Puget Sound Energy (PSE) has recently completed the revision of its Integrated Resource Plan (IRP), requiring increased energy efficiency and the development of more renewable power as well as additional natural gas-fired power generation to meet the growing energy needs of customers over the next 20 years.

Revised every two years, the plan sets out the company’s long term forecast for acquiring new energy resources in the most cost effective and environmentally responsible manner and was developed during a two-year period in which U.S. and global economic conditions changed drastically. As such it includes demand forecasts and scenarios incorporating post-downturn information about economic conditions.

Despite the current economic slump PSE predicts that there will be continuing long term growth, with a need for an additional 676 MW of generation capacity by 2012, 1,084 MW by 2016, 2,453 MW by 2020 and 4,239 MW by 2029 to meet customer demand. In part this is due to expiring contracts and retiring assets, but the company also estimates that there will be approximately 1 million more Puget Sound residents requiring service 20 years from now.

However, options for resource additions remain limited. Wind is, generally speaking, still the only renewable resource capable of economically generating utility-scale power for PSE, while new hydroelectric projects are not feasible, nuclear projects are unlikely to gain approval, and coal remains constrained by legislative restrictions and environmental concerns.

Therefore, the plan recommends additional wind resources to fulfill renewables requirements of 1,100 MW by 2029. In addition there should be as much demand side resources as possible, including an expansion of PSE’s already ambitious energy efficiency programs (1,064 MW by 2029), with natural gas-fired generating plants filling the remainder of need.

In 2008 PSE’s energy efficiency programs helped customers save electricity equivalent to the power usage of 23,000 homes, and enough natural gas to serve the need of 4,000 homes. Over the next 20 years more than 530 MW of additional power savings can be achieved, sufficient to meet the electricity requirements of 400,000 households, as well as 90 million therms of achievable natural gas savings, enough to satisfy the total gas needs of 108,000 households.

“Our challenge is not only to meet our customers’ growing energy needs in an economically prudent way, but in a way that protects our planet as well,” said Kimberly Harris, executive vice president and chief resource officer for PSE. “Our resource plan takes the right approach with more energy efficiency and renewable resources, augmented by more clean-burning natural gas generation.”

The plan also projects a significant increase in demand for natural gas, both to generate electricity and to serve gas customers’ direct energy needs. Peak wintertime use of natural gas is expected to jump by more than 38% over the next 20 years, while peak gas usage for wintertime power generation is predicted to rise by 108%. To address this need PSE should secure more natural gas pipeline capacity into the Northwest and more natural gas storage resources.

PSE, a subsidiary of Puget Energy, is Washington state’s oldest local energy utility, serving more than 1 million electric customers and nearly 750,000 natural gas customers in 11 counties.