Just across the bay from Vote Solar HQ, the team of researchers at Lawrence Berkeley National Lab has been busy as ever cranking out tomes of invaluable information on clean energy markets, policies, costs and benefits. A couple recent reports that we found particularly illuminating:
State RPS Policies are Key to U.S. Solar Market Growth
Just today the dynamic Wiser/Barbose duo issued a report on the various approaches to RPSs taken across the country – and their effectiveness in deploying solar.
The results are in: RPSs with solar carve-outs (currently in place in 16 states + DC) have been an important factor in the solar market growth the U.S. has experienced of late. And with new programs gearing up in states nationwide and solar prices becoming competitive with the lower cost renewable resources, this policy mechanism is set to seriously kick up the solar wattage in the coming couple years. BUT not all RPS policies are created equal when it comes to deploying solar. The RPS is just the target – the solar market needs the right policy road to get there, and states have had varying success in providing a smooth path to growth. Resource constraints, restrictive cost caps, inadequate contract terms and a general lack of transparency and predictability can undermine solar deployment under a state’s RPS.
These are issues we discuss with policymakers in forums from Arizona to Pennsylvania. No longer a theoretical exercise, state leaders can now draw on real world experience and proven best practices to design effective programs. This report from LBNL provides a roadmap for navigating those RPS lessons learned.
Geographic Diversity Smooths Solar Output
For folks in the business of keeping the lights on, there’s much debate around how much variable renewable power the grid can support before it becomes a problem . . . the wind doesn’t always blow, clouds happen, how are utilities supposed to deliver the reliable power their consumers demand? Does adding significantly more renewables require more dirty generation to balance it? Or can we really depend on wind, solar and other clean energy sources to meet our nation’s electricity needs? Lots of questions, and there are just not many answers founded in real world data out there.
That’s why we were so excited to see an LBNL’s report on the topic: ”Implications of Wide-Area Geographic Diversity for Short-Term Variability of Solar Power.” Full PDF here: http://eetd.lbl.gov/ea/emp/reports/lbnl-3884e.pdf and slightly more digestible PPT presentation here: http://eetd.lbl.gov/ea/emp/reports/lbnl-3884e-ppt.pdf
Conventional power quality analysis has typically looked at output from a single PV system – as you can imagine, a passing cloud can have a real impact on the hour-by-hour performance of that solar system. But LBNL questioned whether that would ring true for the aggregate output from distributed systems across multiple sites. So they tracked solar data from 23 sites throughout Kansas and Oklahoma taken at one-minute intervals for a year to find out.
Conclusion: geographic diversity can significantly reduce extreme changes in aggregated PV output, the resources required to accommodate that variability, and the associated costs of managing variability. These smoothing benefits correlate closely with distributed wind energy production as well.
Low carbon grid, here we come.