GE and Southern California Edison recently worked on a project together to more efficiently ramp up generation in the evening when the sun is starting to set and people are coming home to turn everything on. My research assistant a.k.a. my mom just pointed me to this interesting new method that combines a lithium ion battery system with two existing natural gas turbines. The total output of the system will be 50 MWs, and they are calling it the LM6000.
Before there was so much solar and wind power on the grid, energy supply and demand were smoothly coordinated by slowly ramping up natural gas turbines for up to twelve hours. This process worked fine in the old days, but with today’s variable renewable energy sources it is a much bigger challenge. The traditional system of ramping up a gas turbine wasted a huge amount of fuel and therefore released a ton of carbon into the atmosphere. The reason for this is that traditional systems have to burn fuel for hours while they are is standby mode and waiting to connect to the grid.
With the LM6000 system SCE will be able to instantly begin discharging power from the energy stored in batteries while they ramp up the gas turbines. This system allows for much more flexibility then current technology because they can literally start providing energy supply in seconds as opposed to hours. This is going to add stability and reliability to the grid for all of the end customers. By having this capability SCE is also positioning itself to be able to acquire more solar Power Purchase Agreements (PPA) without fear of how to balance supply and demand. Another benefit to the new set up is that is that it can be economical because instead of wasting all of that fuel to start up the gas turbines now they just turn on the battery. Then as the gas turbines start ramping up. All of that energy can actually be sent into the grid instead of being wasted as heat.
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Lead Photo Credit
If you have been following my blog I think you will know that a key challenge to bringing renewable energy to mass market is storage. We have the ability to generate a huge amount of cheap solar energy during the day time, but we really struggle to deliver it at night time. One approach to solving this lies in battery storage. Battery storage has a lot of potential (no pun intended), but we are not able to store municipality levels of energy in batteries yet. Another method that is being tested to store energy is using compressed air. The idea is that we can compress air with electricity generated by solar panels during the day, and release it across a turbine at night time.
This is a clever idea and it does actually work. The problem is that every time we convert energy we lose some efficiency. Air compressors have notoriously low efficiencies which can be between 65% and 80%. This means that for every 10 KW you put into compressing air, you only get about 7 KW of usable air. At this point a reader might ask, “I thought we can’t create of destroy energy, so where does the rest of the energy go?” Great question, I’m glad you asked. You are correct that we can’t destroy energy in reality most air compressors lose a lot energy in the form of heat. All of the energy that is lost in the process of compressing and expanding air across a turbine makes it hard to remain economical.
But all hope is not lost for this method of storing energy. An innovative company called LightSail Energy seems to have figured out a better way. LightSail Energy uses technology that both compresses air for later use, and captures and stores the waste heat for later use. By capturing and storing the heat, LightSail is able to greatly increase the efficiency of the process. Which means they are able to make this type of project much more economical. Another nice thing about compressed air energy storage is that you can scale it up by storing air in large underground caverns.
This company really understood the root problem and came up with a viable solution to solve it. Keep an eye out for LightSail Energy in the future because they are doing a lot of things right. They recently received large rounds of funding from big investors including Bill Gates.
If you have any thoughts on this innovative new technology please share them in the comments section.
Lead PC: https://www.waterpik.com/shower-head/buying-guide/images/high-pressure-shower-head-buying-guide.jpg
CAES PC: https://www.pge.com/pge_global/local/images/data/en-us/about-pge/environment/what-we-are-doing/compressed-air-energy-storage/caes.jpg