The Coming Crisis in Electricity Generation
Location: New York
Date: 2013-04-24
For more than 100 years electricity generation and
distribution systems have evolved to become one of the most reliable
services imaginable - one which has been the foundation of the
industrial expansion and prosperity of the developed world. Our
society is totally dependent upon this and even relatively short and
localized interruptions in the power supply (for example during the
Sandy superstorm) cause major disruptions to everyday life.
The reliability of the system depends upon a rather delicate
balance of supply and demand that varies throughout the day and
throughout the year.
Huge thermal base-load steam turbine generation plants that can
reliably provide the same power output 7x24x365 are the foundation
of the system in most parts of the world. Historically these have
been fueled by coal which generates "dirty" (in some cases toxic)
ash and a lot of CO2. More recently single cycle and combined cycle
natural gas plants have played an increasingly important role. These
plants are cleaner and much more efficient than coal plants in that
they transform more of the energy generated by combustion into
electricity. The disadvantage of these plants is that natural gas
has historically been much more expensive than coal.
In regions where there are large rivers that drop hundreds of meters
in a relatively short distance it is possible to build hydro
facilities. These were the earliest source of large scale electrical
generation and are still used extensively. Unfortunately, most of
the best hydro locations in the world have already been developed.
Starting in the 1950's nuclear plants were added to the mix and
generate a significant percentage of electricity in many countries
(the highest being 75% of electrical output in France).
These base-load plants are designed to run all the time at a
relatively constant output receiving a fixed price for the
electricity generated. That is how they run most efficiently and a
constant and predictable revenue stream underlies the calculations
used to get the building of these plants financed and the operating
costs paid. In most cases the payback on these facilities is
achieved only after many years of operation.
When electrical demand starts to peak in the late afternoon and
evening peaking plants come into play. These are typically single
cycle natural gas turbine plants that can come on-line in a matter
of 15-20 minutes or less. Because they run only during peak demand
times the expectation is that the electricity they generate will
command a higher average price. It is also assumed that they will be
able to generate revenue most days although that varies with time of
year and the weather. For example, very hot summer days and very
cold winter days will result in higher peak demand than moderate
days in spring and fall.
This complex balance of base-load and peaking power plants has been
in place for decades and has resulted in a very reliable electricity
supply. The most common source of power outages are storms that
bring very strong winds, knocking down trees and branches that take
down overhead electrical lines.
Over the past decade that balance has been disrupted by the
introduction of renewable energy sources such as solar and wind.
These are both unreliable in the sense that it is not possible to
match supply with demand, and highly variable due to passing of
clouds in the case of solar or frontal weather systems for wind. As
an example, on Christmas day, 2012 Texas set a new wind generation
record of 8.638 GW (26% of total supply) for a few hours. The very
next day across the whole of Texas there was essentially no wind
generated electricity available for 6 consecutive hours.
In most jurisdictions renewables are given priority access to supply
the electricity grid regardless of whether or not there is demand.
In order to balance supply and demand thermal generating stations
have to cut back output, electricity is exported to neighbouring
jurisdictions (typically at very low prices) or hydro stations
"spill water" by redirecting the flow from penstocks to spillways.
As long as renewables made up a relatively small portion of total
generation capacity the physical problems could be handled. But the
economic issues are now coming to the fore as the development of
renewables continues.
With base-load and peaking thermal plants now sitting idle (as
spinning reserves) for more and more of the time the economics of
running these plants has been significantly eroded. Many of these
plants are marginally profitable or are actually losing money. There
is no realistic hope that this trend will do anything but accelerate
in coming years. As a result it is becoming increasingly difficult
to get financing for the construction of new thermal generation
plants.
In the United States the situation is particularly dire. The MACT
regulations issued by the EPA in December, 2011 will result in the
closure of many older coal-fired plants (estimates run as high as 34
GW of capacity or more). Plans to replace this capacity are both
vague and uncertain. For example, Georgia Power's announcement
that 2 GW of coal-fired capacity would be shuttered by 2015 was
justified by the addition of 2 nuclear powered plants in 2017 -
plants which may well run into significant construction delays. What
happens between 2015 and 2017 (or later)?
Texas already has inadequate electrical generation reserves as
highlighted in a strongly worded letter
from the North American Electric Reliability Corporation. In an
effort to get utilities to build new base-load generation facilities
the Texas regulator (ERCOT) is raising the maximum peak price for
electricity to $9,000/MW-Hour. The hope is that if you let a
base-load plant charge 170x the average annualized price for the few
hours that it is not idle then construction of the plant still makes
sense. Call me a skeptic but I have to say "that dog don't hunt."
In Europe various studies referenced in Paul-Frederik
Bach's excellent blog postings outline similar issues.
Beyond supply and reserve issues the economic disruption caused by
renewables is producing some very strange consequences; in "green"
Germany coal-fired plants are being used in preference to cleaner,
more efficient gas-fired plants due to costs; in Ontario they are
spilling water at "green and renewable" hydro dams in order to make
room for "green and renewable" wind generation; the Danes end up
using Swedish nuclear-generated electricity when the winds are calm
even though they banned nuclear power generation; in Texas they are
selling wind energy at negative prices almost 10% of the time
because Production Tax Credits provide a profit.
Declining reserve capacity and uncertainty regarding the economics
of new thermal plants will destabilize the electric grid. Rolling
blackouts and/or regional grid failures will occur on a more
frequent basis. These are the unavoidable consequences of continued
aggressive development of renewable generation.
There are public policy initiatives that could make the transition
to renewables less risky and disruptive but these would take time to
implement. However, I personally don't see any public support or
political will to try and slow down the introduction of renewables
in order to proactively protect the integrity of the electrical
system, particularly in North America and Europe. Instead, I fear
that we will have to experience repeated significant failures in the
system before the scale of the problem is fully appreciated.
Sometimes it seems like we just have to learn things the hard way!
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