By Reuters Staff (Adds order books covered, background on other scheduled listings) MADRID, April 28 (Reuters) - Spanish renewable energy company Ecoener has slashed the target size of its share issue by almost half, a day before closing order books and fixing a final price for what will be Madrid’s first initial public offering this year. Ecoener had planned to raise up to 200 million euros ($219 million) to spend on new facilities including wind farms and solar parks, but said on Wednesday it was now aiming for a maximum of 110 million euros. “During the process of placement (of orders ...