pepejimenezblog.files.wordpress.com · Web view2017-05-09 · Context Memo. This paper reviews the current information about CO 2 emissions and their impact on public health. For

Jiménez Santiago José Luis

Context Memo

This paper reviews the current information about CO2 emissions and their impact on public health. For the general public global warming is a well known topic and not a great explanation has to be done about it. This context memo contains the explanation of some terms that might be unique or confusing for the public in order to follow the paper. These definitions are in order of appearance in the paper.

UNFCCC: The United Nations Framework Convention on Climate Change was the first historical attempt in 1992 to reduce the global CO2 emissions. This convention leads to good behavior commitments from the nations. There were no net results from this meeting in terms of GHG reductions but it was the reference for future attempts.

Paris Agreement: In 2015, this was the second and most important global attempt to reduce emissions. In this agreement, the nations present their intended nationally determined contributions to reducing the emissions about 20% of the level in 2005.

IPCC: The Intergovernmental Panel on Climate Change assesses the scientific, technical and socio-economic information relevant for the understanding of the risk of human-induced climate change.

GHG: Green House Gases involves the next components; CO2, methane CH4, nitrogen oxides, and Sulphur oxides. These gasses are the pollutants that increase the global temperature.

Global warming: Is the process by which the GHG increase the temperature. These gasses have the characteristic of absorbing the radiation that the earth reflects from the sun. Thes molecules interact with the solar radiation and their internal energy increases. Since the entire atmosphere has these molecules, the water, nitrogen, and oxygen (mainly components of the atmosphere) of the air begin to increase the global temperature.

DALYs: The disability-adjusted life year is a measure of the years lost due to the environmental conditions, in this case, the GHG levels. By definition, the DALY is obtained by adding the years of life lost to the years lived with disability. This helpful unit was developed in the 90s and is useful to quantify the health damage and the life expectancy.

SRES scenarios: These are the trustworthy projections of the future. The IPCC calculate these scenarios with the best available models. These scenarios are necessary because projections of climate change depend heavily upon future human activity. There are 40 different scenarios, each making different assumptions for future greenhouse gas pollution, land-use, and other driving forces. Assumptions about future technological development as well as the future economic development are made for each scenario. The next table shows the general view of each scenario. The parameters are Globalization or Regionalization versus economic or environmental focus. The next image from Wikipedia can help to visualize these four possible scenarios.


The power train is the mechanism that translates the energy from the engine into kinetic energy. This term is used for conventional vehicles and for electric vehicles.

In the electric vehicles section, some battery technologies are mention like Li-ion, Li-air, Ni-MH. These technologies have a common structure which is an anode made of a metal and a cathode that can be a metal or a polymer material. The main difference among these batteries is the material between the electrodes, in some cases, it is a liquid conductor, in others a solid in which the charges can flow. The last section of the paper includes a new concept, the smart grid. Smart grid is a complex interconnected network of electricity sources and customers. In the future, this new infrastructure will be necessary to connect EVs to the grid (V2G). With the V2G technology, the people can connect cars into houses during peak hours, where the electricity is more expensive, and use the electric leftovers of the EV.


Role of current electric vehicle technology for reducing the health damage caused by GHG emissions

Abstract

Global warming has negative repercussions on public health. This damage is measured by the future climate, economic development, and population growth. This paper presents the calculus of two different types of research for future health damage for the four SRES scenarios. The disability-adjusted life year (DALY) is used to quantify the damage. These results will guide future environmental policies that reduce GHG emissions by incentive green energy and transportation. In this context, electric transportation is a promising solution to the climate change issue. Despite the environmental and economic benefits of EVs, this technology is a risk for the current electric grid. Appropriate charging management, for example, a smart power grid can lead the large integration of EVs to the electric grid. This paper reviews the current state of the electric vehicle research like the battery, the power train, the impact on the environment and power grid of this technology.

Introduction

In 1992, international concern about climate change led to the United Nations Framework Convention on Climate Change (UNFCCC). The ultimate objective of that Convention was the “stabilization of greenhouse gas concentrations in the atmosphere at a level that prevents dangerous anthropogenic interference with the climate system” [1]. The global emissions of CO2 are about 33 Gtonnes per year. The consequences of the increase in the global temperature are 1. Extreme weather events over the world. 2. Reduction of biosphere and fauna. 3. Health damage influenced by economic development and population growth [2].

This review will focus on the last consequence because it has huge economic and policy implications. Global governments have been trying to identify potential energy policies that maximize health benefits and reduce climate change impacts. For example, the Intergovernmental Panel on Climate Change (IPCC) is “highly confident” that global warming is responsible for premature deaths and diseases around the globe. However, it has been difficult to demonstrate the correlation between global warming and public health damage because it is difficult to calculate this damage. Some models have been developing to quantitatively estimate those damages. In the last edcade De Schryver et al. [3] made a calculation of the CO2 health damage over 20 and 100 years, this method does not count the fact that the GDP and population growth is changing over the time. More recently, Tang et. al. [4] analyze the health damage of global warming considering the future society scenario. This is the only model that considers these factors for a quantitative estimation and for this reason is the most relevant paper about this topic. The results of this research will be exposed and compared with some previous models in this field.

The CO2 emissions reduction has to be conducted by good policies that increase the use and development of other sources of energy in order to shift from fossil fuels. To find a feasible solution to this problem two categories have been proposed to classify the sources of GHG, stationary sources and mobile sources. Stationary sources that are responsible for about 60% of the global emissions are mainly electric power plants that burn coal or natural gas to produce electricity and industry [5]. Some efforts to reduce the GHG emissions are capturing the CO2 from power plants for further underground storage. Or the use of renewables to supply the energy demand, but with


our current technology, it is not possible to accomplish that yet. On the other hand, the category of mobile sources, which is mainly the transportation sector, accounts for 25% of the global GHG. Consequently, there is a lot of space for improvement in this field with the objective of reducing emissions [5].

Some efforts to reduce the emissions from the transportation sector include the development of new fuels and the increase of the efficiency in the conventional vehicles [6]. Although, several studies have found that plug-in electric vehicles or hybrid vehicles are a promising solution. This is because they emit less CO2 and other pollutants into the atmosphere than conventional vehicles. Other benefits include the development of new industries and the energy security by using different sources. Electric vehicles often use electricity that is produced from fossil fuels. Hence, the environmental impact of this technology depends on the source of electricity that is used for EV. This opens a lot of opportunities for renewables sources in order to make these vehicles more friendly with the environment [7]. The discussion will be focus on the power train, battery and battery charginf technology. The purpose of this review is to show the current status and potential of this technology that has shown to be a feasible strategy to mitigate the impact on the public health of global warming.

Overview of emissions and climate change

The Paris Agreement 2015 states the basis for global policies for GHG mitigation. At this moment, developed countries are trying to identify potential energy policies that increase the benefits in public health (air quality) and reduce the climate change impacts. Figure 1 shows the historical anthropogenic CO2 emissions from different sources with an impressive increasing in the slope of the total emissions in the last ten years. In this context 2005 was the year with the maximum CO2 emissions [8].

Figure 1. Historical CO2 emissions [8]

The correlation of Figure 1 and 2 suggest that anthropogenic CO2 emission have increased the global temperature by 1°C in just 50 years. The average temperature of the earth has been changing over the last centuries but never increased more than 0.2 degrees. The planet has seen the first consequences of global warming like the cycles of “El niño” in the oceans and the migration of species from poles and the Equator. Recently, there have been studies of the impact in human health because we cannot adjust to the variations, based on that a quite number of papers have been published to determine the impacts over the next 30 or 50 years in the human health [1].


Figure 2. Historical temperature change [8]

Overview of Health damage related to CO2 emissions

In 2009 a complete model for quantifying the effects of GHG emissions was published De Schyver et. al.[3]. This paper quantifies the impact of 63 GHG in the public health damage and the ecosystem damage. First, for the public health damage the parameter used was the Disability Adjusted Life Years (DALYs) per unit emission related to malaria, diarrhea, malnutrition, drowning, and cardiovascular diseases. Second, these parameters were analyzed in three different scenarios based on Cultural theory perspectives. These scenarios were individualistic, the hierarchical and the egalitarian. The individualistic view states that humans have a great ability to adapt and that technology is development quickly. On the other hand, the egalitarian perspective is the worst scenario with the less adaptative rate and a “bussines as ussual” perspective []. Finally, the hierarchical perspective considers that consequences can be avoided with the right policies and technology. This is the most probable scenario for the future because there is balance in the positive and negative assumptions (imput) for the model [3].

The results of this research show that the CO2 damage ranges from 1.1×10-2 to 1.8×101

DALY per kton of emission. The greatest contribution in public health is due to malnutrition. The consequences of climate change affect directly the poorest countries, which pollute the less [3].

In order to develop a better model to quantify the damage and include the economic and social factors Tang et al [4] used the information from the Special Report on Emissions Scenarios “SRES”. They determined the health damage factors for the four SRES scenarios. For their calculation, a single framework was used for each scenario in order to establish the most accurate and relevant data.

The four scenarios of the SRES for the year 2100 are A1B, A2, B1 and B2. The next Table shows the different values of population, GSP, CO2 emissions and temperature used in each scenario. The variation among each one depends on different assumptions for future technology, environmental policies, fossil fuels sources and demographic growth. The SRES are the most accurate and trustworthy source about the future ecmissions, economical and population scenarios [4].

Table 1. Characteristics of each SRES scenario.


The results of this research are shown below in Figure 3. The largest contribution on damage is due mostly to malnutrition and diarrhea. Malaria has the third place and cardiovascular diseases the fourth. These results are in accordance with those from Lee et. al. [2] These results suggest that with the current emissions small changes in the present won´t make a difference in the future. This research also found that the health damage was concentrated in Africa, Middle East and Southeast Asia, regions with the lower economic growth.

Figure 3. Results of damage in DALYs by SRES scenario [4]

This research has to be developed to determine the damage not only caused by global warming but also from environmental effects that are a consequence of global warming. The information presented in this section is a very strong argument to build new policies to reduce GHG emissions. It is costly to reduce emissions and the industry would not make it happen unless the law states that is illegal to emit GHG.

Electric vehicles as a solution

Electric vehicle technology has the potential to reduce more than 40% of GHG emission from the transportation sector. Electric vehicle technology is developing quickly over the last two decades, mostly the powertrain, battery and charging infrastructure [7]. In this context, the battery is the component of EV with the most improvements over the last decade. The research has been led by the use of batteries in all electronic devices and by the potential of the electric vehicle industry. In the next section, the current technology of EV will be discussed. In addition, the environmental impacts of this technology will be analyzed.

Power train

Electric Vehicles can be classified into three major categories depending on their power train configuration: hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs). HEVs have an electric motor and an internal combustion engine. These vehicles cannot accept a charge from an external source, and these vehicles make their own charge by the internal combustion engine and by converting the kinetic energy of the car into electricity. This electricity can be stored in the car batteries. PHEVs are quite the same as HEVs but the difference is the amount of batteries because PHEVs can be recharged from the electric grid. Finally, BEVs do not have and internal combustion engine and only can be charged from the electric grid [7].

Due to the similarities among the PHEVs and HEVs technologies, a few power train configurations have been developed in order to achieve different objectives, for example, improve the fuel economy, or improve the power. The most common power


train configurations are series, parallel, and series-parallel. Figure 4 shows these examples.

Figure 4. Power train configurations: (a) series HEV, (b) parallel HEV, (c) series-parallel HEV, (d) series PHEV, (e) parallel PHEV, (f) series-parallel PHEV [6]

A series HEV (a) uses the power from the electric motor as the only propulsion source. The electric motor and the combustion engine are decoupled and only the electric motor is connected to the transmission and wheels. This configuration is convenient for the city, where the vehicles have to stop and run several times. This simple design can increase the efficiency of a car in the city about 25% [7].

In a parallel power train configuration (b) both the electric motor and the combustion engine are coupled with the transmission and wheels. This configuration increases the efficiency by 40% and because it has two propulsion sources is suitable for city and highway driving. Some examples of this kind pf power train available in the market are the Honda Insight and the Ford Scape [6].

The series-parallel HEV ( c) combines the advantage of the previous configurations. This car uses the series configuration in the city and the parallel configuration in the highway driving mode. The design is more complicated and expensive. The Toyota Prius is an example of this configuration [7].

Similar to HEV, PHEV has the same configuration, series, parallel, and series-parallel. The difference is the larger battery equipment because these vehicles can be charged from an external source. PHEVs can be all-electric vehicles [7]. These characteristics make PHEV the most reliable configurations.

Finally, the third major group is the BEV configuration, Figure 5. BEVs are all electric and for this reason, the distance it can travel is based on the battery capacity. At this moment, Nissan Leaf has 24 kWh batteries that can run 160 km on a single full charge. This amount of energy is huge and it is only obtained with an ion-lithium battery.

Figure 5. Power train configuration of BEV [7]


Understanding this differences and applications of each power train we can design cars with a specific purpose. This technology has a great potential to many transport application. The current research is focused on the design the power train for each kind of city and power source, the CO2 mitigation is the result of a well understanding of each part of the puzzle, in this case, the transportation system.

Battery

From the previous analysis of the power train we notice the importance of the battery, especially for the PHEVs. It is also the only source of propulsion for the BEVs. The current EV battery technology has a low energy density and specific energy compared with liquid fossil fuels. The consequence is a lower drive range compared with conventional electric vehicles. Other barriers to the battery design are the cost of the materials and the short life cycle of the batteries. Nevertheless, battery technology did go through enormous improvements over the past decades. Figure 6 [7] summarizes the advances in this field. At this moment the Li-ion batteries are the best technology, however, lithium-zinc alloys and Lithium and Zinc oxides have shown to increase the energy density of the battery [6]. The Pb-acid batteries were the first approach for EVs, the major concern of this battery its environmental impact because it can be a hazard. The Nickel- based batteries replace the acid battery. The best example of these batteries is the Nickel-metal hydride (Ni-MH) battery, and this technology was applied over the last decade in the EVs [9]. Nonetheless, the low charge-discharge efficiency made these batteries obsolete. At the same time the sodium-nickel chloride (ZEBRA) battery was developed, the advantage of this one is the highest energy density and power density. However, the operating temperature of 240-300°C has placed pressure on safety concerns [9].

Figure 6. Development timeline of EV battery technology [7]

Table 2 [4] shows the comparison of the current battery technology for EV. The characteristics of the batteries have been detailed. For example, the cost is around 60-350 dollars per kWh depending on the battery. The life cycle has been optimized to over 3000 charge-discharge cycles. The normal voltage is related to the electrochemical potential of the reaction in the cell. Lithium-based batteries have largest nominal voltage, however, new materials have been proved to increase this number. For example, the LiPo (polymer) contain metal organic frameworks (MOFs) that increase this Nominal Potential. The energy density is the key for the selection of a battery because the driving range depends on this number. Tesla, Honda, and Toyota are working on Li-ion batteries with 200-250 Wh/kg, this is equivalent to to 400 km driving range. The volumetric density is another concern. This parameter refers to the volume of the battery that will be placed in the car. In this context, Ni-MH and Li-ion are best in terms of volume [4]. The Lithium-ion phosphate has the greatest specific power which is useful for highway speeds but is costly and has a low energy density. So far, the conclusion of this analysis is that there is not a better battery and the choice on one depends on the final use. The state-of-the-art batteries are the Li-air, the Li-Sulphur


and Zn-air batteries, the energy, and volumetric density are around 1300-2000 Wh/kg and 1500-2000 Wh/L respectively. This is not a mature technology and is in the research stage. It has to overcome the high price of 100-150 dollar per kWh and the life cycle of 100-200 charging cycles. In the next two or three years Table 2 will be obsolete and the improvements will increase the amount and efficiency of EV batteries [1].

Table 2. Available batteries in the market with its characteristics.

Environmental Impacts

For the analysis of the environmental impacts a new parameter has been introduced for EVs, this is the “whells-to-wheels emissions” parameter. Whells-to-wheels has the objective of comparing the net emissions from a vehicle over its entire life. This parameter includes the energy and materials to power the vehicle. Many researchers conclude that EVs have a lower whells-to-wheels emission than conventional vehicles [1]

It is true that EVs have zero tailpipe emissions but EVs are not necessary environmental friendly. The reason is that often the electricity comes from fossil fuels power plants that have a huge amount of GHG emissions. In addition, the energy losses when the car is not used increase the carbon footprint of the EVs. However, controlled charging can reduce the cost with savings around 60% and the integration of renewable energy sources in the power grid reduces the CO2 emissions. The next paragraphs contain the strategic environmental impacts of the EVs implementation. These impacts are mostly referred to the power grid, because it is the source of energy from these vehicles [2].

The first impact of the EVs is on the power grid. The negative consequences of EVs to the power grid include system losses, voltage drop, phase unbalance, increase of power demand, equipment overloading and stability issues [1].

Second, EV implementation will affect the load profile of power grid because EVs are additional loads to be connected to the power grid. When EVs are charged during residential load peaks the power grid gets saturated. The solutions for this problem include the implementation of a tariff system and new management charging strategies [7].

The system components will also be affected by EVs. Some examples are the distribution transformers and cables. EV´s are additional loads that will increase the use of system components. To overcome this limitation, proper network planning and management are necessary for future EV implementation [2].

The next consequence is the system losses. When the EVs are receiving charge the current flow increases and also the system losses. In order to reduce the negative


impact of EV in electric losses, a good strategy could be supplying EV loads with nearby distributed generation. Renewable sources play a positive role here, PV and wind power plants could be designated exclusively for EV loads to reduce the impact on the power grid [1].

Finally, a new electric network that combines the renewables sources with the smart management is necessary in order to plug-in the EVs to the grid. More detailed studies are required in order to understand this matter. In addition, EV models that include electric grid are crucial in order to prepare the cities for EV implementation.

Smart grid

We have seen the urgent need of a green transportation and the current status and challenges of the EVs. The present transportation sector is decoupled with the power grid. However, the situation must change in order to adopt the EV market []. In addition, electric mobility is confronted with several barriers like the high cost and the lack of charging infrastructure discussed in the previous section. EV deployment requires the developed of a smart grid [10]

Smart grid is a modernized electric network that uses the computer technology and automatization to improve the reliability, efficiency, and sustainability of the power grid supply. The purpose is to get a more sustainable electric grid with fewer losses and incorporate the EV in the electric grid [7]. The main different of the smart grid compared to the conventional grid is communication between the source of power and the final user. In the conventional grid, this communication is unidirectional, whereas in the smart grid the communication is bi-directional. Another difference is the monitoring control. In the conventional grid is manual, totally different in the smart grid,, which is autonomous and intelligent. Other characteristics of the smart grid are the inclusion of sensors and meters, the active participation of the customer, the distributed power generation and feasible energy recovery in the grid [10].

There are several smart grid projects around the world according to the Global Smart Grid Federation Report. Some of the leading projects are smart grid projects are the Smart Grid Smart City in Australia, Ontario Smart Metering Initiative in Canada, Low Carbon London in Great Britain, ECAR Project in Ireland, Yokohama Smart City Project in Japan, Jeju Smart Grid System in South Korea and Houston's Smart Grid in the United States [10]. The Figure 7 shows how a smart grid framework looks like. The main characteristic is the bi-directional communication through the grid.

Figure 7. Smart grid framework [10]


Some applications of these two-way communication paths are the advanced metering infrastructure, the home automation network, demand response and vehicle-to-grid (V2G) [10]. The V2G concept will become feasible in this scenario, all the time the vehicle charge is monitored and allowed to be discharged to the electric grid. In this case the EV is a dynamic and distributed energy container. Researchers are convinced that C2G technology is the most sustainable way to incorporate a large fleet of EV to the electric grid of a city [9].

Conclusion

This research establishes the correlation between CO2 emissions and damage in public health. Electric vehicle technology has been developing over the last decade and shows to be a solution to mitigate the CO2 emissions. EV benefits are not limited to the environment, but also to the public health and the power grid.

However, EV technology is not fully mature at this time. There have been huge improvements in the past decades but the Li-ion batteries have a restricted energy density, a relatively short live cycle, and a high cost. Further research is needed to improve the battery technology. For example, the Li-air and Sulphur batteries have a high potential but are in the experimental phase. The Li-air battery is a promising technology that is reaching the large scale production.

Finally, the “Whells-to-wheels emissions” parameter is introduced to account the net emissions of the EVs and determine the emissions avoided. A significantly GHG reduction is not possible with the current power grid. A Smart Grid with V2G is neccesary to overcome the “small fleet” limitation . The GHG emission reductions with EV requires better policies to incentive the citizens and increase the fleet of EV.

References

1. Sioshansi, R., & Denholm, P. (2009). Emissions Impacts and Benefits of Plug-In Hybrid Electric Vehicles and Vehicle-to-Grid Services. Environmental Science & Technology, 43(4), 1199-1204. doi: 10.1021/es802324j

2. Lee, Y., Shindell, D. T., Faluvegi, G., & Pinder, R. W. (2016). Potential impact of a US climate policy and air quality regulations on future air quality and climate change. Atmos. Chem. Phys., 16(8), 5323-5342. doi: 10.5194/acp-16-5323-2016

3. De Schryver, A. M., Brakkee, K. W., Goedkoop, M. J., & Huijbregts, M. A. (2009). Characterization factors for global warming in life cycle assessment based on damages to humans and ecosystems. Environ Sci Technol, 43(6), 1689-1695.

4. Tang, L., Ii, R., Tokimatsu, K., & Itsubo, N. (2015). Development of human health damage factors related to CO2 emissions by considering future socioeconomic scenarios. The International Journal of Life Cycle Assessment, 1-12. doi: 10.1007/s11367-015-0965-9

5. Perez, L., Trüeb, S., Cowie, H., Keuken, M. P., Mudu, P., Ragettli, M. S., . . . Künzli, N. (2015). Transport-related measures to mitigate climate change in Basel, Switzerland: A health-effectiveness comparison study. Environment International, 85, 111-119. doi: http://dx.doi.org/10.1016/j.envint.2015.08.002

6. Martin, N. P. D., Bishop, J. D. K., & Boies, A. M. (2017). How Well Do We Know the Future of CO2 Emissions? Projecting Fleet Emissions from Light Duty Vehicle Technology Drivers. Environmental Science & Technology. doi: 10.1021/acs.est.6b04746

http://dx.doi.org/10.1016/j.envint.2015.08.002


7. Yong, J. Y., Ramachandaramurthy, V. K., Tan, K. M., & Mithulananthan, N. (2015). A review on the state-of-the-art technologies of electric vehicle, its impacts and prospects. Renewable and Sustainable Energy Reviews, 49, 365-385. doi: http://dx.doi.org/10.1016/j.rser.2015.04.130

8. IPCC, 2005. IPCC Special Report on Carbon Dioxide Capture and Storage.Prepared by Working Group III of the Intergovernmental Panel on ClimateChange [Metz, B., O. Davidson, H.C. de Coninck, M. Loos, and L.A. Meyer(eds.)]. Cambridge University Press: Cambridge, United Kingdom and NewYork. http://www.ipcc.ch/pdf/special-reports/srccs/srccs_wholereport.pdf

9. Tan, K. M., Ramachandaramurthy, V. K., & Yong, J. Y. (2016). Integration of electric vehicles in smart grid: A review on vehicle to grid technologies and optimization techniques. Renewable and Sustainable Energy Reviews, 53, 720-732. doi: http://dx.doi.org/10.1016/j.rser.2015.09.012

10. Herrador, M., Carvalho, A., & Feito, F. (2015). An Incentive-Based Solution of Sustainable Mobility for Economic Growth and CO2 Emissions Reduction. Sustainability, 7(5), 6119.

http://dx.doi.org/10.1016/j.rser.2015.09.012

http://dx.doi.org/10.1016/j.rser.2015.04.130

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pepejimenezblog.files.wordpress.com · Web view2017-05-09 · Context Memo. This paper reviews the current information about CO 2 emissions and their impact on public health. For