Renewables dominated proposals submitted to Puget Sound Energy’s 2018 all-resource solicitation for new generation resources. Only a handful of natural gas resources were even submitted, according to information PSE provided to Clearing Up.

Perhaps the biggest change from the utility’s previous request for proposals was the explosion of battery storage bids. Before 2018, solicitations from PSE yielded six proposals incorporating battery storage. This time, the company received nearly 40 bids with some degree of battery storage. In addition, many more of the bids could be reconfigured to include battery storage, said Sheri Maynard, a resource planning and acquisition analyst with PSE.

In all, PSE received nearly 100 proposals for its resource RFP, and received 10 proposals for a demand response RFP issued at the same time.

The company cut the resource bids, with total capacity of 12,938 MW, down to 23 proposals for further consideration, based on the log of submitted bids that PSE provided to Clearing Up. The initial cut basically identifies proposals with “fatal flaws,” Maynard said.

The shortlisted candidates will be extensively vetted by PSE. From that analysis, the company will begin negotiations with developers.

Solar generation accounted for the biggest resource among the bids. PSE received 36 solar-power bids with 4,645 MW capacity. The vast majority of them were for projects sited in Washington, and 20 of these were paired with storage—19 with batteries and one with pumped hydro.

Sixteen bids provided solar only with no storage. The available information does not indicate how many of those projects could be altered to add storage capacity.

PSE selected five solar plus battery projects to advance in the RFP process. One was subsequently withdrawn by the developer, leaving four in the running. One is sited in Oregon and three are in Washington. Most proposals are for solar generation around 100 MW. There is greater variability in the storage duration and discharge capacity—from a low of one hour at 30 MW to a high of four hours at 50 MW for a total of 200 MWh.

Four solar-only bids were selected to advance, ranging from 35 MW to 275 MW. All proposed building new facilities in Washington with contract lengths of 15 to 25 years.

Twenty proposals incorporated wind power, totaling 4,538 MW. Of those, seven made the initial cut, ranging from 100 MW to 401 MW.

Three of the eight are Montana projects, and range from 202 MW to 401 MW.

With one exception, the other four wind proposals still in the running are smaller in output and proposed for sites in Washington. Only one of the bids included a build-to-buy option for PSE as initially proposed. Again, the commercial structure could change as proposals move along.

In all, the 23 proposals still in the running for the all-resource RFP have 3,896 MW of capacity, with wind and solar energy making up 2,976 MW. Those 23 bids include three for unbundled RECs.

Two natural gas-fired proposals with a combined 765 MW capacity also advanced to the second round. PSE received four natural gas bids in all, with an aggregate capacity of 1,377 MW.

The two second-round natural gas proposals have shorter contract durations than most other bids. One is for 520 MW from a gas-fired facility with a combined-cycle combustion turbine that came online in 2002. The proposal was for a 10-year tolling power purchase agreement.

The other natural gas proposal is for a new development in Washington for a simple-cycle combustion turbine with a 5-year tolling PPA for capacity of 98 MW to 245 MW. The bid includes an option to buy.

In the wake of passage of Washington’s Clean Energy Transformation Act earlier this year, PSE will be moving away from carbon-emitting resources over the next decade. However, that does not preclude the possibility of adding new natural gas resources while retiring older units.

Selecting natural gas, though, is all but certain to draw the ire of environmental advocates.

“We are on high alert,” said Doug Howell with Sierra Club’s Washington chapter. “We don’t think they need to build gas, and we’ll be pissed off if they do” select natural gas.