Are You Really Ready for a Renewable Energy System?
With numerous advantages presented by renewable energy and the monetary subsidies at various levels, the desire to install a renewable energy solution is at its highest now. But do you know much cost reduction is possible by just conserving energy? Research answers this ……
Energy intensity index is a term which refers to the energy consumption per GDP normalized with respect to certain time. By efficient use of energy it is possible to reduce the energy intensity index while not changing or increasing the amount of work gained. With 1961 as a baseline, Denmark has been able to reduce its energy intensity index by 40%. Within US, California has reduced by about 12% while the US as a whole has only reduced by about 3%. This statistic heavily stresses on the need for efficient energy use.
Yalcintas et al., present an insightful article in the journal Energy Policy, which compares the cost benefits of installing solar systems versus making existing buildings energy efficient. This study was performed for the state of Hawaii, which gets about 90 percent of its energy from imported fossil fuels. The authors present 4 interesting case studies, where they compare replacement or retrofitting of old and inefficient equipment with new energy-efficient technologies with installing renewable energy systems. Solar systems were the best possible renewable options given the urban setup of the 4 locations considered for the studies. Of the four cases presented, two cases were highly impressive.
In one of the cases involving a 2200 room hotel, a two step solution of installing energy management systems (EMS) in the rooms and installing variable frequency drives in the air handling units was employed. The EMS systems were configured to control the cooling in the rooms based on occupancy. These two enhancements resulted in a saving of $264,500 at an installation cost of $1,125,000 – which meant a 4.3 years payback period. On the other hand, if solar systems were used to create the same energy saving effect, it would cost about $7,250,000 ($4,575,000 after tax credits & other savings) – which meant a 17.3 years payback period. Additionally, the solar panel installation needs 725,000 sq.ft of open area, which is impossible in an urban setup.
In another case involving a manufacturing facility, 316 metal halide lighting fixtures were replaced with 299 4L-T5HO lighting fixtures with new ballasts. Each of the 4L-T5HO fixtures had 4 lamps as compared to the single lamp in the halide fixtures. This change resulted in more than 50% drop of the power used for lighting. Financially, this cost about $90,000 while the yearly estimated savings is $103,000 – a payback period of only 1 year. Had solar panels been used, for the same energy savings it would have cost $2,020,000 – a payback period of about 20 years.
The other 2 cases presented involved replacement of selective cooling equipment and resulted in significant savings. The authors continued to estimate that such energy conservation techniques save more than 50% on an average as compared to deploying renewable energy options to save equal amount of energy.
It should here be stressed that energy conservation is a good first step, however once all possible energy conservation options are exhausted deploying renewable energy options are the natural end point.
At residential levels, heating, cooling & lighting cover about 70% of energy used. Simple solutions like replacing with higher efficient equipment and avoiding wastage (example: room cooling vs central cooling) will result in drastic savings of energy. Only upon energy optimizing all the equipments, installation of renewable energy options should be considered, for enhanced financial savings as well as long term over all energy savings.
Journal Reference: doi:10.1016/j.enpol.2009.04.029
