Very informative, Chuck, and timely. Count me as one of the avid readers of all of those pieces that talk about the alternatives with "nary a mention" of storage, as you point out. So what constitutes storage for alternative wind and solar energy--Is it containers, is it smart grid technology (whatever that constitutes)? What exactly are we talking here? Are there any early leader technologies that are likely to steer the way?
Beth: Pumped hydro, which has been around for decades, is the leading way to store energy right now. When power is available, they pump water up a hill and store it in a lake or some other body of water. When power is unavailable (i.e., the wind isn't blowing or the sun isn't shining), they use gravity to let the water run back down. As it runs down, it spins a turbine that's used to create electricity. There are other methods used today, such as compressed air energy storage (CAES), which is gaining some momentum. Those methods are probably unlikely to replace the loss of nuclear plants, however, because of "siting" issues. Most areas either don't have the geography or the willingness to use them. More recently, battery farms have started to gain favor. But we would need incredible numbers of batteries and battery facilities to make that happen. Another method is "vehicle-to-grid," which is a proposed idea in which electric cars would send their battery charge back to the grid. The bottom line is this: Electrical power is used at the moment it's created; if we have large percentages of intermittent power, such as wind and solar, we'll have to learn how to store it.
Thanks for clarifying, Chuck. So if I'm following you correctly, it's not necessarily tapping the excess power generated by a wind farm or solar array and storing it somewhere for later use (like we store data in server farms, for example), but rather creating yet another alternative power source or methodology to kick in when those alternative wind and solar power sources aren't live due to lack of wind or sun. Is that what you're saying?
I definitely have mixed feeling on nukes. But having lived within less than 10 miles of a plant my entire life, both in NY and in Massachusetts, why not make R&D investments in improving nuke storage and disaster recovery technology. That way, we turn aging infrastructure into state-of-the-art operations centers that can go the distance for the energy demands of the next few decades.
Beth: Right, it's a matter of using the electrical current when it's available to create a potential source of energy that can be used at a later time when the current is unavailable. The problem is electrical current can't be stored. We use it as it's created. When a wind turbine is spinning, we have to use its power immediately. If we depend on it for 40% or 50% of our power and the wind stops blowing, we risk having no power.
I agree Beth. Nuclear energy definitely has its safety and environmental concerns but is a primary source of low carbon emission energy. It seems that this would be a good time to start investing again in advancing this technology. The cost of replacing existing nuclear plants with the same or greater capacity will have a serious impact on the cost of business or on carbon dioxide emissions. It is going to take a robust and mature technology to reliably replace 14% of the worlds electrical generation.
Energy storage seems to be a limiting factor in many of our alternative energy technologies. I think an up-and-coming issue for storage is the environmental impact of the storage technologies. For instance, battery farms comprised of lead-acid batteries may be low cost but present their own environmental concerns and challenges when applied on the required scale. Energy storage is also an additional cost to renewable energy sources which are currently more expensive per KW than conventional sources. In the end the whole package needs to meet the energy needs of a country at a cost that is competitive to other generation methods.
I suspect that these and other factors will in time swing the pendulum back towards nuclear energy.
Nice article, Chuck. You mentioned pumped hydro for storage. Is it possible that could be a solution on a larger scale? Or, are there efficiency problems (perhaps energy loss in the storing and retrieving). Can it be done on a scale that doesn't involve a lake?
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.
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.
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.
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.
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