Solar energy vs. shade - Solar, Wind and Land: Conflicts in Renewable Energy Development - page 108

purpose of protecting solar access. For example, the City of Ashland,
Oregon, has adopted a Solar Access Ordinance that imposes
“[s]olar [s]etbacks” on nearly all private property within that juris-
diction. Under the ordinance, newly constructed structures must
not cast a shadow taller than a certain height at the north property
line. Greater structure heights are allowed at greater distances from
northerly boundary lines. The City of Boulder, Colorado, has adopted
similar provisions for certain zones within that city, referring to these
height and setback requirements as “solar fence[s]”. In both cases,
the applicable height limitations vary among zones within the juris-
diction, allowing for greater building heights in certain commercial
or industrial zones.
At first blush, shade-based setbacks are appealing in that they largely
avoid the arbitrariness and strategic behavior problems that charac-
terize some Lot-By-Lot Statutes. The rules apply uniformly within a
given zone, like any ordinary setback or height restriction. They may
also be less administratively burdensome than Lot-By-Lot approaches
and may provide greater certainty to landowners.
Nevertheless, statutes that impose shade-based setbacks on all
properties within an area—not just those situated near solar panels—
are probably not cost justified. If the aggregate value of all the myriad
airspace uses prohibited by a shade-based setback rule exceeds the
aggregate value of solar access it preserves, the rule is likely ineffi-
cient. Less than 0.5% of residential rooftops in the United States
presently hold solar panels. Thus, more than 99% of the time, Solar
Users that hold the scarce Airspace Entitlement under these statutes
do not exist. Until rooftop solar systems become far more prevalent,
it seems a dubious presumption that the solar access protected under
broad shade-based setbacks is of greater social benefit than the endless
number of other legal uses of airspace within a jurisdiction that are
prohibited by the setbacks.
(Troy Rule, Shadows on the Cathedral: Solar Access Laws in a
Different Light , 2010 U. Ill. L. Rev. 851, 878-80 (2010))
Given the shortcomings inherent in all of the above-mentioned policy
approaches, it may be easy to understand why the majority of jurisdic-
tions in the United States and across the planet have no laws to protect
solar energy systems from shading. In most jurisdictions of the western
world, landowners are generally not liable for shading their neighbors'
solar panels, so solar energy users can only obtain protection against such
shading through voluntarily negotiated private agreements. Of course, even
this “hands off” policy approach seems unsatisfactory to those who favor
solar energy because it wholly fails to address what can be a significant
obstacle to distributed solar energy development.