Floating Wind Turbines

The energy demand is increasing day by day and is expected to nearly double by 2050. To fulfill this demand in cheap, economic and without having the negative impact on environment , the best move forward is to focus on renewable energy resources. Solar power and wind energy has vast potential to meet this demand. Conventional wind energy farms have been exploited from decades but a relatively new concept of off-shore floating wind turbine farms are now under the consideration of many industrialized countries to harness the electricity from it. European countries have been exploiting this new concept of offshore floating wind turbines very efficiently but a lot of work is still needed to be done in The United States of America.GWEC_PRstats2016_EN_.indd figure: Global Wind Energy Council Data.

Apart from variability in the wind speed, the major obstacle in the wind energy sector is the integration of wind energy into the grid. The power supplied to the grid should be able to balance the load requirement of the various industries, customers and commercial purposes. This balancing of supply and demand is the most crucial factor which is needed to be kept in mind. The mass storage of the wind excess power produced by these wind farms can be a very pivotal factor for the growth of offshore wind energy sector.

Their are various other forms of energy storage facilities available like flywheel, super capacitors, fuel cells etc but these technologies have very limited range of storage capacity.  And to use the electrical energy in efficient manner , mass storage techniques are needed to be developed. Pumped Hydro storage technology is been used for a while but it has its own obstacle in the form of geographical constrains and limited prospects.

The most promising development till now in the field of mass storage is the introduction of Compressed Air Energy Storage technology (CAES). This is a no fuel no emission storage technology that can be used for mass storage of electrical energy. Various developments have been made in the cycle of CAES. Combination of offshore wind energy and Compressed air energy storage has a potential to balance the supply demand requirements.

This paper will cover the offshore floating wind turbine energy and its current capacity, Various storage technologies used, Compressed Air Energy Storage (CAES) and how it can be integrated with offshore wind energy , the technological development in the CAES, economies related to it, and its future prospects.


  1.  Binghui Li , Joseph F DeCarolis -A techno-economic assessment of offshore wind coupled to offshore compressed air energy storage.


2) Foating offshore turbines Tande, John Olav Giaever; Merz, Karl; Paulsen, Uwe Schmidt; et al. WILEY INTERDISCIPLINARY REVIEWS-ENERGY AND ENVIRONMENT   Volume:   Issue:   Pages: 213-228   Published: MAY-JUN 2015

3)   Alami, Abdul Hai; Aokal, Kamilia; Abed, Jehad; et al.  – Low pressure , modular compressed air energy storage system for wind energy storage applications RENEWABLE ENERGY   Volume: 106   Pages: 201-211   Published: JUN 2017.


Blog Assignment 3 – “Primer” for Energy Storage Paper

Blog Assignment 3 – “Primer” for Energy Storage Paper

By now, you have identified a topic of interest in the energy storage arena, spent some time searching for relevant review articles on that topic, and perhaps even refined your topic based on that initial research.  It’s now time to make your first impression. A key component to writing your paper is producing an introduction section (this is not an abstract) to your paper, which is what makes the reader want to continue reading your paper. The introduction also serves as a “roadmap” for your paper, giving the reader insight into how the paper will be organized and the major points you will cover in the paper.

A good introduction attracts the attention of the reader and this can be done in a number of ways, whether it is surprising statistic, interesting quote, question that makes the reader think about the topic, or another “attention-grabber.” The introduction should also include a transition to some relevant background on the purpose/thesis/main point of your paper. This part of the introduction leads the reader from your “attention-grabber” to the specific area you will be discussing in your paper, and helps them understand the content you will be presenting in your paper.  The last part of your introduction should be the overall point you want to make in the paper.

For this blog assignment, write the introduction section of you paper utilizing the research you have done thus far (10 references for Blog 2, assuming they were all useful and relevant) and using additional references that you have found since Blog 2 or will find prior to writing Blog 3. Feel free to use the suggestions noted above on how to construct the introduction of your paper. Make sure to cite sources/references. The entire blog should be no longer than 600 words (not including references.)




Which tools did you use to find your articles? Did you find one of the tools easier to use?  If so, why?

I used Google scholar and Web of science for selecting articles on my topic of research. They both were equally helpful in figuring out the necessary articles. But, I found Web of science more efficient as it had a lot more filters to add on to the search.

In the course of this search, did you have any useless searches? If so, how did you improve the search?

Yes, there were a few links that deviated from my topic of concern. I added on filters and appropriate key words. Also, the key words in quotations improved my quality of search.

What searches did you use to find your articles (what keywords, in what set up, with what tool)? An example of this would be: I used Web of Science with the Topic search and the review article refinement, using the key words Lithium Battery.

I used Google scholar and Web of science for my searches. Initially, I browsed using just the key words to figure out the research papers on my topic and then, added review article filter to retain just the review papers on the topic.

How might you improve your search to get even better results next time? If your successful search had gotten only non-relevant results, what might you have done to improve your results?

I would have given in more relevant key words for the searches. Also, if my search had been unsuccessful, I would have tried adding in more filters in order to obtain results closer to what I have been looking for. I would have tried other search engines too.



  • Assessment of feasible strategies for seasonal underground hydrogen storage in a   saline aquifer

Sainz-Garcia,A ; Abarca, E ; Rubi, V ; Grandia, F

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Volume: 42, Issue: 26, Pages: 16657-16666, Published: JUN 29 2017

Abstract- The paper focuses on conversion of surplus electrical energy to hydrogen and its storage in geological formations. A maximum hydrogen recovery ratio of 73% is implementable. Hydrogen has a lot of complications if not stored without a cushion gas. However, shallow extraction wells can minimize its effects. Steep drooping geological structures are key for efficient hydrogen storage.

  • Mathematical modeling of unstable transport in underground hydrogen storage

Hagemann, B ; Rasoulzadeh, M ; Panfilov, M  ; Ganzer, L ; Reitenbach;

ENVIRONMENTAL EARTH SCIENCES, Volume: 73,Issue: 11, Pages: 6891-6898, Published: JUN 2015

Abstract-The hydro dynamic behaviour of Hydrogen, despite of microbial activity is distinctive compared to natural gas storage. Underground energy storage using hydrogen helps in the storage of intermitents energy generated from the renewable energy sources, utilizing them to their maximum.

  • A coupled, pore-scale model for methanogenic microbial activity in underground hydrogen storage

Ebigbo, A ; Golfier, F ; Quintard, M .;

ADVANCES IN WATER RESOURCES; Volume: 61; Pages: 74-85; Published: NOV 2013

Abstract-Seasonal fluctuations in energy production and storage can be sorted using underground hydrogen energy storage. The model pertains to a process of conversion of hydrogen gas to methane, diffused into microbial thin films of multiple species  and their consumption.A simulation has been performed showing the growth process of these bio films.

  • Hydrogen underground storage in Romania, potential directions of development, stakeholders and general aspects

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; Volume: 39; Issue: 21; Pages: 11071-11081; Published: JUL 15 2014 

Abstract-This paper shows a case study of Hydrogen Underground storage in Romania and the potential for sustainability in terms of lasting energy consumption. The situation in Romania report to potential use in chemical industry,transport sector and salt industry. More study is to be done in order to enhance the storage and usage options of underground hydrogen energy storage.


INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; Volume: 4; Issue: 6; Pages: 559-569; Published: 1979

Abstract-This paper describes about the various aspects of underground storage, its merits and demerits over each other and the choice of selection based on the geography and type of storage.

  • Re-envisioning the role of hydrogen in a sustainable energy economy 

John Andrews, Bahman Shabani

Abstract-This paper’s concept of convergence is towards the sustainability and suitability of Hydrogen as an energy storage option pertaining to renewable energy resources’ intermittent tendency.

  • Overview of current development in electrical energy storage technologies and the application potential in power system operation

Xing Luo, Jihong Wang, Mark Dooner, Jonathan Clarke

Abstract-This is a paper that over views on the many available types of energy storage and the state of art in electric energy storage(EES). A compilation of the reviewed technologies’ merits and demerits are listed henceforth.



  • The survey of key technologies in hydrogen energy storage

Zhang, Fan ; Zhao, PC (Zhao, Pengcheng; Niu, Meng; Maddy, Jon

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; Volume: 41; Issue: 33; Pages: 14535-14552; Published: SEP 7 2016

Abstract-The paper provides an overview on the key elements involved in  hydrogen energy storage system, from hydrogen production by fossil fuels to electricity generated from renewable power sources and hydrogen storage in both pressurized gas, liquefied and material-based methods, as well as associated electricity generation technologies using hydrogen. The emphasis on Hydrogen as a mode of energy storage has been clearly established in this paper. 

  • Technical and economic assessment of methods for the storage of large quantities of hydrogen

J.B.Taylor, J.E.A. Alderson, K.M. Kalyanam, A.B.Lyle, L.A.Phillips

International Journal of Hydrogen Energy (ISSN 0360-3199); vol. 11, no. 1, 1986, p. 5-22.

Abstract-Storage of hydrogen can be generally done above or below the ground level. The storage of hydrogen in the underground involves storing them as cryogenic liquids or high pressured storage. This involves naturally and artificially created cavities. Cost effectiveness of each scenario is described and not compared with one another. To increase the flexibility of the storage and to add economic aspect to the large storage, cost of storage can be added between 30-300% of cost of  Hydrogen.  The result involves considering many factors in mind while oping for Hydrogen energy storage.

  • Storage of hydrogenous gas mixture in geological formations: Self-organisation in presence of chemotaxis

Toleukhanov, A; Panfilov, M ; Kaltayev, A

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; Volume: 40; Issue: 46; Pages: 15952-15962

Abstract-The Hydrogen storage is still under study even in the 21st century despite its very high potential to store energy in chemical form. This is due to the potential reactions that could occur inside the storage.

This paper addresses the concept of reaction of hydrogen and carbon-di-oxide to form methane due to microbial reactions. It considers qualitative theories for the same and more complex cases and provides the solution for two phase flow in a porous medium and bacterial movement.

To find a purple unicorn, first find how to find unicorns.

In researching how storage and solar power can be cost effective in low-income and affordable multifamily (MF) housing, I found little literature and no scholarly literature on that specific subject. I started in google, which resulted in some good industry papers on the topic. These sources, while informative, may not be useful due to their lack of peer review and references. Using Google Scholar and Web of Science both resulted in no articles on the full topic search. But a search for parts of of my subject, for example renewable energy(RE) in MF housing and even RE in low income MF, eliminating “storage” resulted in more results. That is, broadening my search by eliminating “storage” resulted in more results, from which I was able to find a few articles to start. I eventually found materials on PV and storage by eliminating “low-income” and will have research PV/storage issues separate from low income issues and work them together in my paper.

I think the most important advice for future searches would be to use the “review” search to find articles on the topic, or sub-topic if there is nothing on the entire topic, and then search the articles referenced in the review articles.

One article that touched on multiple areas in my topic was, “Clean energy utility for multifamily housing in a deregulated energy market”1 This is a computer modeling of a MF housing building in Dayton, OH that looks at Energy Efficiency and Renewable Energy (EERE.) While not focused on low income, the article does address the split incentive barrier of MF vs. resident-owned facilities. The article also investigates battery storage and finds that storage has the potential further savings by reducing demand charges.

The previous article cites an article by CNT-Energy that investigates the effective use of utility programs to fund EE measures in MF buildings. (Full disclosure, CNT-Energy became Elevate Energy, my current employer.)2 This article will be instrumental in looking at the mechanisms of funding RE and battery storage in the same manner of previous EE programs. In Illinois, the utilities have an interest in funding RE and potentially battery storage for grid reliability and capacity deferrals. And starting in 2018, with the implementation of the Future Energy Jobs Act (FEJA) this will be required by law. It does not appear Refworks was able to automatically format the reference for a bill/act properly for Nature, final citation in the proper format for paper will have to edited manually.

While not an article, one of the sources necessary when investigating RE in IL will be FEJA3 This legislation lays out requirements of the EERE programs that will be implemented by the utilities. Central to my paper will be the sections on community solar and Distributed Generation (DG) and incentives for low-income households therein.

Removing the search requirement for low-income and MF yielded a wider selection. One review article, “Stationary battery technologies in the US: Development Trends and prospects.”4 This article looks at the technologies and the uses. This will be used to understand the methods of using storage for economic benefit, such as arbitrage, demand reduction, capacity reduction and frequency regulation. It also will have resources for looking at case studies as to the viability in international and US markets. While not specifically MF, it will help to understand the markets and mechanisms and barriers as they apply to MF.

The previous article lead to one specific article on arbitrage5 and a second on arbitrage specifically in PJM territory.6 Both of these article will aid in determining how this method of generating income could be used and determining the value of arbitrage. Articles on frequency regulation(FR) from RE and storage will help with determine the economic value of FR and the costs, i.e. FR precludes full use of the batteries for arbitrage or resilience.7

As is the case in many aspects of solar energy, countries such as China, Japan and Germany have more research and applications of storage. A study in Germany determined incentives for storage will be needed in the short run.8 This study will be helpful for determine costs for PV and storage, albeit in China. Translation to US markets will be necessary.9 And lastly, an article looking at the importance of storage with solar on residential markets.10




  1. Raziei, A., Hallinan, K. P. & Brecha, R. J. Clean energy utility for multifamily housing in a deregulated energy market. Energy and Buildings 127, 806-817 (2016).
  2. McKibbin, A., Evans, A., Nadel, S., Mackres, E. Engaging as Partners in Energy Efficiency: Multifamily Housing and Utilities. ACEEE A122 (2012).
  3. 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. (2016).
  4. Telaretti, E. & Dusonchet, L. Stationary battery technologies in the U.S.: Development Trends and prospects. Renewable and Sustainable Energy Reviews 75, 380-392 (2017).
  5. Bradbury, K., Pratson, L. & Patiño-Echeverri, D. Economic viability of energy storage systems based on price arbitrage potential in real-time U.S. electricity markets. Applied Energy 114, 512-519 (2014).
  6. Sioshansi, R., Denholm, P., Jenkin, T. & Weiss, J. Estimating the value of electricity storage in PJM: Arbitrage and some welfare effects. Energy Economics 31, 269-277 (2009).
  7. Dreidy, M., Mokhlis, H. & Mekhilef, S. Inertia response and frequency control techniques for renewable energy sources: A review. Renewable and Sustainable Energy Reviews 69, 144-155 (2017).
  8. Hoppmann, J., Volland, J., Schmidt, T. S. & Hoffmann, V. H. The economic viability of battery storage for residential solar photovoltaic systems – A review and a simulation model. Renewable and Sustainable Energy Reviews 39, 1101-1118 (2014).
  9. Lai, C. S. & McCulloch, M. D. Levelized cost of electricity for solar photovoltaic and electrical energy storage. Applied Energy 190, 191-203 (2017).
  10. Agnew, S. & Dargusch, P. Effect of residential solar and storage on centralized electricity supply systems. Nature Climate Change 5, 315-318 (2015).

Ideas for energy storage


  1. Hydrogen/Bromine regenerative electrochemical cell.


This cell is good in storage applications where there is a lot of peak shaving, load management and other distributing utility applications. The energy is stored by consuming electricity in electrolyzing hydrogen bromide into hydrogen and bromide reactants as stored chemical energy. The cell is regenerative, later on the hydrogen and bromide react with each other to produce electrical energy. This cell operates as a battery, exchanging electrical and chemical energy with the exception of storage. The reactants are stored outside the cell, whereas in battery the reactants are stored inside the cell. Therefore, to increase capacity (kWh) it’s necessary to increase the number of reactants instead of batteries.

Off-peak periods are longer than On-peak periods. Electricity is inexpensive during off-peak periods and is generated more, during on-peak periods the generation capacity is at maximum and electricity is expensive. The difference between the lengths of periods gives the chance to produce more hydrogen than required for its fuel cell (on-peak discharging) mode providing excess or supplemental hydrogen bromide electrolyte is available during the electrolysis mode (off-peak charging).

Page 2 from https://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/30535ag.pdf

  1. Ultra-battery

Ultra-Battery combines ultra-capacitor technology (stores energy in electric field instead of a chemical reaction, storing much more charge and discharge cycles than batteries) with lead-acid battery technology in a single cell with a common electrolyte. Ultra-Battery has a single positive electrode and two negative electrodes – a carbon, another lead, in a common electrolyte. Together these make up the negative electrode of the Ultra-Battery unit, but specifically the carbon is the electrode of the capacitor and lead is the electrode of the lead-acid cell. The single positive electrode (lead oxide) is typical of all lead acid batteries and is common to the lead acid cell and the ultra-capacitor. This technology gives a different performance characteristics to conventional VRLA batteries.  Ultra-Battery technology suffers significantly less from the development of permanent sulfation on the negative battery electrode – a problem common in conventional lead acid batteries, hence is much better in terms of energy storage.


  1. Molten Salt storage

Abundance of sea water and sun light makes this type of energy storage easier to handle and use. The heat collected by concentrated solar energy. The heat later is converted to superheat steam to power conventional steam turbines and generate electricity in abnormal times. Salt melts at 268 Fahrenheit, then it’s kept liquid at 550 Fahrenheit and stored in insulated cold storage tanks. Then the liquid is pumped to solar collector through panels during which its heated to 1051 Fahrenheit. Then it’s sent to hot storage tank, and when electricity is needed hot salt is pumped to steam generator to produce superheated steam.