5.2.1 The Problem with Coal

Unlike natural gas or oil, coal is mostly carbon – so when it is oxidized or burned, the result is mostly carbon dioxide. Thus from a climate protection point of view, quitting coal is critically important. That rule applies to the coal you may burn in your campus heating or power plant. It also applies to the embodied coal in purchased electricity.

Leading NASA climatologist James Hansen and others have argued that to effectively put the brakes on climate change we must stop burning coal except where carbon dioxide emissions are captured and permanently sequestered – a condition which does not presently apply to coal-burning at any college or university and, with the exception of perhaps a small number of well-funded large university campuses, is unlikely to do so in the future -- given the complexities, costs, and uncertainties of carbon capture and storage.

Of course, quitting coal is more easily said than done. There are at least two big hurdles – the potentially much higher cost of alternative fuels (e.g. natural gas, biomass, etc.) and the cost to build a new campus heating/power plant or retrofit an old one.

Many colleges and universities, especially those in coal states in Appalachia and the Midwest, have traditionally used coal for what seemed to be good reasons before we became aware of the problem of climate change. Coal is, after all, plentiful and cheap – though during the first half of 2008 increasing international demand caused the price of coal to double before returning to normal once the global economic meltdown occurred later in the year. Higher coal prices may return once the world economy gets back on track. Moreover, coal prices will definitely rise to much higher levels as effective cap and trade or carbon tax regimes are disproportionately applied to coal to actively discourage its use. Coal mining presents a raft of troubling environmental and health issues as well. And as many facilities managers know, coal is dirty to handle and can have adverse health impacts on facilities staff – a reality campuses that burn coal may not want to admit for liability reasons.

So it makes sense to look at alternatives to coal burning – perhaps making plans to convert your power plant once the economy picks up and revenues become available. Schools in coal-producing regions of the country may want to expand their examination of alternatives to coal to include research on transitioning local communities away from coal mining and, if needed, direct assistance to workers and communities affected by this transition.

There can be a silver lining to quitting coal. Switching to a higher price heating fuel will increase the incentive your campus has to implement energy conservation measures to reduce your heating load. And those measures will further reduce your carbon footprint. In any event, schools committed to make significant reductions in GHG emissions with on-campus coal plants can’t avoid this very difficult issue.

5.2.2 Alternatives to Coal

What fuel options besides coal exist for campus heating or power plants? The obvious traditional one is natural gas. Less obvious though more climate-friendly choices are biomass, landfill gas, and geothermal.

Natural Gas
Natural gas industry advertisements have told us for years that natural gas is clean and efficient. In fact, it is a fossil fuel and even burning it efficiently produces ample quantities of carbon dioxide that contribute to climate change. To avoid the worst consequences of climate change we will need to reduce our reliance on all fossil fuels including natural gas. Nonetheless. natural gas is the cleanest of fossil fuels from the point of view of conventional pollutants as well as carbon dioxide emissions. On a BTU basis (CO2/BTU), natural gas produces about half the GHG emissions as coal. Thus switching from coal to natural gas combustion is a step in the right direction though not a long term fix. While coal is regarded as cheap and plentiful, natural gas supplies are more constrained and natural gas has been relatively expensive until the recent economic downturn.

Campus planning involving heating or power plant fuel choice should anticipate future carbon tax penalties. These penalties will close the cost gap between coal and natural gas. It is also important to note that natural gas can be burned more efficiently than coal.

Cogeneration or “combined heat and power,” an option for coal and natural gas, further increases the efficiency of fuel use (especially if combined cycle technology is used) and thus can play an important role in lowering costs and making natural gas use more affordable. However, a note of caution: as previously mentioned, while cogeneration is generally regarded as an energy efficiency measure, implementing it at any given school could decrease or increase its carbon footprint -- depending on (a) the carbon intensity of the fuel used to cogenerate and (b) the carbon intensity of the purchased electricity cogenerated electricity replaces.

Biomass
Biomass fuel consists of organic material such as wood chips, oat hulls, corn husks, etc. Finding a long-term reliable supplier with enough fuel from those sources to power campus heating or power plants can be a challenge. Ensuring that the biomass is produced sustainably is also a challenge. Other challenges associated with biomass are biomass’ relatively low heat density (requiring greater volumes of fuel), transporting and handling issues, and its air emissions and ash waste products.

Biomass is not only renewable but also theoretically carbon neutral because the carbon that’s released into the atmosphere when biomass is burned can be captured and sequestered into new biomass as that biomass grows. Sustainable biomass presumes that annual biomass production equals consumption and is accomplished without environmental damage, e.g. cutting down forests. Since some fossil fuel inputs are generally involved in growing, harvesting, chipping, and transporting biomass fuel, it can be argued that biomass is not actually carbon neutral despite often being regarded as such. Calculating the life-cycle net carbon emissions of biomass-based heating or electricity production would be a great project for students and faculty.

Sustainable biomass can include waste products like wood waste from furniture plants, urban tree trimmings, or clean wood extracted from municipal solid waste, and agricultural crop waste. While the waste-to-energy industry sometimes claims that general municipal solid waste is an acceptable biomass fuel, it is not regarded as such by environmentalists because of the dirty air emissions and toxic solid waste by-products its combustion produces and because burning municipal solid waste generally undermines municipal recycling programs.

Before proceeding with plans to convert to biomass campus heating or power generation it is essential that a fuel availability study be conducted. While a consultant can be hired to perform this study, it could be a great project for students with support from faculty and facilities management staff. Students could study the net availability of suitable biomass resources within a given distance from campus. This research would examine existing resources as well as the potential biomass resource if a market for biomass were created by demand from your proposed plant. Students could identify sustainable forestry or crop practices that your school could require for biomass purchases including consideration of the Forest Stewardship Council’s best practices. If you proceed with a biomass plant, once it is up and running students can study the supply chain to determine and evaluate what is actually happening on the ground. This is but one example of an operational step toward reduced carbon emissions that provides a unique and important learning experience for students. Your CAP should identify and utilize these.

While converting your heating or power plant from coal to biomass may be a long-range strategy due to the costs involved, in the meantime – depending on boiler type -- it might be possible to co-fire biomass and thus reduce GHG greenhouse gas emissions. Co-firing generally involves displacing some coal combustion by burning biomass and coal together. The National Renewable Energy Laboratory has published a useful factsheet on biomass cofiring.

Middlebury College provides an example of biomass cogeneration while the University of Iowa provides an example of co-firing oat hulls.

Landfill Gas
Landfill gas is methane produced by the decomposition of garbage in landfills. Since methane is a powerful GHG gas which on a mass basis and 100 year time horizon has over 20 times the global warming potential of carbon dioxide, it is important that it not be vented to the atmosphere. Collection systems can be installed in landfills to harvest methane. It is then scrubbed and often burned on-site to generate electricity or both heat and electricity. It can also delivered elsewhere via pipeline. While burning landfill gas produces carbon dioxide, it also prevents methane emissions – and thus has the effect of a substantial reduction in GHG emissions. While not readily available to all college campuses, landfill gas can be a suitable fuel for campus power plants or any kind of boiler or cogenerator.

University of New Hampshire offers an example of campus cogeneration using landfill gas.

Geothermal
Geothermal energy takes different forms. It may be possible to tap very hot water or steam through deep wells and use that heat energy to heat buildings or generate electricity – though this type of geothermal is very site specific and would not be available to many campuses. In contrast, ground source heat pump (GSHP) systems will work in most areas. They also rely on wells but they use the earth as a heat source and heat sink through the use of electrically powered heat pumps. Heat pumps move heat using a refrigerant gas and a refrigeration cycle much like the one used in a home refrigerator. Usually GSHP systems are used to heat and cool individual buildings – though if you drill enough wells, run enough heat exchanger pipe, and have enough heat pumps, it is theoretically possible to abandon a coal-fired power plant and heat and cool an entire campus this way. If the heat pumps are run on electricity generated from wind turbines or another renewable energy source, you have carbon-free heating and cooling.

Oregon Institute of Technology offers an example of geothermal heating and electricity production on campus and Ball State University provides an example of GSHP replacing a co-fired campus power plant.

Of course, irrespective of the fuel type used by your heating or power plant, you can reduce your carbon footprint and fuel costs by reducing the amount of fuel you burn. That can be done by reducing your campus energy load through energy conservation efforts.

5.2.3 Reducing the Carbon Footprint of Oil Burning

Many sites have limited heating fuel choices and rely on fuel oil as a primary heating source. If cleaner burning natural gas is available nearby, the cost of connecting to it and upgrading boilers & burners to use natural gas can be calculated. A reduction in GHG emissions will be a certainty with this change because on a BTU basis (CO2/BTU) natural gas emits 30% less CO2 than does fuel oil. Also, it may be possible to burn natural gas – especially when cogenerating -- more efficiently than oil, thus further reducing GHG emissions.

Where switching to natural gas isn’t feasible, consider the use of #2 oil vs. the dirtier (but less expensive) #4 or #6 types. On a BTU basis, #2 oil emits 7% less CO2 but emissions reduction will be greater than that because #2 oil does not have to be heated in storage (a requirement for #4 and #6 oils in colder climates to allow the oil to be pumped).

Of course, if you are need of a new power plant or are prepared to replace your oil-burning boilers, then you can consider a wholesale switch to biomass, landfill gas or geothermal.