Monday, May 18, 2015

100% Renewable Energy by a Global Wireless Power Transmission System

Last Tuesday 21st April, the Japanish Magnetic Levitation train, normally called Maglev, broke its own speed record after reaching 603 km/h (375mph). The record was made in a test section of 42 km (26 miles) in Yamanashi, in west Tokio.
The magnetic levitation technology works by linear motors close to the railway to elevate the train 10 cm over the railway, making it levitate and drive forward, out of any contact, just the air.


Figure 1_Picture of Levitation Magnetic Train in Japan_souce: Wikipedia: File:JR-Maglev-MLX01-2.jpg.

Accordingly with last paragraph, it is mandatory to introduce other technologies more in relation to the topic of this blog, and in this case, Wireless Power transfer (WPT) or wireless energy transmission.
In this wireless technology, the relevant subject is the transmission of electrical power from a point A, to a point B. Where point A is the power source, and B, is the reception of this power, of course, without using wires or conductors in its different technologies, using time-varying electromagnetics fields.


Figure 2_Depicted Generic block diagram of a wireless power system_source: Wikipedia_Wireless Power.

For getting in more detail of the technology exposed, it is necessary to introduce the two main categories of Wireless power techniques, non-radioactive and radioactive.

In non-radioactive techniques, the power is transferred over short distances by magnetic fields, using inductive coupling between coils of wire, or by electric fields between two electrodes, using capacitive coupling.
Nowadays, it is possible to find some applications for wireless power technologies such as; electric toothbrush chargers, RFID tags, smart cards, artificial cardiac pacemakers, and inductive Electric Vehicles (EV) chargers, being two possibilities; static or in motion.

In radiative or far-field techniques, also called power beaming, the power is transmitted by beams of electromagnetic radiation; like microwaves or laser beams, those techniques can transport energy in longer distances, but must be aimed at the receiver.
Proposed applications for this type of technology are wireless powered drone aircraft and solar power satellites. 
It is important to mention that the issue associated with all wireless power systems is the limitation in the exposure of people and other living things to potentially injurious electromagnetics fields.





Figure 3_To Left: Structure of Magentron. Right: Mica Waveguide Cover for a Microwave oven (MW). In MW, the cooking chamber has a hole for the passage of microwaves, generated by a specialized vacuum tube. The mica waveguide cover it allows microwaves to reach food, and at the same time, preventing foods and moisture to impact on the electronics components of the oven. MW basically is made by; 1) the shell and the cooking chamber, which provides the structure of the appliance and the protection for keeping the microwaves inside the appliance, 2) the magnetron, a specialized vacuum tube, and a high-voltage transformer, originally used in military radar applications. 
The MW heats and cooks the food by electromagnetic radiation (microwaves). The molecules of the water, includes in food, are moving by the pole of the waves, the positive and the negative periodically. In this movement of the shift from positive to negative, it creates a friction, the reason for heating. Understanding this shift at a frequency of 4.5 MHz., the friction is heating the water of the food_source: Structure of Microwave / Mica Waveguide Cover for a Microwave.



Notwithstanding wireless power techniques are being developed in different topics, hereby; it is mandatory to talk about this topic in relation to Renewable Energies and Smart Grids.
Space-based Solar Power (SBSP) is in research since the early 1970s. It is the concept of collecting solar power in space, by a Solar-Power Stallite (SPS), or also called Satellite Power System.
SBSP would differ from current solar collection methods for having energy collectors on an orbiting satellite instead of the Earth's surface.

This technology, which converts solar energy into electrical energy by powering a microwave transmitter or laser emitter (this last technology under reviewing by the losses in meteorological conditions - e.g.: clouds), is based in three basic elements. 
In first term, the solar collector in space, secondly, the transmission system from the collectors to earth, using mostly microwave transmission, and the receiver power on earth, mainly by microwave rectenna, because with the conventional microwave antenna, the reception efficiency is better, but it cost and complexities are greater.

The benefit of this technology is a higher and longer collection rate in front of night time and atmosphere conditions, for having more intense sunlight and avoiding the lack of obstructions such as atmospheric gasses, clouds, dust and other weather events, and being the satellite illuminated already 99% of the time.
In terms of power transmission, is possible to redirect the transmission directly to areas where is more needed on demand to different surface locations based on geographical base load or peak loads of power in a determined necessity.

Unfortunately, the effects of reflection and absorption, and the downtime (for fixed flat-plate collectors) are losing around 55-60% of the yield.
The main issue of this technology is the micrometeoroid damage and the radiation. In case of radiation for its intensity in and outside the receiver, being over 95% of the beam energy will fall on the rectenna. The remaining microwave energy will be absorbed and dispersed; so nearby towns or other human activity should be completely unaffected.

In addition, a design constraint is that the microwave beam must not be so intense to injure wildlife, in particular, birds, in case of rectennas in offshore emplacements; it presents serious problems for biological contamination, a part of corrosions and mechanical stress.  

Besides, it is necessary to consider, the large cost of launching a satellite into space, the hostile of the space environments and the high cost of the assets in this environment. 
The panels suffer eight times more degradation than in Earth environments, and considering the density of the air in the capacity of the electric fields, which is increasing, but at contrary, the lower density of the air decreasing the performance of the cooling systems, with great relevance for Photovoltaic cells.  
Furthermore, the necessity to develop telerobotics systems for the maintenance.

Notwithstanding having practical examples or the microwave power transmission, it is possible to mention, a project in Hawai, with NSS Space Solar Power. Nevertheless, the most-recent publication from IEEE, exposes a test in Japan for the Wireless Power Transmission for Space-Based Solar Farms from Japanish Aerospace Exploration Agency (Jaxa) and Mitsubishi. 


Figure 4_Picture for a Space-Based Solar Farms_source: Inhabitat webside.


Making a reflexion of this Renewable Energy cutting-edge technology and with the information exposed, is easy to think about the possibilities in terms of applications, not only for the exposed herein, for solar power energy production. 
Otherwise, it is necessary to think about the possibilities of this technology for applications in the transmission of the electricity, for providing a worldwide 100% Renewable Energy model using the resources in the most optimum emplacement, with no limitation of distance.

First example proposed, is the application for isolated electric systems, cases of Japan or New Zealand, not supported by continental grids like UK in Europe.

New Zealand is an isolated system for geographic reasons. The electric system has a high production mix of hydropower, being located in the sud of the southern island, with high level of Wind Energy Power, with high intermittency. 

It is for that, New Zealand TSO (Transpower) has the necessity to transmit (HVDC line) the power generated by hydropower in the south of the southern island, to the main consumption centers in the big cities, mostly in remote regions from south. 

The power wireless technology has the possibility to support in future a great solution for New Zealand, in spite of to collaborate with Australia in a common TSO system with wireless power technologies.
By this way, this common TSO by the mentioned wireless technology will manage the transmission of electricity in both countries in case of emergency, or even for mixing the production of Solar Power generated in Australia, or a collective investment of Wind Offshore farms based in floating systems mixed by tidal or marine energy and supported by energy storage systems.

Based on this principle, is possible to think in creating a universal TSO with this technology, to manage the worlwide electric generation by renewable energies.
In concrete by Wind Offshore, marine or tidal energy in international waters or with Concentrated Power Solar or Photovoltaic in Sahara, helping with the investments to develop the local area and minimize migrations or wars, or radical groups, and supplying the world by 100% renewable energies with a global investment and management.

Consequently, it is possible to think a global TSO system with a grid of satellites which will be able to support countries or areas in an emergency situation. With the creation of a grid of satellites to transmit the electricity from the generation points to other places, which are not capable to support the electric system operation.
Related to this, for example, with the case of Nepal in the last weeks, it is possible to think in an installation of microwave rectennas to restore, as soon as possible, the electricity, connecting to the existing grid after inspection of the infrastructure.



Figure 5_Picture of Ocean Wind Power_source: NASA




Figure 6_In left: Picture of the Environmental disaster in Gulf of Mexico_source: BBC. In right: map of main migrations from Africa to Europe_source: The Telegraph


An exemple given in this willigness to changes its Energy Policy in relation with the possibilities of Solar Energy in Sahara, is Egypt, with solar and wind energy deals (even with a rotor blade factory). Other example is in Ghana with a desalination plant. All this projects can help the development of regions in Africa.





Figure 7_Nikola Tesla was the first discovered for resonant coupling during his pioneering experiments in wireless power transfer_source: wikipedia_Nikola Tesla


Bibliography:


Related Blogs: SuperGrids - Future of the Electric Systems, Renewable Energy Investments - CSP, Energy Storage, Synchrotron Alba



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