How Do We Solve the Demand On Our Electric Grid?

Paul Valenta | Jun 12, 2012

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The future of energy and the Smart Grid is dependent on smarter buildings that use disruptive technologies such as energy storage and building automation to be more efficient.

Demand on our power grid continues to rise. Last summer, the East Coast experienced a massive heat wave that set record high temperatures in multiple states and caused over thirty heat-related deaths. Record high temperatures naturally led to increased use of air-conditioning, and a major strain on utilities up and down the Atlantic Coast. The strain became apparent when New York City had power outages and buildings were dimming lights and turning off unnecessary equipment in order to avoid overloading the grid.

A recent Wall Street Journal article pointed to problems already for 2012, and we haven't even entered the hot season yet.

According to the article, "Southern California could be hit with rolling blackouts this summer if reactors at the San Onofre nuclear plant remain shut down for repairs, officials warned this week. The reactors, which normally supply enough electricity to light 1.4 million homes, have been out of service since Jan. 31 after a leak revealed premature aging of vital equipment."

The article continues, "Steve Berberich, chief executive of the organization that manages the electric grid for most of California, said officials are developing a plan to encourage local conservation. But a heat wave still could force officials at his organization, the California Independent System Operator, to instigate rolling blackouts to prevent uncontrolled power outages. Rolling blackouts typically last 15 to 30 minutes at a stretch, spreading the pain."

The concern here is that utilities don't have a plan in place for these types of issues, including extreme heat in the summer months. As the California Independent System Operator looks to devise a plan for conservation, the larger issue of too much demand on a strained grid continues to be the main problem.

Many commercial buildings, which are some of the largest consumers of electricity in the United States, are using over-sized inefficient "just in time" cooling systems. During the summer, most of a building's energy costs are due to air-conditioning during peak daytime hours, when demand and costs are high. Although these over-sized systems have become more efficient, they don't provide viable long term solution to reducing demand on the grid during hot summer months.

The answer to rising demand -- Thermal Energy Storage

An alternative to large just in time cooling systems is to use a hybrid cooling system that includes thermal energy storage. Thermal energy storage (TES) is proven, reliable and the cheapest form of energy storage, yet it is rarely mentioned as part of the energy storage solution. TES tanks store energy in the form of ice, chilled water, hot water or a chemical and water mix. This stored energy can then be used later when the air-conditioning system experiences high demand and or high cost. For example, ice thermal energy storage systems will use electricity during the low demand hours to produce ice, which is stored in tanks. The next day, the stored ice is used to cool the facility when building temperatures rise due to high outdoor temperatures, direct sunlight, occupant body heat and the use of machinery and electronics. The comfort of building occupants is never compromised and relative humidity within the building could be lowered. Meaning the temperature in the building can be higher without the occupants feeling the heat.

Thermal Energy Storage = energy when you need it

We can compare TES to something everyone is familiar with -- hybrid cars. Standard cars have oversized engines for when there is a larger load or a burst of speed is needed for merging and passing on highways. Hybrid cars have smaller engines, which provide greater efficiency and an adequate amount of power. When more power is needed, the stored energy is used to provide the necessary burst of power or the stored energy can be used when traffic is creeping along or at idle for even better efficiency. Commercial cooling with TES is similar. Engineers design cooling systems for peak design days and unanticipated cooling loads. This results in large cooling systems with large supporting infrastructure. Adding storage into these designs allows smaller "cooling system engines" to be used that are more efficient over a wider operating range. When prices are high, or the load is great and a boost is needed, the storage provides capacity. Similarly, when loads are small (at idle or creeping along) the entire cooling load can be supported with low cost stored energy. The connected load is smaller, which is good for everyone, while the safety capacity is provided by storage. The capital for storage comes from installing a smaller electric chiller and support equipment.

TES is beneficial to the environment, too. Utilizing TES reduces the amount of source energy and emissions being released into the atmosphere. A large component of night-time electricity is renewable wind generation. This night-time energy is also more efficiently produced by base-load generation plants. Discharging stored cooling during peak demand hours means utilities don't have to turn on the peaking plants which are usually the oldest and dirtiest utility assets. These peaking plants only come on to meet peak demand mainly caused by air-conditioning.

Not only is TES beneficial to the environment, it saves users money. Grid operators, more and more rely heavily on variable pricing to change consumption to reduce peak demand. As such, demand response revenue opportunities are increasing for users that can shift or change consumption. The price of electricity during daytime hours, when the power grid is reaching maximum capacity, is increased in order to discourage use and relieve stress on the grid. On the other hand, the price of electricity is lower during the nighttime hours when demand on the power grid is at its lowest and supply the greatest. The Edison Electric Institute has said that the only form of energy that has not increased in cost in the last 40 years, when converted to today's dollars, is off-peak electricity. The next logical step for commercial buildings to hedge against price increases and energy pricing volatility is to shift as much energy consumption to off-peak hours when utility demand is lower and rates are less expensive. Shifting cooling off peak can result in a savings of up to 40 percent in cooling costs.

The Smart Grid needs smarter buildings that use disruptive technologies

TES does not diminish the importance of grid energy storage technology, but complements it for greater energy efficiency. The building industry needs to design systems that are able to be better integrated into the Smart Grid. Changes need to be made now in order to help manage our future energy consumption. After all, you can't have a smart grid with dumb buildings.

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Comments

From their website:

"CALMAC is the world leader in the product design and manufacture of thermal energy storage."

Since the author did not disclose, "By the way, I sell TES systems", I thought I should.

There is certainly much economic value in purchasing low-cost, off-peak power to drive refrigeration technology to produce giant ice blocks in the basements of skyscrapers. The NE-USA also undergoes massive seasonal swings in temperature . . . ice cold winters and sweltering summers. There is great potential for seasonal TES in these regions.

A seasonal TES installation using underground storage has operated for several years in Alberta, Canada . . . . heat from concentrated solar thermal energy is pumped underground, in LARGE SCALE. This heat sustains multiple buildings in an entire community during the cold winter months.

It is also possible to cool porous rock located deep in the earth during winter, at places like Chicago, Boston and New York City . . . then use the stored coolness to cool buildings during hot summer weather.

Small-scale TES has merit in buildings and is compatible with grid dynamics. Large scale, underground TES promises to be cost-competitive and would enhance the economics of some forms of renewable energy and possibly nuclear energy.

The Canadian experience is instructive. Being a fan of electric and thermal storage I've watched the industry for years. The problem is always that building owners decide not to use storage because of the economics. Why can't they do it the way Canada did? The following from a Solar Thermal article describes the funding for the project:

The Government of Canada’s Technology Early Action Measures program and Natural Resources Canada (TEAM, PERD and REDI program funding) have contributed $2 million to the building of this project. The Federation of Canadian Municipalities’ Government of Canada-funded Green Municipal Fund has invested an additional $2.5 million. The Government of Alberta’s Innovation Fund has contributed $625,000. Sustainable Development Technology Canada (SDTC) has contributed $1 million and Alberta Environment has contributed $500,000. The other project partners include United Communities, Sterling Homes, ATCO Gas, the Town of Okotoks, Climate Change Central, and EnerWorks.

In addition to Natural Resources Canada’s initial contribution, the department has also been funding the performance monitoring, along with addressing model calibration and system optimization work with PERD funding since 2006/2007, which has amounted to an additional $ 1.3 million in funding.

Interesting article but there are many ways to keep buildings cool. Ground source heat pumps can both heat AND cool buildings and could be readily installed at the construction phase of a building. Also in Toronto the City takes cool water from the deep waters of Lake Ontario and pumps it around the City. Buildings can tap into the cool water using a simple heat exchanger and you have a building cooled by Lake Ontario that uses very little electricity compared to an electric air conditioner. Building design can also be used to keep buildings cool by reflecting the heat away. In short electric air conditioners are about the worst way of cooling a building - but good for the electricity business.
Many cities around cool bodies of water could use this technology but of course very few do. And it is worth noting that power stations already deploy this method to cool condensers in steam cycle turbines so as they say - we have the technology but not the collective will to implement it.
Malcolm

There are indeed lots of ways to cool commercial and residential buildings. In addition to some of the methods mentioned by commenters, some operators have taken advantage of a method known as precooling, in which the component materials of the building are used to store energy. Jim Braun at Purdue has done a lot of research in this area and California's Public Interest Energy Research organization has published a number of papers that prove the idea works. I can vouch for the fact that it is very effective in a wood frame home - it's how we avoided the expense of air conditioning during Silicon Valley's warm summer months. I'm aware of at least one commercial building in Chicago that employed precooling to cut its energy bill by as much as 40%.

What I find profoundly disturbing is how, after spending money to prove the idea, California's policymakers have allowed the idea to sit on the shelf even as they wring their hands over the potential for involuntary load curtailments in Southern California this summer.

I think it's also fair to point out that no rational business person would build storage in California without sizable subsidies for both the capital and operating costs. Under current market conditions, it is too expensive to build and daily price differentials are too small even during the summer to recover a storage device's operating costs.

The answer is really simple and less costly than many think to leveal the power grid where needed from a combination of techs that are emmeraging of known and exsiting techs combined in 1 structure. It is known as renewable (thermal)=wind power the energy power source. 1969 high school knowladge now combined for a on demand power source that does not depend on 1 source to run. Its the best of 8 known naturals & 6 man made thermal transfure systems.
the public awearness eductation site is all 1 word renewablethermalwindpower.com
This system does not depend on the wind or solar to make a on demand power source. Getting the word out to the public is all the responssiablillity of any body the lives on this planet and cares about the environment.

Jack, I agree there is much that can be done to improve existing and new buildings. In colder climates like Canada if every house was properly insulated in the attic and in the walls it would be a great start.

The Government of Canada spent a fortune coming up with the R2000 house concept but could not make those standards mandatory for builders because that is controlled by the Provinces. The energy savings of just building to that standard would have saved billions of cubic feet of natural gas, millions of barrels of oil and countless megawatt hours of electricity. Governments spout the energy conservation mantra but lack the political will to really do anything about it. One simple legislative change of one line of the Building Code is ALL they need to do.

But these things are controlled by politics not by technology. Wasting energy is preferable to losing votes unfortunately.

Malcolm

The article and the comments seem to accept the idea that the energy demand is a given and we have to figure out ways to respond to that demand. I'd like to see the dialogue include options for moderating the demand and thus reducing the need for electric storage. Of course, Demand Response will come to mind but this doesn't really save any energy, only defer when the energy is consumed.

The most relevant peak demand issues are during hot summer afternoons when air conditioning drives electricity demand. If it were possible to prevent buildings from heating, the peak demand would look quite different. It turns out there are options for doing this. Apart from the usual appeals for insulation and sealing, a significant savings can be realized by reducing the heating from infrared in sunlight. The options are available now and with good economics. LBNL at Berkeley is studying these options to document both the economics and the effectiveness. They call it their Technical Analysis of Window Attachments. With a little prevention (by blocking IR heating) we may not have to be so clever with how to cool hot buildings.

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