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The cost of renewable energy sources is decreasing rapidly and is now competitive with or even lower than that of traditional power plants in some regions. However, there is a key drawback that must be addressed before renewables can fully replace conventional energy sources. That's the way to even out your power usage over time, eliminating issues with weather and peak usage. The good news is that work is being done and, in some cases, has already produced remedies.
With their fast-disappearing costs, wind and solar are attractive options for generating electricity. In many circumstances, the cost of wind and solar energy is only half that of a coal plant. In fact, maintaining operations at 74% of current U.S. coal facilities is more expensive than installing new solar or wind farms to replace them. 1 Overwhelmed by the costs, utilities are abandoning plans for coal and natural gas plants in favour of renewable energy sources like wind and solar. After originally planning to shut down only two of its five coal facilities by 2023, Northern Indiana Public Service has now committed to shutting down all of its coal plants within the next decade.
The increasing share of renewable energy sources in the grid, however, poses a difficult electrical load problem for utilities. This is the dreaded "duck curve." Yes, we are going to discuss a duck.
Normal electricity use would serve as a good case in point. See the accompanying demand graph for a typical day in California in 2016 below. You can see that demand is lowest between 4 and 5 in the morning, gradually increases throughout the day, and reaches its highest point between 7 and 8 in the evening. One way to visualise the power curve from solar generation is to imagine it as a function of time during the day. The day's peak production time is about lunchtime, and production slows down just as the day's peak demand begins. 3 improper application.
The well-known duck shape emerges when solar output is subtracted from total demand. Yes, it's a stretch, but bear with me... If I could meet the person who came up with the term "duck curve," I'd ask them to draw me a duck. for the simple reason that I have never seen a duck that looked like that. In any case, the duck's back gets steeper and more slanted as more solar power is added to the system. What's the big deal here? Well, the proper amount of electricity needs to be generated so that switches can be flipped on whenever they are needed. There are now two kinds of power plants used for this: baseload plants and peaker plants.
The power generated by baseload plants is consistent throughout the day, the week, and the year. As such, they are not flexible in terms of the rate at which they produce electricity and are instead intended to just... run. Common examples include coal and nuclear power facilities. This would be programmed to operate close to the minimum point on a demand curve.
The solution lies in the use of "peaker" plants. The ramp-up time is shorter compared to a base-load plant; hence, these are only used during peak demand. Peaker plants typically run on fossil fuels like natural gas or oil.
The steeper the duck curve, the less the base load plant can be operated at once, necessitating the use of peaker plants to meet the shortfall. Obviously, I've oversimplified, but that's really the crux of the issue we're facing with certain forms of renewable energy, such as solar.
However, this can be worked out. With the use of energy storage, solar power can be produced more steadily, eliminating the need for costly peaker plants. The current solutions and projects are exciting and interesting to me.
As anyone who has seen any of my videos may guess, batteries play a significant role in the resolution. Different large-scale battery deployments have shown their worth to the grid in a variety of ways. Tesla's 100 MW Hornsdale project made headlines since it has reduced Australia's electricity bill by approximately $40 million AUD in its first year of operation. 6 That's equivalent to a little more than a third of the total price of the system. Since around half of South Australia's electricity comes from renewable sources, Australia becomes a wonderful test bed for this. 8 As a result of their achievement, Tesla was awarded the contract to construct a 1.2 GWh energy storage system for PG&E in California.
Next to an existing solar power plant, Florida Power & Light is constructing a 900 MWh battery energy storage system. For the past two decades, FPL has been upgrading its infrastructure by mostly replacing oil-based powerplants with natural gas units. However, as solar and batteries become more cost-effective, FPL is also investing in those areas. FPL plans to shut down its final coal plant in Florida before the end of the year.
The concept of flow batteries is intriguing. It's a rechargeable cell in which two electrolyte liquids are combined after being pumped from separate large vats. During the ion exchange between the positively and negatively charged liquids, electricity is produced. 11 The largest vanadium-flow battery project in the world is being constructed in the Chinese province of Hubei. An expansion of this 12-MWh storage system pilot project into a 500-MWh system is possible in the future. 12 Huxley Hill, a wind farm in Australia, and Tomari Wind Hills, a wind farm in Japan, are only two examples of the many wind farms that make use of flow battery systems.
There are also hybrid battery setups to consider. The hybrid sodium-sulfur and lithium-ion battery system was constructed in the German state of Niedersachsen. To perform various grid-balancing functions, it employs lithium-ion batteries with a capacity of 2.5 MWh and sodium-sulfur batteries with a capacity of 20 MWh.
Pumped-storage To store electricity, hydroelectricity is among the most economical options available today. The system operates by transferring water from a lower reservoir to a higher reservoir using electricity that is either surplus or cheap. When more electricity is needed, water from a higher reservoir is discharged and runs through turbines on its way back down to the lower reservoir. It's not a complicated system, but it does the job.
Dinorwig Power Station is a network of tunnels beneath Elidir Mountain in the United Kingdom. In periods of low demand, the water supply is supplemented by pumping it to a high-elevation reservoir. When electricity is needed, the water is allowed to run backwards via the turbines, producing around 11 GWh.
The Bath County Pumped Storage Plant in Virginia is the world's largest pumped-storage station with a maximum capacity of 24,000 MWh. About 1,260 feet (380 metres) separate the two reservoirs on the map. Similarly to how the Dinorwig Electricity Station operates, the top reservoir is filled by pumping water during periods of low power demand. The water can be released at the time of greatest need.
I think it's awesome that you came up with this. It's not radically different from pumped storage in principle, but it's easier to implement and doesn't necessitate huge quantities of water or land. Simply lifting big objects into the air and letting them fall into a generator is all that's required to harness their kinetic energy. It's a method that's been around for hundreds of years and that, at some point in their lives, I'm sure everyone has encountered. You've probably seen this in action in the form of a pendulum clock.
Gravitricity18 is a firm that is significantly expanding this idea. They propose drilling new mine shafts or repurposing abandoned ones to hoist and lower massive weights instead of requiring a vast amount of room to store batteries or reservoirs. The smart use of previously used mine shafts drastically cuts down on construction costs. It's an intriguing option because it has a 50-year expected lifespan, produces between 1 and 20 MW of peak power, and can ramp up from zero to full power in under a second.
This option is still in the process of becoming commercialised, but it represents a promising development in the field of energy storage.
The technologies mentioned above are by no means all that are currently available or will soon be introduced. Several alternatives exist, including salt water batteries, molten salt batteries, sodium-sulfur batteries, and even fly wheels. Intriguing developments are being made, but the main point is that large-scale energy storage for the grid is feasible. It's often already here and widely employed. Renewable energy critics often cite the inconsistency of their sources' energy output as proof that the concept is doomed to failure. We can't let ourselves be convinced by the status quo that the disadvantages of renewable energy today are insurmountable tomorrow. In this instance, necessity truly is the mother of invention.
You can call me an idealist, but I think this bodes well for the development of alternative energy sources like solar and wind. A more adaptable and reliable power grid benefits everyone. one that can supply all of our energy needs in a sustainable manner while also cutting down on our costs.
Where do we stand with the obstacles to solar power generation?
To put it another way, the supply and demand curves don't match up. In fact, if solar energy cannot be stored or poured into water heating, it may be necessary to turn off solar systems during peak generation times. Solar panels have the potential to be a very sustainable energy source if they are used for the full 20–25 years that their guarantee specifies.
If solar energy is so great, why isn't it more widely used?
There is concern that the existing power grid infrastructure isn't equipped to handle the variability of solar energy production because it was designed to handle more stable power generation levels. The capacity factor measures how often power is generated and is another aspect that lowers solar energy's competitiveness.
To what extent do the benefits of solar energy outweigh the costs?
Low return on investment (ROI) due to high upfront material and installation costs; however, with the cost of solar falling over the last decade, solar is becoming more cost-effective by the day. Lacking perfect efficiency, it requires a large amount of room. The lack of solar power at night necessitates a sizable battery bank.
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