Decentralized power and smart grids
- January 2, 2012
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Distributed generation (DG)—synonymous with decentralized power—will become a bigger component of smarter grids going forward, particularly in urban environments to improve grid reliability. Because distributed generation represent islanded loads that can be managed, they can allow a controlled step-up in load as centralized power comes back online in a black start.
Distributed generation technologies also offer efficiency gains in their use of fuel (90 percent efficient versus, say, coal-fired power, which is closer to 35 percent efficient) as well as placing supply closer to loads, cutting out the role of transmission, which suffers 10 percent to 15 percent losses.
And as smarts are added to the grid, that enables the addition and control of distributed generation. As distributed generation proliferates, that will drive the market for grid-scale energy storage.
All this according to Tomasz Kaminski, a research analyst specializing in renewable energy for Frost & Sullivan, who recently focused on DG-related technologies.
We've discussed this subject before in various columns, including "Smart Grid Analytics: From Data to Decisions," "Central and Distributed Power: Symbiotic?" and "Enabling Distributed Generation" by my colleague Kate Rowland, editor of Intelligent Utility magazine, and "Power to the People: Distributed Generation Can Strike a Balance, Change the Paradigm," by Doug Houseman in the November/December 2011 issue of Intelligent Utility magazine.
The two most-favored technologies for distributed generation currently are natural gas-fired microturbines and renewable energy in the form of hydrogen-based fuel cells and solar photovoltaics, Kaminski told me last week.
"In my view, microturbines will grow probably quite rapidly for another 5 to 10 years," Kaminski said. "The reason is that there's a need for decentralized power generation and microturbines are a major, familiar technology, known for many years. Another reason for their growth is that they run on natural gas, which is widely available and still considered quite 'clean' when compared with coal."
This trend will continue for another 5 to 10 years, but then, in Kaminski's view, this growth will slow and renewables will show greater growth.
The setting most often will be urban environments, cities, where reliability and efficiency can be improved. A single building, where a micro-turbine can put out 30 to 250 kilowatts and serve as a combined heat and power (CHP) source, would provide an exemplary opportunity, according to Kaminski.
The Four Seasons Hotel in Philadelphia, for instance, has installed microturbines that generate nearly 200 kilowatts, according to its vendor, Capstone Turbine Corporation. The vendor claims its system reduces the facility's annual energy costs by 30 percent and the combined heat and power design provides the hotel with all its hot water needs and 15 percent of its heating needs. The vendor touts CHP microturbines for hotels, telecom facilities, large retailers, university campuses, hospitals, data centers, landfills, oil and gas facilities and hybrid electric vehicles, where onboard microturbines recharge electric batteries, increasing range.
Though distributed generation originated in the United States, according to Kaminski, currently, the European Union's "20-20-20" plan (20 percent decrease in greenhouse gases, 20 percent increase in energy efficiency and a 20 percent increase in renewable energy use by the year 2020) will drive faster adoption rates there than in the U.S., which has no comparable, over-arching policy.
We'll talk more later in the week about microgrids, which incorporate distributed generation and have fascinating applications in both dense urban environments and in rural, under-developed countries.