Even though Solar Panels and Natural Gas Home Generators allow us to Disconnect from the Grid we Shouldn’t

Posted by PITHOCRATES - April 21st, 2013

Week in Review

I remember losing power for a couple of hot and humid days.  The kind where you stick to everything because you’re just covered in sweat.  Making it almost impossible to sleep.  But I was able to borrow my father’s generator.  So I would not have to suffer through that insufferable heat and humidity.  While I was able to run my refrigerator, turn the lights on and even watch television I could not start my central air conditioner.  Even when I shut everything else off.  It was large enough to run the AC.  But it was just not big enough to start it.  I tried.  But as I did that inrush of current (about 40 amps) just stalled the generator.  Which could put out only 30 amps at 240 volts.  So even though I had a 30 amp generator to start an air conditioner that was on a 20 amp circuit breaker it wasn’t big enough.  Because of that momentary inrush of current.  So I suffered through that insufferable heat and humidity until the electric utility restored power.  And I never loved my electric utility more than when they did.

Now suppose I wanted to go to solar power.  How large of a solar array would I need that would start my air conditioner?  If one square inch of solar panel provided 70 milliwatts and you do a little math that comes to approximately a 950 square-foot solar array.  Or an array approximately 20 FT X 50 FT.  Which is a lot of solar panel.  Costly to install.  And if you want to use any electricity at night you’re going to need some kind of battery system.  But you won’t be able to run your air conditioner.  For one start would probably drain down that battery system.  So it’s not feasible to disconnect from the electric grid.  For you’re going to need something else when the sun doesn’t shine.  And because there can be windless nights a windmill won’t be the answer.  Because you’re going to need at least one source of electric power you can rely on to be there for you.  Like your electric utility.  Or, perhaps, your gas utility (see Relentless And Disruptive Innovation Will Shortly Affect US Electric Utilities by Peter Kelly-Detwiler posted 4/18/2013 on Forbes).

NRG’s CEO David Crane is one of the few utility CEO’s in the US who appears to fully appreciate – and publicly articulate – the potential for this coming dynamic.  At recent Wall Street Journal ECO:nomics conference, he indicated that solar power and natural gas are coming on strong, and that some customers may soon decide they do not need the electric utility. “If you have gas into your house and say you want to be as green as possible, maybe you’re anti-fracking or something and you have solar panels on your roof, you don’t need to be connected to the grid at all.”  He predicted that within a short timeframe, we may see technologies that allow for conversion of gas into electricity at the residential level.

If you want carefree and reliable electric power you connect to the electric grid.  Have a natural gas backup generator sized to power the entire house (large enough to even start your central air conditioner).  And a whole-house uninterruptible power supply (UPS).  To provide all your power needs momentarily while you switch from your electric utility to your gas utility.  Well, all but your central air conditioner (and other heavy electrical loads).  Which would have to wait for the natural gas generator to start running.  Because if you connected these to your UPS it might drain the battery down before that generator was up and running.  No problem.  For we can all go a minute or two without air conditioning.

So this combination would work.  With solar panels and a natural gas generator you could disconnect from the electric grid.  But is this something we should really do?  Not everyone will be able to afford solar panels and natural gas generators.  They will have to rely on the electric utility.  Some may only be able to afford the solar panels.  Staying connected to the grid for their nighttime power needs.  But if our electric utilities cut their generation and take it offline permanently it could cause some serious problems.  For what happens when a day of thunderstorms blocks the sun from our solar panels and everyone is still running their air conditioners?  The solar panels can no longer provide the peak power demand that they took from the electric utility (causing the utilities to reduce their generation capacity).  But if they reduced their generation capacity how are they going to be able to take back this peak power demand?  They won’t be able to.  And if they can’t that means rolling brownouts and blackouts.  Not a problem for those with the resources to install a backup generator.  But a big problem for everyone else.

We should study any plans to mothball any baseload electric generation.  For renewable sources of energy may be green but they are not reliable.  And electric power is not just about comfort in our homes.  It’s also about national security.  Imagine the Boston Marathon bombing happening during a time of rolling blackouts.  Imagine all of the things we take for granted not being there.  Like power in our homes to charge our smartphones.  And to power the televisions we saw the two bombers identified on.  We would have been both literally and figuratively in the dark.  Making it a lot easier for the bombers to have made their escape.  There’s a reason why we’re trying to harden our electric grid from cyber attacks.  Because we are simply too dependent on electric power for both the comforts and necessities of life.  Which is why we should be building more coal-fired power plants.  Not fewer.  Because coal is reliable and we have domestic sources of coal.  Ditto for natural gas and nuclear.  The mainstay of baseload power.  Because there is nothing more reliable.  Which comes in handy for national security.



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With a Great Trust in Technology Germany may go all Green in Power Generation

Posted by PITHOCRATES - April 7th, 2013

Week in Review

In 2003 one power plant went off line for maintenance in Ohio.  As their electrical load switched over to other power lines the extra current in them caused them to heat up and sag.  Coming into contact with some tall trees.  And the electric power flashed over to the trees.  This surge in current opened some breakers and transferred this electric load to other cables.  Overloading these lines.  More breakers opened.  More lines disconnected.  And with the electric load switching around it caused some electric generators to spin a little wildly.  So they disconnected from the grid as designed to protect themselves.

Eventually this cascade of failures would cause one of the greatest power outages in history.  The Northeast blackout of 2003.  Affecting some 55 million people.  And taking 256 power plants offline.  Apparently there was a software bug in the computer control system that didn’t warn them in time to rebalance the grid on other power sources before this cascade of failures began.  Once the event was over it took a lot of time to bring the power back online.  Three days before all power was restored.  Because you have to reconnect generators slowly and carefully.  As you are connecting generators together.  If these generators are not running in phase with each other fault currents can flow between them.  Damaging them and starting another cascade of failures.

So the electric grid is a very complex network of generators, cables, switches and computer control systems.  The more generation plants added to the grid the more complicated the switching and the computer controls.  Which makes having large-capacity power generation plants highly desirable.  For it reduces the complexity of the system.  And their large power capacity makes it easier for them to take on additional loads when another plant goes offline or a cable fails.  It provides a safe margin of error when trying to balance electric loads between available generation.  In Germany, though, the politics of green energy may take precedence over good engineering practices (see Linked Renewables Could Help Germany Avoid Blackouts by Paul Brown and The Daily Climate posted 4/5/2013 on Scientific American).

Critics of renewables have always claimed that sun and wind are only intermittent producers of electricity and need fossil fuel plants as back-up to make them viable. But German engineers have proved this is not so.

By skillfully combining the output of a number of solar, wind and biogas plants the grid can be provided with stable energy 24 hours a day without fear of blackouts, according to the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) in Kassel.

For Germany, having turned its back on nuclear power and investing heavily in all forms of renewables to reduce its carbon dioxide emissions, this is an important breakthrough…

Kurt Rohrig, deputy director of IWES, said: “Each source of energy – be it wind, sun or biogas – has its strengths and weaknesses. If we manage to skillfully combine the different characteristics of the regenerative energies, we can ensure the power supply for Germany.”

The idea is that many small power plant operators can feed their electricity into the grid but act as a single power plant using computers to control the level of power…

The current system of supplying the grid with electricity is geared to a few large producers. In the new system, with dozens of small producers, there will need to be extra facilities at intervals on the system to stabilize voltage. Part of the project is designed to find out how many of these the country will need.

The project has the backing of Germany’s large and increasingly important renewable companies and industrial giants like Siemans.

If you are a heavy electric power consumer in Germany you might want to build your own power plant on site.  For if they go ahead with this they are going to create one complex and costly monster.  Which is why IWES and Siemens no doubt are on board with this.  For it would give them a lot of business in a recession-plagued Eurozone.  But the amount of switching and computer controls to make this work just boggles the mind.

Just imagine a night of high winds that shuts down all wind farms.  Which is something a wind turbine does to protect itself.  You can’t switch over to solar at night.  So you will have to switch that load over to the remaining power lines that are connected to active generation.  Heating those wires up.  Causing them to sag.  Perhaps flashing over to a tall tree.  If these lines disconnect from the grid will those small producers be able to pick up the demand?  Or will they disconnect to protect themselves from an overload?  Once the event is over how long would it take to bring all of these generation sources back in phase and back online?

If they move forward with this chances are that the Germans are going to learn a very painful and costly lesson about green energy.  It may make you look like you care but it won’t keep the lights on like a coal-fired or a nuclear power plant can.  Which they may learn.  The hard way.



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