Thursday, August 15, 2013

Power, Power Everywhere but Not a Watt to Drinkl!

The NY Times has a piece regarding wind power. Namely they seem to present the argument that the wind power generating companies spend too much time idle because of how the grid is managed.

Let us briefly consider how power works. Let us assume that instead of electricity we assume we have a water system to lots of homes. We need to guarantee say 20 lbs/sq in pressure from any hose that is turned on. Now with no load on the system we need very little pump power to keep up that pressure. There is some loss along the pipes but very little. Now assume we have a very hot day and everyone turns on their hoses. Thus we need to turn on the pumps to force more water through the pipes and ensure the pressure.

Actually one way the town deals with the constant pressure is to use the water tower as primary source. They fill it up and then as it is drawn down, they pump more water into it. If it gets drawn down too quickly they turn on more pumps to keep the pressure up. The tower is a check on pressure and levels the load, the pumps can be made variable to keep the tower at a minimal level. Unfortunately we have no such analog for electricity in our current world, except batteries, which are quite costly. It is cheaper to modulate demand with generators.

This is generally done with little effort. However the water company must deal with low and high loads. But as many of us know if we were to open the fire hydrants then the water pressure may drop, and if we were to have to fight a fire somewhere we may not have enough pressure and thus have a problem.

This is akin to the problem of the power companies except compounded by wind. If it is a still hot day, lots of power and no wind. So the grid must get power from some reliable source. Unlike a water system which can pump some water into the towns water tower one cannot do so with electricity. Thus an expensive but reliable source is better than a cheap green one.

Now the Times states:

Except when they aren’t allowed to spin at their fastest. That has been the case several times in the farm’s short existence, including during the record July heat wave when it could have produced enough much-needed energy to fuel a small town. Instead, the grid system operator held it at times to just one-third of what it could have produced. 

“We were being told to turn on diesel-fired units that are very expensive and dirty and told to ramp down what is renewable, cost-effective energy for our customers,” said Mary Powell, chief executive of Green Mountain Power, the utility that owns and operates the wind plant. “We should go with the sources that can have the highest value, especially during peak times.” 

 The argument falls on deaf ears. Reliability is essential. Wind power may work if the grid is widely connected and over the connection area power can be redirected at low to zero marginal costs. But remember it is unreliable power and not easily controllable.

They continue:

Indeed, in New England in recent months, the grid system operator has cut back power from wind and hydroelectric plants several times, generally, its representatives say, because they were making too much electricity. New wind farms are frequently located in sparsely populated areas or along mountain ridges where there has not been a need for transmission lines with a robust carrying capacity, officials say.  

I see this all too often in New Hampshire. Dozens of wind towers sit idle on the mountain tops like giant dinosaurs, frozen in time, generating neither power or money.

This is a complex systems problem, and the stuffing of this green energy into a half thought out system will just waste more of our taxpayers money. But it is again our Government, not the brightest bulbs on the block.