Page 570 - Sustainable Cities and Communities Design Handbook

The Los Angeles Community College District Chapter j 27 539

on-site renewable energy resources is equal to the amount of energy used. This
is inherently different from an “off-the-grid” concept where at any point in
time, all campus energy demand is met through renewable resources. Despite
having strong financial support, whether the LACCD can actually realize its
goal of developing a net zero energy school system has yet to be determined.
Using renewable energy resources to generate a portion of a campus energy
demand is already difficult, let alone establishing a net zero energy operation.
Currently, a number of viable renewable energy technologies exist, including
solar photovoltaic (PV), wind, hydroelectric, and to a certain extent micro-
turbines. However, one of the biggest concerns when considering installing
renewable energy systems (RES)dand often times the deciding criteria of such
projectsdis the duration required before a return on investment (ROI) is
observed. The limited number of case studies of tertiary institutions with RES
installed and the relatively recent trend of installing such systems makes it
difficult to accurately determine a payback period. Further complicating these
calculations are government incentives, rebate programs, and initiatives that
vary by state. As shown in Table 27.1, studies investigating small-scale
(>1 MW) RES estimate ROI times anywhere between 3 and 30 years,
although these are largely theoretical calculations. There are cases of deploying
renewable technologies, but the approaches have largely been used to demon-
strate technological capability rather than providing economic analyses.

TABLE 27.1 Summary of Estimated ROI Times for Various RES Projects
Estimated
Study Type of RES Size of System 3 ROI (Years)
Dalton et al. (2008) Wind/diesel hybrid 1.8 MW 4.3
Rhoads-Weaver Wind 100 kW 7
and Grove (2004)
Yang (2004) Solar PV 11.2
Smestad (2008) Solar PV 1 GW 15
Edwards et al. (2004) Wind 3.6 GW 20
Solar PV 3 MW 30
Biomass 1000 L of ethanol 11
Yue and Yang (2007) Wind 10 kW 12
Forsyth et al. (2002) Wind/diesel hybrid 1.8 MW 4.3
PV, photovoltaic; RES, renewable energy systems; ROI, return on investment.

3. MW ¼ megawatt ¼ 1,000,000 W; GW ¼ gigawatt ¼ 1,000,000,000 W.