Smart Energy Management for Households

University of Toledo

University of Toledo

Soma Shekara Sreenadh Reddy Depuru
University of Toledo
Toledo, Ohio, USA

Energy is the ability to work and is available in different forms. Energy is the most discussed and influential topic for the last few decades. Electrical Energy is the life to technology. Several forms of available energy is used for the generation of electricity which is then transmitted from generating station to the load through long transmission lines. Generation and transmission of electrical energy involve many operational and conducting losses. Demand for Energy by the commercial and industrial load will be very high at a particular period of time, which is termed as the peak period. Utility companies have to supply a huge amount of additional energy in order to meet the peak load requirement. At this period, generating units operate at full capacity affecting the reliability of the whole power system. Adoption and implementation of smart energy management techniques conserve a major portion of energy consumption, enhance energy security, improve efficiency, and help utility companies manage generation and transmission during the peak period.  Implementation of such techniques in household level saves a lot of money on utility bills in and also helps achieve green and zero energy houses [1].

Supply and Demand of Electrical Energy

Utility companies discourage wastage or unwanted usage of electricity during peak load by imposing relatively high tariff for the energy consumed during peak period. Utility companies provide incentives to the customers by offering electricity at a low billing rate during off peak periods. Electric power supplied in Ontario on the 26th of April 2009 is 17000 MW from 11 AM to 5 PM during peak load and 11500 MW at 3 AM during off-peak load [2]. These values show that exploring an alternative solution for being dependent on the grid at peak period and opting for efficient utilization and co-generation of energy enhances the reliable operation of generation, transmission and distribution equipment of the utility company. By the year 2030, demand for electrical energy in the United States is expected to reach 5,064 billion kWh with a total increase of 1317 billion kWh compared to 2007 [3]. But, we have identified only half of the total required resources for generation of electricity by that time. To meet the required demand of energy, distributed generation and smart energy management has to be adopted.





“No single issue is as fundamental to
our future as energy,” Obama at a
White House press conference on
January 26, 2009.

Available co-generation and storage options

  • Renewable energy sources like solar panels and wind turbines can substitute for the energy from distribution grid. In many places, solar and wind energies are unreliable, uncertain, and discontinuous sources of energy. In spite of such disadvantages theses sources of energy are renewable, clean, sustainable and have got many advantages over conventional fossil fuels in their long term operation as co-generation units.



  • A plug-in hybrid electric vehicle (PHEV) is a hybrid vehicle with a connecting plug to charge the internal batteries from an external power source. A fully charged PHEV operates on electric power until the batteries are depleted and then the internal combustion engine will start to work. PHEVs are fuel efficient and may require only about 25% as much energy as cars that consume gasoline. Off-peak electricity is used for charging these cars and that energy can be used for operating the car or the energy can also be fed back to the grid during the peak load.

  • Compressed Air Energy Storage systems allow compression of air into an underground air-storage vessel using off-peak electrical power and later this air can be used to operate a gas-fired turbine generator complex to generate electricity during the peak period.

  • Proper management of water can be done by storing the water in overhead water tanks using the electric pump that we use for getting water to the home from a utility company. By pumping this water during off peak period, electricity is stored in the form of potential energy. Water stored in the overhead tank can be used all day without any pumping device.







“We have known for decades that our survival
depends on finding new sources of energy,“
Obama, address to the joint session of
Congress on July 6th, 2009 in a newspaper
interview.

Smart energy management

The strategy is to utilize solar energy, wind energy, compressed air energy storage, and PHEVs through proper management tools during peak load as shown in fig.1. During the off peak period, a portion of electricity from the grid is used for operation of compressed air storage devices, charging PHEVs and for water management. During the off peak period, generated electrical energy from solar panels, and wind turbines is stored in the batteries. During the peak period, the energy stored and generated in the form of D.C  is inverted into A.C. form of electrical energy and can be utilized for household purposes. If the electricity generated exceeds total utilization of the household, then this surplus energy can be supplied to the distribution grid. Though the quantity of energy conserved might be small when compared to total household consumption, this would be a great contribution to the utility company, as we are trying to reduce the load on the generation unit instead of being an additional load. These processes would bring a huge impact on the generating and distribution system after successful implementation and operation. Power system security and reliability are major concerns for any utility company. Many household appliances that we use inject unwanted harmonics into the feeder which affects the power quality. So, harmonics induced because of a particular load can be reduced by limiting them to their own entity by integrating energy storage devices. Decentralized generation reduces transmission and distribution losses, improves power quality and the load balance during peak period.

Smart meter

Smart meter is an advanced energy meter that identifies consumption of electricity with more details and parameters compared to the conventional meter and can communicate this data with a utility company. Smart meter manages and controls energy from the grid, all the co-generation units and household appliances. Emerging software technologies can be used to program the smart meters to control and manage all the components according to the load demand. Adoption of smart meters will enable customers to find the quantity and cost of energy that is being consumed at that point of time. Smart meter allow customers to enable or disable the supply of electricity for all home appliances. During the peak period, smart meter helps us conserve a lot of un-utilized energy by reminding us about the total household energy consumption and suggests disabling of power supply to some appliances. After a few reminders, if the customer does not request for holding the power supply, supply of electricity to some preselected appliances will be disabled. In many proposed models of smart meters, customers can remotely monitor and control all home appliances by enabling or disabling the electricity supply.
Fig.1. Components of smart energy management

Fig.1. Components of smart energy management



Capital cost and savings
From a Customer or neighborhood point of view, capital cost involves investment on installing the smart meters, implementing the compressed air storage system, installation of solar panels, wind turbines, storage batteries, buying and integrating the PHEVs. Total investment on the equipment depends on the quantity of energy to be generated and stored. Cost on the investment for integrating co-generation and energy storage devices is paid back in the form of incentives from the government and savings in the utility bill. From the tariff chart of Orange & Rockland, customers were charged 1.28 cents/kWh during off-peak period from 9:00 PM to 10:00 AM and as high as 19.889 cents/kWh during peak load from 12:00 PM to 7:00 PM [4] for the months of June through September. Opting for co-generation and efficient utilization of energy during the peak period saves a lot of money on the utility bill to customers. Conserving a small amount of electricity by all households shaves a considerable amount of the load irregularities during the peak period.

Theft of electricity

Theft of Electricity has a huge impact on the power quality, energy audit, Tampering with the meters and tapping of energy directly from a distribution feeder bypassing the energy meter were most commonly adopted ways of pilfering electricity. Electronic and electromagnetic meters are still used for the billing of household energy usage in many parts of the world. Electromagnetic meters can be tampered by installing a shunt between the incoming and outgoing meter terminals. Radio frequency devices are installed to influence the accuracy of the meter reading. In the case of electronic meters, electrostatic charges are injected or they can be exposed to strong magnetic fields to wipe out the meter’s memory. In the United States, about $1 billion worth of electricity is pilfered each year, which accounts for 0.5-3% of the total revenue [5] . Portions of these losses for the utility company will be borne by genuine customers. So, traditional energy meters were to be replaced by tamper proof smart meters in order to reduce the theft of electricity.

Effect on Environment

The objective of achieving green and energy efficient households can be made more viable using renewable energy sources and smart energy management technologies. The possible implementation of compressed air energy storage depends on the environment, location, and availability of land. Though this technology uses a portion of unused land, it is of not much impact on the environment when compared to the total energy that is being conserved using smart management of electricity. Conserving a small quantity of electricity generated from the fossil fuels will have a positive impact on the environment. Conservation of un-utilized energy and using renewable generation technologies reduces emission of pollutants and environmental wastes into the atmosphere enhancing the ecological balance.

References

[1] “Zero Energy Home Design,” US Department of Energy, [Online]. Available:http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10360. [Accessed: Sep.25, 2009].

[2] “Ontario’s Micro generation Feed-Tariff,” Virtual Nonsense, [Online]. Available: http://renaud.ca/wordpress/?cat=3. [Accessed: Oct 13, 2009].

[3] “Annual Energy Outlook 2009 with Projections to 2030,” US Department of Energy, [Online]. Available: http://www.eia.doe.gov/oiaf/aeo/pdf/table18.pdf. [Accessed: Sep. 22, 2009].

[4] “Time of Use Rate,” Orange & Rockland, [Online]. Available: http://www.oru.com/programsandservices/incentivesandrebates/timeofuse.html. [Accessed: Sep. 15, 2009].

[5] “Pulling the plug on Energy theft,” Electric Light & Power, [Online]. Available: http://www.elp.com/index/display/article-display/305071/s-articles/s-utility-automation-engineering-td/s-volume-12/s-issue-9/s-features/s-pulling-the-plug-on-energy-theft.html. [Accessed: Sep 17, 2009].