A review of the various electrical energy storage technologies and the importance of Carbon Footprint of the life cycle of batteries in their use for renewable energy integration.

1. Carbon Footprint of the life cycle of batteries –A key parameter for the
sustainability of their use inelectrical energy storage
Dr R S Mahwar, Environmental Adviser and Former Additional Director, Central Pollution
Control Board (Ministry of Environment, Forest and Climate Change), Delhi
1.0 Introduction
Carbon dioxide (CO2) gas plays a number of important roles in the earth’s ecosystems. It
absorbs infrared radiations in the atmosphere. It is the raw material for photosynthesis
and its carbon is incorporated into organic matter in the biosphere which may eventually
be stored in the Earth as fossil fuels. It is also plays a crucial role in the weathering of
rocks.
Most of the sun's energy that falls on the Earth's surface is the visible light portion of the
electromagnetic spectrum. Part of the sunlight is reflected back into space depending on
the reflectivity of the surface and the rest is absorbed by the Earth and held as heat
(thermal energy). This heat is then re-radiated in the form of longer wavelength infrared
radiations. While, the dominant gases of the atmosphere (nitrogen and oxygen) are
transparent to infrared radiations, the so-called greenhouse gasses (GHGs), primarily
water vapor (H2O), Carbon Dioxide (CO2), and methane (CH4) absorb some of the infrared
radiations. The absorption of re-radiated heat i.e. the infrared radiations by the GHGs
results into warming of the globe called as global warming. It has been predicted that if
not slowed down, this warming will result into melting of the polar ice causing a rise in the
sea level and many of the land areas will get submerged forever. It has also been
established that the human activities contribute a great deal of GHG emissions. The Total
amount of the GHGs produced to directly or indirectly support the human activities is
called the “Carbon Footprint (CFP)”of these activities.
The controlling or slowing down the global warming therefore needs changes in the
human activities for reduction in the emission of the GHGs. In –fact the main aim of the
universal agreement of Paris at COP21 is to keep a global temperature rise this century
well below 2 degrees Celsius and to drive efforts to limit the temperature increase even
further to 1.5 degree Celsius above the pre-industrial levels.
The fossil fuels (coal, oil etc) which are the main support systems for the human
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2. activities not only have a limited availability but their use is also the major source of
GHG emissions. It has therefore become imperative to shift from the conventional fossil
fuels to the renewable sources i.e. solar and wind for the generation of electrical energy.
The solar and wind as energy as sources are of a variable nature in the sense that the sun
isn’t always shining nor is the wind always blowing. The global demand for electricity is
huge, and it’s growing by approximately 3.6 percent annually. Also, for technical reasons
the amount of electricity fed into the power grid must always remain on the same level as
demanded by the consumers to prevent blackouts and damage to the grid. Also, there are
situations where the energy production is higher than the demand for a specific period or
vice versa. This is where, energy storage technologies come into play, as they are the key
element to balance out these flaws. This article gives a review of the various electrical
energy storage technologies and the importance of Carbon Footprint of the life cycle of
batteries in their use for renewable energy integration.
2.0 Electrical Energy Storage Technologies
There are mainly four types of Electrical Storage Systems (ESS) namely, mechanical
(pumped hydro, compressed air etc), electrical (capacitors), chemical (Batteries, fuel
cells), and thermal (cryogenic storage). While some energy storage technologies are
mature or near maturity, most are still in the early stages of development and currently
struggle to compete with other non-storage technologies due to high costs. The
characteristic that makes EES very attractive and special when it comes to their
application for stationary purposes is its capacity to shift the energy across time
dimension, similar to the way the transmission and distribution systems are capable of
transferring energy across distances. This way EES helps in managing electricity grid
during hours of peak demand and peak generation (in the case of renewable). EES also
helps in increasing the grid reliability and power quality and can act as standby reserve.
Although, the ESS will require additional attention before their potential can be fully
realized, these have the potential to support our energy system’s evolution. Among the
four systems, the battery storage technology is considered as the most promising to
tackle the challenges involved in the generation and use of electricity from renewal
sources specially wind and solar.
3.0 BatteryTechnologyinRenewable Integration
3.1 Global Objective of Renewable
The main objective of the global shift from fossil fuel based energy generation to the
renewable sources especially solar and wind is to reduce the emissions of GHGs from
human activities (i.e. the Carbon Footprint of the activities) which are essential for

3. slowing down the global warming. This requires that the process from the generation of
electricity from solar or wind to it consumption do not involve emissions of the GHGs or
these emissions to be kept to the best possible minimum.
There is a need of comparing the life cycles of the different battery technologies for
making the choice of a sustainable battery technology in the sense of its overall
environmental impacts i.e. minimum emission of GHGs with the best possible
performance to the cost ratio involving least social impacts. The Carbon Footprint of the
battery technologies therefore becomes the key parameter for the sustainability of
battery technologies especially in view of their being linked to the slowing down the
global warming through reduction of GHG emissions.
3.2 Life Cycle Assessmentof BatteryTechnologyandCarbonFootprint
Life cycle assessment (LCA) of the battery technologies in relation to CFP refers to a
comprehensive assessment of the involvement of GHG emissions associated with the
product’s life cycle right from extraction through the use phase to the final disposal
(including recycling) after the end of its life. The stage upto the dispatch of the finished
product is usually referred as “Cradle to Gate” and the stages following this as “Use
Phase”.
The life cycle assessments help preventing CFP involved even in shifting from one stage
of the lifecycle to another, from one substance to another, from one country to another
etc. The LCA takes care of the linkages and interactions between different components of
the entire product systemand provides a firm basis in integrating sustainability into the
product design, innovation and framing the environmental policies. The various stages of
the life cycle of a typical product are shown in Figure 1.

4. Figure 1 : Life cycle stages of a typical battery
(Source: MitavachanHiremath (2014) “Comparative LifeCycle Assessment of Stationary Battery
Storage Technologies for Balancing Fluctuations of Renewable Energy Sources”, Master’s Thesis,
Carl vonOssietzky University of Oldenburg, Germany.
4.0 Life Cycle of Electric Vehicles and Control of GHGs
The impact of the introduction of electric vehicles (e.g. electric rickshaws in Delhi, India) on
the emissions of the GHGs can be easily understood form the following questions (only few
given and the list can be exhaustive):
 What is the carbon Footprint of an electric vehicle?
 Whether the power/energy supply involved in the production of the electric
vehicles and batteries is generated from non- fossil fuel based sources?
 Whether the power supply available for recharging of batteries is generated from
the non-fossil fuel based sources?
 Whether the addition of the electric vehicles has added to the traffic congestion
resulting into an increase in the fuel consumption by the petrol/diesel/CNG
vehicles?
 Do the battery recycling industries have non-fossil fuel based power supply?
It may be noted here that the energy demands for the electric vehicles right from their
production to recharging of the batteries is being met mainly from the coal/fossil fuel

5. based power generation. Itis only the conversion of the existing fossil-fuel based
vehicles into electric vehicles or providing of power from renewable sources for the
various life cycle stages of electric vehicles as well as the batteries which will have
meaningful reduction in the GHG emissions in the global context. The addition of the
battery based electric vehicles that are produced from and operated on the fossil fuel
based energy sources will help (at the most) only in improving the air quality within
the area of their operation.
5.0 Conclusions and Recommendations
The sustainability of the application of the battery technologies for electrical energy
storage applications in relation to the reduction in the overall Carbon Footprint or
emissions of GHGs in the global context is expected to be meaningful only if the various
stages of the life cycle of batteries are made to run on the electrical energy generation
from the solar or wind energy. A life cycle analysis of the batteries carried out by each of
the battery producers to identify and minimize the GHGs emission involving activities in
their manufacturing process will help them in their continued sustainability specially under
the scenario of changing from fossil fuels to solar/ wind energy in the context of the
unavoidable need of minimizing the GHG emissions for slowing down the global warming.
6.0 Reference Documents
Comparative LifeCycle Assessment of Stationary Battery Storage Technologies forBalancing
Fluctuations of Renewable Energy Sources
http://www.uni-
oldenburg.de/fileadmin/user_upload/f2/projekte/cascadeuse/PDFs/Master_Thesis_LCA_o
f_Batteries.pdf
BatteryStorage for Renewables: MarketStatusandTechnologyOutlook
http://www.irena.org/documentdownloads/publications/irena_battery_storage_report_20
15.pdf
Energy Storage Technologies & Their Role in Renewable Integration
http://www.geni.org/globalenergy/research/energy-storage-technologies/Energy-Storage-
Technologies.pdf
Technology Roadmap Energy storage
https://www.iea.org/publications/freepublications/publication/TechnologyRoadmapEnergy
storage.pdf
Energy Storage Opportunities and Challenges - A West Coast Perspective White Paper
http://www.ecofys.com/files/files/ecofys-2014-energy-storage-white-paper.pdf

6. DG ENER - Working Paper The future role and challenges of Energy Storage
https://ec.europa.eu/energy/sites/ener/files/energy_storage.pdf
Environmental impacts of batteries for low carbon technologies compared
http://ec.europa.eu/environment/integration/research/newsalert/pdf/303na1_en.pdf
LIFE CYCLE ASSESSMENT OF LEAD ACID BATTERY. CASE STUDY FOR THAILAND
http://epe.pwr.wroc.pl/2013/1-2013/Premrudee_1-2013.pdf
Lead-based Batteries LCA – International Lead Association
http://www.ila-lead.org/UserFiles/File/LCA%20Lead_Based%20Batteries.pdf
Life Cycle Analysis: Automotive Lithium-ion Battery vs. Automotive Lead Acid Battery
http://users.humboldt.edu/lpagano/project_pagano.html
ENVIRONMENTAL ASSESSMENT An Eco-balance of a Recycling Plant for Spent Lead–
Acid Batteries
http://www.environmental-
expert.com/Files%5C6063%5Carticles%5C4927%5CN2235269G77M4X47.pdf
Assessment of the sustainability of battery technologies through the SUBAT project
http://etec.vub.ac.be/publications/2005VandenBossche216.pdf
Environmental assessment of vanadium redox and lead-acid batteries for stationary
energy storage
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.194.9741&rep=rep1&type=pdf
Progress in electrical energy storage system: A critical review
http://www.sciencedirect.com/science/article/pii/S100200710800381X
Electric Battery Actual and future Battery Technology Trends
http://www.futureage.eu/files/dd33e86df1_prezentace_Birke.pdf