Energy Storage
A reader asked a question on compressed air storage the other day, and pointed to a web site that had some information.
http://www.doc.ic.ac.uk/~matti/ise2grp/energystorage_report/node7.html
Energy storage seems to have captured the imagination of the public. Indeed, the wind industry has been caught up in this too. An Irish wind developer invested in a battery system from VRB in Vancouver. An Iowa wind developer is investing in a compressed air storage system.
I think the interest in storage comes from people who want a complete transition of our electricity supply to renewable energy. They know that this can’t happen until storage is available widely, and at low cost. Renewable energy of all types has variable output, depending on the wind, sun, rain, waves, or tides, and so some storage is required to be to 100% renewable.
You will notice that the title of this entry is energy storage. It is not electricity storage. We already store energy in a myriad of ways.
We store heat in hot water tanks. We store cool in office buildings, refrigerators, and freezers. We store potential energy behind a dam. We have industrial processes, such as manufacture of steel or aluminum, that have a vast amount of energy stored in the material transformation. We have batteries, which store energy chemically. And we have the ultimate storage medium – fossil fuels.
The benefit of storage, even without renewable energy, is obvious. In Ontario, for example, we have a peak demand of 27,000 MW, but average demand of 17,500 MW. If we had unlimited storage, and the stored energy was immediately available, we would not need to build 27,000 MW of capacity. We could build only 17,500 MW, and still meet our needs. And that would save $ billion’s in capital construction cost.
We can shift demand to accomplish the same benefit offered by storage. If we can shut off the hot water heaters, the steel mills, the water pumping, the air conditioning, or the heating, even for a short time, we can shift our peak demand to a time when demand is lower. The Smart Meter proposal for Ontario may allow this, although details are still sketchy. The UK used to have surplus power at night. So they offered a very low price. Consumers built heating closets, full of rocks, which they heated at night using resistance electrical heat. The heat was then released during the day. Demand for heat shifted from daytime to night. Shifting demand is an underutilized resource in Ontario.
The biggest conventional source of stored energy is hydro dams. In Ontario, we regularly have about 3000 MW waterpower energy available for use during peak periods. Some places have installed pumped storage, including Niagara Falls, on both sides of the river. Water is pumped at night to a storage reservoir, and released through the generators during the day. Pumped storage has an efficiency of 85-90%, so if you use 100 MWh to pump the water, you will get back 85-90 MWh when you release it.
Compressed air requires large sealed underground reservoirs. These would usually be salt formations, or abandoned natural gas wells, that have demonstrated an ability to store gas for millions of years without leaking. Leaks would hurt your efficiency dramatically. Compressed air is not in widespread use, but might be worthy of more consideration. Ontario has the world’s largest salt mine – we must have some suitable sites.
Battery storage is in widespread use in off grid applications, but is seen as too costly to provide backup for the main electricity grid.
But one of the largest storage mediums we have by far is fossil fuels. If you are producing power from a wind turbine, you don’t have to burn them to make electricity. And that means you can store the fossil fuel for the future. The first use of wind energy should always be to reduce the burning of fossil fuels.
February 12th, 2007 at 1:55 am
Using this article, i can understand the info about ENERGY STORAGE. I would like to give a thank to publish this article.
February 17th, 2007 at 10:53 am
Several articles report that wind is 95% off-peak. To make wind viable, storage is essential.
Demand and supply are the major components of the cost of electricity. If we lower peak demand, supply will increase and the cost of power will fall significantly.
The primary method available to reduce demand is to make ice when electricity is cheap. Melt the ice for air conditioning when electricity is expensive or in high demand. This is a simple alternative to spending billions building new coal fired electric power plants.
Thermal Energy Storage, TES systems have been in use since in Texas since the 1920’s when 3 Dallas churches installed systems. One of the original applications was to use a small inexpensive compressor to make ice all week long and then melt all that ice to cool the sanctuary for two hours on Sunday. A common TES system is using tank type water heaters (hot thermal storage) to avoid large instantaneous gas or electric water heaters.
So why don’t we find a TES air conditioner in every house and small business? The answer is also simple:
• Most electric rates are averaged so it is not less expensive to buy electricity when it should be cheap and it is not more expensive to buy electricity in high demand periods when the price should be exponentially higher.
• In very round numbers it costs thousands of dollars per kW (or ton of A/C) to fund the construction of electric generation plants, transmission and distribution (TD) infrastructure. There are no mechanisms to divert funds from coal fired generators to funding TES systems in your home or business. The current conservative estimate of avoided costs to build generation, transmission and distribution infrastructure is $1000. per kW per year. This adds up to more than $45,000. over the 15 year life of a 3 ton TES system.
Should we invest $45,000 in new coal generating plants or invest a fraction of that in your home TES system?
If the above economic rationalization isn’t enough to convince you, consider the following additional benefits on TES.
• Running your air conditioner at night to make ice for daytime use is much more efficient because the ambient outside temperature is much lower and you’re a/c unit operates more efficiently.
• Running the generating turbine at night is much more efficient for the same reason, lower nighttime temperatures.
• All power plants run more efficiently when they are fully loaded and demand is predictable.
• Transmission and distribution is more efficient at night.
A massive deployment of TES will postpone the need to build additional power plants for many years and lower the cost of power for consumers. We can land on the moon. Why can’t we make ice?
March 9th, 2007 at 11:33 pm
[...] Another way of thinking of Demand Response as “dispatchable demand.” In general, the electic utility matches supply and demand of electricity by controlling supply and trying to keep it in sync with demand from customers. But the other side of this coin is to allow customers to respond to price signals from the utility to allow them to choose to use electricity when it is easier and cheaper for the utility to supply. I see the widespread use of demand response (along with energy storage) as essential if we are going to meet our energy needs with intermittent resources such as solar and wind. [...]
April 13th, 2008 at 1:49 pm
Our global dependence on fossil fuels and our urgent attempts to free ourselves from this dependence have revealed a significant deficiency in our current energy generation and supporting infrastructure. We are making great strides in the energy generation field with a nuclear renaissance on the horizon and the emergence of new and innovative ‘green’ technologies; nonetheless, these gains are offset by the inefficiencies inherent in our infrastructure. Unless we invest in and develop our capabilities to store efficiently the energy that we are producing, we are only going to add to the problem. We need a cost-effective, reliable and efficient energy storage platform to 1) transfer energy into, 2) store the energy, and 3) release it when needed. If this ideal platform existed today we would be much closer to true energy independence. The consequence of such a break-through in energy storage technology would truly change the face of the globe and help us realize our dreams.
In order to gain a better perspective on what a universally desirable energy storage device should comprise, we should look at each of the processes above. This may be an overly simplistic view of energy storage, but it does provide insight into what we are up against. Of the three processes, numbers 1) and 3) are the biggest culprits when it comes to wasting the energy we are trying to conserve. These losses are repetitive and additive and are a consequence of the inability of the energy storage device readily to accept energy and its reluctance to release it when needed. For example, if you take an ordinary lead acid battery, the amount of energy required to recharge it is always greater than what is actually stored, and you can never get as much out of it as it can store. These inherent short-comings have been accepted in the industry and design philosophies have followed suit. The industry as a whole has adopted a design philosophy that compensates for energy storage device inadequacies rather than trying to fix the problem. In other words, the industry accepts the energy storage device ‘as-is’ and then designs its systems to work around the problem. This line of thinking is wrong and it is not an acceptable approach for those interested in energy conservation. AGT has identified, and is targeting the root cause for these energy losses by attacking it at the most fundamental level.
AGT’s patent-pending technologies (protections held in the US, Canada and Europe) offer customized Ultrasonic Energy Efficiency Improvement (UEEI) solutions for all battery based applications. AGT uses high-frequency, low-level ultrasonic energy to alter the electro-chemical conversion process within the energy storage device. Specifically, the ultrasonic signal is tailored to enhance the energy storage devices internal electro-chemical diffusion characteristics. By doing so, the energy losses (waste) associated with this limiting characteristic during the transfer of energy to and from the energy storage device are significantly reduced. AGT recaptures the wasted energy and uses it for its intended function. Until now, this energy storage device characteristic was considered fixed and dependent on the chemical make-up of the energy storage device—AGT recognized that it is also dependent on the influence of ultrasonic energy. Thus, the energy storage device becomes an integral part of the solution, an active and controllable component of the system, rather than part of the problem. AGT is not settling for the energy storage device in its manufactured (as-is) form; we take a commercial product, we modify it, and we control it to fit our application.
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Benefits of AGT’s Patent-Pending Technology and Process
• The size of a battery pack can be greatly reduced, to 1/3 of 1/2 of its original size
• Higher peak currents are available during discharge (power), up to 3X greater
• Faster charge times to 100% State of Charge (SoC), as much as 5X faster
• It will last 5-10 times longer, sharply reducing the need for battery pack replacement
• Its charge acceptance at lower currents is significantly increased (Solar)
• Its internal impedance can be adjusted to compensate for less than ideal wind speeds (Wind)
• The level of control is limitless and it is real-time, thereby allowing for compensation for load changes, environmental changes, etc
• The level of control can be altered via customized software solutions: A programmable battery pack
• Less weight compliments the plug-in hybrid initiative (40 miles on single charge)
• Lowered impact on the environment, fewer batteries being discarded
• Less gassing and at lower charging potentials, less sensitive to the cold (Fork-Lift)
• Industrial and residential applications
• Truly revolutionize energy storage without disrupting current production and distribution channels
• Cost effective and scalable solutions for energy storage worldwide
If we truly want to minimize or eliminate our dependence on fossil fuels and move toward a ‘green’ environment, we are going to have to change the way we think about energy storage. AGT has dedicated itself to solving these problems and will pave the way for others to follow. The gains achievable with the application of AGT technology are boundless.
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shawnkel@gmail.com