Quote:
Originally Posted by oil pan 4
Grid power storage is a bad idea, you instantly lose up to 10% to 30% of the power you are trying to store by storing it up and releasing it.
Over on wind-sun.com they claim the typical off grid PV to lead acid to ACpower setup as being around 67% efficient by the time the power gets used in your home.
So how do you get more power out of a system by adding on a new system that has automatic losses of up to 30%?
Normally you think batteries are the obvious answer only problem is they have limited life spans and when they go bad you have tons of lead, nickel or lovely cadmium to deal with. The amounts of metal needed would be in the millions of tons tons range. It takes around 50lbs of lead just to hold 1KWH of useable power in a lead acid battery. Lead is the most likely candidate for battery storage.
If you are going to use Nickel based chemistry then you might as well forget about building a whole lot of electric and hybrid car batteries.
If the smart grid uses batteries or some other means to store power its going to be even less efficient and cost more than what we have now.
It sounds like the smart grid has a huge potential to increase wastes of all different kinds.
The only grid storage that has good potential is the one we have been using for years already. Its safe, there are no toxic metals involved and makes up over 99% of grid storage capacity already. Its called pumped hydroelectric storage. Only problem is it doesn't work every where.
|
. . . and a great idea in others.
I have an associate who works for Southern California Edison Gas & Electric (SCEGE) Eastern. Over dinner, he described the ongoing retrofit of one of their power plants from two large oil-fired steam generators to 4 combined cycle gas fired generators. The 1000+ MW production capability was not just the only advantage, but the ability to more easily match load with production as the new turbines could be stopped and started in about 30 minutes compared to the old steam units which took hours. He mentioned how in the day, they would dump excess electricity into resistive loads to balance the minimum output of the steam generators. Now, he says, they rarely dump their excess but simply put it on the grid so the night time industries out in the Los Angeles Basin can more easily balance their loads. Because they also give PM electrical discounts, many commercial industries have taken advantage and run night shifts.
This has been brought about because of the so called "smart grid". Local capacity is more easily diffused into the surrounding areas.
Electric vehicle charging at night would be welcome because it just means overcapacity is used.
When asked about local storage of overcapacity, he mentioned the overriding thing is going to be cost. The operators have to look at capital payback and profits of course. Efficiency is less of a concern as the energy is often wasted anyways. Reducing, then selling that "waste" energy has been their thrust.
When asked about using old EV packs as overcapacity storage, he said the large variability in design, voltage and capacity would probably prove a nightmare to integrate into the power grid. It simply would cost too much. However, some local entrepreneurs were thinking of buying up used Prius packs and charging them at night rates and selling quick charge services at a premium price during daytime loads. They also wanted to be able to sell back to the grid during peak hours but operators only buy back at the reduced rates, so there would be no profit as of the moment. That may change in the future.
The recycling of battery chemistry as an aside, excess load storage can be workable if costs are low enough to tempt the power producers to use them.