|
|
| Fig. 1: Is solar energy the answer? (Source: Wikimedia Commons) |
Solar energy, once thought to be the future of energy independence for not only the United States, but also for the entire world, has recently fallen out of favor due to high costs, inefficient designs, and because solar power needs much more room to generate the same amount of energy than traditional power plants.
The idea of solar islands, essentially offshore solar energy plants, have been discussed before but now two companies, namely DNV Kema based out of the Netherlands, and Nolaris, based out of Switzerland, are attempting to turn the idea into reality. These two companies hope to prove that by harnessing solar power offshore, it is possible to mitigate three pivotal problems facing solar power: the Not In My Back Yard (NIMBY) phenomenon, the space constraint issue, and the overheating of solar cells.
The Nolaris solar island design does not feature any solar panels. Instead it uses mirrors to concentrate the solar power on to tubes carrying water to generate steam. The steam is then collected in the center of the island and converted into electricity to be transported back to land. The 200 m diameter island boasts a surface energy density of 6.5 kWh/m2/day which translates to an overall power capacity of 8.5 MW. The unique aspect of this design is that the floating platform aligns its mirrors to face the sun optimally using azimuth tracking. The prototype has been rotating since 2009 and has routinely been with .02 degrees of the ideal position. Such tracking allows the design to benefit from a 15% increase in efficiency compared to its land based counterparts. [1]
SUNdy, the name of DNV Kema's project, has a 2 MW capacity structured in a hexagonal design featuring 4,200 thin-film 560 W solar panels (See Fig. 1). The solar panels are thin and flexible allowing them to undulate with the ocean waves, which is different than the Nolaris design that rests 20 meters above the sea level to ensure its mirrors do not get wet. The simplicity of the SUNdy design is easy to manufacture, and comes pre-wired to minimize the need for offshore assembly. Once the island is in the water, it requires very little maintenance, and can me paired with multiple separate modules in order to produce as much power as needed for the specific areas. [2]
A recent study by the US Chamber of Commerce revealed that 45% of clean energy projects are derailed due to NIMBY-related complaints. [3] That is a staggering number of potential power sources failing in the planning stages because people are unwilling to sacrifice their own land, or pretty landscapes for a sustainable future. By placing these solar islands offshore, they will be visible to essentially no one and since no one owns the ocean, there will be no litigation battles to purchase the land.
Also important is that over although only 17% of the United States are considered coastal areas, 55-60% of the population lives in such areas. [4] Not only is land scarce since the ocean limits development in one direction, but also placing renewable energy plants on the other side of the city runs the risk of limiting potential growth in the future. By placing the islands approximately 5 miles offshore, it minimizes the transmission line losses that often occur when power plants are hundreds of miles away from city centers in desolate areas.
Many current solar panel assemblies suffer from overheating, and thus efficiency is lowered when the sun is supplying the most power. The benefit of placing these solar panels in the ocean is that there is an abundance of available cooling water surrounding the panels at all times.
There is little doubt that renewable energy will play a larger part in the United States' energy future than it has up to now. The only question is what type of infrastructure will supply this energy. The United States used 4143.4 TWh of energy in 2010. [5] This translates to .47 TW of energy which would mean 24,000 of DNV Kema's design or 5,700 of Nolaris'. While this is certainly a large number, installing these solar islands would provide the United States with a clean renewable electricity source without figuring out which land to put it on and arguing with those who do not want the unsightly views. It may be farfetched, but it might just be genius as well.
© Lucas Prokopiak. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] A. Zacharias, "RAK's Solar Islands Could Power Emirate," The National, 13 Sep 10.
[2] "Solar Islands Floated as Clean Energy Source for Crowded Continents," The Guardian, 25 Oct 12.
[3] S. Pociask and J. Fuhr Jr. "Project, No Project", TeleNomic Research, LLC, 10 Mar 11.
[4] D. Hinrichsen and S. Olsen, Coastal Waters of the World: Trends, Threats, and Strategies (Island Press, 1999).
[5] "Key World Energy Statistics", International Energy Agency, 2012.
