Over seven million electricity customers in Europe could sign up to renewable energy sources if electricity retailers put more effort into marketing green tariffs, claims market analyst Datamonitor. Take-up of green tariffs is less than 1% of the customer base across six countries studied by Datamonitor. But experience in the Netherlands, where 30% have signed up, shows that "environmental sentiment" could become a powerful force, it says. Nonetheless, Datamonitor's research shows that customer awareness and trust of green energy products is low. And too often utilities consider their green tariffs as a tool for improving their corporate image. Datamonitor points out that heavy marketing has transformed the market for bottled water -- and practices by some Dutch and American utilities show this could be applied to the green tariffs market. To succeed in developing the green market's vast potential, utilities must assign larger budgets and adopt the emotionally driven marketing theories, advises Datamonitor. As a reward, research reveals green customers are likely to be three times more loyal to their retailer.