agreements between the TSO and the NPP operator, if there are not equivalent legal obligations placed on the TSO from the government or energy ministry in the country.

11.10. READINESS TO COMMISSION

The feasibility study may have identified various additions and enhancements to the grid that were needed for the connection of the NPP. After the start of the NPP project, the NPP developer and the TSO would have discussed and agreed to the design of the substation for the NPP and its connection to the rest of the grid system, and other additions to the grid system that were needed. During the construction of the NPP, the NPP developer should monitor that the construction projects for the additions and enhancements are progressing to schedule, so that they will be ready before the NPP is due to start commissioning. A final check should be made before the NPP is due to start commissioning that all these works have been completed, and that they are consistent with what was included in the bid invitation specification, and the applications for construction or operating licences.

The NPP developer should also confirm that any additions or changes to TSO’s operational procedures that were required for the NPP have been completed, and that the TSO’s operating staff have received the necessary training in any new or revised procedures.

12.EFFECTS OF CLIMATE CHANGE

12.1.INTRODUCTION

It is well established that the concentration of carbon dioxide in the atmosphere has increased during the last

few centuries, and the concentration is still increasing at an accelerating rate, due to human activities and the use of fossil fuels. The international scientific consensus is that this increase in the concentration of carbon dioxide, and some other gases, in the atmosphere is causing global temperatures to rise as a consequence of the greenhouse effect, and this will cause changes in climate that may change the frequency and severity of extreme weather events.

12.2. EFFECT ON NPPS AND TRANSMISSION SYSTEM RELIABILITY

NPPs that are being planned or constructed now, have planned operating lives up to 60 years, so there is the potential for significant change to climate and weather conditions during the life of the plant. The change in weather conditions may lead to more frequent periods of severe weather, or weather events that are more extreme. These events may affect the reliability of the grid system, so this should be considered during the design of the NPP and its grid connections. The effects of severe weather events on the transmission system are summarized here.

12.2.1. Strong winds

Experience worldwide is that strong winds can cause considerable disruption or damage to lower voltage distribution networks, because of falling trees, but generally do not have a significant effect of higher voltage transmission circuits, because of the greater height of transmission towers. Transmission circuits are generally only affected by extreme high winds, which cause physical damage to transmission towers. The risk of such damage can be reduced by designing the towers for higher wind loading.

Strong winds from a salty sea will also pollute insulators on overhead lines and in switchyards situated in the vicinity of the coast and increase the risk for flashover.

Civil structures at the NPP, including exhaust stacks for onsite power sources, should be designed for extreme high winds.

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