Do save water,do save electricity,do save any energy!是否有语法错误

没有语法错误.
其中的do 是对动词起强调作用的助动词,意为：“一定,的确,确实”.
又如：
Do come this afternoon."今天下午一定要来哦."
Tom does have a young brother."汤姆的确有个弟弟."
He did go to the shop yesterday.“他昨天确确实去过那家商店.”