Breath of Clarity

Floating Solar

Original Post by Cary Evans:

The City of Orlando Mayor, Buddy Dyer, formed an initiative called Green Works in 2007 to begin reducing the city’s emissions. In 2013, the Green Works Orlando Community Action Plan was formed to implement sustainability initiatives in order to reach goals by 2040 (Green Works Orlando n.d.). These goals are listed by category which include Clean Energy, Green Buildings, Local Food, Livability, Solid Waste, Transportation, and Water, but the main goal on reaching carbon neutrality is that the city hopes to be running on electricity on 100% clean, renewable energy by 2050. With the help of Orlando Utilities Commission and University of Florida, a study is being undertaken to better understand the potential challenges associated with switching the city over to renewable resources (Green Works Orlando, n.d., 14). The city is also providing resources to the public such as education on solar permits, outreach programs on development and job training, and the potential of expanding their Floating Solar program (I attached a photo below for reference). While it is not stated exactly how a project is funded, sources for many projects in the plan include public funding, establishing trust funds, grants, and partnering with non-profits. Another major decision, made by Mayor Dyer, to reach these goals was the inclusion of Orlando in the Under 2 MOU (Memorandum of Understanding), a United Nations agreement that commits subnational governments to mitigate impacts and a 2 degree rise in global temperatures by 2050. As stated in the 2018 plan, “this commitment aligns with Orlando’s commitment to the Paris Climate Agreement for Cities (to reduce GHG emissions 80% by 2050), as well as the city’s already aggressive GHG emissions reduction goal and strategies for 2040” (Green Works Orlando, n.d., 14).

Link to article:


GreenWorks Orlando. N.d. “2018 Community Action Plan”. Accessed July 30, 2020. to an external site.

Newcomb, James, Coreina Chan, and James Mandel. 2015. “Fort Collins steps up, approves accelerated climate target.” Green Biz. Rocky Mountain Institute. March 18, 2015. Links to an external site.

The McGraw-Hill Companies, Inc. 2013. “Chapter 9: Net Present Value and Other Investment Criteria”. PowerPoint Presentation. Accessed July 27, 2020.

My Comment:

I am interested in the study being undertaken in Orlando, FL to understand the challenges involved in switching the city over to renewables. Educating the public on solar permits is intriguing. Perhaps it may increase public trust that the savings people experience by installing solar on their houses and businesses is not too good to be true. Individuals who are particularly the analytical personality type would be able to see the project equipment, measurements and engineering tactics all illustrated on a single set of blueprints. It also enables people to spread the word about the actual feasibility of going solar to their technical coworkers.

The floating solar panel systems catch my eye. A sourceLinks to an external site. I found depicts construction began at the Godley Reservoir at Hyde in the UK. It has 12,000 panels and is worth 3.5 million euros (Alternative Technology Association 2016). It produces roughly 2.7 GWh per year which is around a third of the United Utilities water treatment plant’s energy requirements (Alternative Technology Association 2016). The purpose of providing those numbers is to show the capability of a large floating solar system along with its price.

The same article talked about solar thermals which are especially useful to Florida considering the massive amount of heat in the summer. Solar thermals do not use photovoltaic panels. Instead, sunlight is concentrated to produce high temperatures (Alternative Technology Association 2016). Residences use thermal to energetically efficiently heat pools. Concentrated solar thermal tower systems use mirrors mounted to tracking frames to concentrate the sun’s rays. Trough and dish systems use independent collectors that concentrate heat at their focal points so no central towers are used (Alternative Technology Association 2016). To enable solar thermal plants to generate for longer periods, they can include thermal storage (Alternative Technology Association 2016). To do so, one increases the volume of heat transfer fluid in the system and stores it in large, insulated tanks. It enables the system to keep generating during non-sun hours and cloudy days (Alternative Technology Association 2016). From the moment the article was written, the Crescent Dunes project near Tonopah, Nevada was the largest solar thermal plant in the world. I included a photo below. It consists of 180 MW turbine with 10 hours of molten salt storage (Alternative Technology Association 2016). The project delivers 110 MW of caseload capacity to Las Vegas between the hours of noon and midnight every day (Alternative Technology Association 2016). It can power a variety of functions such as lights and air conditioning.

Do you think the city of Florida should have different discounting tactics for rooftop solar and thermals compared to floating solar?

Considering the principles of net present value (NPV) as well as climate conditions, are there any type of renewable energy sources that may not work as well in Florida? How about in any of the other cities? Are there specific neighborhoods or rural areas spearheading certain renewable technology based upon the setting?

Comment by Alex McAuliffe:

Floating solar has been an intriguing topic for me since I started this program. Not only does it provide the space need for these solar farms, it saves valuable land space for agriculture and development, as well as provides coverage in hot environments to prevent fresh water evaporation. These added benefits should be included in any cost-benefit analysis. The challenge is putting a dollar value to these benefits.

This technology has been deployed to a reservoir in Malaysia which they conducted a pretty extensive technoeconomic analysis on (Bakar and Nandong 2019). The research conducted reviews several different manufacturers and solar farm layouts. But what caught my eye the most was that one producer, Astronergy, was found to have the best design using 3’x3′ panels based on total cost, coverage area, and stability of the panels. However, when factoring in product warranty and reliability, Panasonic was found to be the most cost effective after 40 years of operation (Bakar and Nandong 2019). Although it does not specify in the article, I would imagine this evaluation was conducted using a net present value calculation.


Bakar, Muhammad S. A. and Jobrun Nandong. 2019. “Technoeconomic analysis of floating solar field for 1 GWh of Electricity Generation.” IOP Conference Series: Materials Science and Engineering 495, (2019) 012064. doi:10.1088/1757-899X/495/1/012064.

My Comment:

Thanks for outlining the benefits of floating solar! I agree it is difficult to put a dollar value on the benefits. While saving land space for agriculture and development is a more visually clear benefit, I appreciate you also mentioned the floating solar provides coverage in hot environments to prevent fresh water evaporation. Perhaps, the latter benefit can be a key factor in determining which locations to consider implementing the floating solar.

I am familiar with Panasonic from my experience in residential solar. It was the premium panel choice for homeowners who wanted the general top-shelf and highest efficiency in terms of converting energy from DC to AC. Longevity is a significant feature of panel-type, as well, because efficiency degradation overtime is an issue.

I wonder how important aesthetics are in a floating solar system compared to a rooftop residential system. In the residential arena, a company was motivated to select a panel with minimal gridlines because it indicated a modern quality and often handled a homeowner’s objection to not wanting panels to interfere with a current roof’s look. I imagine with floating solar systems, since they are designed to provide energy to a mass amount of people, aesthetics are not as much of a significant factor.

Comment by Cary Evans:

Thank you for adding to my discussion. Alex, you provided a great example and explanation of different forms of floating solars. You added that Pansonic estimates it will take 40 yrs for the process to be cost effective, which for many companies may not be a viable payoff. But it could be for well established businesses that are working towards 100% renewable energy. Do you agree/disagree.

Mary, as I talked about in my discussion, the city of Orlando (under the Green Works Orlando Initiative) is working on moving towards more clean, renewable energy resources. Solar energy is promising because Florida (being the sunshine state) has a subtropic climate, providing more sunny days than other climates in the United States. Even though Florida has this advantage, the state is still passed by 19 other states for solar energy use (Penn 2019). One reason for this might be the state’s utilities, which are concerned that the rising popularity of solar energy will put their future at risk. When homeowners attempt to add solar panels to their energy sources, they can be met with delays from energy companies and comments about how solar energy is not as good as it sounds (Penn 2019). Simply a lot of backlash for trying to do something that benefits themselves and the environment.

Personal story: My husband and I are about to buy our first house in Florida (YAY) and one thing we have discussed is the possibility of solar panels. We recently looked into it and there are many incentives for homeowners. The most notable is net metering, which allows homeowners to sell surplus energy, which would add up quickly in the summer for a homeowner that is conscious of their energy usage throughout the day (Solar Metric 2020). Another one that is unique to Florida is the Property Tax Abatement for Renewable Energy Property, which provides 100% on property tax from the state to residents with renewable energy systems. I am not sure if there are specific neighborhoods that are spearheading solar energy. If you go through a business that provides solar panels and services, they will provide a consultation where they come out to your house and determine if your property would or would not be a good place for solar panels, which could limit some areas more than others. In my area especially, there are more rental properties than owned properties. So unless management decides to add solar panels, residents are limited in choosing their energy sources.

Determining whether other renewable energy sources are viable for a city depends on the city’s geographic location and their own resources to obtain them. A city in the Midwest would not benefit as much from tidal energy as a coastal city would and northern states with cooler climates would not benefit as much from solar energy as a states like Florida because of the shorter windows of sunlight throughout the year. In respect to Florida, I think wind energy would be hard for the state to adopt just becayse of the amount of space needed for a turbine farm. There is not much open space left in Florida and those that are left are either developed or conserved, which I think has higher benefits than the addition of wind turbines (ex. biodiversity, tourism, economic growth). Hydro energy would also not be a top choice for an alternative energy source. Besides being more costly than solar energy, many Florida restoration projects are geared towards restoring flows of water ways previously disturbed by dams, channelization, and general habitat disturbance (Ritchie 2017). The costs and risks of producing hydro energy are too great for the state of Florida to consider it a viable source.

Penn, Ivan. 2019. “Florida’s Utilities Keep Homeowners From Making the Most of Solar Power.” The New York Times. The New York Times, July 7, 2019. to an external site..

Ritchie, Bruce. 2017. “Tallahassee to Shut down One of Two Hydroelectric Plants in Florida.” Politico. Politico, LLC. July 20, 2017. to an external site..

Solar Metric. 2020. “Florida Solar Incentives and Rebates 2020”. Last modified February 15, 2020. Accessed on August 1, 2020.

Comment by Professor Thomas:

Interesting that Florida does not have more solar energy generation. You mention that the utilities do not support solar energy development. I wonder if another factor is the high percentage of the state’s population being retirees who may be reticent to invest in rooftop PV because they to do perceive a near-term payback on the investment. Plus older people are by nature somewhat less likely adopt newer technologies.

Comment by Cary Evans:

I think that is definitely a possible factor. It would be difficult for an older individual to justify a purchase when they may not experience a payback. I will say that most of the older generation living in Florida love the idea of stretching out a dollar (especially retirees)vso solar panels in a sunny state are very tempting. Yet the path to installation can still be lengthy and difficult. In the New York Times article I cited, a gentlemen named Mr. Shields purchased solar panels to power his home and electric car. He shared his experience working Duke energy and how the company kept giving him reasons to not install his solar grid like “rain” and “harming the electric grid” (Penn 2019). After purchasing an insurance policy, having another company install the panels, and getting Duke to turn on the system months later, Shields was officially a solar property.

The other side of this argument is that utility companies would have a lot of energy to buy back if more houses went solar. This shift in business needs would alter the way Floridians obtain energy and how utility companies operate. There is also concern for the solar batteries. Solar panels generate DC energy, but it has to be converted to AC for home use. This brings to question how long the batteries last.

Penn, Ivan. 2019. “Florida’s Utilities Keep Homeowners From Making the Most of Solar Power.” The New York Times. The New York Times, July 7, 2019. (Links to an external site.).

My Comment:

Another reason why Florida does not already have more solar energy generation is because the Florida utility’s price/kilowatt hour is far less compared to other states. When I was a residential consultant a few years ago, the Bay area’s Pacific Gas and Electric was charging an average of 24 cents/kilowatt hour while Florida utility companies were charging around 11 cents/kilowatt hour. Many of my fellow consultants were originally from Florida and used that comparison in their sales pitch to emphasize why it makes so much sense in California.