Energy storage

The best way to store energy is gravity.

You heard right! The best way to store energy is perhaps by pumping water upstream (or up to a large container) and letting Potential Energy take over.

If this is the case then, why are we not setting up renewable energy plants next to water sources and pumping water upstream? to then have hydro-electric generation to recuperate the stored energy?

Is it that we are not yet producing enough renewable energy to have to store it? or perhaps its the fact that no one has been able to coordinate power source, high storage and water source?

I have heard a million times that the biggest obstacle to renewable energy was power storage. Everyone points to the battery to be the "next big thing" in clean energy. Why is gravity and potential energy left in the dark?

In the previous weeks I wrote about the electric grid, one of the biggest dilemmas on power generation is weather to have local or centralized power. Many people responded to my post and the more I heard the more I am leaning towards distributed power generation. With distributed power it will be more feasible to have a "full renewable system" in place.

In a "full renewable system" energy generation is not a stand alone solution. We could have power generated from wind (for a small group of houses) and a reservoir to pump water up when the wind provides more than the necessary power. In change, we could use the water reservoir to generate power in low wind conditions and also as a receptacle of recycled water from the same community. This way we will link water recycling with power generation: True Sustainability!

 

Perhaps this is not the right combination of green technologies, perhaps there is a better formula using solar power and water heating solutions. The point is that we are very limited if with think of solutions in a one dimensional aspect (e.g. power generation) versus thinking on multi dimensional levels (e.g. the "full renewable system").

Here are some interesting comments from last week's question regarding the power grid:

"The growth of micro-wind turbines built as vertical axis turbines and mounted onto roof tops of commercial office blocks will do a lot for distributed power"

"Interestingly there have been some recent developments in high voltage dc systems - to ship power between different countries - but so far it's still not a proven technology as far as I can tell."

"The driver for sizing a power plant is the historic consumption and projected consumption for the future. Really it is based on the power markets in the area and pricing. Another large driver is transmission availability"

"I think that the crux of the problem is that you can't have a generator without a load, you can't put power into the grid that no one is going to consume, you must have always a load, that is the reason for having a smart grid that switch on more generators when the power requested from the grid increase and switch off the generators when the requested power decrease."

"Electric grid operators and power plants try to meet the demand of a given region but the real factor is cost and time to bring on new power plants and resources"

"Perhaps DC is the answer to all who are concerned with the fact that you can generate wind power, but you cannot get it to where the heavy electric load is located"

"There is actually a high-voltage, high-power DC line running from the Bonneville Power Authority in the Columbia Gorge to California"

"Generally, there are two types of power plants. Baseload and Peaking. Baseload plants, as you would expect, tend to run at full or nearly full capacity all the time. They tend to be designed for steady efficient power output, like a diesel truck engine. The peakers tend to be less efficient, sometimes much less, but can start up quickly and operate over a wide range of output levels. The respective capacities reflect the somewhat local needs for each type of power. Big transmission can modify that, but only within limits unless you go to.... DC transmission. This IS in use around the world, including the US. The limitations tend to be in the costs of converting from AC to DC and back to AC for final delivery so you only want to use it (generally) for long haul applications"

"Capacity of a power plant to produce power is defined by the total of the MCR (Maximum Continuous Rating) of each of the generators installed at specific conditions. The capacity needs of the power plant in the old regulated days was the capacity required to exceed the predicted load plus an allowance for the shutdown of one or more of the largest generators. This typically meant that 5 to 10 % of reserve capacity was to be available on the peak day to meet the peak load. This peak load is much smaller than the total of all potential loads installed by the various users including homes, businesses, and industry. For example a typical home will only use 10 to 15 % of all the capacity installed within the home on average. The peak demand might be larger and will coincide with other users peak demands on very hot days in the summer. The challenge with matching the electrical production with demand is that the transportation system does not store the electrical energy. Fossil fuel transport systems including natural gas pipelines or even the fuel tank in your car have considerable capacity to buffer difference in production and demand"

"The amount of power generated must exactly match the amount of power being consumed (used or wasted) or the mismatch will increase or decrease the system frequency. The frequency difference is usually very very small but still everyone tries very hard to prevent it. The utility or Independent System Operators (ISO) power dispatchers have a good idea (from historical data and from weather forecasts, etc.) how much power they will need and the time of day they will need it. Then they go to great lengths to measure how much power is going into their bulk power stations, how much is flowing in or out of their interconnection lines and how much is being generated at each plant and by each generator connected to their part of the grid. All of this is fed into a system modeling program in a computer which determines how much power should be generated for the next few seconds and which generator in which plant can generate it most economically"

"Actually, there are quite a few DC grids in the world. Most are found in Europe. On the distribution loss side, DC does not suffer skin effect loss so it does have an advantage there. With the advent of modern DC conversion technology, the argument that it is "harder" to convert DC levels has lost some of it's basis. Finally, after all of the conversion, distributions, and storage - the critical loads are always DC."

Well, I believe this is enough reading for one week. Until next week: SHALOM!