Thermal Energy Storage (TES), ice for example, combined with central geothermal systems offer storage and efficiency. Ice storage with geothermal heat pumps can provide a very efficient flexible cooling system for smart buildings. Here is a great example at this link. http://www.blattnerenergy.com/about_responsibility_green.php
Thermal Energy Storage (TES) in typical applications makes up about 30% of a hybrid cooling system. The amount amount of space required for that is relative equivalent of the amount the water heater requires in the average 2,000 sq. ft. home. Partial ice storage systems require 1/4 of 1% of the conditioned space. Water thermal energy storage requires more space.
Some ice storage systems are 99% reuseable or recyleable making them a very sustainable choice. Ice energy storage systems typically will last over 30 years and not degrade in performance like batteries making them an ideal choice to store energy and lower connected load.
Of course all forms of energy storage will be needed to make renewable energy goals possible and viable. Utilities like to build and manage large projects so TES often is overlooked when it is a viable and necessary part of the solution.
Renewable energy will need the smart grid. The smart grid will need smart buildings. Smart buildings will need energy storage operate efficiently and affordable.
Ivan, the idea of temporary storage at the residential location has some appeal, especially since more and more of us are getting emergency generators (either portable gasoline models or built in natural gas). The question becomes, what size system would be needed at an average size house to meet the minium requirements for service continuation (i.e., a calm day for a wind power system) vs. longer term emergency backup for a couple days when a storm takes out power.
I do remember seeing an article about those mini reactors a while ago. I think the concern with them, at least when I saw it was security. From a purely technical point of view, I did like that solution.
It seems that the major driving force of the renewables is their so-call environmentally friendly advantage. At least, that is what those driving the subsidies to those markets are saying. However, I wonder what the net impact is when the entire systems is looked at. How much space is required for the farms or the hydro storage? What happens when the batteries die? What sort of infrastructure is necessary, say, for a factory to have its own battery house? Even more important, at the end of the day what is cost per KWH?
Increases in the use of geothermal energy particularly in larger buildings does have high potential to reduce electricity need for local communities. Some municipalities have seen this and are starting to mandate the use of geothermal technology on new construction over certain square footage.
I agree that storage is vital piece of a viable renewable energy strategy. Air-conditioning has helped to create demand issues and it can be part of the solution as well.
In 2006 Buildings used over 70% of electricity produced so designs and changes to their consumption can impact the grid dramatically. High Performance Buildings designs, both new and retrofit, using hybrid cooling systems that include thermal energy storage can help provide the grid with energy storage. Buildings with energy storage can act as virtual generators when renewable energy is not available because of weather related issues. Additionally, these storage systems can provide a load for night time wind that is currently wasted because of low night time loads. Thermal energy storage in buildings can help the intermittant aspect of renewable energy while creating a load for it as well making the economics of renewable energy more viable.
Thermal energy storage systems are affordable and can be applied to a wide range of facilites including K-12 Schools, Community Colleges, Universities, Hospitals, and Offices. Product improvements, better design tools, and improved practices have made thermal energy storage systems both affordable and reliable providing cost savings for users, storage for the grid, and lower demand during summer peaks for the utility.
Successful implementors of thermal energy storage include Stanford University, the University of Arizona, SAP US headquarters in PA, Bank of America in NY, as well as Sarasota and Hillsborough County Schools in Florida to name a few.
Thermal energy storage need to be discussed more at state and federal levels to make sure policymakers understand the how thermal energy storage can help. Bills like California’s recently passed AB 2514 represent a good start at the state level. AB 2514 calls on the California Public Utilities Commission (CPUC) to open a proceeding to establish a common framework for valuing the costs and benefits associated with storage, to help ensure that regulated utilities consider storage alongside other options for meeting reliability needs. In doing so, the bill it will bring various stakeholders together and elevate storage into the daily discussions about how we serve future energy needs. What role will storage play, at the lowest possible cost and in an environmentally responsible manner?
On the Federal level, bills like last year’s STORAGE Act can help extend tax credits, financial incentives and loan guarantees to energy storage projects, while the Federal Energy Regulatory Commission, the North American Electric Reliability Corporation, and many state PUCs are taking steps to understand how to value storage in a regulatory sense, and to measure its cost-effectiveness.
So, please, don't forget to mention thermal energy storage as part of the storage solution reqired for implementation of renewable energy.
One very interesting storage concept was a large rotating mass, a flywheel. The idea was to put this mass in a vacuum and spin it very very fast. Material limitations would be the upper limit on rotational speed. As I recall the rotating mass was a disk of carbon fiber strands. Carbon fiber strands had the highest strength in the materials considered. The attached permanent magnet generator was inside the vacuum chamber as well. This energy storage scheme was even proposed for vehicles.
None of these energy storage systems seems scalable and appropriate given all the difficulties so either we need a breakthrough or renewables are going to be limited to the previously mentioned 20% of total national grid capacity. This problem is lost on the public media for the most part.
One other option not discussed here is smaller, 70 Mw, packaged nuclear plants. They are being developed now in Oregon by Nu-Power I think and another company called Hyperion. I believe the advantages are smaller and less costly, much safer, cheap to operate and maintain. they can also be built in a factory and delivered to the site.
Rob: Up to now, pumped hydro sites have been very large. I'm not familiar with any smaller ones, but they may be out there. As I understand it, there has been some "not-in-my-backyard" mentality that has limited it to some degree, not to mention the fact that the bigger sites need tremendous amounts of open land that may be distant from the metropolitan areas that need power.
Ivan: I like your thinking. And over time, a home owner's investment in some type of storage mechanism is no different than having to invest in a fuel tank or a hot water tank or a furnance for that matter. It's all a matter of what you become accustomed to.
Maybe each house and business could have a battery for storing energy to be available when needed. Similar to the vehicl to grid idea except that the homeowner has a stationary battery located on premises.
The cost of the battery might be subsidized to some degree. The incentive for the homeowner would be that power costs are lower when the renewables are online and he can charge his battery. Othertimes when the renewables are not online the cost is higher so the battery kicks in and helps to keep power usage down. The homeowner could choose how much battery he needed.
This would create a bigger market for new battery technologies and promote the use of renewables. It would also allow for the homewowner make use of his own renewables as well if he were to install PV arrays or wind turbines. Another advantage to the homeowner would be that if he has variable rates for the energy he buys then he could charge the battery during low rate hours and use it during his own peak usage hours.
I can see a lot of issues with it but I was just trying to think of some alternatives. Making the battery systems distributed allows the investemnt and benefits to be spread around in a more distributed fashion.
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