[Greenbuilding] Using the grid as a battery

Don Lush donlush at uniserve.com
Wed Dec 9 14:24:52 CST 2015


If you want to see how to NOT integrate green energy into a grid have a read
through the recent Ontario auditor general's report (chapter 3 pg 206).
 
http://www.auditor.on.ca/en/reports_en/en15/2015AR_en_final.pdf

Don Lush

-----Original Message-----
From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org]
On Behalf Of Nick Pine
Sent: December 9, 2015 3:07 PM
To: greenbuilding at lists.bioenergylists.org
Subject: [Greenbuilding] Using the grid as a battery

John Daglish <johndaglish at gmail.com> writes:

>Look at the video to see were the Danes are going :)

>Smart Energy Systems: 100% Renewable Energy at a National Level (Full
>Version)
>https://www.youtube.com/watch?v=eiBiB4DaYOM

They use the grid as a battery with the help of agile load-following CHP
generators.

Dan Johnson <danjoh99 at gmail.com> writes:

>... there is no heat when the sun's not shining.  For this, Nick 
>suggested a heat pump and PV panels, "using the grid for storage". I 
>pointed out that the grid has no storage...

Yes, the grid has no storage, but it can essentially store energy if utility
generators can react quickly. I suggest solar air heaters with enough
overnight heat storage for houses on average January days.

Ryan Carlyle at
https://www.quora.com/Is-nuclear-power-a-viable-alternative-to-natural-gas-p
eaking-power-plants
writes:

"There is a popular (universal?) belief that pressurized water reactor
nuclear power plants must take hours or days to ramp up or down and are
therefore only suitable for base load power. However when you look at the
facts it becomes clear that this is NONSENSE!"

His technical discussion concludes:

"We have non-load-following nuclear power today because we chose to build
base-load nuclear plants. If you want load-following nuclear reactors, you
just have to build them."

http://www.zdnet.com/article/why-baseload-power-is-doomed/ continues with:

"The baseload fallacy

"The notion that renewables cannot provide baseload power is really an
artifact of the way the grid and its regulators have evolved. If all
generators were able to ramp up and down on demand, and if grid operators
were able to predict reliably when and where the sun would be shining and
the wind would be blowing, accommodating any amount of power from renewables
would be no problem."

With sufficient utility generator agility, prediction would not be required.

"A 2010 study called "The Base Load Fallacy" by Australian researcher Dr. 
Mark Diesendorf, an expert on integrating wind into power grids, fingers the
"operational inflexibility of base-load power stations" as the main obstacle
to further integration of renewables. "The renewable electricity system
could be just as reliable as the dirty, fossil-fuelled system that it
replaces," he observes, if demand were more efficient and intelligent, and
supply were made up of a wide variety of renewable sources plus a small
amount of gas-fired capacity to cover the peaks. The perpetrators of the
baseload fallacy, he argues, are mainly the industries who benefit from the
status quo: coal, oil and gas companies, the nuclear industry, power
generators, and industries who depend on them like aluminum and cement
manufacturers.

"Claims that renewables could never generate more than a few percent of grid
power without taking down the grid have been given the lie by the real-world
experience of areas that deliberately adapted their grids."

A few simple simulations could estimate grid storage efficiency as a
function of utility generator capacity (eg 1 GW), utility generator response
time (eg 10 minutes to 10 hours), renewable energy source power (eg 1 kW to
1 MW), number of renewable sources (eg 10 to 1000), renewable source time
correlation (eg 0 to 100%), average renewable source duration (eg 1 to 10
hours per day), and load management ability (eg 10%-50% of the utility
generator capacity.)

Intuitively, a 1 GW utility generator with a 10 minute response time and
1000 10 kW uncorrelated renewable sources with 10 hour average durations
could have close to 100% storage efficiency, especially if the utility can
instantly turn on some off-peak loads like electric car chargers or
municipal drinking-water well pumps. The storage efficiency would be lower
with a 10 hour response time and 1000 1 MW correlated sources with 1 hour
durations.

To simulate source correlation, a simulation could have 1 minute time steps
and 100 virtual pulse generators activated by individual accumulators that
add a fixed amount from a uniform random number generator with each time
step, proportional to the daily source frequency, plus another amount
proportional to source correlation from each pulse generator with an active
output. When an inactive pulse generator accumulator reaches a fixed
threshold, we could dump its accumulator and fire its output for a random
interval with the average source duration.

Nick 



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