These articles below from reNews and the US Energy Information Administration describe how Texas successfully prepared the transmission infrastructure for the development of onshore wind in the state
.
Texas trumpets wind gains
The construction of more than 3500 miles of transmission lines in
Texas has significantly reduced curtailment of wind generation in the
state.
The
US Energy Information Administration said Texas’ Competitive Renewable Energy Zones (CREZ) program has also cut instances of wind-related negative electricity prices.
The Texas grid experienced major transmission congestion when more
than 7GW of utility-scale wind capacity was built in 2006 to 2009.
To address the wind-related transmission constraints, the state
established five CREZ areas with high wind power potential. It
authorized a series of transmission expansion projects that in total
would allow 18.5GW of wind power to be transported from the five zones
to the rest of the state.
All of the CREZ projects had been energized by the end of 2013 at a total cost of $7bn.
The elimination of transmission constraints has also helped wind
generation in Texas reach new heights over the past year. The Electric
Reliability Council of Texas recorded a new peak record for wind output
in March 2014 of more than 10,000MW.
http://renews.biz/69340/texas-trumpets-wind-gains/
Fewer wind curtailments and negative power prices seen in
Texas after major grid expansion
Curtailments of wind generation on the Texas electric grid
have steadily dropped since 2011 as more than 3,500 miles of transmission lines
have been built, largely as a result of the state's Competitive Renewable
Energy Zones (CREZ) program. Occurrences of wind-related negative real-time
electricity prices have similarly declined as the CREZ transmission expansions
have allowed wind power to flow to more electricity demand areas in the state.
Wind capacity in Texas grew rapidly in 2006-09, when more
than 7,000 megawatts (MW) of utility-scale wind capacity (more than half of the
state's current total wind capacity) was built. The Texas grid experienced
major transmission congestion as the large volumes of electricity from these
wind plants, which were concentrated in the rural western and northern areas of
the state, were sometimes unable to reach the population centers in the eastern
half of the state. The limited transmission capacity connecting the wind
production and power demand centers was insufficient for the amount of wind
power being generated in the west. During these situations, excess wind
generation was curtailed by the grid's operator, the Electric Reliability
Council of Texas (ERCOT), in order to keep the transmission network operating
within its physical limits.
In addition to wind curtailments, the regional supply and
demand imbalances caused real-time wholesale electricity prices at the West Hub
in ERCOT to drop, and even go negative, during periods of substantial wind
generation. The negative West Hub prices (see graph above) reflect the region's
local oversupply of wind power compared to its electric demand and the
inability to move the excess wind power to other areas with more demand.
Negative prices occur when generators are willing to pay for the opportunity to
continue generating electricity.
Wind plants can offer power at low prices because they have
low operating costs and, in particular, no fuel costs, unlike fossil fuel and
biomass plants. Wind plants can offer negative prices because of the revenue
stream that results from the federal production tax credit, which generates tax
benefits whenever the wind plant is producing electricity, and payments from
state renewable portfolio or financial incentive programs. These alternative
revenue streams make it possible for wind generators to offer their wind power
into the wholesale electricity market at prices lower than other generators,
and even at negative prices.
To address the wind-related transmission constraints, the
Public Utility Commission of Texas (PUCT) in 2008 established five
"competitive renewable energy zones" (CREZ) with high wind power
potential and authorized a series of transmission expansion projects that in
total would allow 18,500 MW of wind power to be transported from the five CREZ
zones to the rest of the state.
As the CREZ transmission projects have been completed over
the past few years (see maps below), the amounts of wind curtailments and
wind-related negative electricity prices have correspondingly decreased (as
seen in the first graph). As of the end of 2013, the scheduled program
completion date, all of the CREZ projects had been energized, at a total cost
of $7 billion.
The elimination of transmission constraints has helped wind
generation in Texas reach new heights over the past year. As reported in
yesterday's article, ERCOT recently recorded a new peak record for wind output
in March 2014 of over 10,000 MW. And according to ERCOT's annual report on the
Texas renewable energy credit trading program, wind generation in the state was
up 13% in 2013 compared to 2012. The growth is mostly attributable to the large
number of wind plants added at the very end of 2012 (more than 1,000 MW was
added in December 2012), but also partly a result of the reduction in wind
curtailments.
http://www.eia.gov/todayinenergy/detail.cfm?id=16831
