The idea of using sunlight and radiant heat to source electrical and heating/cooling systems is no new phenomenon. Solar powered technology has been developing for decades, since the introduction of solar photovoltaics (PV), a medium of conductive materials (i.e. silicon, cadmium, gallium) designed to convert absorbed sunlight directly into electricity (1). Solar engineers later found that the alternate form of solar energy, radiant heat, could generate solar thermal electricity (STE) through concentrated solar power (CSP) technology. CSP structures are strategically placed to reflect and focus sunlight upon a “heat transfer fluid” (i.e. molten salt, synthetic oil), which then transfers the energy to an engine that produces electricity (1). Although solar technology has existed for several decades, solar engineers continue to make material, installation and distribution improvements on existing PV and CSP structures to stimulate and sustain growing demands for renewable solar technology.
Between solar PV and CSP technology, households and businesses prefer PV energy conversion systems because they are easier to install, show rapid returns on investment, and are compatible with existing policies/markets (1). CSP technology remains as a major source of renewable energy, but requires much more area and maintenance, making it most effective in arid climates.
At 2015 year-end, the worldwide capacity for solar PV was 227 gigawatts, approximately 185 million solar panels, while that of STE was 4.8 gigawatts (3). The U.S. alone increased capacity by more than 10 gigawatts in 2015 and totaled over 800,000 distributed PV systems installed (4). These trends were attained through technological advancement, as well as increasing dialogue around the subject of renewable energy in politics, businesses, and civil engineering. The past decade has shown rising numbers of operating solar energy systems in the U.S. and worldwide due to both scientific and systemic progress.
Material and Manufacturing Improvements
Solar CSP and PV systems are both constructed with large amounts of metal, where CSP structures have also shown a “high metal depletion burden”, “greater than for other power generators” (1). PV systems generate the most waste during the manufacturing process of using crystalline silicon to build PV modules (1). Developments in solar technology materials and manufacturing processes are foreseeable, as it is in solar technology companies’ best interest to find alternative materials and designs that will increase efficiency and durability.
Solar Energy Systems for the Long Haul
Solar power systems’ variability to sun exposure, based on geography, climate, and date, is a continuous challenge for engineers. To account for periods and locations that receive minimal to zero sunlight, solar power engineers have experimented with different materials and chemicals’ power load capacities, battery and storage technology, and transmission systems (1). A broader approach is a systemic change that places solar and wind energy on the power grid, alongside existing electricity grids that are primarily powered by coal and fossil fuels, also known as system value (SV) (5).
Progress in solar power technology has been driven by increasing awareness of climate change, initiatives to counter act global warming, and economic incentives through lower utility costs and public policy standards. Solar engineers are expected to meet the rising demands of government officials, consumers, and businesses by mid-century (5). Engineers and manufactures will be held responsible for increasing production in the coming years, while continuing to develop solar technology that will maximize energy efficiency, sustainability, and distribution.
(1) Hertwich, E.G., Alosisi de Larderel, J., Arvesen, A., Bayer, P., Bergesen, J., Bouman, E., Gilbon, T., Heath, G., Pena, C., Purhit, P., Ramirez, A., Suh, S. Green Energy Choices: The benefits, risks and trade-offs of low-carbon technologies for electricity production.
(2) “Renewables: About solar photovoltaics.” International Energy Agency. n.d. 14 Jun. 2016.
Renewable Energy Policy Network for the 21st Century. Renewables 2016: Global Status Report. REN21, 2016. 13 Jun 2016.
(3) Cantwell, Maria, Sen. Hearing on Near-Term Outlooks for Energy and Commodity Markets, U.S. Senate Committee on Energy & Natural Resources. 366 Dirksen Senate Office Building, Washington D.C. 19 Jan. 2016. Opening Statement. 13 Jun 2016.
(4) Mueller, Simon. Next Generation Wind and Solar Power, From cost to value. International Energy Agency and Clean Energy Ministerial, 2016. 14 Jun. 2016
Image: © Tangencial | Dreamstime.com - <a href="http://www.dreamstime.com/stock-photos-solar-thermal-power-plant-image23345363#res14972580">Solar thermal power plant</a>