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The Electrical Grid and Renewable Energy: Creating a Stable Relationship


TAKAFUMI ARAI

Electric utilities and grid operators face the challenge of integrating distributed energy into the mix without compromising the steady flow of necessary electric power. While utilities recognize that interruptions to the process are an inconvenience, they also acknowledge the need for change within the commercial distribution of electrical power. Takafumi Arai, chief specialist at Toshiba Smart Community, reports.

According to the International Energy Agency, renewable energy accounts for at least 19.5 percent of global electricity[1]. As this percentage continues to grow, so do the challenges associated with the way that power is supplied.

 Electric utilities and grid operators face the challenge of integrating distributed energy into the mix without compromising the steady flow of necessary electric power. While utilities recognize that interruptions to the process are an inconvenience, they also acknowledge the need for change within the commercial distribution of electrical power.
 
This is especially true, given that the U.S. Energy Information Administration estimates[2] national electricity transmission and distribution loses an average of 6 percent of electricity annually from being transmitted and distributed throughout the U.S. With the amount of renewable energy sources on the rise – we must find a way to integrate these renewables into our T&D systems.
 
So, what potential does renewable electric energy actually have? First, it’s important to understand the benefits associated with renewables in electric energy. When the Department of Energy was formed in the 70s it immediately established the Natural Gas Policy Act[3]. So they were certainly aware of the importance. However, the need for renewable energy has changed since this era. Over the last few decades, we’ve put high environmental strains on our grids, and now see the need to reduce that impact. Coal-fired plants that release gases into the air are a major source of pollution effecting the environment[4]. Several policy acts have been developed, but we need to a find a solution to replace the continuous need to build such plants. Today’s energy systems demand efficiency, reliability, and security — and the integration of renewables into our electric grid must support those needs.  
 
While the task will not be without its challenges, the good news is that public utilities benefit from renewables in both time and cost efficiency. In 2013, for instance, the Idaho Power Company received a $94 million grant from the U.S. Department of Energy to modernize the grid and develop renewable energy integration tools. This grant allowed Idaho Power Company to improve its forecasting, using 15% of natural gas-fired reserves instead of 100%. This resulted in savings of roughly $50,000 for the utility and its customers, and IPC is seeing similar results on a consistent basis[5].
 
Inserting renewables in the grid: Overcoming the challenges
 
It’s commonly known that renewables have not always been an efficient, reliable and secure option. Considering the fact that the three most important things used for renewable energy are the sun, wind and rain, basic weather conditions can easily hinder the ability to collect renewable energy. While these elements provide energy, they also create challenges for the utilities. Farms and ranches are great locations for wind turbines, but it is difficult for transmission lines to reach these areas. Therefore, they require long lines — but these increase the potential for energy loss. Another challenge occurs in regions with dark winters, limiting solar panel exposure to the sun.
 
Another issue is simply getting reactive power into the electric grid from an outside source, which often results in problems. The utility controls the voltage levels of its system and injects energy into the grid when necessary, to keep the voltage at an acceptable level and smooth out the natural swings in usage. When renewable energies are injected into the grid, the utility’s synchronous generator may be thrown off. This causes an inability to track where the power is coming from.
 
Overcoming challenges with new technologies
 
The electric utility industry is overcoming these challenges, and even recently announced plans to invest $1.5-2 trillion in infrastructure by 2030 to support renewables in the system[6]. This initiative stems from the belief that distributed energy can resolve several energy and electric power problems facing the U.S. Problems include blackouts, brownouts, energy security concerns, power quality issues, tighter emissions standards, transmission bottlenecks and the desire for greater control over energy costs[7]. As companies begin to incorporate renewable energies into their existing infrastructures, they must address these issues.
 
For instance, voltage management is especially important to control. Companies are using solutions like Secondary and Tertiary Voltage Regulators; reactive power compensators such as the STATCOM (Static Synchronous Compensator); battery systems for storing energy reserves; and pole transformers for remote tap control. Another issue to address is frequency control. When adding renewable energy, a power system often has inconsistent frequencies. Companies are searching for solutions that can adjust frequency variations within a defined range by using a faster regulated response. Companies must also be aware of output fluctuations, which can be offset by absorbing excess energy when excessive output fluctuations occur.
 
Utilities must also consider the recent interest in and adoption of electric vehicles. As they become more popular, vehicle charging creates an increasingly complex problem, because rapid charging can cause a sudden increase in load to the system. Batteries, however, can store excess power and thus minimizing the negative effects of rapid charging on the grid.
 
Demand response is another well-known solution for managing energy, and is increasingly being applied to renewables. This approach allows the system to automatically request that users suppress power consumption during peak hours, and can automatically shift any surplus power load to a later time.
 
These types of tools have the potential to significantly advance the industry’s progress in the use of renewables in the grid, and the development of them should be watched carefully.
 
Technology and political support will be crucial for making advancements
 
Thirty states and the District of Columbia are currently implementing Renewable Portfolio Standards, according to the U.S. Energy Information Administration. This mandates that a certain percentage of electricity is generated by a particular technology, such as solar or biomass[8]. These types of policies, combined with technologies that enable the collection, transmission and distribution of renewables, will drive the global electric ecosystem to a more stable and healthy state.
 
ABOUT THE AUTHOR
Takafumi Arai is the digital marketing supervisor for Toshiba's global smart community projects, which include a variety of renewable energy solutions that the company is implementing and testing in a dozen countries. Follow the community at @SmartCommunityL.


[1] “FAQ: Renewable energy.” International Energy Agency. http://www.iea.org/aboutus/faqs/renewableenergy/.
[2] “FAQ: How much electricity is lost in transmission and distribution in the United States?” U.S. Energy Information Administration.. http://www.eia.gov/tools/faqs.
[3] “Natural Gas Policy Act of 1978”. U.S. Energy Information Administration. http://www.eia.gov/oil_gas/natural_gas/analysis_publications/ngmajorleg/ngact1978.html.
[4] Department of Energy and National Energy Technology Laboratory. “Environmental Impacts of Smart Grid”. http://www.netl.doe.gov/File%20Library/Research/Energy%20Analysis/Publications/EnvImpact_SmartGrid.pdf.
[5]U.S. Department of Energy. “Smart Grid Savings and Grid Integration of Renewables in Idaho” http://energy.gov/sites/prod/files/2013/06/f1/IdahoPowerCaseStudy.pdf
[6] Chupka, M. W., Earle, R., Fox-Penner P., and Hledik R. “Transforming America’s Power Industry: The Investment Challenge 2010-2030”. The Edison Foundation, November 2008. http://www.eei.org/ourissues/finance/Documents/Transforming_Americas_Power_Industry_Exec_Summary.pdf
[7] “Distributed Energy”. Office of Electricity Delivery & Energy Reliability. http://energy.gov/oe/technology-development/smart-grid/distributed-energy
[8] “Most states have Renewable Portfolio Standards”. U.S. Energy Information Administration, February 3, 2012. http://www.eia.gov/todayinenergy/detail.cfm?id=4850

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Energy efficiency  •  Energy infrastructure  •  Photovoltaics (PV)  •  Policy, investment and markets  •  Solar electricity  •  Wind power

 

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