Consumer demand for natural gas in Michigan is seasonal with higher demand during extreme cold periods for home heating purposes and lower demand during the warmer summer months. Natural gas supply, however, is available on a more uniform basis. Because of Michigan's excellent underground geological features, supplies of gas can be delivered on a more uniform basis. Michigan's underground natural gas storage facilities can balance receipts and deliveries for Michigan as well as provide winter deliveries to neighboring states. As shown in Michigan's Energy Appraisal, withdrawals from Michigan storage are sufficient in mid-winter months to provide gas supply for Michigan and neighboring states.
Link to Natural Gas Portion of MPSC Energy Appraisal
Michigan's available underground natural gas storage is significant.
With about 690 billion cubic feet (19.5 billion cubic meters)
of working gas capacity, EIA
statistics show that Michigan has more storage than any other
state. This storage provides for more efficient use of transmission
pipelines that bring supply to Michigan utilities, and helps stabilize
Storage is provided by distribution utilities and gas storage companies under rates and services approved by the MPSC (see Rate Book page). Interstate transmission pipeline and storage companies also provide storage services in Michigan under regulation of the Federal Energy Regulatory Commission (see FERC Tariff Book page, or see FERC's list of pipeline companies).
Michigan's utilities design their purchases for a peak day demand of about 7.5 billion cubic feet (212 million cubic meters), of which over two thirds (5.5 billion cubic feet - 156 million cubic meters) is gas withdrawn from Michigan's storage fields, and the remainder is obtained from direct pipeline deliveries of gas from within and outside of Michigan.
as of October, 2011
Source: data from utilities, utility Annual
Reports, and MPSC Gas Cost Recovery cases
for design (coldest) peak day.
View source data (PDF)
Michigan's gas storage is also useful as an alternative supply in an emergency. For example, in the spring of 1951, floods washed out a section of Michigan Wisconsin Pipeline Company's (now ANR Pipeline Company) pipeline in Kansas, shutting off its supply to Michigan for about a week. While it was being replaced, storage fields near Austin supplied Michigan's and Wisconsin's gas needs.
Michigan's storage also serves as a way of shifting summer supply to the winter. In the late 1940's demand for natural gas in Michigan grew faster than pipelines could be built to meet it. When a gas shortage occurred in Michigan in 1947, Consumers Energy (then Consumers Power) injected propane from 1,200 railroad tank cars into Michigan Gas Storage Company (then a new affiliated company) storage fields during the summer to prevent service interruptions the following winter.
All but two of Michigan's 55 storage fields were once producing fields. They are located throughout Michigan's lower peninsula. They were converted to storage (the first in 1941) by drilling more wells and building pipeline facilities and compressor stations. Unlike producing fields, gas storage fields are designed such that their entire production can be cycled in and out of the field each year. The geologic structures that make up storage fields in Michigan have a high porosity, which makes them among the best in North America.
According to the MPSC's Storage Field Data Summary, most of Michigan's storage fields are located in the Niagaran formation. Other formations include Michigan Stray, A-1 Carbonate, and Reed City. Two of the storage fields are salt caverns. Michigan does not have any aquifer or LNG (liquefied natural gas) storage. The MPSC's Operations & Wholesale Markets Division keeps data on each of Michigan's storage fields.