Rock Products

MAR 2018

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46 • ROCK products • March 2018 www.rockproducts.com Charleston Stone Cooperative Benefit CMEC began investing more time in its relationship with Charleston Stone a few years ago as part of its Key Accounts initiative. The relationship became much stronger after work- ing together on this project. CMEC has been "really good to work with," Tarble said. He believes that working with co-ops is a lot easier because they are smaller and more responsive. "Coles-Moultrie can help us out on a few minutes' notice," he said. Positive Local Economic Impact Concern for community is one of the seven cooperative principles, and electric co-ops demonstrate that concern by participating in economic development efforts. Rural areas usually lack large employers. Charleston Stone's 20 employees are an important part of the local economy. CMEC's assistance on this project has helped Charleston Stone become more competitive, which strengthens the com- pany's ability to retain its 20 local employees and supports the company's plan to hire five more employees over the next three years. A local quarry is an economic asset for a community. If Charleston Stone did not exist, local construction projects would be more expensive, because the high cost of transport- ing stone and aggregate would need to be covered. Farmers in the area benefit from the lime that they use to reduce the acidity in their fields, which enhances productivity. Increased Electric Sales Based on the preliminary estimate of the electric usage for the new crusher, electric sales to Charleston Stone could increase by about $28,000/year, an increase of almost 25 percent (see Table 1). TABLE 1: Charleston Stone electric crusher upgrade. Actual Pre-Upgrade Estimated Pre-Upgrade Annual energy (kWh) 615,000 808,000 Demand (KW) 524 673 Annual electric bill ($) $113,000 $141,000 Expected Reductions in Fossil Fuel Use and Cost The diesel crusher burned about 13,000 gal. of diesel fuel each year. Diesel prices have been volatile over the years. Charleston Stone has paid $1.50 to $3.75 per gal., so they will save about $20,000 to $48,000 in diesel purchases. In order for an electrification project to be truly beneficial, it should have positive environmental impacts. An import- ant environmental metric is carbon emissions. Switching to an electric crusher will reduce CO2 emissions from diesel, but increase emissions associated with electric generation. The mix of electric generation re- sources in a region deter- mines the level of CO2 emitted for each MWh of electric consumption. This conversion project should reduce CO2 emissions slightly, even though the Illinois/Ohio region has higher levels of CO2 emissions per MWh than the national average. Figure 9 shows what the CO2 impact of this project would have been if it had been undertaken in different regions in the country. In many regions around the country where there is less coal generation, this project would have reduced CO2 emissions to a much greater degree. The data from EPA that was used to determine CO2 emissions per MWh is from 2014. Since then, noted Kim Leftwich, gen- eral manager of CMEC, Illinois has seen 4,000 to 5,000 MWs of coal generation shut down, which should substantially reduce carbon intensity. 19 CO2 emissions from electric generation are projected to decline an additional 20 percent over the next five years. When 2017 CO2 emissions data becomes available, it may very well show this project having greater CO2 emission reductions. If projections of continued reductions in CO2 emissions per MWH hold true for CMEC, this project could produce an even more substantial reduction in CO2 emissions. What Challenges Did the Conversion Pose? Charleston Stone is a large, sprawling complex and the Tar- bles own another quarry elsewhere in Illinois, but putting up the money for a million-dollar plus investment was a challenge. As an electric cooperative, CMEC was eligible to apply for zero interest financing from USDA's Rural Economic Development Loans & Grants Program (REDLG). FIGURE 9: CO2 Emissions/MWH from crusher conversion if it were in different regions.

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