Period during which power plants, pipelines, LNG facilities are shut down to carry out, either planned or ad hoc, maintenance work. All power plants, and other energy related infrastructure such as pipelines need to shut down for certain periods of maintenance so that even a coal station that works all year as base load would probably operate no more than approximately 7,000 hours a year. In a GSA agreement, natural gas sellers will usually will have the right to nominate up to [x] days in any year for the purposes of planned maintenance (Maintenance Days). During Maintenance Days, the Sellers will have no obligation to supply natural gas to the buyers. Sellers will give [x] days notice of their intention to exercise this right. The Sellers will use reasonable endeavours to co-ordinate their periods of maintenance with the Buyer