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Scott, I'm confused about the use of the terms solar energy and solar power. Is solar energy both a type of energy and a type of technology? Is solar power both a type of power and a type of technology? It seems like the terms get mixed up and used interchangeably, like kWh and kW do even though these units describe two different things. What are the general differences between solar energy and solar power? Thank you. -- Lee K.
Lee, this is a question I get often, and believe it is worth addressing. Solar "power" usually means converting the sun's rays (photons) to electricity. The solar technologies could be photovoltaics, or the various concentrating thermal technologies: solar troughs, solar dish/engines, and solar power towers.
Solar "energy" is a more generic term, meaning any technology that converts the sun's energy into a form of energy—so that includes the aforementioned solar power technologies, but also solar thermal for water heating, space heating and cooling, and industrial process heat. Solar energy includes solar daylighting and even passive solar that uses building orientation, design and materials to heat and cool buildings.
Now in the early 1980's, I was Political Director of the Solar Lobby, formed by the big nine national environmental groups, that embraced all solar technologies—which we viewed as wind, hydropower, and biomass, along with the long list of traditional solar conversion technologies.
The thesis, which is correct, is that the sun contributes to growing plants, wind regimes, and evaporation and rain (hydropower), so that all the renewables are part of the solar family. Now, of course, most would argue that geothermal, and tidal and wave (effected by the gravitational force of the moon) are not solar, but we included these technologies as well.
While I have this platform on solar terminology, I am routinely annoyed by media stories about solar cells (which they assume describes photovoltaics). Photovoltaics technology has changed over the decades from groups of silicon cells wired together under glass to make a photovoltaic module (panel), to various thin film materials deposed on glass, metal and plastics, and including the newer nanotechnology photovoltaics incorporating light sensitive dyes.
While solar exerts could nitpick that these are indeed other types of embedded solar cells, I would venture, the term is outmoded. The word "photovoltaics" for the direct conversion of sunlight to electricity is sufficient.
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1 watt = 1 joule per second. A watt is NOT an instantaneous measurement; it consumes a second. Therefore, a watt is a unit of Power. So is a watt-hour. Both measure the rate at which work is done over time.
Energy has multiple forms, such as Kinetic (energy in motion like the blowing wind) and Potential (energy ready to be in motion, like water behind a dam). Solar Energy strikes a PV panel to produce potential electrical energy (volts), but produces no Power until it is connected to a load (Work).
We're splitting hairs here. It's usually not important to explain the difference. But accuracy counts. The notion of a Watt being Power and a Watt-Hour being Energy is simply wrong, even if you're an engineer.
Don't buy it? Take a moment to Google "power vs. energy" and start clicking links.
My questions to you are: Who will build, operate and control Tidal power stations?
Who currently owns patents on ALL PV technology?
Who builds and owns all large solar wind farms?
Answer..The same people that own Oil/Natural Gas/Coal
We are spending $330,000,000 A DAY in Iraq. Imagine what 30 days of Iraq spending would look like if it launched dozens of Thermal Solar Power stations in this country. For every two we build, we could designate one for Hydrogen production through electrolysis.
Oh yea I forgot...that spells the end for Big Energy huh? It's shameful...
S H A M E F U L that thermal technologies that were working in THE MID 80's are NOT on the evening news EVERY NIGHT! Front Page of your Newspaper... Talked about By Limbaugh, Hannity, Beck etc...oh yea I forgot all that media is owned by the big boyz too. : (
Your all smart and educated, that's great. Do any of you use any type of "solar powered" contraptions I wonder? We need you guys to do "home shows" for people who have no clue about PV, solar hot water, etc.
Upstate NY (Albany area)has a home show that allows the interested lot to come and see such arrangements by doing "walk and see" tours.
Good luck to all.
The terminology problem is reflected in many of the comments above which seek to define solar energy and solar power through the relationship Power = Energy/Time. The qualitative difference between the technologies rather than the relationship between energy and power is a better grounds of distinction.
I'd say geothermal and tidal belong under the solar heading too. If it weren't for the sun the oceans would be frozen so there wouldn't be any tides. The same thing goes for the geothermal gradient which would be much different without the solar input.
It is worth while to point out once again that 'solar power' or 'solar panels' are NOT synonymous with photovoltaic power or panels, although frequently used that way. Solar panels can produce either electricity (PV panels) or heat or hot water (thermal collectors. Solar power can be produced by PV panels or by CSTP systems (concentrating solar thermal power systems such as those operating in the Calif. deasert to produce up to 345 MW of solar electric power). Of course, wind, hydro, OTEC, etc. are also producers of solar power (and of solar energy, of course). Hence, anyone thnking of PV should NOT use the term solar power or solar panels. Just say PV power and be clear about it.
Tandem PV = ?
Tandem Cell = ?
Photo-voltaic = ?
Photo-thermal = ?
Solar energy = ?
Solar power = ?
Solar cells = ?
Hydrogen solar cell = ?
Hydrogen Power = ?
Solar hydrogen power = ?
Solar hydrogen tandem Cell = ?
Dye sensitised solar cell = ?
Photo-chemical cell = ?
Photo-electrochemical cell = ?
Electrochemical cell = ?
Many thanks in advance.
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