Sonoma Clean Power to tap geothermal for 'EverGreen' program

[caption id="attachment_41811" align="alignnone" width="500"] The 15 existing geothermal plants at The Geysers area on the border of Sonoma and Lake counties would supply power for Sonoma Clean Power's new "EverGreen" all-renewables program.[/caption]

SANTA ROSA -- Planners for a new renewable energy--focused public power agency in Sonoma County on Thursday revealed that the optional all-renewables program will source its electricity entirely from the nearby network of geothermal power plants on the border of Sonoma and Lake counties, adding solar photovoltaic sources in the future.

Discussion of the green-power program, called "EverGreen," furthered a general review by the agency's board of directors of proposed retail electricity rates that began in two key Sonoma Clean Power committee meetings this week. The directors took no action on the presentation, but gave an early nod the a framework that would provide estimated cost savings for the average customer of 2 percent to 3 percent compared with Pacific Gas & Electric Co.'s proposed rates for 2014.

That general power product, called "CleanStart," will offer customers a 33 percent renewable-energy mix and a one-third reduction in greenhouse gas emissions, compared with conventional service from PG&E, when the new program begins service in May. The agency plans to ultimately ramp up in coming years to half-renewable sources, a strict definition that excludes some sources like hydroelectric power.

While board is not planning to finalize the proposed rate structure until January or February, the framework under discussion assumes that the agency will charge its customers 5 percent less than PG&E for the portion of their bill involving electricity generation.

Those savings could be even greater, yet the suggested price would allow the agency to spread some of the value achieved through negotiations with power wholesales to later participants of the program. Sonoma Clean Power is planned to initially enroll a group of around 20,000 customers in May, with 80 percent of the county's ratepayers eligible in the coming years.

The specific costs compared to PG&E depend on a number of factors including time of day and season, and are presented for comparison with surcharges that PG&E would require of Sonoma Clean Power customers. The utility would provide transmission and billing services to those customers while Sonoma Clean Power procures electricity, a model known as community choice aggregation.

A small business consuming no more than 150,000 kilowatt-hours of electricity per year could pay an average of 9.2 cents per kilowatt hour under Sonoma Clean Power versus 9.7 cents under PG&E, according to board materials. A single-family dwelling or separately-metered apartment could pay around 8.8 cents per kilowatt hour under Sonoma Clean Power, compared to 9.3 cents under PG&E.

Customers opting for the EverGreen option could pay an additional premium of around 3.5 cents per kilowatt-hour under the proposed framework. The agency entered into a 10-year agreement with Calpine Energy Service for that geothermal power, the primary operator of power plants at The Geysers area.

A three-year supply contract with Constellation Energy, a subsidiary of Chicago-based Exelon, will supply the majority of the agency’s power needs. The agency entered into those two contracts in November, at an anticipated cost of $37.9 million in fiscal year 2014--2015.

The board also further discussed the nature of its proposed net metering program, which would pay customers for excess power generated from rooftop solar. Like MCE Clean Energy, a CCA operating in Marin County and Richmond, the rules would give customers a credit that does not expire and would pay a full retail rate for excess electricity generated, plus a 1 cent premium.

The net metering program under PG&E also credits producers, but only pays a retail rate up to the ratepayer's total yearly usage at the end of the year and a cheaper, wholesale rate for net excess production.

The rate-setting process is expected to advance at the board's next meeting on Jan. 9.

Show Comment