Massachusetts and California are leading the country in energy efficiency standards according to a study released Thursday. The coastal states’ investments in energy saving targets, electric vehicles and efficient building standards helped them lead the annual study by the American Council for an Energy Efficient Economy.Massachusetts took the top spot for the eighth year in a row due to a number of state programs that encouraged consumers to invest in energy efficiency. Following closely behind, California ranked second on the list thanks to incentives it offers for energy efficient schools, residences and industries.