MIT Faculty Newsletter  
Vol. XXIX No. 2
November / December 2016
A Message From MIT Faculty
Affirming Our Shared Values
Resisting Anti-Science Stances
of the New Administration
Can A University Become Carbon Neutral?
On Gracious Professionalism
Skoltech – A Personal and
Professional Journey
Evolution of Schools, Departments,
and Centers at MIT
Susan L. Lindquist
George Rathjens
An Institute-Wide Festival of Learning
Do you have unreleased software projects you’d like to clean up and release as open source, but don’t have time?
Spread the Joy of Giving
This Holiday Season
The Alumni Class Funds Seek Proposals for
Teaching and Education Enhancements
¡¡¡Retired Faculty Alert!!!
Improving Institute Faculty Meetings
On Gender Differences in Submitting Admissions Maker Portfolios
Access MIT and Transit Commuter Benefits
Keep Up the Good Work
Campus Research Expenditures FY 1997–2016
MIT Research Expenditures FY 1940–2015
Printable Version

Can A University Become Carbon Neutral?

Timothy Gutowski

This is the question we took up as a class project in 2.83/2.813 for the spring term 2016. We looked at the climate action plans of 22 colleges and universities in the U.S. (and four more in Europe), including 10 who signed the American College and University Presidents Climate Commitment (ACUPCC) and claimed they would be carbon neutral by 2016. The short answer to this question is a conditional yes. Of the 10 first movers, five are, or soon will be, carbon neutral; however, the solutions they use are not scalable, or have other issues, and the schools are arguably only able to achieve carbon neutrality because of their unique circumstances. Having said that, we should give them credit for their accomplishments.

The successful schools (all from the Northeast) are generally small, mostly liberal arts colleges in rural settings in states with below average carbon intensity electric grids (Vermont, Maine, and New York). They all appear to have a strong environmental identity and started on their carbon-neutral path as soon as the ACUPCC was signed (2007), or slightly before. They all appear to have sufficient, to significant resources including land as well as money. The most practiced solutions were, approximately in order of prominence: 1) burning wood, 2) buying carbon credits, 3) claiming sequestration from owned forests, and 4) burning syngas from cow manure. Everyone practiced some level of energy efficiency, but it was the four actions listed above that appeared to make the difference.

For larger universities with engineering and science laboratories, or with medical schools, the task is much more difficult. Second Nature, the group that is tracking the progress of the 679 signers of the ACUPCC agreement, provides data showing that “industrial-strength” universities such as MIT are about four times more carbon intensive per full-time enrollment (FTE) than the baccalaureate colleges (28 metric tons of CO2equivalent per FTE versus 7tCO2e/FTE). MIT currently stands at about 20tCO2e/FTE, but our accounting is ongoing with potentially important pieces still missing (for example, institute travel, procurement, and waste).

Our acknowledgment of the success of the five schools is conditional, because each of the methods used to obtain their carbon neutral goal has some level of controversy that needs comment.

Wood burning is often assumed to be approximately carbon neutral over the long term, and can be feasible for a school if pollution is addressed, the demand is modest to reduce truck deliveries, and supply is available. Even so, wider use of wood has several issues: it is limited in supply, land intense, and would compete with cropland and affect food prices if developed on a large scale. In other words, it is not scaleable. Nevertheless, for these small applications, and from a carbon emissions point of view, burning wood cleanly is still better than using fossil fuels. It is worth noting that there are some sophisticated new technologies for burning wood including a 2MW combined heat and power biomass gasification unit at the University of British Columbia. It is also worth noting that there are remaining issues concerning the effect of harvesting on Net Primary Productivity for the decades immediately after the harvest.

The free market approach of paying someone else to reduce their emissions and claiming the credit, i.e., buying carbon credits, could be an efficient way to address this problem. The idea is to direct resources to the best opportunities. We found that four out of the five successful schools used some level of carbon credits to obtain their goal.

Note that for a small school with relatively low emissions, say 4tCO2e/FTE (a real case), one can appear to solve the problem by buying low cost carbon credits at about $10/tCO2e with a resulting cost of $40 per student per year. The chief challenges to this solution are related to risk and a potential moral hazard. That is, the effectiveness of some schemes can be hard to confirm, and potentially could lead to mischief. Morally, the Harvard philosopher Michael Sandel has argued that “turning pollution into a commodity to be bought and sold removes the moral stigma that is properly associated with it . . . [and] may undermine the sense of shared responsibility that increased global cooperation requires.” These problems aside, if you follow this path, it requires an ongoing payment until you actually do get your carbon emissions down. For MIT, buying high quality carbon credits at $20/tCO2e (to reduce risk and ensure effectiveness) and assuming that full accounting puts us at 25 tons CO2 per FTE would cost $500 per student or a yearly total cost of $5.5 million.

Several schools with large tracts of forested land are claiming carbon credits for increasing carbon sequestration on those lands. Although the protocols are still being worked out, the general idea is that by using improved forestry practices, one can manage a tract of land to increase the stored carbon (usually in the standing trees) over some considerable length of time, i.e., 40 to 100 years. If you have enough land, you can even sell these credits and make a profit, as at least one school said they are doing. If MIT were to try to engage in this practice, we would find ourselves at a noticeable disadvantage. Our campus land area of 68 hectares (ha) is about an order of magnitude smaller than our fellow industrial-strength university campuses. We found several examples of this carbon credit method. One was provided by the California Air Resource Board (ARB) with claims of an improvement potential of 1.56 tC/ha/yr (over 100 years) for forest in California (Willits Woods in Mendocino County). Using this number, MIT would need the land area equivalent of about 500 of our current campuses to sequester our 200,000 metric tons of CO2 equivalent per year. That is, we would need to find this land and develop it over 100 years. (This scheme does raise some questions that need more discussion.)

Finally, two schools (both in Vermont) claimed to have developed a scheme to use syngas produced from cow manure. This plan requires, among other things, investment in a bio-digestor, infrastructure to transport the gas to the school (a pipeline is preferable) and, of course, a sufficient supply of cow manure. This struck us as one of the more creative solutions. Unfortunately, we learned from one school that the current low price of natural gas has made such an investment questionable, resulting in a delay and causing that school to develop alternative options.

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In comparison to the smaller schools, the bigger technical universities, with more in common with MIT, have, understandably, much higher emissions and more modest percent reductions. As mentioned earlier, the larger technical universities have roughly four times the carbon emissions per student compared to the smaller undergraduate institutions. In addition, the larger schools we studied have roughly 10 times the students (~20,000 versus ~2,000) hence the emissions from the larger universities are roughly 40 times larger (e. g., 200,000 tCO2e versus 5,000 tCO2). Changes in CO2 emissions from these universities, over roughly the same length of time as the smaller institutions, ~9 years, range from an increase of 6%, to a decrease of 32%, with an average decrease of 9%. While this appears to be a much more modest reduction than the smaller first movers, in terms of absolute reductions, it is actually larger. That is 9% of 200,000 is more than three times the total emissions previously emitted by our prototypical small carbon neutral college (~5,000 tCO2e). Hence, only looking at relative reductions could be misleading. Furthermore, using percent reduction in carbon emissions as the metric to judge improvement has an additional disadvantage in that it can favor late movers, for example those who only recently have converted from coal to natural gas for their power plant. In fact, this is part of the explanation behind the 32% decrease mentioned above. If you remove the power plant conversion from their data, we estimate the improvement is about 22%. For your information, MIT is not at all a late mover. MIT switched from coal to oil in 1935 and from oil to natural gas in 1995.

We found that the improvement strategies at the larger schools were somewhat different than those employed by the successful first movers. There was little mention of wood burning boilers, forest sequestration, and biogas from cow manure. There was a strong emphasis on energy efficiency, as with the small schools, and alternative renewable energy sources.

These renewable energy sources included photovoltaic panels, land-based wind turbines, small geothermal applications, small hydroelectric installations, and even water exchanges from deep lakes for building cooling. The general theme was to look for local opportunities and exploit them. And again, having a large land footprint is very helpful to accommodate these alternative land intensive energy sources. For those who do not have sufficient area to accommodate these projects, they could support their development at remote sites, and could possibly qualify for carbon credits. (More on this later.)

We found it difficult to assess the effectiveness of the various energy efficiency activities because the schools generally report their emissions at an aggregate level without sufficient detail to estimate these effects. However, the average energy use and carbon emissions per building area for some of these schools is far removed from current best practice, and it is reasonable to expect significant potential in this area. MIT has been working at this problem for some time with some success, but even so our current average energy use per floor area is about double best practice. It is worth pointing out that a major component of this high-energy use is our reliance on very high air exchange rates to ensure cleanliness and safety in our laboratories. And in addition, constant travel by people entering and leaving our buildings also leads to high air exchange rates. These are tough areas to address. We cannot compromise our standards for cleanliness, safety, and access, but could we meet them in alternative ways that reduce our air exchange rates with the outside? These problems need special attention if we are to be successful at reducing our building energy use.

Finally, there is the complication that successful universities are often growing. For the 11 universities for which we could gather building growth rates (in terms of floor area), we found a nominal average growth rate of about 3% per year. Yes, this is limited data, but it certainly rings true for us at MIT. A recent article in the MIT News suggests that our energy demand is expected to grow by 10% by 2030. Obviously, this significantly increases the challenge to become carbon neutral.

Part of MIT’s challenge is that we have already made our move to natural gas co-generation. There is no obvious renewable energy alternative that fits on campus and could meet all of our needs.

Here in Massachusetts, the biggest opportunities for renewable energy are not on our campus. They are offshore wind and hydroelectric from Québec. These options are, of course, well known, and are the subject of a recent important initiative by the Massachusetts legislature. But these will take time to develop, so in the meantime what should we (MIT) do? What we know is that many people at MIT are working on this, with new studies and more efficiency improvements in the works. But, we appear to be committed to on-campus natural gas co-generation for the next 20 years with plans to increase our capacity from 1 to 2 new 22MW turbines. So what seems clear, is that some off-site activities (e.g., carbon off-sets, and/or working with the local grid, etc.) will be necessary.

In fact, while this article was being written, MIT announced participation in a large new solar farm in South Carolina. MIT will purchase solar power said to be equivalent to 40% of the Institute’s current electricity use. This seems a significant move by MIT to take these steps in a relatively short time to address climate change. Those who have done this work on our behalf are to be congratulated. At the same time, it would be very helpful if more information about these carbon reduction claims could be made available to the wider MIT community. The article in the MIT News claims that MIT will “neutralize” 17% of its carbon emissions through the purchase of solar energy. But it is not immediately clear how our support for the development of this solar facility is going to neutralize our emissions. One needs to differentiate between renewable energy credits, and carbon offsets. In plain English, enabling low carbon growth and actually reducing real carbon emissions are two different things. Real reductions require that a real source of carbon emissions be attenuated or shut down. Presumably this is part of how the new energy will be integrated into the local grid, but nothing was said about this. More information about this arrangement would be welcomed so we can understand the basis for these claims.

I would like to personally thank the students who worked so closely with me on this class project, in particular, Samantha Houston, the teaching assistant, Patrick Callahan and Rachel Perlman, as well as Sean Caetano, Tyler Capps, Wesley Cox, Aaron Downward, Amanda Hamlet, Matthew Hole, Patrick Linford, Jessica Press-Williams, Michael Sandford, James Slonaker, Prithivi Sundararaman, and Kevin Thomas.

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