Solar energy vs. shade - Solar, Wind and Land: Conflicts in Renewable Energy Development - page 113

landowners who seek solar access protection to reveal whether they truly
value that protection more highly than the market values all other possible
uses of the airspace at issue.
A simple numerical example helps to emphasize this point. Suppose
that Vargas lived in Iowa rather than California and thus could compel
Bissett and Treanor to grant him a solar access easement but had to pay
them fair market value for it. If he were rational, Vargas would purchase
the easement under such a rule only when it cost less than the value he
would obtain from it. In other words, he would have purchased it when
allowing trees in the space was worth $5,000 but not when allowing
trees in the space was worth $20,000—the efficient outcome under both
scenarios.
Table 5.1 below summarizes the advantages and disadvantages of each
of the three general types of policy approach to solar access described in
this chapter. “Policy type #1”—the predominant policy strategy for solar
access throughout the world—is to have no special statutory or other laws
that protect solar energy systems from shading. As shown in the table, this
approach tends to promote the efficient use of neighbors' airspace whenever
occupying that space with trees, buildings or other structures is of greater
value than using it to deliver direct sunlight to a solar energy system.
However, when keeping neighbors' airspace open to protect a solar energy
device from shading would be the highest valued use of the space, this type
of policy offers no sure way for would-be solar energy users to protect
themselves against shading risks. If they are unable to convince neighbors
to voluntarily sell them solar access easements, they have no other way

Table 5.1 Comparing the general efficiency of solar access laws
Types of solar access
conlicts

Policy type #1:
no statutory or
common law solar
access protection
(approach in most
jurisdictions)

Policy type #2:
setbacks, permit-
based protection,
or solar rights
statutes (used in
some U.S. states 56 )

Policy type #3:
statutory options
to purchase solar
access easements at
fair market value
(applies in Iowa 57 )

Conflicts in which
solar access is more
valuable than all
competing airspace
uses

Voluntary bargain
required to reach
efficient outcome

Efficient Efficient

Conflicts in which
solar access is less
valuable than a
competing airspace
use

Efficient Not efficient Efficient