The Citizens Utility Board is urging consumers to conserve energy and participate in efficiency programs offered by utilities as the cost of natural gas increases.  CUB is warning consumers of a potential price spike in March while we are preparing for bad weather this week — including asking large customers to limit usage so there is enough for residential customers.  CUB officials say some companies’ preliminary March gas price is 33 percent higher than February’s rate, although that could change.  CUB spokesman Jim Chilsen says residents can take steps to ease their utility bills by turning down the thermostat and closing doors in empty, rooms among other acts.