At the start of the process, I was aiming to write a paper focusing on how battery storage could be implemented in low income and affordable multifamily housing in the Chicago market. The upcoming Future Energy Jobs Act (FEJA) having specific goals for photovoltaic (PV) generation in low income and affordable markets.(Sen. Chapin Rose – Christine Radogno – Donne E. Trotter – Neil Anderson, Dave Syverson, Robert Rita, Lawrence Walsh, Jr.,Bill Mitchell – William Davis – Ed Sullivan, John C. D’Amico, Edward J. Acevedo, Michael W. Tryon, Patrick J. Verschoore) ) I thought it would make sense to pair solar and storage to take advantage of the common infrastructure of these two technologies. Research so far has supported this idea, but the barriers to implementing battery storage are greater than I had been anticipating. The economics of battery storage are hampered by their classification and other uncertainties in the market. There are certainly regions were battery storage, usually paired with PV generation, are economically competitive for the right investors. At present, the economics are not favorable for low income and affordable multifamily housing entities to pursue battery storage or even solar+storage in the Chicago area. This has caused a slight refocusing of this paper, namely: What are the advantages of and barriers to solar+storage in the Chicago area and what methods can be used to alleviate these barriers and drive this market?
Following the adage, “those who forget the past are condemned to repeat it,” we are periodically reminded that the most vulnerable in our society operate with few fail safes or redundancies. Chicago’s heatwave of 1995 caused 739 heat related deaths, with a disproportionate number occurring in disadvantaged neighborhoods. Similarly, the 35,000 European deaths from the August 2003 heatwave were not equally distributed across the population. (Christopher R. Browning et al. 661-678) Katrina and its aftermath in August 2005 left 1300 dead, again the most vulnerable taking the brunt. (Colten, Kates, and Laska 36-47) There has been progress on improving back up capability for critical buildings, such as hospitals and facilities that care for the elderly. But natural gas or diesel generators are expensive and require skilled maintenance staff and preventative maintenance. The only low-income or affordable multifamily facilities I have seen in Chicago that have had generators have been senior facilities. Even those are few and far between. This is where I see solar+storage and its resilience factor having an important role.
A quick digression to attempts to make phone calls in Africa in the 1990’s. Stationed in “a very small place” about 50km from the nearest payphone, making a phone call was a full day hitch hiking excursion. And the phones often were out of service. A calculation of what it would take to get a phone for each person in Africa (and other developing nations) concluded there was not enough copper in the world to accomplish that; getting phones to everyone was impossible. But in the last few weeks, after two years in the very small place, a cellphone tower went up. What was impossible became common place due to technology improvements.
It is not possible to have diesel or natural gas back up generators in multifamily housing in disadvantaged communities. The expense and maintenance issues are in surmountable. But energy efficiency has been implemented through incentives and programs, and the structure for PV implementation is in the FEJA. Solar+storage is becoming more economical and there are money generating mechanisms that improve the economics. With proper incentives and requirements, solar+storage should follow in the footsteps of energy efficiency and PV to overcome the current barriers. Saving money for the tenants of low-income and affordable housing is a critical mission but the resiliency factor, while impossible to value, is probably even more important.
Christopher R. Browning, et al. “Neighborhood Social Processes, Physical Conditions, and Disaster-Related Mortality: The Case of the 1995 Chicago Heat Wave.” American Sociological Review 71.4 (2006): 661-78. CrossRef. Web.
Colten, Craig E., Robert W. Kates, and Shirley B. Laska. “Three Years After Katrina: Lessons for Community Resilience.” Environment: Science and Policy for Sustainable Development September 1, 2008: 36-47. Print.
Sen. Chapin Rose – Christine Radogno – Donne E. Trotter – Neil Anderson, Dave Syverson, Robert Rita, Lawrence Walsh, Jr.,Bill Mitchell – William Davis – Ed Sullivan, John C. D’Amico, Edward J. Acevedo, Michael W. Tryon, Patrick J. Verschoore). SB2814 Public Act 099-0906. Tran. IL Senate and House. , 2016. Print.
It is feasible for the United States to be powered by 100% renewable energy by 2030, the technology and potential for sufficient infrastructure exists. New deployment of utility scale wind and solar facilities will be required for to shift the US electric grid to 100% renewable energy. However, the required energy storage capacity may heavily influence how much this transition will cost, and how quickly it can occur.
In the 2012 SunShot Vision Study, completed by the U.S. Department of Energy, it was stated that only 0.6% of the US total land area would be required to provide all required electricity for the United States . This study only included annual end-use electricity at that time, which may increase as electric cars become more prevalent. However, that was to cover the entire electric supply which would not be required if solar is supplemented with wind.
Similarly, there is potential for extreme increases in wind power. A NREL assessment of onshore and offshore wind found a potential of about 50,000 TWh/yr. Of this, two-thirds comes from onshore wind and roughly one-third from off-shore wind. This analysis used a 25% capacity factor, and this prediction still comes out to 12x the recorded electrical energy use of the United States in 2012 .
So, there is clearly not a shortage in potential renewable energy in the US. However, these are annual projections. The intermittent nature of these renewable energy sources presents a reliability issue, compromising the ability to balance supply and demand on the electric grid.
A study done by the University of Glasgow simulates a scenario for a 100% Renewable Grid for Great Britain for the year 2025, shown in Figure 1 below . The load profiles would look similar for the United States, potentially with higher variability of the renewable resources. It is clear that there is considerable fluctuation not only on a daily, monthly, and annual basis. An analysis with smaller time-steps, say 15 minutes, would also show considerable fluctuation between available power from renewable energy and energy demand at any given time. Figure 2 shows the day with the highest deficit between power supply and demand.
Figure 1: Combined 100% Renewable Model
Figure 2: Greatest Supply Deficit, January 17, 2025. Worst case at 17:00.
These figures present that no matter the capacity of renewable energy installed, storage in some form will be required to maintain reliability if all fossil-fueled energy sources are removed from the electric grid. The question of how much storage is needed is really one that has not yet been confidently answered. Through sources I have seen, some quote we only need storage capacity for 10% of daily energy production, while others quote the required storage capacity may be up to 2 days of the US total energy production .
Storage also comes in many forms, mainly: compressed air, pumped hydro, and batteries. As of now, storage is much more costly than renewable energy infrastructure. Most sites suitable for pumped hydro and compressed air are already in use, so projections show that additional storage capacity is most likely to be provided by batteries .
The Solutions Project  released an impact report that shows what this transition would look like, state by state, and also for the nation as a whole. Below is a projection for the entire US.
Figure 3: The Solutions Project: Projected Energy Mix in 2050
There are many topics not yet addressed above, such as transportation & industrial processes, cost, policy, etc. For the transportation industry, it’s evident that battery storage will play a huge role.
1 National Renewable Energy Laboratory and U.S. Department of Energy. 1 Feb 2012. SunShot Vision Study.
2 University of Glasgow. “The Grid 2025 Challenge”. 2012. http://www.physics.gla.ac.uk/~shild/grid2025challenge/index.html
3 Lopez, A. et al. US Renewable Energy Technical Potentials: A GIS-Based Analysis. 1 July 2012. National Renewable Energy Laboratory. USDOE Office of Energy Efficiency and Renewable Energy.
4 Heal, G. Reflections – What Would It Take to Reduce US Greenhouse Gas Emissions 80 percent by 2050? Review of Environmental Economics and Policy. 11, (2017)
5 Jacobson, M. et al. 100% clean and renewable wind, water, and sunlight (WWS) all-sector energy roadmaps for the 50 United States. Energy & Environmental Science. 8, (2015)
The idea of generating energy from renewable source (i.e solar, wind etc) emerged once the stored fossil fuels were visibly depleting. As of 2007, the global wind energy production is 94 GW, and is estimated to reach 474 GW by 2020. After seeing these numbers, the first question that comes to the mind is “If JUST wind energy generates astronomical amounts of energy, with other renewable sources why is there a need for a different energy source?”
The problem with renewable sources is there dependency on weather, geographical conditions. In order to meet the energy demand at a constant rate, large scale electrical energy storage (EES) is required. Redox flow batteries (RFB) is one of the promising solutions to large scale EES due to their independently controllable power and energy, quick response time and high energy efficiency. In order to make flow batteries a considerable option for large scale EES, the cost needs to be brought down remarkably. A lot of the RFB’s perform poorly due to several challenging issues (high electrolyte cost, power density). Hydrogen-bromine system on the contrary has super low costs, is available in high abundance and has high energy efficiency. Hydrogen-Bromine flow battery uses reversible kinetics in order to produce electricity. The one major drawback in this kind of system observed is the perflourosulfonic acid membrane used has low conductivity when hydration isn’t enough. In the presence of hydrobromic acid, the membrane behavior performance hampers severely.
Laminar flow electrochemical cells are the proposed solution to address the problems in hydrogen bromine system. By eliminating the need of a membrane in an electrochemical cell, the cost of the cell drops down drastically and the hydration requirements go down with it. Laminar flow cells rely on diffusion to separate reactants. 
Below are some of the observations of performance of a Hydrogen-Bromine flow battery in order to understand some of the many important parameters to their potential success.
In flow through mode, the transfer of masses takes place through forced convection. In flow by mode, the bulk motion and convection is pretty small compared to diffusion, hence the consumption rate of reactant can be related to diffusive transport.
As the electrolyte flowrate increases, the cell performance increases by 8.5% as a result of better mass transport. 
In the below figure, the flow by mode has a density of 0.22 –cm2, whereas flow through mode has a density of 0.15 –cm2. This suggests that Nafion conductivity decreases as its free acid content increases. 
By Kyu Taek Cho, Paul Ridgway, Adam Z Weber, Sophia Hausssener, Vincent Battaglia and Venkat Srinivasan.
By William A. Braff, Martin Z. Bazant and Cullen R. Buie
In practice, Li-O2 battery research is still in its early stages. So far, the results in this field have been stymied due to oxygen storage and clogging issues resulting in low energy efficiency (e.g. large potential gap), lack of stability, and inadequate rechargeability of the batteries. Thus, to overcome these challenges, development of efficient catalysts which can simultaneously enhance both ORR and OER kinetics during discharge and charge processes is essential. Among different class of materials, two-dimensional nano-materials are of increasing interest because of their relatively large surface area, which enables faster reaction rates, and their short diffusion path lengths compared to the bulk1–4
Since the very first successful demonstration of a metal oxygen battery based on carbon electrode by Abraham et al.5 in 1996, many efforts have been placed on the advancement of cathode materials based on the fact that increasing carbon surface area increases the specific capacity of the cell.6,7 Further studies revealed that despite the active surface area of cathode materials and in specific carbon electrodes, mesopore volume (2-50 nm) of carbon catalysts used in their air electrodes also plays a vital role in specific capacity of lithium-air systems.8 Later other groups have put many efforts to increase the activity of carbon nanostructures for enhanced catalytic activity and active surface area for Li-air systems leading to evolution of functionalized carboned based materials such as doped carbon materials and reduced carbon materials.9,10
While carbon-based materials have shown promising performance for lithium-air batteries, still they have limited activity in some systems, especially in charge reactions. Thus, the research on two-dimensional materials has been led to other class of materials with high surface to volume ratio but different catalytic properties.
A new class of two-dimensional inorganic materials, called MXenes including transition metal carbides (TMCs), transition metal nitrates (TMNs), and transition metal carbonitrides (TMCNs), have been investigated recently in energy storage applications due to their low metal diffusion barrier on the surface.11
Another class of two-dimensional materials which have been used for lithium-air batteries are metal sulfides which are also named as transition metal chalcogenides. Their high theoretical capacity and higher intrinsic electrical conductivity, electrochemical activity and their low cost make them a promising candidate to be applied as the electrode material in Lithium-air batteries and supercapacitors.12–20
However most of the research has been focused on the two-dimensional materials for cathode electrodes, there are also a few reports in which two dimensional materials has been implemented in other part of the metal air system. In a recent report, Yan et a. 21 utilized hexagonal boron-nitrate, a member of “Boron Nitrates” families with layered structure for lithium anode protection from dendritic corrosion. Hexagonal boron-nitrate also called as “White Graphene” with strong covalent bonds between boron and nitrogen atoms in layers and weak van der Waals forces between layers make this material a highly thermally and chemically stable.22
Two-dimensional transition metal oxide/hydroxides (TMO/TMH) are also classified as another electrode materials due to their higher specific capacitance and catalytic activity compared to carbonaceous materials. The best approach is to synthesize these materials in 0D, 1D, and 2D format to increase the exposed active surfaces23–32.
In overall, two dimensional materials are widely being studied as the promising candidates for lithium-air systems, however still little is known about wining structure which poses both good electronic property and morphology as an ideal candidate for not only cathode but also other components of the system such as anode and solid state electrolyte. This issue is the main motivation of this review paper during the future weeks.