sustainability poster

Solar Tree: Plant Trees That Provide More Than Just Energy

By Assia Zheng Date: 10/19/2020

With an increasingly high demand for traditional energy, society seeks to find alternative resources that are clean, renewable, affordable, and yet, efficient. Solar energy is one of the fastest-growing sustainable energy that is abundant and "free". It not only produces little waste but also can essentially lower the utility bill. Among all solar innovations in the developing industry, solar trees are one of the most extraordinary. This blog post discusses this new solar device and answers the four Ws:

• What is solar energy? • What are solar trees? • Why solar trees? • Who should buy solar trees?

Solar Energy VS. Traditional Energy

Fig. 1. A massive amount of pollution is caused by firing traditional energies, such as burning coal. The toxic gas is produced worldwide, which affects so much beyond the quality of human life. [1]

Until today, the vast majority of the energy we consume has been produced in traditional ways, such as burning coal, oil, or natural gas (Fig. 1). In 2019, according to the US energy information administration (EIA), there were 5,130 million metric tons of carbon dioxide [2] emission by

fuel. The CO2 pollution generated by fossil fuel (fig. 2) combustion contributes more than 75% of greenhouse gas (GHG) emissions and about 95% of total CO2 production in the US [3]. Aside from producing GHG, the pollution that traditional energies emits is often the leading cause of acid rain, smog, soil infertility, and other health-concerning problems [4]. Not to mention the detrimental effect on the ecosystem of mining those fossil fuels.

Fig. 2. This chart shows CO2 pollution caused by burning fossil fuels from 1990 to 2019. Every year, almost 6,000 million tons of CO2 are being released into the atmosphere, which is highly concerning. [5]

Solar energy, on the contrary, is 100% clean, abundant, and renewable. Firstly, it is available to harness every day in most parts of the world, with no GHG emissions (fig. 3). Secondly, solar energy systems reduce electricity costs. Households who install solar systems can have some degrees of freedom over their electricity generation and escape power outage nightmares. Lastly, solar panels are easy to produce in manufacturers with relatively low costing materials.

Fig. 3. As shown in the left pie chart, 20% of the total energy consumed in 2019 was nonfossil (nuclear and renewable) energy. However, the CO2 Emission by Source pie chart (on the right) omitted nonfossil energy due to their sustainability. CO2 pollution emitted by nonfossils is too little to be considered. [6]

Nevertheless, there are some disadvantages to solar energy. The system, including wiring, panels, and batteries, is quite expensive to install initially to the average household. Though, with the development of technology in this field, it is predicted that the price will reduce in the future. Solar energy is also entirely weather-dependent. Cloudy or rainy weather can dramatically affect harnessing efficiency. More importantly, although solar energy is clean, the production of the solar system is not. Manufacturing the system involves some hazardous materials, especially when making the photovoltaic system. However, overall, the pollution the solar system produce is far less than those emitted by burning traditional energies. [7] Trees That Harness Energy

A solar tree is a solar system formed by a long ground-mounted pole and several solar panels. The panels are branched out in different directions and supported by the long steady pole. By branching out the panels in the air, the design gives the appearance of a tree and uses less land than other solar cultivation systems. [9] Fig. 4. This is a solar tree design blueprint by the

company Spotlight Solar. It presents the variety and flexibility of solar trees. [8]

Advantages of Solar Trees

Solar trees' unique design makes them different from other solar systems. The panels at various locations form layers that enable them to gather sunlight from all angles at all times. The layers not only maximize the system's harnessing efficiency but makes a man- made high-tech energy system look natural and aesthetically pleasing. The supporting pole and branches can hide any dangerous wires, making their use suitable for any age group or scene. The design as a whole takes less space than the set-up of regular solar panels. [10]

Moreover, solar trees can generate more than just electricity. They can serve as street lights at night, resting benches in the park, provide heating or cooling, and offer shades just like an ordinary tree. Due to their high functionality of solar trees, many local governments have been incorporating solar trees in city development.

• Dubai Municipality installed solar trees on the beach, which act as a shaded resting spot, a charging station, and a weather forecaster [11]. The performance of solar trees is endless.

• Singapore incorporated solar trees in its largest garden project, Gardens by the Bay. The designers included 18, at least 25 meters tall, solar trees called Supertrees (fig. 5). These Supertrees strive to help the Singapore government cut 0% of its carbon emissions [13].

Last but not least, implementing solar systems is strongly supported by the US government. Solar trees have qualifications for tax breaks. The tax credit is a federal policy called the Solar Investment Tax Credit (ITC) issued in 2006, which gives a 26% tax credit for solar systems

installed in 2020 used both residentially and commercially. Since 2006, the Solar ITC has helped the US solar energy develop 10,000% [14].

Fig. 5. This picture of the Supertree Grove is taken by Hari K. Patibanda in 2013. Together, these 18 giant trees not only light up the garden at night with solar energy but also serve as a vertical hanging garden. [12]

Best Buyers

The concept of solar trees is relatively new, which causes the price of solar trees to be high. Depending on the energy generation power (unit: kW), the average cost of a solar tree can range from around $130,000 to $600,000 [15]. For example, the same powered tree can cost differently from Envision and Spotlight Solar. As a result, the system is not ready to be introduced to the average household yet. For now, solar panels can be a good option for residential buyers.

However, solar trees can be utterly cost-effective for: • Governments can encourage using clean energy by installing in public areas, such as

parks, airports, and zoos. • Institutions can set up solar trees to showcase an environmental-friendly energy system

to the students. The marriage of design and new energy may also stimulate the students' interests in science and technology.

• Private Companies can purchase solar trees and install them in front of their buildings. The trees not only can make a bold statement but also help save electricity bills.

Conclusion

Without a doubt, solar is one of the most sustainable and low-costing new energy right now. Solar trees are able to maximize harnessing efficiency due to the layered design and provide high functionality, such as generating electricity and providing Wi-Fi, as mentioned previously. Eliminating traditional energy, reducing GHG emissions drastically, and protecting the ecosystem is in the near future.

References

[1] A. Temsamani, Pollution from Industrial Factory. [2] The US Energy Information Administration. U.S. Energy-Related Carbon Dioxide Emissions,

2019 [Online]. Available: https://www.eia.gov/environment/emissions/carbon/ [3] The US Energy Information Administration. Energy and the Environment Explained: Where

Greenhouse Gases Come From [online]. Available: https://www.eia.gov/energyexplained/ energy-and-the-environment/where-greenhouse-gases-come- from.php#:~:text=In%202018%2C%20carbon%20dioxide%20(CO2,total%20U.S. %20anthropogenic%20CO2%20emissions.

[4] C. Nunez, “Carbon dioxide levels are at a record high. Here's what you need to know.,” National Geographic, 14-May-2019. [Online]. Available: https:// www.nationalgeographic.com/environment/global-warming/greenhouse-gases/. [Accessed: 19-Oct-2020].

[5] U.S. CO2 Emissions from Industrial Fuel, 1990-2019. 2020. [6] U.S. Energy Consumption and Energy-Related CO2 Emissions by Source, 2019. 2020. [7] A. Vourvoulias, “Pros and Cons of Solar Energy,” GREENMATCH, 23-Sep-2020. [Online].

Available: https://www.greenmatch.co.uk/blog/2014/08/5-advantages-and-5-disadvantages- of-solar-energy. [Accessed: 17-Oct-2020].

[8] Spotlight Solar. 2020. [9] F. Hyder, K. Sudhakar, and R. Mamat, “Solar PV tree design: A review,” Renewable and

Sustainable Energy Reviews, 10-Oct-2017. [Online]. Available: https:// www.sciencedirect.com/science/article/pii/S1364032117312765. [Accessed: 17-Oct-2020].

[10] S. Dey and B. Pesala, “Solar tree design framework for maximized power generation with minimized structural cost,” Renewable Energy, 04-Aug-2020. [Online]. Available: https:// www.sciencedirect.com/science/article/pii/S0960148120311113. [Accessed: 17-Oct-2020].

[11] F. O'Keefe, “Suntan around these badass solar palm trees in... Dubai!,” Green Prophet, 01- Nov-2015. [Online]. Available: https://www.greenprophet.com/2015/11/solar-palm-trees-3d- printed-dubai/. [Accessed: 17-Oct-2020].

[12] H. K. Patibanda, Singapore Gardens by the Bay Supertree Grove. 2013. [13] “Sustainability Efforts,” Gardens by the Bay. [Online]. Available: https://

www.gardensbythebay.com.sg/en/the-gardens/sustainability-efforts.html. [Accessed: 17- Oct-2020].

[14] “Solar Investment Tax Credit (ITC),” SEIA. [Online]. Available: https://www.seia.org/ initiatives/solar-investment-tax-credit-itc. [Accessed: 17-Oct-2020].

[15] J. Marsh, “Solar Trees: Product Overview, Pricing and Review: EnergySage,” Solar News, 23-Mar-2018. [Online]. Available: https://news.energysage.com/solar-trees-everything-need- know/. [Accessed: 17-Oct-2020].