Driven by state RPS requirements and the desire to diversify their energy sources, U.S. utilities continue to add more renewable power to their generation portfolios. As a result, they must deal with a number of important issues, including resource availability that varies geographically.
U.S. utilities are integrating a growing number of renewable energy technologies into their generation portfolios in response to state renewable energy portfolio standards (RPS) mandates and several other criteria unique to their specific geographical locations. In light of the increasing impact that renewable energy sources are having on the utility industry, this year’s ELECTRIC POWER conference offered a session titled “Utility Perspectives on Renewable Power—Panel Discussion,” which featured an animated exchange between the speakers and attendees (Figure 1).
|1. Renewable track panelists. Left to right: Cochairs Vas Choudhry, a California-based consulting engineer with many years of experience in the electric utility industry, and Angela Neville, JD, senior editor of POWER; Andrew Ritch, director, Renewable Energy Strategy & Compliance, Duke Energy Corp.; Ryan Fair, manager of Project Development, Florida Power & Light; Jeffrey Wilson, research engineer in Research and Environmental Affairs, Southern Co.; and Daniel P. Breig, PE, director, Project Development Division, Southern California Edison. Source: POWER|
Duke Energy’s Commitment to a Sustainable Future
“Duke Energy continues to invest heavily in renewable energy to diversify our fuel mix and reduce our carbon footprint,” said Andrew Ritch, director, Renewable Energy Strategy & Compliance for Duke Energy Corp. “Nearly 40% of the energy we generated in 2010 was from carbon-free resources, enough energy to supply approximately 5.3 million homes.”
Duke Energy is the third-largest producer of carbon-free generation among U.S. investor-owned utilities. The utility has an enterprise-wide goal to triple its renewable generation capacity—from approximately 1,000 MW today to 3,000 MW by 2020, he said.
Duke Energy taps a number of renewable sources. For example, in Indiana, it is purchasing the energy from a 100-MW wind farm. And in North Carolina, the utility buys power from the second-largest solar farm in the Southeast, a 15.5-MW facility located on a 357-acre site. In addition, in the first-of-its-kind program to be approved and completed in its service territory, Duke Energy will own and operate 10 MW of distributed solar generation located on its customers’ rooftops and properties. Also in the renewable realm, Duke Energy has entered into an agreement with FLS Energy to purchase the renewable energy credits from the largest solar water heating installation in the U.S.
The utility has even launched Duke Energy Renewables, part of Duke Energy’s commercial businesses, which focuses on wind and solar projects.
“We launched our renewables business in 2007 with investments in wind energy. We now have approximately 986 MW of operating wind projects at nine U.S. sites,” Ritch said. “Then Duke Energy Renewables entered into the commercial solar power business in 2009. Currently, we have three photovoltaic (PV) solar farms in operation.”
Duke Energy continues to forge strategic alliances with China to help it scale up and commercialize clean energy technologies. These partnerships represent the type of global collaboration that is needed to achieve economies of scale and drive down the cost of clean-energy technologies for a carbon-constrained world, according to Ritch.
From a utility’s perspective, these are the challenges related to renewables that Ritch sees:
- Cost. Renewables can be more expensive (due to solar tax credit normalization requirements and customer rate pressure).
- Scale. Projects are often small scale.
- Intermittency. Many renewables are available only on an intermittent basis (so they are not controllable) and need backup resources such as peaker plants fired by natural gas.
- Location. Resource availability varies geographically, and resources are often a long distance from load centers.
- Legislative requirements. The definition of “renewable” varies by state and is a matter of legislative language.
- Interconnection to the grid. Line congestion and system balancing can be challenges.
Southern Co.’s Diverse Renewable Landscape
Southern Co., which has approximately 42,514 MW of installed capacity, is currently involved in a diverse range of renewable projects that include wind, solar, and biomass.
“Offshore wind may be the best large-scale wind generation option for Southern Co.,” said Jeffrey Wilson, research engineer in Research and Environmental Affairs for the company.
Southern Co. and Georgia Tech partnered on an extensive study of offshore wind potential in the Southeast, identifying and detailing several key challenges that must be addressed. That offshore wind feasibility study was completed in 2007. Southern Co. is also preparing applications for federal leases to construct meteorological towers off the Georgia coast to collect data for assessing the potential for offshore wind generation.
Wilson explained that a wind turbine designed by students at the University of Alabama at Birmingham has been erected atop the Alabama Power headquarters building to collect research data. Wind data also is being collected at Navarre Beach, Fla., and in north Georgia.
Wilson described Southern Co.’s approach to using solar energy by emphasizing that “we need to characterize and determine issues with this variable technology.”
Alabama Power, a Southern Co. affiliate, and the Electric Power Research Institute (EPRI) are conducting a demonstration of different solar PV technologies with microinverters at the Alabama Power headquarters. The four different 1-kW PV technologies are polycrystalline Si, monocrystalline Si, HIT (heterojunction with intrinsic thin layer) hybrid, and amorphous Si thin film.
Likewise, Georgia Power, another Southern Co. utility, is partnering with EPRI in connection with an 18-month study to evaluate how solar PV power systems may affect the utility’s distribution system. Georgia Power is also involved in two other solar projects; it is conducting a demonstration of seven different solar PV technologies at its headquarters building, and it has received regulatory approval to build a 1-MW portfolio of medium-scale solar demonstration projects across the state.
Further afield, Southern Co. is partnering with Turner Renewable Energy on a 30-MW solar PV power plant in Cimarron, N.M.
The company is also conducting research at several plants that looks at cofiring coal with wood chips, wood pellets, sawdust, urban wood waste, peanut hulls, switchgrass, and other biomass to determine the costs and impacts of the process.
Alabama Power has been cofiring grass fuel materials with coal for nine years as part of normal operations at its Plant Gadsden and has been comilling wood in various forms (including chips and sawdust) for eight years. Plant Gadsden’s direct injection system can cofire up to 10% biomass by energy at low loads and 5% at high loads. The facility recently tested the plant Giant Miscanthus as a fuel source.
In addition, Southern Co. has a renewable energy project under way with the Center for Energy Advancement through Technological Innovation (CEATI) to investigate the torrefaction market. Torrefaction, also known as biochar, is a process of roasting wood chips in a large furnace, but not to the point of becoming charcoal. Work is advancing to purchase 500 tons of torrefied wood for a test burn at Plant Gadsden. Southern Co. and CEATI hope that lab- and combustor-scale testing of the material will help them better understand the handling needs and risks associated with torrefied wood.
SCE: Promoting Renewable Energy in California
“Southern California Edison (SCE) is an industry leader in renewable energy, electric transportation, smart grid, and smart metering,” Daniel P. Breig, PE, director of SCE’s Project Development Division, said.
The utility serves a population of 13 million people via 4.7 million business and residential accounts in a 50,000-square-mile service area within Central, Coastal, and Southern California. In 2010, SCE delivered approximately 14.5 billion kWh of renewable energy to customers.
SCE’s 2010 energy resource mix breaks down as follows: natural gas (42%), nuclear (19%), eligible renewables (18%), coal (12%), and large hydro (9%). In the eligible renewables category, the subcategories are: geothermal (9%), wind (5%), biomass and waste (2%), solar (1%), and small hydro (1%).
Brieg explained that the 18% of eligible renewable resources that SCE uses exceeds the overall percentage of renewable resources (11%) used by California utilities. He further contrasted these percentages with the U.S. total for renewables, which is only 4%.
Brieg also discussed the average retail prices of electricity per kWh. These range from a low of $0.06 in Wyoming to a high of $0.21 in Hawaii; California’s average retail price is $0.13, he said. He pointed out that “the U.S. total average price per kilowatt-hour is 9.83 cents.” (Editor’s note: The latest average retail price of electricity in different sectors of the economy by state is available from the Energy Information Administration at http://bit.ly/mcobY9.)
“Are green jobs good or bad?” Brieg asked. He then answered by pointing out the pros and cons of jobs related to renewable energy. On the downside, green jobs add to the cost of renewable energy, so currently, renewables need subsidies to compete with traditional fossil fuels.
After pointing out these challenges, he focused on some encouraging developments. He noted that equipment suppliers are using robots to reduce labor and manufacturing costs. Installers are also innovating to reduce field labor. Operations are increasingly being designed for remote automatic operation. In addition, to decrease maintenance, many renewable energy technologies have no or few moving parts
As for the future of renewable energy in the U.S., Brieg described what he considered to be the important issues and barriers related to promoting the widespread use of these alternative technologies:
- Resource availability
- The cost to electric ratepayers and taxpayers
- Grid integration
- The intermittent, variable nature of renewables
- Connection Standard IEEE 1547
On the positive side, he pointed out that there is now “significant use of renewables in California and a decreased reliance on coal.”
FPL: Advancing a Clean Energy Economy
“We believe it is our company’s duty to address climate change head-on and provide clean energy today and for future generations,” said Ryan Fair, manager of Project Development at Florida Power & Light (FPL).
He explained that NextEra Energy is a large U.S. power company composed of two businesses: NextEra Energy Resources, a wholesale generator and U.S. leader in renewable generation, and FPL, one of the largest U.S. electric utilities, with 4.5 million customer accounts and 23,772 MW in operation.
NextEra Energy is the largest U.S. wind energy generator; it produces 8,078 MW of electricity. In addition, FPL has opened three commercial-scale solar power plants in the Sunshine State (Florida) since 2009.
FPL’s three utility-scale solar facilities make Florida a leading U.S. producer of solar energy:
- The Martin County 75-MW solar thermal facility. The Martin Next Generation Solar Energy Center is the first hybrid solar facility in the world to connect to an existing combined-cycle power plant. It is the largest thermal solar plant outside of California and generates enough electricity to serve about 11,000 homes. A photograph of this facility appears on the cover of this issue.
- The DeSoto County 25-MW solar PV facility. The DeSoto Next Generation Solar Energy Center is one of the nation’s largest solar PV facilities. It uses more than 90,000 panels to turn the sun’s rays into electricity to power more than 3,000 homes, and the project created 400 construction jobs (Figure 2).
|2. Record-setting plant. The 25-MW DeSoto Next Generation Solar Energy Center was a POWER 2010 Top Plant. A detailed profile of the facility is available in the December 2010 issue of POWER and in our archives at www.powermag.com. Courtesy: FPL|
â– The Space Coast/Kennedy Space Center 10-MW solar PV facility. The Space Coast Next Generation Solar Energy Center was the first U.S. private/public partnership for a solar project.
Fair described the impact of one 100-MW solar plant based on statistics compiled by FPL:
- Oil consumption avoided: approximately 700,000 barrels.
- Cars removed from the road each year: 17,600.
- Natural gas consumption avoided: 40 billion cubic feet.
- Greenhouse gas emissions avoided: 3 million tons.
- Projected tax revenues: $50 million.
- Job creation: 4,000.
“If the state were to enable utilities to pursue renewable energy projects up to 2% of revenues, FPL would immediately begin construction of more than 500 MW of new solar projects,” Fair said.
Several FPL projects are permitted and shovel-ready. If these projects move forward, there is the potential for the creation of approximately 10,000 to 15,000 new direct and indirect jobs in the first three years, he explained.
Looking down the road, Fair emphasized the increasing importance of solar energy: “With a strong commitment from the state and investments by utilities, consumers, businesses, universities, etc., we can lay the groundwork for a clean energy economy.”
— Angela Neville, JD, is POWER’s senior editor.