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Urban resilience within the context of deep decarbonisation: a case-study of Pittsburgh, USA

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—When discussing the need for long-term mitigation goals, the immediate changes needed to adapt infrastructures are rarely integrated within governmental planning purposes. Although national-level mitigation goals have been formed, and individual
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  XXX-X-XXXX-XXXX-X/XX/$XX.00 ©20XX IEEE Urban resilience within the context of deep decarbonisation: a case-study of Pittsburgh, USA Joseph Petti and Dr. Katrina Kelly-Pitou Swanson School of Engineering, Pitt Center for Energy University of Pittsburgh University of Pittsburgh  jjp70@pitt.edu, kmkelly@pitt.edu  Abstract   —  When discussing the need for long-term mitigation goals, the immediate changes needed to adapt infrastructures are rarely integrated within governmental planning purposes. Although national-level mitigation goals have been formed, and individual national contributions have been proposed as a means of adaptation, the understanding of how these dually competing processes need to work together have only begun to be understood. By simultaneously conceptualizing immediate vulnerabilities in power supplies whilst keeping in mind long-term sustainability goals, infrastructures, and the cities they power, can better prepare themselves for sudden on-set risks, and also contribute towards broader decarbonization goals. However, without coordinating new energy infrastructure designs within overarching goals for emissions reductions, cities can in fact be in danger of incentivizing technology installations rather than decarbonization. The city of Pittsburgh can be used as a case-study for better understanding how immediate infrastructures changes can contribute towards long-term decarbonization goals. At the same time, projecting Pittsburgh’s current business-as-usual scenario shows how without coordinating adaptation and mitigation levels cohesively, that cities actually can be in danger of increasing their carbon emissions pathways. T his work shows that altering Pittsburgh’s electric generation sources towards low carbon sources will not, in fact, reduce CO 2  emissions to the desired levels. The findings from this work indicate that better coordination between environmental and energy planning is needed to increase the long-term sustainability of the City. Keywords  —  Renewable Energy, Natural Gas, Smart City, Decarbonization I.   I  NTRODUCTION Energy has become a critical component, if not defining feature, of the global political economy. When at one-time energy was thought of as simply a fuel source, today’s energy discussions encompass economic growth strategies, environmental considerations, as well as social health and well-being. In order for the US to make tangible progress on carbon emissions reduction, it has been suggested that greater attention must be paid towards the local-level, thereby helping the US contribute towards “bottom - up” goals of carbon emissions reductions [1]. Although several American cities have made headlines for their commitment to climate change adaptation and mitigation goals, perhaps none gained such strong media acclaim as Pittsburgh, Pennsylvania. Despite Pittsburgh’s Mayor declaring that the City was committed to moving to a renewable energy-powered future as quickly as  possible, little work has actually been done analyzing the energy transition pathway of Pennsylvania  –   which will not be easy due to the lack of sun, coastal areas (off-shore wind  potential), and also nearby availability of fossil-based resources such as shale gas. The City of Pittsburgh has called for both the need for long-term decarbonization goals, yet has also emphasized the need for immediate resilience to defend the city against natural hazards, mainly flooding events. However, the city has not thus created a methodology nor given specific guidelines about how the decisions-taken today in energy infrastructure designs need to mesh with these long-term goals. Yet focusing on the adaptation measures specific to power systems can help  both Pittsburgh and cities elsewhere to understand how new and proposed technologies can be used in tangent to provide  both a low-cost carbon emissions reductions strategy for Pittsburgh, Pennsylvania. The process of identifying and implementing adaptation solutions that are best for increasing neighborhood resilience and contributing to deep decarbonization is a feat not to be underestimated. Although global discussions have focused heavily on understanding what specific long-term actions are needed to achieve global mitigation goals, very little attention has been paid thus far as to how existing infrastructure needs should complement these long-term goals [1]. Unfortunately, today, cities and states without federal or state-level guidance have been left to themselves to manage the challenge of maintaining economic development against the demand for energy sustainability. The planning process of how to navigate environmental, economic, and social challenges is especially difficult for local policy-makers who may not have the technical knowledge or organizational support to properly substantiate innovative policy solutions. Yet cities themselves may in fact be the piece of the missing puzzle when considering the scale of the challenge of carbon emissions reductions currently facing the world. Cities represent a substantial portion of global carbon emissions, simply due to their population aggregation. Making urban centers more sustainable in terms of energy is likely to not only support significant emissions reductions, but to produce increased  benefits in both health and livelihood. With the correct technical analysis and most efficient policy tools in place, cities, and specifically the city of Pittsburgh, can help to   provide insight as to how locally tailored solutions may help to better address the insurmountable challenge of mitigating climate change. Pittsburgh can display how to best plan and coordinate between industry members, state-level government officials, utility operators, and academic partners to deploy the innovation that is needed to address the energy challenges of the 21 st  century. II.   P ITTSBURGH ’ S C URRENT E MISSION P ROFILE  Pennsylvania is the third-largest emitter of CO 2  in the country [2]. With approximately 200 major electricity generation facilities, the Commonwealth ranks second in the nation in electricity generation, fourth in coal production, and second in both nuclear and natural gas production [2]. As the  No. 1 state in in the United States for electricity exports, electricity generation in Pennsylvania has impacts on neighboring states and beyond. Pennsylvania thus far has seen a reduction in its overall carbon footprint, which can be credited largely to retiring coal-generating plants in favor of natural-gas fired power  plants. In 2005, Pennsylvania was responsible for nearly 281.1 million metric tons of carbon dioxide emissions- in 2015, the state emitted 233.2 million metric tons; this represents a nearly 16% reduction. Although market conditions alone may get us close to Pennsylvania’s target under the Clean Pow er Plan of a 27% reduction in greenhouse gas emissions by 2030, there is considerable room to be made for achieving our decarbonization targets of an 80% reduction by 2050 and 100  percent soon thereafter (which is needed to avoid the catastrophic impacts of climate change and extreme weather events) [3]. In order to achieve this, Pennsylvanians will need to come together to identify the appropriate range of infrastructure changes, financial funding, and overall policy mechanisms that are needed to support Pennsylvania’s sustainable economic development. Since the removal of the Clean Power Plan and its accompanying planning resources, many states are now turning internally to identify how to best reconcile their economic paths of development with their overall energy needs. The State of Pennsylvania is particularly conscious of its leadership in the nation’s overall energy discussions and is currently in the process of planning how to combine economic, energy, and environmental policy in ways that will  best serve its citizens. At the same time, although mitigation goals have been formed under the Conference of the Parties as a forum for countries to agree on their long-term contributions to carbon reductions, there is currently no existing globally-agreed forum where cities and states can officially understand how they can best contribute to long-term emissions reductions through infrastructure decisions now. In an era of constant regulatory fluctuation, taking effective decisions at the local level can better contribute to the long-term challenges of sustainability [1]. The City of Pittsburgh recently drafted Climate Action Plan 3.0, yet without a state nor nation-wide agreed upon goal for long-term energy decarbonization. Pittsburgh as a city is embarking down a sustainable path for development unseen before in the US, if ever globally. Pittsburgh is truly choosing and displaying leadership in energy development in that it is a city, yet is choosing to define its development path as a nation traditionally would. If Pittsburgh can clearly understand and show how energy choices that are made today help to reduce carbon reductions emissions, yet can also address issues of energy affordability and energy accessibility for its residents, Pittsburgh can truly help to define methodologically what it means for energy to contribute to a city becoming “Smart”. III.   E XAMPLES OF THE D IVIDE IN D ECARBONIZATION AND A DAPTATION IN CITIES   When looking at Pittsburgh as part of Pennsylvania’s  overall energy consumption, it is currently unclear as to what the actual responsibilities of the City of Pittsburgh would be if the state were to form a deep decarbonization goal. At the same time, we do know that there are certain actions that cities can take but no two cities are alike, nor are any states in the US. Most cities in the US have looked towards using a 100% renewable energy goal to contribute towards their decarbonization The cities have experienced varying degrees of success. The experiences of Aspen, CO, Burlington, VT, Greensburg, KS, Kodiak, AL, and Rock Port, MO are detailed in this section.  A.    Aspen, CO In 2004, the City of Aspen, Colorado, adopted an ambitious goal to supply 100% of its electricity from renewable energy resources by 2015. Through a combination of city-owned and operated hydroelectric projects and power  purchase contracts, approximately three- quarters of Aspen’s electricity had been sourced from renewables by 2014 [4]. The city had planned to construct and own a hydroelectric facility on nearby Castle Creek to generate additional renewable energy. It had also conducted engineering, ecological, and financial studies, and it had purchased some equipment and undertaken some preliminary infrastructure construction,   In addition to its overall renewable energy goals, Aspen had already implemented a broad list of energy efficiency  programs to reduce electricity consumption within its borders. However, the city was not able to reduce its carbon footprint as it aimed to. Therefore, the City approached NREL to consider its expertise in analyzing the both demand and supply-side options for better meeting the City’s goal. NREL then reviewed the city’s previous and current  programs and efforts, and identified additional efficiency measures for the city to consider. The city chose to separate the demand-side analysis from the process for identifying supply-side options to keep city council discussions focused and make effective use of the skills of city staff. As a result, the recommendation was for the City to build, own, and operate its own hydropower facilities to make up for the remaining “renewable gap” that it was not able to purchase from local suppliers in order to meet its goal.   B.    Burlington, VT Each day 1,800 tons of pine and timber slash, are harvested within a 60-mile radius and ground into wood chips, is fed into the roaring furnaces of the McNeil Generating Station, pumping out nearly half of Burlington’s electricity needs. The remaining 50% of Burlington’s 42,000 citizens rely on a combination of hydroelectric power drawn from a  plant it built a half mile up Vermont's Winooski River, four wind turbines on nearby Georgia Mountain, and a massive array of solar panels at the airport. Together these sources helped secure Burlington the distinction of being the country’s first city that draws 100 percent of its power from renewable sources. The net energy costs are cheap enough that the city has not had to raise electric rates for its customers in eight years. Burlington is not done in its quest for energy conservation. Add in the city’s plan for an expansive bike  path, a growing network of electric vehicle charging stations and an ambitious plan to pipe the McNeil station’s waste heat to warm downtown buildings and City Hall’s goal to be a net zero consumer of energy within 10 years starts looking achievable. C.   Greensburgh, KS On May 4, 2007 an EF-5, 1.7-mile wide tornado with 200 mph-plus wind speeds, hit Greensburg and destroyed or severely damaged 90% of its structures [5]. When the initial shock subsided and the time to rebuild arrived, the residents realized that they had an opportunity to turn a tragedy into a triumph  —  an opportunity to make Greensburg something even  better than it had been before. Conversations began about rebuilding as a model “green” community, and the idea quickly picked up steam. The DOE assisted the residents with the technical aspects of rebuilding. DOE’s ultimate goal was to demonstrate energy efficiency and renewable energy solutions that would help Greensburg and could be replicated in other disaster recovery and general rebuilding efforts across the country. Greensburg was an interesting opportunity for the DOE as it gave insight to understanding how far a city, with the opportunity to completely rebuild, could go toward  becoming a net-zero energy community. In order to make Greensburg 100% renewable, two strategies were taken: build energy efficient buildings and install wind generation. Three building packages were developed for residential buildings. The basic, high, and  premium efficiency packages offered energy saving of 30%, 40%, and 50% compared to the standard home before the tornado [5]. Wind generation was chosen due to the ideal conditions presented by Greensburg’s surrounding geography. A wind farm was installed that supplies 12.5 MW of renewable power, enough for 4000 homes. The city will only consume ¼ of the wind energy and sell the rest to KPP, local electric cooperative that offers generation with a strong renewable energy profile [5]. In addition to the sell back  partnership, Greensburg will buy power from KPP to fulfill their goal of 100% renewable energy.  D.    Kodiak, AL Since 2014, Kodiak has generated 99% of its electricity from wind and hydro [6]. For Kodiak, renewable energy came as a need, not a luxury. Kodiak does not have the option of connecting to one of the country’s major power grids.  It used to get 80% of its energy from hydro and 20% from diesel but if there was a dry season then the city would become dependent on diesel, which has unpredictable and high cost [6]. This left businesses and home owners having trouble  predicting their electric bills. The town initially has trouble balancing wind and hydro  power due to the variable nature of the former and the constant nature of the latter. The solution became a battery  bank. The batteries supply the energy needed when the wind ceases to create energy [6].  E.    Rock Port, MO Rock Port is another city that takes advantage of its geographical location to be 100% renewables. John Deere announced its intentions to build a wind farm near Rock Port and local entrepreneurs jumped at the idea to join forces. They crate the private company Wind Capital Group and installed fo ur wind turbines that generate 125% of the City’s energy needs. The town remains connected to the grid so that excess energy can be sold back and to have a stable source of energy when the wind is not blowing.  F.   Observations The transformation these cities went through is very impressive. However, this model may not be viable for the majority of cities to follow. These cities are able to rely upon hydro and/or wind power to become 100% renewable due to their geographical location. Cities unable to harness this natural resources will experience a much more difficult transformation. Therefore, we need to be more creative in the design of renewable energy technologies for c ities that don’t have the hydro or wind available. It is therefore imperative to understand how to best take advantage of the existing resources that specific on-site locations have and take into account new goals for solar installation, whilst also being conscious of seasonal impacts on energy usage. By having an understanding of the costs and technical options available to residential energy consumers, the City of Pittsburgh could help to further incentive solar installations by recommending residential energy districts develop in accordance with commercial energy districts. This approach will foster the development of systems that meet the unique needs of a metropolitan area at the lowest cost, and with the greatest impact. Furthermore, implementing these solutions can serve as a proof of concepts that results in additional deployments in nearby locations. IV.   I  NITIAL METHODS :  UNDERSTANDING ENERGY COMPUSTION IN P ITTSBURGH To begin to understand how and where the city of Pittsburgh could reduce its emissions profile, The Department of Energy, National Energy Technology Laboratory, and the  City of Pittsburgh constructed a baseline report of 2013 energy statistics in order to better understand the current energy usage  patterns: energy usage by sector, seasonal variations, and fuel type usage profile. Analysis focuses on thermal and electricity usage in 2013 it is the most recent year that energy consumption data was available for at the time this study was undertaken.  A.    Energy Consumption Related to Sector and Type The report found incredibly useful discoveries pertaining to Pittsburgh energy consumption: consumption of 59.6 trillion British thermal units (Btu) in 2013, natural gas consumption for thermal usage doubles electricity energy consumption, and the residential sector energy usage is 80% natural gas [7]. Table 1. shows the electricity and thermal energy consumption for three main sectors: residential, commercial, and industrial. Natural gas consumption makes up nearly 2/3 of the total energy consumption in Pittsburgh [7]. Table 1 also shows that the residential sector is responsible for over half of the natural gas usage. This means that residential natural gas usage accounts for almost 1/3 of the city of Pittsburgh’s total energy consumption. Table 1. Load Profile by Sector Sector Electricity (trillion Btu) Thermal (trillion Btu) Residential 5.1 22.9 Commercial 13.0 13.6 Industrial 1.1 3.7 Total 19.3 40.3 Total Energy Consumption 59.6  B.   Seasonal Variation and Regional Observations Seasonal variations in natural gas usage are substantial, with consumption in peak winter months exceeding summer consumption by ~9-11 times. While peak loads in electricity are less pronounced (only exceeding shoulder month usage by 1.3 to 1.5 times), a strong correlation of electricity load to hot weather exists, which may represent an opportunity [7]. C.    Identifying Vulerabilities/Adapation Measures The University of Pittsburgh used the NETL data to map where energy consumption meshes with environmental and social risks in the City of Pittsburgh. Researchers worked with the local DHS to understand where floods, fires, extreme snowfall, and extreme heats occur throughout the city. At the same time, recognizing that energy also has social impacts, (specifically when considering thermal and electrical consumption of energy is a burden for Pittsburgh residents), this same team of researchers worked to identify where residents were paying the most for energy bills throughout the city). As such, researchers were able to “map” where energy vulnerabilities occurred throughout the city. Several regions within Pittsburgh were identified as high risk areas. In some cases, these areas are contiguous, and coincidentally also constitute a significant portion of total usage. Figs 1 and 2 illustrate these areas, first in terms of standardized risk occurrence and secondly in terms of normalized risk occurrence. Fig 1. Standardized Graphic Representation of Heat and Energy Consumption throughout the City of Pittsburgh Fig 2. Normalized Representation of Heat and Energy Consumption These maps show that there are four specific areas that  both contribute towards high-energy consumption in the City,  but also are frequently in danger of power outages and environmental damage. Therefore, these main areas stand out as particular districts that can be used to both increase social and environmental resilience, yet also help contribute towards long-term mitigation goals. These areas represent the downtown area of Pittsburgh (its main commercial building district); the Hill District (the lowest income community in the City); Oakland (the area with the most hospitals and Universities in the city); and the Northshore (heavily commercial and includes key sports stadiums). Together, these areas represent the highest population density areas in the City, and the neighborhoods containing the most significant critical infrastructure vulnerabilities. V.   C OMPARING P ITTSBURGH ’ S IMMEDIATE V ULNERABILITIES AGAINST ITS LONG - TERM GOALS The City of Pittsburgh set lofty goals for emissions reductions. These goals are necessary to stimulate the relatively dormant state of the clean energy transformation. The goals were set in respect to 2005 emission levels. This work will reference 2013 statistics due to the lack of 2005 data and the belief that emission levels have not experienced  significant change during the time due to low importance  placed on the subject of reduced emissions during the ten years between the two periods. Table 2 shows the reduction goals by year. Table 2. Emission Reduction Goals Emissions Reductions Goals for the City of Pittsburgh 2025 2050 27% 80% *Below 2005 Levels VI.   G ENERATION P ROFILE  In order to determine the total emissions by electric generation, metric tons of CO 2  various generation profiles must be analyzed to determine the emissions per MMBTU  produced. Fig 3 shows the generation mix for the PJM territory [7]. Using this data, Pittsb urgh’s 2013 carbon footprint from electricity and natural gas usage is 1.035 trillion metrics tons of CO 2  and 2.133 trillion metric tons of CO 2 , respectfully. This is proportionate to the total energy consumption ratios examined earlier, as natural gas produced about 2/3 of CO 2  emissions, just as it accounted for 2/3 of energy consumption. Fig 3. PJM Generation Profile  A.    Projecting Future Energy Consumption In order to determine the best decarbonization method for Pittsburgh the impact of the region around it must be taken into consideration. Pittsburgh is a city so it does not produce its own energy; it simply is a consumer thus far. Therefore, to understand how plan what to do in Pittsburgh, a detailed analysis must be performed to understand what might happen around it. PA has yet to analyze its energy futures, so we took a few different scenarios to understand the best case, worst case, and business usual scenario’s for the city of Pittsburgh. In order to reach Pittsburgh’s e mission reductions goals the electric generation mix must be altered to reduce CO 2  emissions. This section will examine three future generation scenarios: the same generation profile as 2013, energy consumption of entirely natural gas, and electricity generation composed of entirely renewable resources. The carbon footprint of thermal energy consumption will remain unchanged in each scenario from the 2013 levels. The amount of electrical energy consumption is altered each year based on assumptions made about the electricity usage of the future. PA is predicted to have no population growth in the immediate future therefore population will not cause a change in electricity usage [8]. Technology is expected to have an efficiency increase of 1.1% per year, causing electricity consumption to fall at the same rate [9]. The Pennsylvania Public Utilities Commission recently approved phase 3 of Act 129 which requires cumulative average savings of 3.7% in energy efficiency, reducing electricity generation by the same amount [10]. It is also expected that weather variability will increase, causing a 0.42% increase in energy consumption. When all factors are considered the electricity consumption of Pittsburgh should fall by 4.36% a year. Table 3 shows the  predicted electric energy consumption for 2025 and 2050. Table 3. Electrical Energy Consumption City of Pittsburgh Electrical Energy Consumption (Trillion MMBTU) 2013 2025 2050 19.3 11.3 3.7 1)   Scenario 1: Current Generation Profile The first scenario will examine the effects of keeping the generation profile the same as it was in 2013. Because there are no changes made the average conversion ratio of MMBTU to metric tons of CO 2  is unchanged. Therefore, the only reduction in emissions will come from the change in electric energy usage profile. The predicted emissions for 2025 and 2050 are 606,651.18 and 199,034.44 metric tons of CO 2 , respectfully. This reduces the total carbon footprint of 2025 and 2050 to 2,740,075.80 and 2,332,459.05 metric tons of CO 2 , respectfully. These levels represent reductions of 13.54% and 26.40% compared to the 2013 level of 3,169,196.79 metric tons. 2)   Scenario 2: Entirely Natural Gas The second scenario will examine the effects of transforming the generation profile to entirely natural gas. The average conversion ratio of MMBTU to metric tons of CO 2  is decreased because the conversion ratio of natural gas is more efficient than the generation mix of 2013. Therefore, the reduction in emissions will come from the change in electric energy usage profile and the reduction in the conversion ratio. The predicted emissions for 2025 and 2050 are 596,797.9 and 195,801.71 metric tons of CO 2 , respectfully. This reduces the total carbon footprint of 2025 and 2050 to 2,730,222.51 and 2,329,226.32 metric tons of CO 2 , respectfully. These levels represent reductions of 13.85% and 26.50% compared to the 2013 level of 3,169,196.79 metric tons. 3)   Scenario 3: Entirely Renewable Resources The third scenario will examine the effects of transforming the generation profile to entirely renewable resources. The average conversion ratio of MMBTU to metric tons of CO 2  is decreased substantially because this study uses a conversion
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