21st Century Energy Workforce Act of 2018 This bill directs the Department of Energy (DOE) to establish a 21st Century Energy Workforce Advisory Board to develop a strategy for the support and development of a skilled energy workforce. Based on the board's recommendations, DOE shall establish a clearinghouse to: maintain and update information and resources on training and workforce development programs for energy- and manufacturing-related jobs; and act as a resource and provide guidance for secondary schools, institutions of higher education (including community colleges and minority-serving institutions), and workforce development, labor management, and industry organizations that would like to develop and implement such related training programs. DOE shall also establish a pilot program to award grants on a competitive basis to eligible entities for job training programs that lead to an industry-recognized credential. Grant amounts are limited to $2 million for any one fiscal year. The federal share of the cost of a job training and education program using a grant shall be up to 65%, while the non-federal share may not be less than 50% cash.