Stephen Walker Sentenced to 18 Months in Prison by Mark Friedman Posted 7/20/2012 04:20 pm Updated 5 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 stories older than 15 days. Purchase Now Already have archive access? Login to view this article.