What are green technologies?

Solar energy is radiant light and heat from the sun. Other indirect sources of solar energy include wind and wave power, hydroelectricity, and biomass because these sources derive from the sun.  Except for geothermal and tidal energy, all renewable energy is derived directly or indirectly from the sun.

Solar power can be created by converting light into electricity by using solar panels, sometimes called PV (photovoltaic) panels.  Panels convert light into electricity by using the photoelectric effect where photons in sunlight are absorbed by semiconductor material which then gives off electrons.  The free electrons that are produced set up a potential difference and a direct current (DC) is produced.  The direct current can be used as-is or converted to alternating current (AC) by use of an inverter.  The AC power can be used by standard appliances or fed into the electrical grid.  Concentrating photovoltaic systems (CPV) use reflective surfaces to focus sunlight from several points onto a single receptor photocell.  Tracking systems are used to keep the sunlight focused to a single point as the sun travels across the sky.  Tracking systems can be utilized in both PV and CPV systems as the efficiency of energy transfer to solar panels improves when the light strikes perpendicular to the cell surface.  The electricity generated by PV systems can be affected by dust and gases in the Earth’s atmosphere, weather, the seasons, or by local obstacles like mountains or trees.

Energy from the sun can also be utilized for interior lighting, hot water heating, solar cooking, pool heating, space heating, or generating electricity and process heat by concentrating the sun’s energy and reflecting it to a focal point on a steam generator.  Solar distillation can be used to distill undrinkable water then disinfect it to provide clean water in developing countries. 

Solar power is intermittent and isn’t available at night.  Part of the challenge in fully utilizing solar energy is storing the power produced during the day to be used at night or on cloudy days.  Buildings may utilize thermal mass to store heat to be released at night, excess electricity may be used in pumped storage, battery systems, or thermal storage media, or the electricity may just be put on the electrical grid displacing fossil fuels being used.

Lake Land offers TEC 061, Solar Energy, TEC 062, Solar Thermal Applications, TEC 066, Resource Sustainability, and TEC 069, Site Assessment for Renewable Energy, as part of the green technologies program dealing with solar energy.  These courses allow students to determine the feasibility of solar installations, the types and installation methods of practical solar energy & heating technologies, and how solar energy fits in to a sustainable future.

Career pathways might include Solar Panel Installers or Technicians, Solar Water or Pool Heating Installers or technicians, Sales Representatives, Site Assessors, Estimators, Solar Installation Managers, Solar Designers, Engineers, Electricians, Plumbers, or many other careers in manufacturing, sales and distribution, and installation, as well as utilities.