Avista Corp. is projecting slower growth in customer demand and expects to have adequate power generating resources to meet customers' electricity needs until 2020.

Avista filed its 2013 Electric Integrated Resource Plan on Aug. 30 with regulators in Washington state and Idaho. The plan details projected growth in demand for energy and new resources needed to serve customers during the next 20 years.

Between 2014 and 2033, Avista says it anticipates customer growth of just over 1 percent annually, which is down from 1.6 percent annual customer growth projected in its 2011 electric plan.

The company also expects to incorporate in the next 20 years what the energy industry calls demand response for participating commercial and industrial customers, which is a method to meet peak load growth by temporarily reducing the demand for energy.

The demand response method employs technology installed by Avista as part of customers' equipment, and it cuts load to those specific customers during peak demand periods under controlled conditions. Typically, customers enroll in programs allowing the utility to change its usage in exchange for discounts, the report says.

Additionally, Avista says its strategy for new renewable resources that it outlined in a 2011 plan were met with a 30-year purchased power agreement with Palouse Wind and the Kettle Falls Generating Station.

During the next 20 years, Avista expects that transmission upgrade projects will be necessary, such as projects in the Long Lake area, at a preliminary estimate of about $9.9 million, and near Rathdrum, Idaho, with an early estimate of up to $30 million.

Avista says ongoing energy efficiency is expected to reduce load growth by 42 percent over the next 20 years. During 2012, the utility says it processed just over 4,200 energy efficiency projects and paid more than $13.5 million in rebates to customers to offset the cost of their projects.

The company is required by state regulators to submit its 20-year resource plan every two years with a forecast of electric demand and potential new resources to provide that service.

Avista Utilities provides electric service to 359,000 customers and natural gas to 320,000 customers. Its territory includes Eastern Washington, North Idaho, and parts of southern and eastern Oregon.