“I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that.”
This quote opened last week’s “Alternative Energy Science” class with Dr. Tali Zohar, Director of the Center for Renewable Energy and Energy Conservation, on the technologies and applications of solar thermal energy, power production, and heating applications.
Students learned many basic and interesting facts about solar energy: The heat and light from the sun comes to the earth as electromagnetic energy, a radiant energy produced from the sun’s fusion process. In other words, radiation; its power is measured in watts. Ideally the power of the sun would produce 1360 watts per square meter. That however is not achieved because of non-constant conditions such as geographic location, time, the seasons, the atmosphere. In fact only 50% of solar radiation reaches the surface of the earth, and other factors can reduce that number further. For example, there is more energy from the sun on Mt. Everest, with the sun’s radiation going through less of the Earth’s atmosphere, than at the Dead Sea. This is also caused by the inverse-square law which says that the greater the distance radiation travels, causes it to spread over a larger area, causing less energy per unit area.
The most common way to produce energy from the sun is with photovoltaic (PV) panels, there are however other forms of solar energy. Concentrated Solar Thermal Power (CSP) uses the radiation of the sun to heat a surface in order to produce steam which then turns turbines that produce electricity. This generator is built with coiled copper wires that are surrounded by magnets – the interaction caused by the spinning produces electricity.
Dr. Zohar also critically discussed the environmental contribution made by solar panels. While solar energy systems provide a sustainable solution to move away from fossil fuels, their negative effects on the environment should be taken into consideration. These include use and degradation of open land that affects ecosystem services causing environmental imbalances; heat islands produced which can be harmful to migrating birds); building material waste. Waste is also created by PV panels and structures, as technology advances and previous models are replaced by more efficient and bigger panels. Onshore wind and solar PV technologies are however less expensive than the cheapest fossil fuels, and particularly solar PV have the potential to become the main source of energy as humanity goes forward.
Other classes this semester will explore wind and hydro-energies, energy storage, off-grid technologies, and more. The “Alternative Energy Science” class will also host a special guest lecture by Dr. Tareq Abu Hamed, Executive Director of the Arava Institute, about his research on clean hydrogen energy engines.
Submitted by Rabbi Michael M. Cohen
