Natural gas prices will be going up again this winter in Kentucky. An increase in gas-fired power plants and an unstable market are responsible for the increase.Most of the natural gas that will be used this winter was purchased and stored in the summer, during a price spike. That was caused by a rush on Wall Street to purchase commodities, which seemed safe in an uncertain market.Kentucky Public Service Commission spokesperson Andrew Melnykovych says the same uncertain market may protect prices from another spike next year.“Typically what happens to energy prices when you’ve got an economic downturn is the energy prices tend to come down because the demand either declines or just doesn’t grow as fast," he says.Melnykovych says natural gas will cost about 17 percent more this coming winter, which is close to the national average increase.