Biogas at Apple's NC data center

Thursday, May 10, 2012

Continuing to look at Apple's plans for energy supply at its data center in Maiden, North Carolina:

This spring a series of filings by Apple to the Federal Energy Regulatory Commission gave the public some insight into Apple's planned electric generation facilities at the Maiden data center, home to Apple's iCloud service.  (See Tuesday's blog entry for a look at its solar photovoltaic project, and Wednesday's entry for its fuel cell project.)

Fuel cells convert fuels into electricity through a chemical process that does not rely on combustion.  According to one of Apple's filings with FERC, Apple plans to use biogas to power its fuel cells:

The Systems will be fueled with biogas that will be transported via a natural gas pipeline system.  To be injected into the natural gas pipeline system and qualify as pipeline-grade gas, biogas must meet strict heat content and quality requirements.  Consequently, raw biogas must be upgraded (i.e., cleaned and separated to remove components such as hydrogen sulfide, chlorine, and sulfur and to increase methane content) prior to being injected into a pipeline.  Once injected into the pipeline system, it comingles with conventional natural gas and is indistinguishable from conventional natural gas in terms of safety and burning quality.  The biogas, having been upgraded/cleaned to pipeline-quality and then injected into the natural gas pipeline system displaces a comparable quantity of conventional natural gas.
The volume and heat content of the biogas will be measured at a utility-grade meter at the point of injection.  The biogas will then enter the natural gas pipeline infrastructure that has an established balancing measurement system regulated by the Federal Energy Regulatory Commission (Commission).  The biogas will be nominated for the Facility in accordance with the pipeline’s posted business practices and relevant Commission requirements.  Not only the contract and purchase of biogas, but also the nomination process demonstrates compliance with 18 C.F.R. § 292.204 (b).  A utility-grade meter at the Facility will measure actual gas consumption by the Facility.  A revenue-grade meter will measure electricity generated by the Facility.

Furthermore, because the biogas can be upgraded to flow in a pipeline system and nominated for a particular facility, it allows for flexibility in the location of the generating unit.  This flexibility will provide for increased efficiency (operational and maintenance), enhanced reliability, and improved land use. These benefits were recognized by the North Carolina Utilities Commission (“NCUC”).  The NCUC ruled that biogas fuel, which is derived from a renewable energy resource, cleaned to pipeline quality, injected into the pipeline system and nominated for an electric generation facility within the state of North Carolina, is a renewable energy resource known as “Directed Biogas” (NCUC Order Issued March 21, 2012, in docket SP 100, Sub 29). 

This Facility is in keeping with the stated reasons for the implementation of the Public Utility Regulatory Policies Act of 1978 (PURPA), specifically the increased conservation of electric energy, increased efficiency in the use of facility and resources by electric utilities, and the conservation of natural gas.  In the case of this Facility, the use of biogas, which displaces conventional natural gas, to generate electricity will reduce greenhouse gas emissions and smog forming pollutants while also diversifying the fuel used to generate electricity.  The Systems that make up this Facility consume less fuel and produce less CO2 than other technologies.  Each System emits less than 0.07 lbs/MW-hr of NOx , negligible SOx, less than 0.10 lbs/MW-hr of CO and less than 0.02 lbs/MW-hr of VOC.  Additionally, the Systems require very little water, with an average usage of approximately 0.00001 gallons/kWh. The low carbon footprint, de minimus criteria pollutants, small land use and negligible water use, make this Facility a prime example of an initiative that furthers the Commission’s stated goal of increasing renewable energy and investing in environmentally beneficial technologies.

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