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Rock-Tenn Coverpage

The Minnesota Department of Commerce has two interesting reports on its site in the "What's New" section. One study looks at plug-in hybrid vehicles (PHEVs) and the other is a Green Institute report on the potential of biomass fuels to supply the Rock-Tenn plant with energy.

The "Air Emissions Impacts of Plug-In Hybrid Vehicles in Minnesota's Passenger Fleet" report resulted from legislation calling on the Minnesota Pollution Control Agency (MPCA) "to evaluate the emissions impacts of incorporating PHEVs into the vehicle fleet."

This study models the environmental impacts, specifically criteria pollutant and greenhouse gas emissions, associated with converting portions of all light-duty vehicles operated in Minnesota to PHEVs. We also evaluate the emission consequences of converting the fleet of light-duty vehicles owned or leased by the State of Minnesota to PHEVs. Light-duty vehicles include compact cars, sedans, and station wagons. Emissions are evaluated for 2020. To understand how PHEVs would affect emissions in 2020, a base-case non-PHEV scenario relying on conventional vehicles operating with standard internal combustion engines (ICE) was developed. As an additional alternative to conventional ICE vehicles, a scenario involving pure hybrid electric vehicles (HEVs) was considered.

They examined four future electricity generation scenarios - 100% coal (eek, a bleak future), 80% coal / 20% wind, 60% coal / 40% wind, 100% wind (I'm not sure this is plausible, even in the most blustery days of an autumn with Winney the Pooh).

They also considered different PHEV adoption rates as the cars become available - but if you want to know more about that you'll have to go to the trouble of reading the Executive Summary.

To summarize, generally the use of PHEVs in place of conventional gasoline-driven ICE vehicles will reduce air emissions. The sole exception appears to be SO2 emissions, which rise due to the high sulfur content of coal combusted to generate electricity. The effectiveness of PHEVs depends on the all-electric range capability; a PHEV with a 60 mile range has greater impacts on emissions than a PHEV with a 20 mile range. In comparison to hybrid electric vehicles, PHEVs emit less NOx, VOCs, CO, and particulate matter, but more CO2 and SO2. This results from the high sulfur and carbon content of coal per MMBtu. Depending upon our choices for electricity generation in 2020, it is possible that the impacts on carbon dioxide and sulfur dioxide could change.

No real shock that PHEVs will emit more carbon dioxide than convention hybrids in this region given our reliance on coal. The take home message should be that we need to incentivize low carbon options - from increased miles-per-gallon efficiency to mass transit.


The report on the Rock-Tenn plant is particularly interesting to me - we have discussed it previously and I have a neighbor who works there. The report is "Renewing Rock-Tenn: A Biomass Fuels Assessment for Rock-Tenn's St. Paul Recycled Paper Mill."

The Rock-Tenn St. Paul mill is the largest paper recycling plant in the Upper Midwest, recycling 1,000 tons of paper per day and employing approximately 500 people. It is also one of the largest energy users in the Twin Cities. Since the mid-1980s, Rock-Tenn has received its process steam via pipeline from the Xcel Energy High Bridge coal-fired power plant near downtown St. Paul. The High Bridge plant is closing by the end of 2007, to be replaced by an adjacent natural gas-fired power plant currently under construction. Thus this source of steam will no longer be available, and Rock-Tenn must find another energy source.

I poked through the executive summary and it offers some insight into the modern world of biofuels - what is available, what is reliably available, what will be reliably available for 20 years, and the like.

The solution appears to be a microcosm of the world-wide energy challenge posed by climate change ... they may need an amalgamation of several solutions rather than one (struggling NOT to write "silver bullet") all-encompassing solution.

There are sufficient quantities of biomass fuel sources within 75 to 100 miles of Rock-Tenn to provide all of Rock-Tenn’s energy needs. However, considering current and projected future demand for these sources, no single source of biomass considered in this study could supply all of Rock-Tenn’s long-term fuel needs. The one possible exception is agricultural sources, which could be sufficient if a long-term fuel contract were signed with an entity (or entities) with the necessary capabilities and assets to securely back up a 20-year contract.

The Twin Cities Daily Planet recently covered the Rock-Tenn plant with the background behind the study and where the process goes next.

Decision-making rests with several players. Obviously, Rock-Tenn will decide what kind of fuel to use and whether to keep the plant open. The St. Paul Port Authority, Ramsey County, Washington County and the City of St. Paul are among the public entities whose decisions factor in the process, including decisions on financing and public subsidies. District Energy currently has an agreement with Rock-Tenn to build an energy plant on Rock-Tenn's campus, and can decide either to continue or to end this agreement.

Once the various parties have reached a decision, a proposal would need to be made to the Minnesota Pollution Control Agency (MPCA) with an Environmental Assessment Worksheet. After the MPCA evaluates this worksheet, it will decide whether a full-scale (time-consuming and expensive) Environmental Impact Statement is necessary.

Community input into the process could happen at community meetings to be scheduled in May, and through a citizen advisory committee still under formation.