every year. Alongside sulphur-free gas, Nuon also uses coal, furnace oil and blast furnace gas for the production of electricity and heating. Coal and furnace oil contain sulphur which is converted during the burning process into SO2. Blast furnace gas is a residual product from the iron and steel production of Corus in IJmuiden. It contains various components, including sulphur compounds, which are also converted into SO2 upon incineration. In 2006 we made adaptations to the flue gas desulphurisation installation of the coal-fired power station at Hemweg 8, thus reducing our annual SO2 emissions by an estimated 100 tons per year.
Nitrogen oxides (NOx)
Just like other EU member states, the Netherlands has entered into an obligation to bring down the emissions of NOx by 2010. The limit for the Netherlands has been set at a maximum of 260 kilotons per year by 2010. To achieve this target, the Netherlands has introduced an NOx emissions trading system with mandatory participation for all large installations since June 2005. Companies have been set a target that they are required to meet. Those who overshoot the target can choose between improving their installations or buying emission rights via the trading system. The target is reduced annually with a view to achieving the national reduction target for Dutch industry in 2010.
In 2006 Nuon emitted about 7,500 tons of NOx. The mitigation of nitrogen oxides must mainly take place during the burning process through the application of modern incineration techniques. These adaptations have been made in all power stations that produce for the basic load that is maintained to meet the demand for electricity and heating. Nuon’s NOx emissions were stable in 2006 and met the limits laid down by law and in the permits.
In 2006 there were little or no NOx trading activities in the Netherlands. Nuon and other companies mainly took their own reduction measures. In May 2005 Nuon decided to equip the coal-fired power station at Hemweg 8 in Amsterdam with a denitrification or DeNOx installation. This was taken into service at the turn of the year 2006/2007. This installation is expected to remove 2,500 to 3,000 tons of NOx annually, thus lowering Nuon’s NOx emissions by about 30%.
Cooling water
Cooling water is used in large quantities for cooling purposes and to maximise the energy supply from steam turbines in power stations. When discharged, cooling water has a higher temperature than the surface water into which it is discharged. The temperature of the water has an impact on the aquatic environment. For this reason, the power stations need a permit for discharging water under the Act on Surface Water Pollution and the Water Management Act.
Virtually all power stations of Nuon are cooled with surface water. In the first quarter of 2006, a new assessment system was introduced to determine whether discharges are permissible (the ‘LBOW’ method). In this connection it was decided that all major users of cooling water must apply for a new permit. The application is assessed on the basis of the new system, after which a new permit is issued in conformity with the LBOW discharge criteria. Nuon is going through the procedures to obtain new permits for its power stations. At the end of 2006 the first digital models of the discharges were available. These form an obligatory part of the application for a new discharge permit.
It is our ambition to deliver the residual heat from our power stations to the built environment and industry. Where this is already taking place, we aim to expand delivery. The discharge of residual heat into the environment and surface water can thus be reduced.
At our IJmond power station located on the Corus site, we are looking with Corus for a way of reducing the amount of bleaching liquor dispensed into the cooling water to counter the growth of organisms such as algae and fungi in the cooling water installation. By optimising the dispensing method, we hope to reduce the required dosage in the future.
Waste water
In 2006 a working group was started up to optimise the entire feeding and venting system of the wet electrostatic filter of the IJmond CHP plant at the Corus site in Velsen. This filter cleans the blast furnace diluting gas before it is used in the power station. The waste water from this process is currently cleaned and then discharged into the surface water. In future, however, it may be possible to (partly) reuse this waste water in Corus’s production processes.
