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
- 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
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
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
- 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
- In 2017, solar PV and solar thermal were both responsible for 4% each of renewable energy consumption worldwide
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
Solar PV vs Solar CSP Electricity Generation
- In 2016, Solar PV electricity generation was 317,613 GWh, and Solar CSP was 11,037 GWh
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.
- 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.
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%
- [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
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:
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.