Blue Cross/Blue Shield of Tennessee (BCBST) is warning that its customers will face sticker shock with premiums next year because of the Affordable Care Act (ACA), also known as “Obamacare.” Many of the 2010 law’s key provisions kick in next year, including the requirement for all Americans to have health insurance. BCBST, the state’s largest insurance provider covering more than 3 million Tennesseans, is projecting that individual policy holders will see average premium increases around 30 percent, while small group customers will pay about 10 percent more. Large employers will see a 3 to 5 percent spike, BCBST officials said.