A parabolic trough collector directing solar energy to generate CSP.

Summary

  • The solar industry is inevitably growing as the push for green energy increases. Now deemed the cheapest electricity available, solar panels are leading the transition to a clean energy future.
  • There are various ways to harness the sun’s energy, including concentrated solar power (CSP). CSP uses reflective surfaces to direct solar rays onto a receiver where a heat transfer liquid absorbs the energy. The liquid produces steam, which turns a turbine to generate renewable electricity.
  • There are four types of CSP plants, two of which can track the sun’s movement throughout the day—improving efficiency. There are some concerns with CSP water consumption and the effect these plants may have on soil temperature. However, there is no denying the positive impact solar energy has on the environment, from improving air quality to reducing fossil fuel use.
  • Despite the advantages that CSP plants offer, energy investors tend to choose solar PV technology over CSP. This is essentially due to the competitive cost of solar PV systems, government schemes and public acceptance of using solar panels.

Introduction

Solar panelled roofs and farms are becoming a regular sight, and it’s no secret that this rise in renewable energy is benefiting the environment.

The solar power industry has disrupted the energy market and cemented its place in history as one of the safest, cheapest forms of energy. Solar panelled roofs and farms are becoming a regular sight, and it’s no secret that this rise in renewable energy benefits the environment. However, it may come as a surprise that multiple solar technologies are available, all contributing to a clean future in their own way. Among these is concentrated solar power (CSP), a mirror system that directs sunlight to generate heat and electricity.

This article explores how CSP generates electricity, its position in the solar market and how it compares to solar photovoltaic (PV) technology.

An infographic showing a concentrated solar power plant using a central tower to collect solar energy.

What is Concentrated Solar Power?

This substance is heated to approximately 600°C to 1200°C, producing steam to operate a turbine that generates electricity.

If you were an adventurous child, you might have experimented with sunlight and a magnifying glass. This is the basic principle of CSP as it uses reflective surfaces to concentrate the sun’s energy. CSP is also referred to as solar thermal electricity. These thermal systems use mirrors to direct sunlight to a heat absorber containing heat transfer fluid (HTF). This substance is heated to approximately 600°C–1200°C, producing steam to operate a turbine that generates electricity. Essentially, the power plant collects the sun’s energy and converts it into heat, while another system converts the heat into electricity.

There are four main types of CSP technology that convert solar energy into usable electricity.

Linear Fresnel Reflector (LFR) – Large mirrors reflect the sun’s energy onto a linear receiver tube. Interestingly, experts can design hybrid LFR systems to work alongside fossil fuels. Fossil fuel supplements the system during periods of low solar radiation. While this may be ideal for transitioning away from fossil fuels and increasing solar capacity, it may not be a long-term solution due to the catastrophic effect of fossil fuels on the environment.

Parabolic Trough CollectorTrough collectors use a set of long concave mirrors to concentrate solar rays on a receiver tube in the focal point. The collector tilts as the sun’s position changes throughout the day to improve the efficiency of these systems.

Central Receiver – A solar tower stands among an array of reflectors positioned towards the central solar receiver. As the sun’s rays hit each surface, the mirrors direct the sunlight to the tower, where the energy is converted into heat, then electricity.

Parabolic Dish Collector – This is similar to a parabolic trough collector; however, instead of a set of long concave mirrors, this method uses a large dish with a central point. Together, the dish and receiver track the sun to maximize solar intake.

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How Does CSP Compare to Solar PV Technology? 

CSP systems use Thermal Energy Storage (TES) technology, while solar panels can store power in a solar battery for later use.

Unlike CSP, solar panels convert sunlight into electricity by knocking electrons loose, creating a current. An inverter switches the flow from direct current (DC) to alternating current (AC), supplying the grid and households with electricity. In fact, this is one of the primary differences between solar power and CSP. While solar farms can generate electricity for the grid, solar PV technology is commonly used to produce renewable energy for residential homes and commercial buildings. On the other hand, CSP is only available on a larger scale because the equipment is costly.

  • CSP technology may be more efficient
    Both PV and CSP technology are reliable sources of renewable power. Because the sun rises and sets every day, there are guaranteed periods of electricity generation. However, CSP equipment is a little more advanced as it can track the sun, following it to ensure sunlight is hitting the fluid throughout the day. This technology maximizes the efficiency of the device.
  • Solar power provides renewable energy to the grid
    Unlike solar PV panels, CSP creates an AC, meaning it can supply electricity directly to the grid. As CSP is easier to distribute, it may provide greater grid stability than power generated through PV panels. 
  • Energy storage can supply solar power at night
    Solar storage was revolutionary for the solar industry as it addressed the critical downfall of solar power generation—reduced efficiency during periods of low solar radiation. With the addition of an energy battery, solar power can be stored for use during the night, overcast days or dark winters. Both solar PV and CSP equipment can store solar power. CSP systems use Thermal Energy Storage (TES) technology, while solar panels can store power in a solar battery for later use. The addition of these storage systems addresses irregularity issues and makes solar power a reliable energy option.
  • CSP equipment is costly compared to solar PV
    It’s no secret that solar PV technology has become more affordable. In fact, the cost of solar PV equipment has fallen by 82% in the last ten years, with these prices continuing to drop in the face of COVID. Unfortunately, CSP equipment is larger, more complex and takes longer to build, making it very costly.
  • CSP plants may affect local wildlife
    Concentrated solar power plants take up a large area to direct the sun’s energy to the receiver. Some reports suggest that the high temperatures from these plants are harming birds. One study found that a solar plant may be responsible for 600 bird deaths per year. While this number may be considered small compared to oil and gas waste sites that are responsible for approximately 1 million bird deaths annually, it is still an environmental concern affecting local wildlife. 

An infographic depicting parabolic cylinders generating concentrated solar power.

Energy Investments for the Solar Power Market 

Due to the increasing demand for solar panels, government incentives and growing climate concerns, PV technology has become a lucrative solar investment.

When deciding which solar stocks to buy, energy investors are concerned with competitive power costs. As CSP takes longer to build and requires a large site, it is costly to construct. On the other hand, solar PV is far cheaper and easier to create. Due to growing climate concerns, demand for solar panels and an increase in government incentives, PV technology has become a lucrative investment. It has been this way for years, causing the financial gap to grow between CSP and PV systems.

Therefore, because solar panels are favoured for their affordability and versatility, green energy investments have slowed for CSP. That said, any solar investment may be a good one as the International Energy Agency (IEA) predicts solar power to dominate the energy industry by 2050 as more people turn to solar in a bid to control climate change.

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Key Takeaways

Concentrated solar power generates renewable electricity on a large scale, providing greater grid stability and reducing the demand for fossil fuels. CSP systems are also referred to as solar thermal electricity because they use heat to create steam to power a turbine and produce electricity. However, extreme temperatures may result in a higher death rate in birds. That said, the figures are dramatically lower than oil and gas waste.

It’s clear that solar power can help displace fossil fuels, but solar PV remains the favoured energy investment as CSP technology is expensive and high-risk. Compared to CSP, solar PV can provide renewable energy to electric car charging points, homes, businesses, and more. Either way, the solar industry is on an incline, and it doesn’t look like it’s slowing down any time soon.

Frequently Asked Questions (FAQs)

What is concentrated solar power?

Concentrated solar power (CSP) directs the sun’s energy onto a solar receiver, where it heats the fluid and produces steam. This steam turns a turbine to generate renewable electricity. There are four types of CSP systems, Linear Fresnel Reflector (LFR), Parabolic Trough Collector (PTC), Parabolic Dish Collector (PDC) and Central Receiver. Some of them track the sun to ensure maximum efficiency. CSP systems generate alternating current (AC) to provide reliable electricity directly to the grid.

 

How hot can concentrated solar power get?

CSP is also known as solar thermal electricity. It differs from solar thermal panels, which heat water directly to provide warm water and air to homes. Depending on the technology used, CSP concentrates sunlight 300–1500 times, causing it to reach temperatures up to 600°C 1200°C.

 

Which is better, PV or CSP?

Solar photovoltaic (PV) panels and CSP differ significantly. Solar PV systems convert sunlight directly into electricity, whereas CSP uses the sun’s energy to heat a liquid, create steam and turn a turbine. Solar panels have become a common sight on rooftops, but this can’t be said for concentrated power. In fact, CSP plants are only viable on a large scale because the equipment is bulky and expensive. PV panels are more versatile and can be used to power individual homes as well as large areas. Both types of solar power positively impact the environment because they do not emit greenhouse gases during energy production, thus reducing the dependence on fossil fuels.

 

Is concentrated solar power good for the planet?

A study conducted in China investigated how a large-scale CSP plant may impact the environment. The results highlight that water usage and soil temperature may be the primary concerns. CSP plants use water to produce steam for turbines, cooling the system and washing the mirrors. The researchers found that a 50-megawatt plant used 1,600,000m3 of water annually to cool the systems. In comparison, a ‘dry’ cooling system only uses 400,000m3 annually. Moreover, a CSP plant affects soil temperature, which may disrupt sensitive growing conditions for local produce.

Solar power technology does not produce harmful greenhouse gases, providing improved air quality to the local community. Solar technology has minimal environmental impact compared to fossil fuels, and it’s deemed the safest form of energy.

 

Is CSP worth investing in?

The solar industry provides reliable investments as solar technology is set to dominate the energy industry by 2050 to reach global climate goals. Due to public acceptance of renewable energy, solar PV systems remain the favoured energy investment. Solar panels and solar farms are cheaper, easier to build, and often have more government support. Compared to PV technology, CSP may pose a higher risk due to storage and cooling issues. Alongside these challenges, CSP plants are larger and more expensive to build, making them less desirable to potential energy investors.

 

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