Tag Archives: peak demand

Texas Population Growth and Future Energy Demand


Photo:  Austin, TX Downtown Skyline

Forbes has released their annual list of fastest-growing cities in the U.S.  For the third consecutive year in a row Austin came out on top.  The Austin metro region grew at a 2.8% clip in 2012 bringing our regional population to 1.8 million people.  Austin has been roughly doubling in size once every 20 years since its founding in 1839.  The second and third fastest-growing cities on the list were Houston and Dallas.  San Antonio came in at #9 on the list.  Texas overall added 427,000 people to the state’s population from August 2011 to July 2012 bringing our state population to 26 million.  Texas is growing at a staggering rate of more than 1,000 people per day.  With Texas metros growing at such a breakneck pace, the challenge for Texas going forward will be to keep up with our state’s future energy demand [1][2].


Photo:  ERCOT Operations Center

The Electric Reliability Council of Texas (ERCOT), the state’s grid operator, recently released a study showing that Texas will struggle to keep pace with future energy demand especially during peak demand times for energy.  Peak energy demand in Texas occurs from 3 p.m. to 7 p.m. during the summer months.  ERCOT’s method of tracking whether the state will be able to cover its current and future energy needs is based on a reserve margin metric.  Reserve margin is a useful tool that measures how much extra generation capacity will be available based on what the anticipated future peak energy demand will be.  ERCOT’s reserve margin goal for the Summer of 2013 is 13.75%.  However, with total generation capacity expected to be 74,633 megawatts (MW) and peak demand expected to be 65,952 MW during the Summer of 2013, ERCOT will fall short of its goal with a reserve margin of only 13.2%.  ERCOT’s reserve margin is expected to decline to 10.9% by 2014, and it will eventually fall to just 2.8% by 2022.  ERCOT’s strategy going forward will be focused on introducing new market incentives for power plant operators across the state to build new generation capacity.  ERCOT will also focus its efforts on encouraging energy conservation through demand response initiatives [3].

Energy conservation efforts such as Austin’s Pecan Street, Inc. smart grid demonstration project is a great example of how Texas’ booming metros can reduce overall peak energy demand.  Pecan Street’s smart grid demonstration project is leveraging a $10.4 million DOE grant as well as resources from the University of Texas at Austin, Austin Energy, and a consortium of industry leading high tech companies.  Pecan Street is studying the benefits of integrating rooftop solar, energy storage, electric vehicles, natural gas, smart appliances, and home energy management networks to manage peak energy demand within neighborhoods and also to help customers reduce their monthly utility bills.  Pecan Street’s smart grid demonstration project has grown to include 600 residential homes.  Lessons learned from Pecan Street’s research projects will go towards helping cities across the state and country better understand how to satisfy future energy demand when facing rapid population growth [4].

Introducing Pecan Street, Inc.

[1]  Austin is America’s fastest-growing city: http://www.bizjournals.com/austin/blog/morning_call/2013/01/austin-is-americas-fastest-growing-city.html

[2]  Forbes; “America’s Fastest Growing Cities”:  http://www.forbes.com/sites/morganbrennan/2013/01/23/americas-fastest-growing-cities/

[3]  Future electric outlook shows improvement:  http://www.ercot.com/news/press_releases/show/26358

[4]  Austin’s Pecan Street, a Smart Grid ‘City Bloc,’ Adds PV Solar and EVs:  http://www.pecanstreet.org/2011/10/austins-pecan-street-a-smart-grid-city-bloc-adds-pv-solar-and-evs/


Filed under energy

Thermal Energy Storage and the Benefits of Distributed Power Storage

As the total electricity consumption in the US is projected to continue rising, innovative use of technology can more efficiently use the existing generation capacity to meet this increase in consumption without having to build additional power plants, by shifting the peak demand of electricity usage.  In effect, level out the load curve by shifting the consumption of electricity from peak hours (i.e., during the day) to off-peak hours (i.e., during the night). 

A large percentage of peak demand is generated by the summer time use of residential air conditioners.  Residential air conditioning accounts for the largest percentage of total electricity consumed in the home, approximately 16.0%[1].  During hot summer days, meeting the electricity demands from residential air conditioners can be problematic for utilities, which may be required to build additional power plants just ensure that the electricity demanded at peak hours during a couple of the hottest summer days can be met.

This is where the use of innovative technology, such as thermal energy storage, can shift the timing (peak hours to off-peak hours) of electricity usage from air conditioners and thereby reduce the need to expand generation capacity.  A company called Ice Energy is attempting to do exactly that, by using ice. Ice Energy recently signed a contract with Southern California Public Power Authority to provide 53 MW of storage in the form of rooftop air conditioner units that use off-peak electricity to make ice that is then used during the day to provide the cooling[2].  These units thereby reduce the electricity required during peak demand by relying on the ice instead of an electric compressor to cool the air. 

The use of these types of thermal energy storage systems can be considered a type of distributed energy storage because they are located at the load instead of the source.  This can have several advantages over a centralized power source (e.g., a gas peaking power plant) in that they require no additional infrastructure, no permitting or siting requirements, and they only require electricity that is already available.      

As the US grabbles with how to satisfy increasing energy consumption, deal with potential climate legislation, and meet the rising cost of energy production (the current price for a 300MW coal-fired power plant is about $1 billion[3]) the use of distributed energy storage systems could help address all of these challenges, at least partially. 

[1] http://www.eia.doe.gov/emeu/recs/recs2001/enduse2001/enduse2001.html

 [2] http://greeninc.blogs.nytimes.com/2010/01/27/storing-energy-as-ice/?scp=3&sq=energy&st=cse

 [3] http://www.jsonline.com/business/29482814.html


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