Sustainable Green Energy Storage
Solar PV and wind farms have made great strides as a source of sustainable green energy at scale. However, such energy sources continue to face two key challenges:
Intermittency - There are no guarantees the sun will shine, or the wind will blow at a speed the turbines can use.
24/7 operations - PV has developed over the past 30 years to provide inexpensive daytime electrical power. The challenge with PV is it's incredibly expensive to store electricity at scale in batteries or BESS (Battery Energy Storage Systems).
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That raises the question, what can you do at night. PV has been paired with BESS, which in effect are large Lithium Iron (or derivative there of) packs. There are three main draw backs to BESS:
1. Cost - Typically at scale BESS systems cost more that $120 per MWH which is expensive.
2. Duration - BESS systems typically release there charge over a 4 to 6 hour window. So still not typically 24 hour supply.
3. Disposal - Currently the cost of recycling BESS systems far out strips the value of the materials extracted. Consequently, PV and BESS systems are predominantly consigned to landfill.
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PV is typically used to top up the grid during the day and non renewable energy utilised at night.
How Does ASC-WE Solve The Storage Problem?
ASC - WE and our partners have studied existing CSP technologies and looked at the reasons those solutions have failed to have mass adoption. See Basic Concept page and developed fixes for each of those challenges.
Why did we pursue CSP over other renewable energy solutions?
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Simple answer, STORAGE.
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Benefits of Thermal Storage over Electrical Storage:
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1. Cost - Heat can be stored for long periods of time with little losses. It can also be stored in many different mediums. Molten Salts, Thermal Oils, Sand, Rocks etc. No rare earth materials or expensive fabrication.
2. Dispatchability - Heat can be stored overnight and extracted to create steam throughout the nigh to supply a turbine. We can gather energy during the day and create electrical power 24 hours a day, unlike batteries which are limited to 4 to 6 hours only.
How Do We Store Energy To Produce 24Hrs a Day?
Below is a depiction of the daytime charging and nighttime discharging cycles. During the day, approximately 2/3 of the heated Molten Salt is stored for use at night, and approximately 1/3 is used during the day to produce high pressure steam for power production. The temperatures indicated on the schematic are indicative, they are project dependent.
Below is a typical arrangement of Hot and Cold storage tanks.
How Do We Size The Project?
Every ASC CSP project is unique. The energy produced per ASC varies depending on two factors:
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1. The sites Direct Normal Irradiation (DNI) This varies significantly around the world. To check your location, use this tool https://globalsolaratlas.info/ If your location has a higher than 5 kwh/m2 per day, we can help.
2. The size of the power output per hour. Steam turbines convert the thermal energy to electrical. Generally, the larger the output the more efficient the steam cycle efficiency.. The higher the efficiency the more productive each ASC will be. See example below.
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Although the KWth is constant according to the local DNI ie. DNI 9 = 47.4 KWth;
the electrical power is variable depending on the Steam Cycle Efficiency of the turbine converting the thermal energy into electrical.
The higher the power output on the turbine, the higher the efficiency.
The efficiency ranges from 28% to 47%.
This improves as the DNI gets higher.
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Example below:
For more information on how we deliver 24 hour, dispatchable heat and power, contact us