Driving around I notice numerous Solar Photovoltaic (PV) systems, producing clean electricity, on commercial and residential buildings! Over a decade ago, the average cost of a residential solar PV system was $8.50 per watt and has now decreased to about $2.80 per watt. That’s quite an impressive improvement in cost in such a short period of time! However, peak efficiency of Solar PV panels has lagged a bit behind, increasing from 14% in 1960 to 22.8% in 2015. That’s right the best a commercially available PV solar panel can do is convert less than a quarter of the sun’s solar irradiance into electricity! The good news is that researchers have been hard at work developing more efficient PV panels that are about 47% efficient.
Let’s take a high level look at how PV solar panels work. A semiconductor material is used to make a PV cell. Energy in the form of light strikes the surface of the PV cell, as shown in the Figure. As these photons hit the cell’s surface, there are three key possibilities. One possibility is that it would be reflected off the surface. Two, it has the potential to pierce the surface. It may also be absorbed by the semiconductor material, which is the third possibility. Only the photons absorbed by the photovoltaic surface are converted to electricity.
The Good:
Solar PV System prices have drop substantially allowing for clean affordable electricity. Research is being conducted to increase commercially available Solar PV panels efficiency to near 50%. Individuals can reduce their current electric bill substantially!
The Bad:
Current commercially available Solar PV panels have maximum efficiency of 22.8%, which means solar panels generally require a substantial amount of surface area (roof space & land). The largest issue associated with Solar PV Systems is variability in electricity generation and the fact that production is limited to daylight hours.
The Solar:
Today, over 3% of U.S. electricity comes from solar energy and with solar estimated to play a pivotal role in transforming our grid, we have a long way to go before said grid is powered completely by renewable energy. Over the last few years, Solar PV technology has advanced significantly. Solar PV technology has emerged as one of the most promising renewable energy sources, despite many technical, economic, environmental, and social barriers. With continued efficiency improvements, decreased cost, and coupling with other renewable energy generators (Hybrid Energy Systems) solar energy has great potential in helping to provided future generations with 100% renewable energy.
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