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Solar Screen Test

Making room on the local grid for small-scale PV.

Fortnightly Magazine - May 2012

sequential studies and restudies of feasibility, system impacts, and required facility upgrades), the inconvenience of failing the fast-track screen test was seen as real enough, especially for small-scale DG project developers, who typically operate with much smaller budgets than their utility-scale counterparts.

Today however, seven years later, everything has changed. What once was a backwater is now big business. With costs falling, PV is booming.

According to the most recent U.S. Solar Market Insight, a joint report by Greentech Media Research and the Solar Energy Industries Association (SEIA), grid-installed solar has exploded, rising about 2,300 percent since FERC issued its SGIP rule—up from 79 MW at the end of 2005 to 1,855 MW by year-end 2011. The Interstate Renewable Energy Council posits a similar increase. PJM reports that in 2008 solar projects counted for only about 2 percent of all projects entering its interconnection queue, versus 62 percent in 2011. PHI, which owns Potomac Electric (PEPCO), Delmarva P&L, and Atlantic City Electric, reports that as of March 1, its subsidiaries had interconnected more than 5,000 distributed solar PV systems, with a capacity over 100 MW, with the number and size of individual projects increasing each year:

“This represents a growth of nearly 2,000 percent in the number of interconnected PV systems and nearly 4,400 percent in installed capacity since Order 2006 was first issued.”

To keep the interconnection process functioning amidst this crush of applications, SEIA has now petitioned FERC to revamp its SGIP rule. Among various requested reforms, SEIA wants an alternative fast-track screen test—but only for solar projects:

• A new, higher 10-MW cap on capacity eligible for fast-tracking, or else no cap at all;

• An alternative screen test, for solar generation only, based not on 15 percent of annual peak load, but rather, on the daytime minimum load occurring between 10 a.m. and 2 p.m.;

• A rule requiring local retail utilities to provide data to solar developers to apprise them of circuit-specific peak and minimum loads; and

• The option of seeking expedited, independent third-party expert technical review of upgrade requirements proposed by local utilities as a condition of interconnection. (See, SEIA Petition for Rulemaking, FERC Dkt. RM12-10, filed Feb. 16, 2012.)

The key idea behind the proposal would do away with the fiction of estimating minimum load based on peak. Rather, SEIA’s reform would attempt to measure actual minimum load—but not in the way you might think.

Moving the Minimum

No one today questions that daily minimum loads during the five-day work week occur during the overnight hours, from midnight to 6 am. But as SEIA points out, those minimums should be considered irrelevant, since solar generation during those hours is nil. Instead, SEIA proposes to weigh solar capacity not against the daily 24-hour minimum load, but against the minimum load recorded during the four-hour interval from 10 a.m. to 2 p.m., because that’s when solar generation peaks—and the time when solar PV will pose the greatest threat to the integrity of distribution circuits. If minimum customer load during those hours is strong enough to meet