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The Sverdrup Gold Medal is "granted to researchers who make outstanding contributions to the scientific knowledge of interactions between the oceans and the atmosphere." The award, in the form of a medallion, will be presented at the AMS Annual Meeting to be held on 2–6 February 2014 in Atlanta, GA.

John Marshall is an oceanographer with broad interests in climate and the general circulation of the atmosphere and oceans, which he studies through the development of mathematical and numerical models of physical and biogeochemical processes. His research has focused on problems of ocean circulation involving interactions between motions on different scales, using theory, laboratory experiments, and observations as well as innovative approaches to global ocean modeling pioneered by his group at MIT.

Current research foci include: ocean convection and subduction, stirring and mixing in the ocean, eddy dynamics and the Antarctic Circumpolar Current, the role of the ocean in climate, climate dynamics, aquaplanets.

Professor Marshall received his PhD in atmospheric sciences from Imperial College, London in 1980. He joined EAPS in 1991 as an associate professor and has been a professor in the department since 1993. He was elected a Fellow of the Royal Society in 2008. He is coordinator of Oceans at MIT, a new umbrella organization dedicated to all things related to the ocean across the Institute, and director of MIT’s Climate Modeling Initiative (CMI)

Jennifer Chu, MIT News Office

Nitrous oxide is commonly associated with laughing gas — the pleasantly benign vapor that puts patients at ease in the dentist’s chair. But outside the dentist’s office, the gas plays a serious role in the planet’s warming climate.

After carbon dioxide and methane, nitrous oxide is the third-largest contributor of greenhouse-gas emissions to the atmosphere. The colorless gas is also the top culprit in the depletion of ozone — the layer of the atmosphere that protects Earth from the sun’s ultraviolet radiation.

The majority of nitrous oxide emissions arise naturally from soil, where microbes break down nitrogen, releasing nitrous oxide as a byproduct. However, human activities such as farming, and the use of fertilizer, in particular, have increased nitrous oxide emissions over the last 35 years — a rise that has contributed to the overall warming of the planet.

Now scientists in MIT’s Center for Global Change Science have developed a highly detailed model that simulates levels of nitrous oxide emissions in different regions and ecosystems of the world. Based on local soil temperature and moisture content, some of the simulations were able to reproduce actual nitrous oxide measurements.

From their simulations, the researchers discovered a surprising pattern: Regions around the world typically experience a decrease in nitrous oxide emissions during El Niño events, which periodically create unusually warm waters in the Pacific Ocean, affecting temperature and rainfall patterns around the world. Conversely, they found that emissions rise during periods of La Niña, the opposing weather pattern, in which colder waters take over the Pacific. The findings suggest a feedback mechanism in which nitrous oxide not only contributes to global warming, but may also be affected by climate patterns. 

“If more emissions are released into the atmosphere, there will be more global warming … and with higher temperatures, we would have more nitrous oxide coming out,” says Eri Saikawa, who led the research as a postdoc at MIT. “Many people may not consider the nitrogen cycle, but we do have to realize it is pretty important.”

Saikawa, who is now an assistant professor of environmental studies at Emory University, collaborated with Ron Prinn, the TEPCO Professor of Atmospheric Science at MIT and director of the Center for Global Change Science, as well as principal research scientist Adam Schlosser. The group has published its results in the journal Global Biogeochemical Cycles.

A seesaw of emissions

To simulate nitrous oxide emissions around the world, Saikawa adapted a model of soil temperature and moisture content that is often used by hydrologists to track the movement of water through soil.

Saikawa added to this model a component that calculates how much nitrous oxide is likely emitted from a region, given variables such as soil temperature and moisture. She simulated monthly global nitrous oxide emissions from 1975 to 2008; to check that the model generated accurate calculations, Saikawa simulated nitrous oxide emissions in regions where actual nitrous oxide measurements were available, including 25 locations in the Amazon, North and Central America, Asia, Africa and Europe.

For many of the sites, the model’s calculations agreed with observations, verifying its ability to accurately simulate nitrous oxide emissions. Looking at the variability of emissions from year to year, Saikawa noticed a dramatic correlation with the El Niño/La Niña climate pattern, particularly in tropical regions near the equator: Nitrous oxide emissions dipped during periods of El Niño, and spiked during La Niña events.

Saikawa says this periodic seesaw in emissions makes sense: As El Niño warms the Pacific, rainfall increases to the east, causing flooding in parts of South America, and droughts in parts of South Asia. Saikawa points out that the largest sources of nitrous oxide emissions arise from South Asia; Saikawa observed that decreased soil moisture from El Niño led to a large dip in emissions from those regions, with the opposite effect from La Niña.

“We thought we would see some variability, but we didn’t think it would be this significant,” Saikawa says. “There is a need for more research to really determine what are the possible impacts from future climate change.”

William Horwath, a professor of soil biogeochemistry at the University of California at Davis, says the group’s model, while relatively simple, generally does a good job of predicting nitrous oxide events. However, to truly dig down to the root cause of emissions, he says the model will have to incorporate many more factors, including the presence of iron, which Horwath says is a big player in regulating microbes and nitrous oxide emissions.

“Future modeling studies stand to gain valuable information by considering iron among the regional drivers of N₂O emission,” Horwath says.

Modeling better fertilizer 

Going forward, the team will incorporate agricultural components into the model, to simulate the effect of certain fertilizers on nitrous oxide emissions. Many types of fertilizer introduce nitrogen to the soil — an ingredient that nitrogen bacteria thrive upon. The more fertilizer nitrogen there is in soil, the more bacteria break it down, releasing nitrous oxide as a byproduct.

Prinn says that deforestation has also stirred up nitrous oxide emissions, particularly in regions such as Brazil. The Brazilian government, he says, is exploring the increased production of biofuels, fertilizing croplands in place of forests.

“Brazil and other countries are very concerned about the sustainable production of biofuels in the future,” Prinn says. “What damage will it do to soil health? … Will they be making biofuels that are causing nitrous oxide and carbon dioxide emissions?”

A model like Saikawa’s, he says, may help simulate the effect of biofuel production on nitrous oxide emissions, and present more sustainable methods for growing biofuel crops.

“We should think about the impact that we have from our agricultural activities,” Saikawa says. “Over-fertilizing our soil could be potentially quite damaging for the climate and also for the ozone.”

China’s deployment of renewable electricity generation – starting with hydropower, then wind, and now biomass and solar – is massive. China leads the world in installed renewable energy capacity (both including and excluding hydro) and has sustained annual wind additions in excess of 10 gigawatts (10 GW) for four straight years. Half of the hydropower installed worldwide last year was in China. And solar and biomass-fired electricity are expected to grow ten-fold over the period 2010-2020. Most striking amidst all these impressive accomplishments has been the Chinese government’s seemingly unwavering financial support for renewable energy generators even as other countries scale back or restructure similar support programs.

The balance sheets of the central renewable energy fund are changing, however. Supplied primarily through a fixed surcharge on all electricity purchases, it has faced increasing shortfalls in recent years as renewable growth picked up, which may have contributed to late or non-payment to generators. Especially as more costly solar comes online, both the revenue streams and subsidy outlays to generators will require difficult modifications to keep the fund solvent. More broadly, investment decisions are largely influenced by the historically high penetration of state-owned energy companies in the renewables sector, which have responsibilities to the state besides turning a profit.

Recognizing these challenges of solvency and efficiency, the central government is facing a crossroads in its policy support for renewable sector, of which one possible approach would be migrating to a hybrid system of generation subsidies coupled with mandatory renewable portfolio standards (RPS). This fourth and final post in the Transforming China’s Grid series looks out to 2020 at how China’s renewable energy policies may evolve and how they must evolve to ensure strong growth in the share of renewable energy in the power mix.

Policy Support to Date

Investment in renewable energy has risen steadily in China over the last decade, with the wind and solar sectors hitting a record $68 billion in 2012, according to Bloomberg New Energy Finance (BNEF). These sums – together with massive state-led investments in hydropower – have translated into a surge of renewable energy capacity, which since 2006 included annual wind capacity additions of 10-15 GW and a near doubling of hydropower (see graph). Renewables now provide more than a quarter of China’s electricity generating capacity.

Early on in both the wind and solar sectors, the tariffs paid to generators were determined by auction in designated resource development areas (called concessions). These auctions underwent a number of iterations to get at rates the market will bear before policy support was transitioned to the fixed regional feed-in-tariffs currently in place: 0.51-0.61 yuan / kWh (8.3-10.0 US¢ / kWh) for wind, and 0.90-1.00 yuan / kWh (15-16 US¢ / kWh) for solar. The result of this methodical policy evolution was the steady growth of wind and solar power capacity year-after-year. Contrast these with the uneven capacity additions of wind in the U.S., attributable to the haphazard boom-bust cycles in U.S. wind policy (see graph). Hydropower project planning is directed by the government and rates are set project-by-project (typically lower than the wind or solar FITs).

Also important to developers – thought not captured in BNEF’s investment totals – are reduced value-added-taxes on renewable energy projects, preferential land and loan terms, as well as significant transmission projects serving renewable power bases socialized across all ratepayers. On the manufacturing side, the government has also stepped in to prop up and consolidate key solar companies.

Guiding these policies has been continued ratcheting up of capacity targets beginning with the Medium to Long-Term Renewable Energy Plan in 2007. These national goals – while not legally binding – shape sectoral policies and encourage local officials to go the extra mile in support of these types of projects. The most recent iterations call for 104 GW of wind, 260 GW of hydro, and 35 GW of solar installed and grid-connected by 2015 (see table). In addition to these “soft” pushes, generators with over 5 GW of capacity were required under the 2007 plan to reach specified capacity targets for non-hydro renewables: 3% by 2010 and 8% by 2020. However, there appeared to be no penalty for non-compliance: half of the companies missed their 2010 mandatory market share targets.

China’ renewable energy targets as of September 2013
(GW, grid-connected)

Sources
 

Rubber Missing the Road in Generation

Amidst the backdrop of impressive capacity additions, a separate story has unfolded with respect to generation. Wind in China faces twin challenges of connection and curtailment, as I outlined previously, which result in much lower capacity factors than wind turbines abroad. These have persisted for several years, so one might think that wise developers would demand higher tariffs before investing and a new, lower equilibrium would be established.

But the incentives to invest in China’s power sector are rarely based on economics alone. The vast majority of wind projects are developed by larger, state-owned enterprises (SOEs). In recent years, SOEs have been responsible for as much as 90% of wind capacity installed (for comparison, SOE’s are responsible for an average of 70% for the overall power mix). In 2011, the top 10 wind developers were all SOEs which faced some scrutiny under the 2010 mandatory share requirements because of their size. In addition, because generators only faced a capacity requirement, it was more important to get the turbines in the ground than get them spinning right away (though as we saw, many still missed their capacity targets). Grid companies, on the other hand, had generation targets (1% by 2010 and 3% by 2020), which were also unmet in some locations. The next round of policies have sought to address both generation and connection issues.

Other Cracks in the Support Structure

Though generation lagged capacity, it was still growing much faster than predicted, leading to shortfalls in funds to pay the feed-in-tariff. A single surcharge on all electricity purchases supplies the centrally-administered renewable energy fund, which fell short by 1.4 billion yuan ($200 million) in 2010 and 22 billion yuan ($3.4 billion) in 2011. Prior to the recent surcharge rise, some estimated the shortfall will rise to 80 billion yuan ($14 billion) by 2015. The difference would either not make it to developers or have to be appropriated from elsewhere.

In addition, from 2010-2012, there were long delays in reimbursing generators their premium under the FIT. The situation was so serious that the central planning ministry, the National Development and Reform Commission (NDRC), put out a notice in 2012 demanding grid companies pay the two-year old backlog. These receivables issues are particularly damaging to wind developers who operate on slim margins and need equity to invest in new projects.

To address the solvency of the renewable energy fund, in August, the NDRC doubled the electricity surcharge on industrial customers to 0.015 yuan / kWh (0.25 US¢ / kWh), keeping the residential and agriculture surcharge at 0.008 yuan / kWh (0.13 US¢ / kWh) (Chinese announcement). With a little over three-quarters of electricity going to industry, this will increase substantially the contributions to the fund. At the same time, solar FITs were scaled back slightly by instituting a regional three-tier system akin to that developed for wind: sunny but remote areas in the north and northwest offer 0.90-0.95 yuan / kWh (15-15.5 US¢ / kWh) while eastern and southern provinces close to load centers but with lower quality resources offer 1 yuan / kWh (16 US¢ / kWh) (Chinese announcement).

Additionally, distributed solar electricity consumed on-site (which could be anything from rooftops to factories with panels) will receive a 0.42 yuan / kWh (6.9 US¢ / kWh) subsidy. Excess electricity sold back on the grid, where grid connections and policy are in place, will be at the prevailing coal tariff, ranging from 0.3-0.5 yuan / kWh (5-8 US¢ / kWh). It is unclear if these adjustments will mitigate the expected large financial demands to support solar (whose FIT outlays per kWh are still more than double wind).

Wind, whose FIT has been in place since 2009, may not be immune to this restructuring either. Some cite the falling cost of wind equipment and the fund gap as cause for scaling back wind subsidies.

Where to Go From Here

Despite this budget squeeze, the Chinese government seems intent on sustaining the clean energy push. Even as it weakens financial incentives for renewable energy, the central government is getting smarter about how to achieve its long-term clean energy targets. Last year the National Energy Administration (NEA) released draft renewable portfolio standards (RPS), which would replace the mandatory share program with a tighter target focused on generation: an average of 6.5% from non-hydro renewables by 2015. Grid companies will have purchase requirements ranging from 3% to 15%, and provincial consumption targets range from 1% to 15% (more details here, subscription req’d). This approach appropriately recognizes the myriad regulatory barriers to increasing wind uptake by putting responsibility for meeting targets on all stakeholders.

China is paving new ground as it shifts further toward low-carbon sources of electricity. What has worked in the past, when wind and solar’s contributions to China’s energy mix were minor, will likely not be sufficient to meet cost constraints and integration challenges out to 2020. As with all policies in China, designing the policy is less than half the battle; implementation and enforcement are central to changing to the status quo.

Alli Gold Roberts
MIT Joint Program on the Science and Policy of Global Change

Yesterday, the United Nations Conference on Trade and Development released the 2013 Trade and Environment Review. The report encourages policy makers to “wake up before it is too late” and suggests a series of technologies, practices and policies to make agriculture more sustainable.

The report included contributions from more than 60 international experts, including MIT Joint Program on Global Change Research Scientist Kenneth Strzepek.

Strzepek and his colleague Brent Boehlert of Industrial Economic, Inc. of Cambridge wrote a commentary on the future threats to water availability for agriculture.  Their research shows that by 2050 population growth, increasing water use, extreme weather and rising temperatures will significantly threaten water resources.

“Unfortunately, unless broad changes are made to the way environmental and water resources are governed, we predict conflicts over water for agriculture will increase significantly by the middle of the twenty-first century,” Strzepek says.

In their report, Strzepek and Boehlert recommend a series of water governance measures that can be used to better manage and allocate water for agriculture. Policy and management measures include assigning an economic value to water resources to encourage efficiency, switching to more sustainable and drought resistant crops, improving rain-fed irrigation infrastructure, and more equitably distributing water resources.

“There is no one-size fits all solution to this problem,” says Strzepek. “But it is important — and essential — that water planning efforts be coordinated and integrated across sectors to prepare for a changing climate in the future.”

Environmental controls designed to prevent leaks of methane from newly drilled natural gas wells are effective, a study has found — but emissions from existing wells in production are much higher than previously believed.

The findings, reported today in the Proceedings of the National Academy of Sciences1, add to a burgeoning debate over the climate impact of replacing oil- and coal-fired power plants with those fuelled by natural gas. Significant leaks of heat-trapping methane from natural gas production sites would erase any climate advantage the fuel offers.

One concern is the potential release of methane during hydraulic fracturing, or 'fracking', which uses injections of high-pressure fluids to shatter rock and release trapped gas. Before production can commence, the well must be 'completed' by removal of the fracking fluids, which contain gas that can escape to the air.

To test the effectiveness of current controls, the researchers installed emissions-monitoring equipment at 27 wells during their completions in 2012 and 2013. Their results suggest that current controls reduce emissions in such wells by 99% compared to sites where the technology is not used, says lead author David Allen, an engineer at the University of Texas in Austin.

The researchers' estimate of annual emissions from wells undergoing completion, 18,000 tonnes per year, is also roughly 97% less than the estimate given in 2011 by the US Environmental Protection Agency (EPA).

Less encouraging was what the team discovered at 150 other well sites that were already producing natural gas. Such wells often use pneumatic controllers, which siphon off pressurized natural gas from the well and use it to operate production-related equipment. "As part of their normal operation, they emit methane into the atmosphere," Allen says.

His team's work suggests that emissions from pneumatic controllers and other equipment at production wells is between 57-67% higher than the current EPA estimate. However, the study also finds total methane emissions from all phases of natural gas production to be about 2.3 million tonnes per year, about 10% lower than the EPA estimate of 2.5 million tonnes…More.

Henry Jacoby, an economist and former director of the Joint Program on the Science and Policy of Global Change at Massachusetts Institute of Technology in Cambridge, agrees. "This is important work," he says, "but the great bulk of the problem is elsewhere, downstream in the natural gas system", including poorly capped oil and gas wells no longer in production.

Read the complete article here.

Reprinted by permission from Macmillan Publishers Ltd: Nature (doi:10.1038/nature.2013.13748), Copyright 2013.
Photo Credit: Steve Starr/Corbis

The MIT Energy Night is a celebration of the ingenuity, innovation, and imagination of MIT faculty, researchers, students, and alumni. Hosted annually at the MIT Museum and organized entirely by students, the MIT Energy Night features over 70 interactive poster presentations from every energy affiliated department at MIT as well as early stage start-ups based on MIT technologies. Presentation topics span conventional energies, renewable energies, energy storage, energy efficiency, and other areas.

This year’s event is poised to attract MIT students, faculty, energy investors, business leaders, researchers, and educators on October 18, 2013 from 5:00-8:30pm at the MIT Museum. Complimentary food and soft beverages will be provided. Alcoholic beverages can be purchased at a low cost.

The event is free and open to the general public. No registration is required.

Event URL: http://mitenergynight.org/

By Chris Knittel and John Parsons

Professor Robert Pindyck has a new working paper (CEEPR-WP-13-XXX) that has attracted a good share of attention since it steps into the highly charged debate on the reliability of research related to climate change. But in this case, the focus is on what we learn from one class of economic model, the so-called integrated assessment models (IAM). These models have been used to arrive at a “social cost of carbon” (SCC). For example, in 2010 a U.S. Government Interagency Working Group recommended a $21/t CO2 as the social cost of carbon to be employed by US agencies in conducting cost-benefit analyses of proposed rules and regulations. This figure was recently updated to $33/t. Professor Pindyck’s paper calls attention to the wide, wide range of uncertainty surrounding key inputs to IAM models, and to the paucity of reliable empirical data for narrowing the reasonable range of input choices. The paper then suggests profitable directions for reorienting future research and analysis.
 
Reflecting the highly charged nature of the U.S. political debate on climate change, Professor Pindyck’s paper has been seized on by opponents of action. In particular, certain blogs have cited his paper in support of their campaign against any action. Here is one example—link.
 
Interestingly, Professor Pindyck is an advocate of action on climate change, such as leveling a carbon tax. So his own view of the implications of his research are quite different than that of those who oppose any action. This post at the blog of the Natural Resources Defense Council includes more extensive comments by Professor Pindyck on the debate—link.
 
An alternative approach is to think about Professor Pindyck’s review as a guide for future research on the costs of climate change which is better focused to address the important uncertainties in a way that can better contribute to public discussion and analysis. CEEPR researcher Dr. John Parsons emphasizes this point in his blog post about Pindyck’s paper—link.

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