How Does Solar Work? Solar Energy Technologies Office The amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year. Solar technologies convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation.
- This energy can be used to generate electricity or be stored in batteries or thermal storage.
- Below, you can find resources and information on the basics of solar radiation, and technologies, electrical grid , and the non-hardware aspects () of solar energy.
- You can also learn more about how to and the .
In addition, you can dive deeper into solar energy and learn about how the U.S. Department of Energy Solar Energy Technologies Office is driving innovative in these areas.
Is solar the cheapest form of energy?
by Kevin Schofield This week’s “long read” is light on words and heavy on charts and graphs. It’s a comparison of the cost to generate electricity from a number of different sources, both clean and dirty. The business and finance consultant company Lazard has compiled an analysis of the “levelized cost of energy” every year since 2007.
By “levelized,” they mean that they factor in all of the costs: capital costs to build out electricity generation facilities, including the materials, manufacturing, construction, installation, permitting, and property; ongoing operational and maintenance costs; fuel costs for the types of generation that require fuel; and regulatory costs.
They calculate the expected operational lifetime of a power generation facility and then divide the sum of the costs by the total expected power generation over a facility’s lifetime to arrive at a cost per megawatt-hour. And there is some very good news for the planet: Solar and wind power, at the scale that a major utility would deploy them, are now the cheapest form of power. 
Chart depicting a levelized cost of energy comparison with light blue bars representing renewable energy and dark, navy blue bars representing conventional energy. Sourced from “Levelized Cost Of Energy, Levelized Cost Of Storage, and Levelized Cost Of Hydrogen” by Lazard.
- There are some important caveats and nuances to this story, however.
- The first, and perhaps the most important for those of us looking to put solar on the rooftops of our homes, is that solar is all about size.
- Residential rooftop solar is still very expensive: A decent-sized roof installation can generate enough power for your home with some to spare, but the up-front costs are still significant.
Larger installations at commercial, industrial, and “community solar” sites are more cost effective, and of course the huge solar farms run by utilities are the cheapest. Wind and solar also have one significant drawback: They are intermittent. Solar doesn’t help you in the middle of the night, nor does a wind turbine when the wind isn’t blowing.
- In order to have reliable, 24-hour power, you need to complement them with another “baseline” source such as gas, nuclear, or geothermal — or hydropower here in the Pacific Northwest.
- Until large-scale batteries get much better (and cheaper), we’re unfortunately still a long way away from entirely cutting our reliance on conventional power generation.
That said, the drop in the cost of “green” energy over the past fifteen years has been phenomenal. Solar power generation today costs 10% of what it did in 2009. Wind power costs less than 30%. In contrast, coal is unchanged and nuclear power has become more expensive. 
Chart depicting cost of energy trends over time with grey lines representing gas, dark brown representing nuclear, light blue representing solar thermal, yellow-brown representing coal, blue-grey representing geothermal, green representing gas, periwinkle blue representing wind, and yellow representing solar.
- Sourced from “Levelized Cost Of Energy, Levelized Cost Of Storage, and Levelized Cost Of Hydrogen” by Lazard.
- Even better, solar and wind technologies continue to improve rapidly, driving up the amount of power you can generate in a given space and driving down the cost even further.
- Given that every day we hear about the increasing impacts of climate change, the fact that green power is now cheaper than dirty power is welcome news indeed.
Lazard’s Levelized Cost of Energy Analysis 
Kevin Schofield is a freelance writer and publishes Seattle Paper Trail . Previously he worked for Microsoft, published Seattle City Council Insight , co-hosted the “Seattle News, Views and Brews” podcast , and raised two daughters as a single dad. He serves on the Board of Directors of Woodland Park Zoo, where he also volunteers.
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