Ameren Illinois said it made an additional $500,000 available to its neediest Central and Southern Illinois customers to help them pay their energy bills during the summer heat wave. Ameren Illinois President and CEO Richard Mark said the money comes as extreme heat in recent weeks has made life difficult for many of the utility's customers. The latest funds will be distributed through local support agencies, and eligible customers must meet federal low-income guidelines. For a four-person household, the maximum gross annual income is $49,500. Officials said the utility has contributed roughly $1.2 million in energy assistance to low-income residents since the beginning of the summer.