Natural gas pipeline deliverability that is properly contracted and nominated will be critical to ensure service reliability as renewable penetration increases.  In the West, natural gas has been and will continue to be the fuel used to meet the variable load-following demand requirements of electric generation.  As electric generation from renewable sources increases, hourly variability of natural gas demand will increase. “Renewable firming,” a product of developing the appropriate pipeline services and infrastructure such as market area gas storage, is required to meet intermittent demand created by renewable generation.