This is a comparison guide on Solar PV (photovoltaic) vs Solar Thermal (CSP – Concentrating Solar Power) Energy.
We look at what each of these types of solar technology are, their differences, and examples of each in terms of solar projects and operational solar farms worldwide.
Summary – Solar PV vs Solar Thermal/CSP
Solar PV (used for electricity) and Solar CSP (used for electricity, or heating water) are different solar technologies
Each can be used on a large utility scale (big solar farms with hundreds or thousands of panels that produce electricity for utilities), or on a distributed residential scale (for individual households, buildings and locations)
Solar PV (photovoltaic) currently leads Solar Thermal/CSP by a very wide margin in terms of annual investment of money, annual and total installed capacity, electricity generation, and electricity consumption
This trend (of PV outpacing CSP) is only expected to continue into the future with continued investment in and expansion of Solar PV projects.
Although, solar CSP is still expected to grow into the future
Despite Solar PV’s popularity, Solar CSP has a few small advantages (dispatchability, and generating electricity while the sun is down) over Solar PV
What Is Solar PV
A solar panel made up of solar cells that converts sun light energy into electricity
– vivintsolar.com
Solar PV can be utility scale (solar farms), or distributed (usually rooftop installations and other standalone solar cells that help stabilise or support a power system in the event of power disruptions, blackouts etc.).
How Solar PV Works
Sunlight (light photons) hits the solar cells on a solar panel
The solar cells convert sunlight into DC electricity
DC electricity is fed to the inverter (might be a string inverter or a microinverter) that turns DC energy into AC electricity
This AC electricity can be used directly or stored in a battery for later use
– vivintsolar.com
What Is Solar Thermal/CSP
The use of the Sun’s thermal energy to generate electricity or heat water
There’s several different types of Solar Thermal plants such as Linear Fresnel, Tower, Dish and Trough (cleanenergycouncil.org.au)
How Solar Thermal/CSP Works
Solar CSP uses mirrors (lenses and reflectors) to capture the Sun’s thermal energy (infrared radiation) to heat a (thermodynamic) liquid or an oil, create steam, drive a heat engine/generator, and generate electricity
Solar CSP can also be used for heating and desalinating water
– wikipedia.org, sciencedirect.com, cleanenergycouncil.org.au and irena.org
Global Installed Capacity, Production & Consumption Of Solar Energy
Worldwide, solar energy installed capacity, production and consumption stats are:
At the end of 2018, solar as a whole made up 20% of installed capacity for renewables
At the end of 2018, solar PV made up 2.4% of total global electricity production
At the end of 2016, solar was the third most consumed renewable energy source for electricity
Between 2012 to 2018, solar PV led all renewables in annual additional installed capacity by a wide margin (55% alone in 2018), followed by wind energy, hydropower, and all other renewables as a group behind that (including solar CSP/thermal)
Solar thermal/CSP made up 0.4% of total global electricity production in 2018 along with other renewables like geothermal and ocean power
– vox.com
In 2017, solar PV and solar thermal were both responsible for 4% each of renewable energy consumption worldwide
– iea.org
Solar PV vs Solar CSP Installed Capacity
In 2018, global Solar PV installed capacity was 480,357 MW, and Solar CSP was 5,469 MW
– irena.org
Solar PV vs Solar CSP Electricity Generation
In 2016, Solar PV electricity generation was 317,613 GWh, and Solar CSP was 11,037 GWh
– irena.org
Solar PV vs Solar Thermal – Differences, Cost, Efficiency & More
Solar PV and Solar Thermal are both used on the large utility scale, and on the smaller distributed/individual scale.
Cost, efficiency, and other variables can differ depending on the scale they are used.
Apart from the obvious differences of investment, installed capacity, electricity generation and electricity consumption, and how they actually work (light energy vs heat energy), some of the key differences at the utility/large scale are:
[solar CSP] provides a dispatchable energy supply – that is, their power output can be adjusted based on grid demand.
This makes them more flexible than traditional solar PV plants.
– cleanenergycouncil.org.au
One of the main advantages of a CSP power plant over a solar PV power plant is that it can be equipped with molten salts in which heat can be stored, allowing electricity to be generated after the sun has set.
– irena.org
Overall, CSP on the utility scale probably faces more barriers and challenges than Solar PV which is far more widely used.
On a household and individual level, greenmatch.co.uk mentions some of the cost, efficiency, flexibility and other differences between the two technologies at https://www.greenmatch.co.uk/blog/2015/04/solar-panels-vs-solar-thermal
For example, solar thermal is usually used for heating water on homes, whereas panels might be used for electricity.
Investment In Solar Energy
Future Of Solar Energy (Solar PV & Solar CSP)
By 2023, solar PV is expected to grow to 8% of renewable energy consumption worldwide, whilst solar thermal is expected to stay the same at 4%
– iea.org
[there is expected to be] a 46% growth over the period 2018 to 2023 in renewable energy as a whole … with solar PV accounting for more than half of this expansion [and, supportive government policies and market improvements are some of the main causes]
Utility-scale projects represent 55% of this growth
China alone accounts for almost 45% of global solar PV expansion
CSP is expected to grow 87% (4.3 GW) over the forecast period, 32% more than in 2012‑17
[some of the barriers facing CSP expansion individually are] technology risk, restricted access to financing, long project lead-times, and market designs that do not value storage continue to challenge CSP deployment
– iea.org
Examples Of Solar PV & Solar Thermal Worldwide – Largest Solar Farms, & Countries With The Most Solar PV & Solar CSP
You can view lists of the largest solar PV and solar thermal power stations at:
- https://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations
- https://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations
Countries with the highest installed capacity:
In 2018, China, Europe, the US, Japan and Germany had the highest installed capacities of Solar PV in MW.
In 2016, Spain and the US easily had the highest installed capacities of Solar CSP in MW.
– wikipedia.org
Sources
1. https://www.bettermeetsreality.com/installed-capacity-production-consumption-of-renewable-energy-worldwide-by-country-by-source/
2. https://www.bettermeetsreality.com/countries-that-invest-the-most-in-renewable-energy-what-they-invest-in/
3. https://www.bettermeetsreality.com/the-different-types-of-renewable-energy-sources-with-examples/
4. https://en.wikipedia.org/wiki/Solar_power_by_country
5. https://www.sciencedirect.com/topics/engineering/solar-thermal
6. https://www.vox.com/energy-and-environment/2019/6/18/18681591/renewable-energy-china-solar-pv-jobs
7. https://www.iea.org/renewables2018/
8. https://www.iea.org/renewables2018/power/
9. https://www.irena.org/solar
10. https://www.vivintsolar.com/learning-center/how-does-solar-power-work
11. https://www.cleanenergycouncil.org.au/resources/technologies/solar-thermal
12. https://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations
13. https://en.wikipedia.org/wiki/List_of_solar_thermal_power_stations
14. https://www.greenmatch.co.uk/blog/2015/04/solar-panels-vs-solar-thermal
15. https://www.iea.org/newsroom/news/2018/october/modern-bioenergy-leads-the-growth-of-all-renewables-to-2023-according-to-latest-.html
I don’t buy the argument that only CSP can store thermal energy. The truth is that regardless whether a CSP or PV system is used to capture the solar energy, in both cases energy could be stored as thermal energy (molten salts or whatever material is chosen). I note it would be foolish to do this from PV if the intended end use is electricity however if the intended end use is thermal (eg defray gas-fired DHW, space heat, process heat) then thermal storage may be cheaper than battery storage for PV.