The rise in the popularity of solar power energy comes with the expansion of the technologies associated with it. After all, once people realized that the sun can be used to generate electricity, they would understandably find ways on how to do it. And so far, there are two technologies that are used nowadays to generate solar power. These are Concentrated Solar Power (CSP) and Photovoltaic (PV).
But what is the difference between these two? And if possible, which among them is the better option? To answer these questions, it’s better that we compare and contrast these two technologies to see how they differ and what advantages and disadvantages do they offer.
Concentrated Solar Power (CSP) vs. Photovoltaic (PV)
To begin with, Concentrated Solar Thermal systems (CSP) produce electric power by converting the sun’s energy into high-temperature heat using various mirror configurations. The way these particular technology works is that the sun’s energy is concentrated by various reflectors, and this concentrated energy is then used to drive a heat engine and drive an electric generator. The plants that utilize this system consists of two parts: one that collects solar energy and converts it to heat, and the other that converts the heat energy to electricity.
CSP is an indirect method that generates alternating current (AC), which will then be easy to distribute on the power network.
Photovoltaic (PV) solar panels, on the other hand, are completely different from CSP. Unlike CSP which uses the sun’s energy, PV solar panels make use of the sun’s light instead. In other words, photovoltaics is the direct conversion of light into electricity. The way this works is that the solar PV cells absorb light, which will then knock electrons loose. Then once the loose electrons flow, a current is created, and this current is then captured and transferred into wires, thus generating a direct electric current (DC). After the direct electric current is generated, it is then converted into AC, usually using inverters, so that it will be distributed on the power network.
Energy Storage and Efficiency
CSP systems are capable of storing energy through the use of Thermal Energy Storage technologies (TES). As a result, they can use it at times when there is little to no sunlight, like during cloudy days or during night time, to generate electric power. Because of the CSP’s ability to store energy, the penetration of solar thermal technology in the power generation industry is increased since it helps overcome irregularity issues.
Meanwhile, PV systems aren’t capable of producing or storing thermal energy since they use direct sunlight instead of the sun’s heat. And in addition to that, storing electricity (for example, in batteries) is also not easily done, especially at large power levels.
Because of this, it is then clear that in terms of energy storage and efficiency, thermal energy storage technologies are better, thus making CSP systems the far more attractive option for large scale power generation. Furthermore, since CSP systems are able to produce excess energy and store it for future use, they can help improve the financial performance and also the sharing ability of solar power and flexibility in the power network.
Market Update: Investor’s Perspective
There are three main factors that energy markets consider when deciding on power sources: cost of energy, ancillary services, and power dispatch-ability on demand. Obviously, for energy investors, the competitive cost of energy is the most important issue. And since PV is a lot cheaper than CSP, more and more energy investors choose it. This trend of investors choosing PV over CSP will continue so long as PV remains cheaper. And it seems like that’s going to continue to happen because PV panels have recently demonstrated a large price drop — about 30% to 40% in just a couple of years — and some expect that these prices will keep on dropping.
As for CSP, if these systems want to be attractive to investors, then they have to find a way to be able to demonstrate high performance in all three attributes. Because they may be more efficient and able to store a lot of energy for future use, but if they also cost a fortune, no one would want to invest in them.
Aside from the cost, energy market players have also reported that PV systems are a lot easier to build. Building them doesn’t cost much, and it also doesn’t take too much time. This is not like CSP because CSP plants need more space for large-scale applications, and they also have greater risks. Some of these risks include higher investment, challenges with thermal shortage, and cooling.
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Integration for Increasing Solar Power Penetration
Even though it seems like PV installations are favoured just because they don’t cost that much and they’re easier to build, the comparison between CSP and PV will still remain a point of contention. Some might even argue that trying to decide which of them is the better choice is pointless because, at some point in the future, they may no longer have to compete against each other. They may actually merge together and work as one to increase solar energy penetration into the power industry.
In fact, according to the latest research activity at the U.S. National Renewable Energy Laboratory, TES can supposedly increase the penetration of solar or wind power — which are intermittent renewable energy technologies — into the power industry. This means that CSP, along with the capabilities of Thermal Energy Storage, can be used as a complementary solution to solve the intermittency problems of other renewable energy technologies like solar PV and wind turbines. Both of these technologies heavily depend on environmental conditions, which are unpredictable and unstable, so their reliability, as power generation solutions, are rather limited. Thankfully, CSP and TES might just be able to solve that.
So is CSP really competing with PV?
With all these comparisons between Concentrated Solar Power and Photovoltaic, one would get the idea that these two are competing against each other. At first glance, it actually makes a lot of sense to make this inference because after all, CSP and PV are two kinds of technologies that the solar power industry uses. However, when you look closely, you’ll realize that CSP is actually not competing with PV. Instead, it is competing with natural gas.
As we have already established earlier, CSP makes electricity by using the sun’s heat primarily. This would then make this technology a thermal kind, and because of this, we can say that in reality, CSP is actually competing with other sources of energy that are thermal in nature. There are many examples of this, but the energy source that CSP is really strongly battling against is natural gas.
CSP vs. Natural Gas
The reason why CSP is competing with natural gas is simply because of the fact that they are both dispatchable. Since CSP absorbs the sun’s heat to generate electricity, it can be dispatched whenever it’s needed. Likewise, natural gas can be withdrawn from natural gas or crude oil wells and then stored in processing plants to be used to generate energy. Basically, both CSP and natural gas are attractive forms of generating energy because of their ability to be dispatchable. But unfortunately, between the two, natural gas is the preferred one, simply because of its affordable price.
And the fact that natural gas is the preferred option poses a big problem for all of us. To begin with, natural gas is not safe for the environment — just like the other fossil fuels. It’s true that natural gas emits lower emissions during power generation than coal, but methane still leaks during the drilling and the transporting. And methane is a greenhouse gas that is 20 times more potent than carbon dioxide. In other words, natural gas is something that can literally kill people and animals.
Another downside to natural gas is the fact that it has volatile fuel costs. Its prices are unpredictable. They may look reasonable now, but over time when the resources run dry, these prices will definitely shot up. And that’s not a piece of good news.
Long story short, CSP and natural gas both offer the same desirable characteristic of being dispatchable on demand. And though between the two, CSP is the safer and better option, natural gas still wins because its prices are way more affordable than CSP’s. That is why if CSP aims to be an attractive option of electricity generation, it has to compete with natural gas and eventually win.
CSP and PV Projects
So, now that we already know that CSP and PV have their own advantages and disadvantages, it shouldn’t surprise us anymore that there are many projects for these two. Some of the most popular and the largest projects of CSP and PV are as follows:
Ouarzazate Solar Power Station
The Ouarzazate Solar Power Station (OSPS), also called as Noor Power Station is a solar power complex that is located in the Drâa-Tafilalet region in Morocco. With an installed capacity of 510 MW, it is the largest concentrated solar power pant of the whole world. And as though that number is not big enough, the Moroccan Agency for Solar Energy has supplemented an additional 72 MW photovoltaic system so as to allow the plant to produce 582 MW at peak. The total cost of this project is expected to be around $9 billion.
Ivanpah Solar Power Facility
The Ivanpah Solar Electric Generating System is a concentrated solar thermal plant located in the Mojave Desert in the United States. The plant has a gross capacity of 392 MW, and it deploys 173,500 heliostats, each with two mirrors focusing solar energy on boilers located on three centralized solar power towers. With the plant’s installed capacity, it’s one of the world’s largest solar thermal power stations.
Solar Energy Generating Systems
Solar Energy Generating Systems (SEGS) consists of nine solar power plants in California’s Mojave Desert where insolation is among the best available in the United States. Initially, there was a plan to construct a tenth plant. But the developer, Luz Industries, filed for bankruptcy in 1992 because it was unable to secure construction financing. The combined capacity of all nine solar power plants is 354 MW, thus making SEGS as one of the world’s largest solar thermal energy generating facilities.
Longyangxia Dam Solar Power Park
The Longyangxia Dam is a concrete arch-gravity dam that was initially built for hydroelectric power generation, irrigation, ice control, and flood control. However, in 2013, a solar PV station was built, and this station, named the Longyangxia Dam Solar Power Park, was completed in 2015. The completed solar power park has an installed capacity of 850 MW, which can generate about 200,000 households. With this installed capacity, Longyangxia Dam Solar Park is considered as the world’s largest PV project.
Solar Star is a solar photovoltaic power station located in Rosamond, California. It is operated and maintained by SunPower Services, and it uses about 1.7 million solar panels, spread over a total area of 3,200 acres. These solar panels are form-factor, high-wattage, high-efficiency, higher-cost crystalline silicon modules that are mounted on single-axis trackers. When it was completed back in 2015, it was considered as the world’s largest solar farm with a generating capacity of 579 MW.
Topaz Solar Farm
The Topaz Solar Farm is a photovoltaic power station that is located in the San Luis Obispo County of California. This project cost around $2.5 billion, and it includes 9 million CdTe photovoltaic modules based on thin-film technology. Construction for this project began in November 2011 and ended on November 2014. With an installed capacity of 550 MW, the Topaz Solar Farm is considered one of the largest solar PV farms in the world.
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Nowadays, there are two technologies that dominate the solar power industry: the Concentrated Solar Power (CSP) and Photovoltaic (PV). These two may be similar in that they both use the sun in order to generate power. But beyond that, they are as different as can be.
To start with, CSP makes use of the sun’s radiation to heat a liquid substance that will then be used to drive a heat engine and drive an electric generator. Meanwhile, PV uses light through the “photovoltaic effect” — the absorbing of light which then leads to the breaking of the electrons — to generate an electric current.
Both CSP and PV have their own pros and cons. In terms of energy storage and efficiency, CSP is superior since it can store energy with the help of TES technologies. PV, on the other hand, is incapable of producing or storing thermal energy since they directly generate electricity. Aside from that, it’s also difficult to store electricity.
Although CSP is obviously the more efficient one in terms of energy saving, that doesn’t mean it’s the best option. Between the two, PV is cheaper, so energy investors are more inclined to use it than CSP. In other words, despite its advantages, CSP isn’t the favoured one.
However, all these debates — of which is better the option — are pointless because they don’t have to compete against each other. In fact, the world will be a better place if they actually work together. Hopefully, one of these days, a new technology for solar power will arise, and it will be a hybrid of the two.
Whatever the case, both CSP and PV are helpful in promoting the solar industry. They both made solar power possible, and they will be the reason why solar power will be here to stay.
The rise in the popularity of solar power energy comes with the expansion of the technologies associated with it. After all, once people realized that the sun can be used to generate electricity, they would understandably find ways on how to do it. And so far, there are two technologies that are used nowadays to generate solar power. These are the Concentrated Solar Power (CSP) and Photovoltaic (PV).