Stephen Walker Sentenced to 18 Months in Prison by Mark Friedman Posted 7/20/2012 04:20 pm Updated 6 years ago Stephen R. Walker, the former COO for Phoenix Renewable Energy of Hot Springs, was sentenced to 18 months in federal prison Friday afternoon in connection with a tax evasion of assessment charge. Want the Full Article? Get Unlimited Archive Access for $19.95 per Year Readers must pay to access articles older than 15 days. Articles newer than 15 days are not included in this offer. Purchase Now Already have archive access? Login to view this article.