Georgia Power has completed a preliminary engineering study on converting the coal-fired Plant McIntosh to determine performance, emissions projections and a total project cost estimate for converting the plant to biomass stoker firing.
As a result of the study and questions about new environmental standards, the Southern Co. (NYSE: S0) subsidiary has decided to hold off on some conversion projects for now.
The study examined the retrofit of a water-cooled vibrating gate to the existing furnace while maximizing steaming rate, the utility said in an update to its renewable energy plan filed April 16 at the Georgia Public Service Commission. The study predicted a steam capacity de-rate while firing the specified biomass. Other modifications that would be required for the conversion include a multi-clone dust collector, water coil air heater and tubular air heater.
In December 2011, the U.S. Environmental Protection Agency proposed changes to both the major source and area source Industrial Boiler Maximum Achievable Control Technology (MACT) Rules. The rules contain a number of significant revisions based on additional comments and data received following publication and the simultaneous notice of reconsideration in March 2011. EPA intends to finalize this reconsideration by this spring, although this self-imposed deadline could change based on further legal action in a pending case before the U.S. District Court for the District of Columbia.
“These potential changes could impose additional challenges related to cost and design for the conversion to biomass,” Georgia Power noted. “The company continues to monitor the EPA IB MACT as it progresses. Additionally, the company has performed preliminary research on other alternative biomass technologies, such as direct injection, that could potentially be employed at Plant McIntosh.”
Also because of uncertainties surrounding these EPA rules, the company has also delayed the decision to proceed with a biomass conversion at Plant Mitchell. In October 2011, the PSC approved Georgia Power’s plan to delay that conversion project for two to four years.
On March 1, Georgia Power requested the commission authorize it to complete a study of Direct Injection (DI) technology for the Mitchell project. The study will help preserve options for the project. The DI method involves injecting woody biomass directly into the existing pulverized coal boiler and requires significantly fewer changes to the existing Mitchell generating unit as compared to the conversion to either a stoker or bubbling fluidized bed (BFB) boiler. As a result, the conversion to DI may cost significantly less than originally projected for the stoker or BFB conversions. Additional study is needed to better determine the costs and benefits of DI at Mitchell Unit 3.
Utility makes progress on Green Energy Program
Georgia Power also reported that it issued a request for proposals (RFP) in May 2011 to supply its voluntary Green Energy Program by purchasing the full output of energy produced by solar PV electric generating systems of up to 1,325 MWh per year (or approximately 1 MW), at a price not to exceed $150 per MWh.
Bidders were able to submit proposals to provide either a portion of, or the entire 1,325 MWhs annually of solar PV energy. Georgia Power sought procurement of energy starting on or before June 1, 2012. The company also sought a contract term for a period of ten or fifteen years. There were three bidders that submitted four bids into the RFP. The winning bidder was Solar Design & Development LLC.
In December 2011, Georgia Power executed an agreement for the purchase of solar energy and renewable energy credits with Solar Design & Development. Solar Design & Development will design, develop and install a solar PV generation facility consisting of about 4,255 solar panels located in Hannahs Mill, Ga., with a total capability of producing about 1 MW of electric power.
Work being done on large scale solar projects
In June 2011, Georgia Power filed its 2015 Large Scale Solar (LSS) proposal with the commission, which proposed purchasing up to 50 MW of solar photovoltaic resources, and capping any individual proposed project at 30 MW. The proposal was unanimously approved by the commission in August 2011.
The price Georgia Power will pay for the solar energy was developed using the company’s long-term avoided energy cost plus a capacity credit based on the operational characteristics of solar energy. This credit was benchmarked to market pricing obtained under Georgia Power’s 2015 RFP. Applicants who met the program criteria were awarded contracts on a first-come, first-served basis.
Georgia Power executed five power purchase agreements (PPAs) in December 2011 for 50 MW of solar energy with two solar developers in Georgia. The PPAs are for twenty year terms and fully subscribed the LSS Program. Those two solar developers are:
- Simon Solar Farm LLC, which contracted to build one 30 MW solar project near Social Circle, Ga.; and
- Solar Design and Development LLC, which contracted to build four solar projects totaling 20 MW on sites in Mitchell, Meriwether and Upson counties.
The commission approved these five PPAs in December 2011 and January, respectively, however, Solar Design and Development defaulted on one of the PPAs, which was contracted to deliver a total of 1 MW of solar energy to the LSS Program, the utility reported. As a result of the default, Georgia Power is pursuing execution of a 1 MW replacement contract with the next LSS participant in the queue to ensure the LSS Program is fully subscribed at 50 MW. The required commercial operation date for the solar resources is June 1, 2015.
No methane projects pinpointed so far
Georgia Power said it also continues to seek cost-effective renewable projects and has either evaluated, or is currently evaluating, landfill methane gas, digester methane gas, wood biomass and solar PV projects with developers as well as customers. Evaluations have been made on 30 potential biomass, landfill methane gas, or digester methane gas projects and over 50 potential PV solar projects to date, however, no commitments have been made for specific projects.
Contributing factors that have affected the development of renewable projects include that decreasing avoided costs largely due to lower natural gas prices have made financial hurdles more difficult to clear in order to develop one of the three 30 MW or less renewable projects at or below avoided cost.
University of Georgia wants to get rid of coal boiler
The University of Georgia (UGA) is seeking to identify cost-effective renewable technologies and fuels which could reduce or replace the current use of coal in its central steam plant. In the fall of 2010, UGA Physical Plant Energy Services (PPES) issued a Request for Information (RFI) to companies specializing in renewable technologies. Georgia Power responded to the RFI and met with UGA.
The RFI process enabled UGA PPES to discover that while renewable technologies have potential for steam generation, most of the technologies that offer the greatest hope for lowest air emissions are either cost-prohibitive or not commercially available at the consistent level needed for the production of steam on a research university campus, Georgia Power reported.
The university’s coal-fired boiler produces less than one-third of the steam needed to heat and cool buildings, provide hot water for residential and dining facilities, maintain constant temperatures in sensitive research facilities and sterilize equipment in research labs and the veterinary hospital. The coal boiler operates as a supplement to the natural gas boilers, which limits the amount of emissions while maintaining a reliable source of heat during the peak heating season each winter. The coal-fired boiler is nearing the end of its operational life, however, UGA has not set a specific date to be coal-free.
“UGA PPES will not appoint a task force to consider this issue,” the utility noted. “However, they are committed to studying all options in a deliberate manner. UGA PPES will devise a solution that is fiscally responsible, environmentally sound and effective in implementation. The ultimate decision will follow consideration of many factors including air quality, capital funding, operational cost, reliability, fuel availability, location and other campus master plan considerations. Georgia Power will continue to monitor this issue and will respond to a request for proposals when/if issued by UGA.”
Georgia Power works with Defense Dept. on renewables
Georgia Power said it continues to investigate renewable energy options that would enable the U.S. Department of Defense to meet a portion or potentially all of its legal and policy obligations for renewables, resource conservation, greenhouse gas emission reduction and energy security under federal law and regulations.
The company is seeking to determine if joint projects with Robins Air Force Base, Kings Bay Naval Base, Marine Corps Logistics Base, Fort Stewart and Fort Benning could meet each of their needs and be in the best interest of the company’s other customers. In addition, Georgia Power participated in Biomass Industry Day at Fort Stewart, which was a planning session to assist in the development of a long-term vision plan for Fort Benning, and provided feedback on a draft RFP for Large Scale Renewable Energy Production for Army installations.
Turning capped ash disposal sites into new energy
Georgia Power has assembled an internal project team to evaluate the feasibility of flexible membrane caps that could accommodate a cost-effective installation of thin film solar PV on ash ponds at generation facilities. The project team is developing a high-level cost screen of a traditional cap for an ash pond in comparison to the new solar membrane cap. The team is also evaluating the environmental impacts of the potential project.
Georgia Power received approval from the commission to build a 1 MW solar portfolio. Through the portfolio, the company will gain additional experience in the development, operation and economics of solar projects including siting, permitting, engineering, construction and maintenance. Solar energy generated from the projects would become part of Georgia Power’s renewable generation portfolio but is not planned to supply the Green Energy Program.
The company has evaluated more than 50 potential projects at proposed locations around the state. The proposed projects have included partnerships with customers for both ground and rooftop applications as well as projects that may be located on company-owned facilities. All of the projects are expected to be owned, operated and maintained by Georgia Power. None of the 50 potential projects that have been examined have yielded a project that will meet both the commission’s cost directive and the company’s portfolio goals. Georgia Power said it will continue to evaluate potential projects.