Monday, 8 June 2015

The Energy Internet – A Sustainable Decentralised Energy Infrastructure

Most of the human race is familiar with the first Internet, the communication Internet, which is now ¼ of a century old and has roughly 3 billion users. This internet still is by no means universal and that just shows that we have only struck the tip of the iceberg in its scope not only in information and entertainment but in development, production and industry.

Sharing renewable energy laterally, in power, communications and transport networks that stretch across continents, like how we now share information virtually in networks across the internet, is going to radically transform the world both economically and politically. Just as the first industrial revolution followed the print revolution, the global information revolution could be the forerunner to a new industrial revolution at which access of clean renewable energy will be one of the main outcomes.

In particular, the creation of an energy internet spanning a particular continent, Europe or Asia say, could allow hundreds of millions of people to produce their own green electricity and share surpluses with one another across that continent. At the very least it is conceivable that continental smart-grids could be set up with a feed-in tariff that gives users a premium for sending their electricity back to the grid, where they get will more than the market price, hence giving incentive to set up solar panels, micro wind turbines on the rooves of their homes.

This apart, the groundwork for a green future has already started. Asia has immense potential in terms of renewable energy as both India and China are abundant in natural resources and will have much more incentive to develop new energy infrastructures due to the sheer size of the populations with a huge growth in the Asian middle class which will create the need for a completely non-classical energy distribution system.

We are also seeing a move towards renewable energy across Europe and the United States, where millions of buildings, homes, offices, factories, retail stores that have been transformed into micro power plants and they are producing their own green electricity on site, solar panels on the roof, vertical wind on the property, geothermal pumps for energy underneath the ground, bio converters to convert garbage to biomass energy in the kitchens, etc.

The two major power generating technologies that are going to be at the core of the energy internet are essentially photovoltaic solar power and small to medium scale wind turbines with everything else being secondary to these two sources due to their abundance, technical simplicity of converting them to usable energy and the ease at which they can be installed with ubiquity in rural communities, suburban homes, city buildings, parking lots and places of commerce transforming virtually anywhere that there is human activity in a place where the energy needed to do that activity is available.

Photovoltaic Solar

Solar energy is obtained by capturing the heat and the light emitted by the sun in the form of electromagnetic radiation. Thanks to its characteristics, solar energy generation is clean and continuous. Sunlight is the most abundant source of potential energy on the planet. If harnessed properly, sunlight could easily exceed current and future electricity demand. According to the U.S. Department of Energy, every hour, enough energy from the sun reaches Earth to meet the world's energy usage for an entire year.

It is important to note that the power of these solar radiation and its use for power generation vary according to time of day, atmospheric conditions and geographic location.
The modules fully harness the energy of solar radiation They are known as solar panels. This concept includes both solar collectors (that capture the energy of the radiation and convert it into thermal energy) and photovoltaic panels (composed of numerous cells that convert light into electricity).

It is considered the physical Alexadre-Edmond Becquerel as one of the first to recognize the photovoltaic effect in 1839, since the study photovoltaics, optics and electricity generating significant scientific contributions.

The first solar cell designed and built in the 1883 by Charles Fritts with an efficiency of 1%, which is used as a semiconductor selenium with a thin layer of gold. The predecessor of the solar cells used today is created and patented by Russell Ohl in 1946 and also used as a semiconductor silicon.The cells of most modern and similar to the current silicon developed in 1954 in the Bell Labs.

These technological advances enabled that appear on the market the first commercial solar cell with 6% in 1957. The efficiency which began to be used in space satellites in both the Soviet Union and the US, with efficiency increasing the operational capacity of the electronics and mechanics of spacecraft, allowing them to increase in size and operational distance from the sun, with current solar-powered spacecraft now being efficient enough to function as distant as Jupiter, as the Juno spacecraft is designed to function on solar power. Solar energy is still used to power the International Space Station and the vast majority of satellites.

On Earth, photovoltaic panels have also proven useful for providing electricity to remote locations that are not supplied by a local electric utility. Photovoltaic power uses solar cells that convert the energy of sunlight directly into electricity through the photovoltaic effect.

The photovoltaic effect is a process by which light from the sun hits a solar cell and is absorbed by a semiconducting material such as crystalline silicon. The photons in the sunlight knock electrons loose from their atoms, allowing them to flow freely through the material to produce direct electric current (DC) electricity. For household or utility use, an inverter must be used to convert the electricity to alternating current (AC).

The individual solar cells are arranged onto a solar panel. The solar panel is coated in glass or another laminate to protect the cells from damage. New technology using amorphous silicon or CIGS allows solar panels to be placed on a thin strip of backing, usually aluminum, and covered with a plastic film, which decreases the weight and cost of a solar panel and moreover can make them foldible allowing for an increased ease of transport and installation of solar technology. These thin-film solar panels are becoming more common, although traditional glass- or laminate-coated panels continue to make up the majority of the solar panel market.

Usually, several panels are arranged into an array, which can be scaled to produce enough capacity to generate the desired amount of power. A single cell can produce enough electricity to power a small device, such as an emergency telephone, but larger arrays are required to power a house or building. Utility-scale photovoltaic plants consisting of thousands of solar panels are a more recent occurrence.

It is important to highlight the fact that in recent years the use of such devices to capture energy from the sun, has experienced significant growth. Many homes already have implanted plates and similar products with the clear aim of being able to use the sun's radiation to illuminate them and to use the equipment they need to operate energy. Thus, ostensibly it reduces electric power consumption which means reducing financial costs and reduce pollution. Moreover, the reduction in costs of buying solar power installation and the reduction in the size and complexity of the equipment itself has made it more easier than ever to turn any building with a roof into a private solar power plant.

Solar powered lighting in sheds is a very practical project and a great start in building a decentralized energy outlet. The idea of decentralized energy infrastructure in general changes very little from the design below. The solar cells are themselves regulated in voltage and current by a charge controller system. This system then charges the battery bank using direct current (DC), which can be of almost any variety (Gel, Lead-Acid, Lithium ion, etc). This is then converted to alternating current (AC) using an inverted. The AC is then able to be used in outlets such as wall sockets and lighting, just as you would power things on the grid.

Different parts of the world, due to their distance from the equator, distance from the oceans and their climate in general will obviously affect the efficiency of acquiring energy from the sun. While no model can fully replace actual measurements to fully assess the potential of a site, solar irradiance maps can provide a first insight. The following map show the average annual energy values on fixed, due-south facing surfaces that are optimally inclined.

In addition, system designers and project developers should take into account effects of intermittency and annual variations, in other words the average time between periods of direct sunshine and diffuse sunshine during the days of each season.

From this map we can see that areas with a high proportion of diffuse light include Northern Europe, South-East China and the tropical belt around the equator where cloud cover is high.

In spite of the unfair global distribution of direct sunlight, most of the PV solar capacity is not necessarily in the sunniest places on earth. Germany has proven that you do not necessarily need to be in a very sunny country to have the incentive to invest and install solar panels to produce electricity for homes and business and owns almost 1/3 of the world's PV solar capacity despite it having only average direct sunshine levels.

Italy has half of Germany's PV capacity, giving it 1/6 of global PV, Spain has 1/12 of the world's PV capacity and the rest of Europe has roughly another 1/6 of the world's PV capacity giving Europe as a whole over 2/3 of the world's total PV capacity. The entire US, in contrast has less than half of Italy's PV capacity even though it receives far more power per unit area than the whole of Europe. Australia, given its high levels of sunshine is relatively deficient in solar energy, having half the PV capacity of Spain and compares with  only should .

Given its location and climate, if any nation should be using solar energy, its Australia. However, like the USA, it chooses to act in the opposite extreme and is, of the OECD countries, often the most reliant on fossil fuels. Australia used to have greater share in the PV market, at up to 7% before 1992, quite good given the price of photovoltaics back then, but since 1992 their share has plummeted while the price of solar also plummeted which does not make sense other than assuming that Australia has decided at government level to abandon development of sustainable energy. In comparison, Germany has clearly decided to move towards sustainable energy which is the main crux of the argument that a renewable energy infrastructure will not happen unless their is the will to do so, regardless of the availability of energy in the surrounding environment.

  • In some countries, like Germany, solar energy playing a major role; in the late 80s and early 90s it was launched several plans for the construction of solar power plants and solar roofs.In addition, the German government has encouraged the implementation of this type of energy.
  • Rajasthan (India), solar cookers have been built, with the capacity to feed 1,000 people a day. The world's largest solar cooker can serve 33,800 meals a day.
  • Cyprus is the country that more solar energy produced per head, and over 90% of its buildings contain solar thermal collectors.
  • Greece is capable of supplying about one in four people with solar energy and solar energy facilities account for over 20% of all Europeans.
  • In Israel, a law introduced 20 years ago, it requires that buildings are equipped with solar collectors, which means that 85% of households have solar energy.
  • The world's largest solar plant has been installed in India.

Wind Turbine Energy

Wind energy is one that is obtained from wind, ie the kinetic energy generated by the effect of drafts and likewise by vibration air produces.
The main vehicle for this energy are the wind turbines, large mills between 40 and 50 meters and blades up to 23 meters in diameter, which with its blades that transform kinetic energy into mechanical energy.
Wind turbines can be installed both on solid ground (onshore) and on the ocean floor (offshore ).

The earliest use of wind was as a means of transport as evidenced by Egyptian drawings, going back 5000 years, showing ships with sails used to travel along the Nile.It was also common in ancient times to use wind-powered mills to grind grain or as a means to pump water.

Milestones in the history of wind energy:

  • In 1854 Halladay introduces a cheap, light wind mill
  • Charles Francis Brush built in 1888, which is believed, the first wind turbine to generate electricity, which was improved in subsequent years.
  • The first windmill large for electricity generation, was built in Vermont in 1945, the Smith-Putnam turbine.
  • In 2005 first generation of wind turbines that produce more than 5 MW are developed 

The visible parts of a wind turbine is the nacelle (enclosure protects its internal mechanism) and the rotor blades (which may up to 20 meters long) plus long pole holding the turbine. But there are of course several elements within that in fact generates the power which cannot be seen without taking the turbine apart such as the rotor, gearbox, generator, tower and control system.

Conventional small wind turbines, rated at less than or equal to 10 kilowatts, utilize a propeller or rotor mounted on a horizontal shaft to drive an alternator or generator.  Newer vertical axis turbines are starting to appear on the market.  They capture the wind's energy by rotating a series of swiveling airfoils around a vertical shaft to generate power.

Let's begin by examining the components of a horizontal axis wind turbine:

Horizontal wind turbines use a direct drive shaft to connect the rotor to the magnets rotating in the alternator section.  Power in these turbines is generated with relatively high RPM and low torque as opposed to hydro turbines that have low RPM and high torque.  The direct drive connection is the simplest and most efficient.  Avoiding gears, belts and pulleys reduces energy loss and maintenance.

The nose cone streamlines the main housing and protects the alternator section which contains permanent magnets that rotate in close proximity to stationary coils.  This rotation generates alternating current (AC) within the coils.   Due to the constant variation in wind speed this alternating current is sporadic and unsuitable for powering appliances in its raw form.

To overcome this condition, the unstable AC is converted to direct current (DC) using a rectifier. The rectifier may reside inside the turbine housing or be located in a control panel at the base of the tower.  When converted to DC, power can be used to charge batteries directly or it can be inverted back to a stable AC by using an inverter if adequate power is available.

Regardless of where the rectifier is located, the energy must be carried from the rotating platform to a stationary tower.  This transfer occurs through a set of brushes and slip rings located next to the yaw bearing.  The yaw bearing allows the wind turbine to rotate freely so it can weather vane into the wind.  Electrical brushes track along their designated paths on the slip ring transferring current from the rotating housing to the fixed stub mast.

Small wind turbines normally work best in wind speeds of up to 25 MPH.   Winds above this level can over speed or burn out the turbine if speed controls are not used.  One way to control turbine speed is to feather the rotor blades to a point of near stalling to slow them down.

A simpler, more common method is to furl the tail vane.  As wind speed nears maximum, the tail vane rotates off centerline pointing the rotor into the wind at an angle. Rotor speed decreases when the turbine is not pointed directly into the wind.

Efficient power generation from the wind obviously requires high wind speed. There are four main factors that affect wind speed. The first is pressure gradient which is generated by differences in atmospheric pressure between two adjacent areas. The second is frictional force which is increased by features on the earth's surface such as trees and mountains. The third factor is the Coriolis Effect which deflects the direction of wind flow on the earth's surface. Finally, elevation plays a major role in wind speed as there are fewer obstacles at higher elevation to block wind creating higher wind speed.

These factors make certain sites particularly well suited for areas to locate as suitable to use wind turbines. Some of the best sites for wind turbines are in coastal regions, due to the lack of obstacles which reduce wind speed and the larger area for which to sweep turbine blades. Wide open plains are also god for the same reason however setting up in remote areas is costly and requires centralized and expensive energy transmission infrastructure.

The suitability of a site can be determined by measuring the Annual Mean Wind Speed (AMWS). From this number can be derived the expected capacity factor at a given site over the year and therefore how much power can be expected.

Due to the close proximity to the continental shelf and the open ocean, coastal and island nations such as Ireland, the United Kingdom, Japan, New Zealand as well as Denmark, Norway and Chile have the highest potential to generate energy from small scale, easy to transport and install wind turbine technology. Denmark already leads the world in reliance upon wind power, producing 20% of its electricity from wind turbines.

In practice only the most efficient wind turbines, which are just entering the market today, can reach capacity factors above 40%. Wind developers will ideally aim to develop sites with capacity factors above 35%, meaning sites with winds upwards of 5 m/s and to a maximum of 25 m/s. 11 This may sound low, but all forms of power generation waste most of the energy produced. Coal power plant efficiency is generally around 35-40% and the average solar power cell efficiency is 5-15%.

This chart compares the quality of sites for wind turbines and what the expected capacity factor will be depending upon the wind speed:

Another thing to consider when sizing a wind generation project is the sweep area of the rotor as this determines the amount of power that can be expected from the unit.  Power is directly proportional to the to the sweep area of the rotor which is simply the disk area in which the rotor blades spin. In simple terms, the larger the area the turbine blades sweep, the greater the power produced.

Wind Turbine Rotor Sweep Area Since sweep area increases at the square of the diameter we find the amount of power produced does likewise.  In other words, if you double the diameter of the rotor, sweep area quadruples and so does the power, theoretically.  Other factors such as rotor mass, type of bearings, blade aerodynamics and alternator or generator efficiency can have an affect on power output when scaling up a design.

The height and strength of the supporting tower is also affected by sweep area.  Increasing this area means the tower must be built to sustain higher wind loads and swing longer turbine blades.

More durable technology such as carbon-nanotubes embedded in polyurethane may allow for thin, light but incredibly strong wind turbine blades that could allow for a larger scale at which wind turbines can be built without being too heavy to transform the nebulous wind energy into usable power. The same technological developments will allow for more compact, lightweight and damage-resistant small scale wind turbines that will produce power in a decentralized infrastructure.

Additional height may be needed to keep the full sweep area in unobstructed wind flow, especially in wooded locations. this is the main reason why the most efficient location for large scale wind farms is in seas and oceans near the coasts of continents.

Today many countries have wind power as a source of primary energy in full development. The countries that stand out as world powers in wind energy are:

  • Wind power installations in all the member countries of the IEA ranks with the top 5 being: China (62 364), USA (46,916) and Germany (29 075), Spain (19,606) and India (22,465).
  • Spain covers its national demand for electricity from wind power by 16.6%, while China only makes 1.6%, US 2.9% and Germany 7.6%.
  • The number of installed power by all global producers of wind power reaches 238 038 MW. 
  • From 2011, the global increase in wind power was 24%.The most pronounced growth of all countries was the Chinese, with 39% increase in growth.
  • The estimated number of jobs in the wind energy sector in China is 260,000, 101,100 in Germany and 75,000 in the United States.
  • The economic impact of wind energy is 14.4 billion in the US and 8.9 billion in Germany.

Energy Storage

Current technologies, such as solar photovoltaics and wind turbines, can generate energy in a sustainable and environmentally friendly manner; yet their intermittent nature still prevents them from becoming a primary energy carrier. Energy storage technologies have the potential to offset the intermittency problem of renewable energy sources by storing the generated intermittent energy and then making it accessible upon demand. In addition to energy grid applications, energy storage technologies also have the potential to transform the transportation system. Functioning energy storage devices could replace the powertrain systems of current transportation technologies from a chemical fuel-based powertrain into an electricity-based powertrain. The electric car is a prime example of how energy storage technologies can transform the transportation system into a more sustainable model. Electronic devices, which have become ubiquitous in modern society, are also heavily reliant on energy storage technologies. The breadth of products and industries which energy storage affects shows how valuable advances and breakthroughs in this field will be in the future.

Currently, the dominating energy storage device remains the battery, particularly the lithium-ion battery. Lithium-ion batteries power nearly every portable electronic device, as well as almost every electric car, including the Tesla Model S and the Chevy Volt. Batteries store energy electrochemically, where chemical reactions release electrical carriers that can be extracted into a circuit. This can be illustrated with the example of the lithium ion battery: 

During discharge, the energy-containing lithium ion travels from the high-energy anode material through a separator, to the low-energy cathode material. The movement of the lithium releases energy, which is extracted into an external circuit. When the battery is charged, energy is used to move the lithium ion back to the high-energy anode compound.

The charge and discharge process in batteries is a slow process and can degrade the chemical compounds inside the battery over time. As a result, batteries have a low power density and lose their ability to retain energy throughout their lifetime due to material damage.

An increasingly popular energy storage reservoir for energy-harvesting applications is the supercapacitor or ultracapacitor. The supercapacitor uses a different storage mechanism to batteries. In the supercapacitor, energy is stored electrostatically  on the surface of the material, and does not involve chemical reactions. These electrochemical capacitors have a relatively large volumetric energy density when compared with traditional ceramic, electrolytic, or tantalum capacitors, as shown in the figure below. Supercapacitors tolerate hundreds, thousands, and even millions of charge-discharge cycles, which is two to three orders of magnitude greater than is possible with rechargeable batteries. Supercapacitors can also be charged/discharged very quickly. While their volumetric energy density is a couple of orders of magnitude less than typical primary lithium cells, when combined with an energy harvester, such as a solar cell, they never need replacement. Additionally, they don't contain toxic chemicals.

The main shortcoming of supercapacitors is their low energy density, meaning that the amount of energy supercapacitors can store per unit weight is very small, particularly when compared to batteries. Additionally, the cost of supercapacitor materials often exceeds the cost of battery materials due to the increased difficulty in creating high-performing supercapacitor materials, such as graphene. However, recent advances in creating new supercapacitor materials and improving material production methods may soon bridge the energy density gap for some commercial applications.

The proper selection and sizing of a supercapacitor for a given application is essential. Their performance is affected by time, temperature, voltage, and charge cycling. Consequently, a capacitor whose initial capacitance and equivalent series resistance (ESR) barely meet the requirements of the application is not recommended. ESR is the quantifiable resistance of all the parts that are used to describe the impedance of electrical components. Because capacitance and ESR degrade as time progresses, designers should determine the minimum voltage and energy requirements of the application and then de-rate the initial capacitance of the supercapacitor.

The two technologies in this energy storage war, the battery and supercapacitor, remind me of the turtle and the hare from the famous fable. The battery represents the turtle as a slow and steady energy supplier for large energy demands, and the supercapacitor represents the hare that charge and discharge quickly for low energy demands. Yet, instead of viewing them as competing technologies, it may be more useful to view them as complementing technologies.

A hybrid system of supercapacitors for quick energy harvesting and high current volume batteries for long term energy storage may be the key to developing an efficient charging and discharging decentralized power system. 

At present, deep-cycle batteries offer the simplest, in terms of installation and maintenance, and incidentally the most renewable way to store electricity. Lead-acid batteries, which can be a source of very dangerous contamination and pollution if recycling is not done with care for both humans and the environment, are nevertheless an incredibly renewable source of power storage in terms of recycling, with Lead–acid battery recycling is one of the most successful recycling programs in the world. In the United States, The National Recycling Rate Study, commissioned by Battery Council International, concluded that 99% of all battery lead was recycled between 2009 and 2013 meaning that production of the components used to make the batteries can be dropped almost to 0. An effective pollution control system is a necessity to prevent lead emission. Continuous improvement in battery recycling plants and furnace designs is required to keep pace with emission standards for lead smelters.

A typical 12 volt lead acid battery is actually made up of six identical 2 volt cells. Each cell contains lead plates of different compositions sitting in dilute sulphuric acid. Lead dioxide plates (linked to the positive terminal of the battery) react with the acid to form lead sulphate giving up electrons (leaving the plate positive). The pure lead plates (linked to the negative terminal of the battery) react with the sulphate ions to also form lead sulphate. The pure lead plates therefore supply two positive charges and so are left negative. The passage of electons from the lead oxide plates to the pure lead plates is the current of electricity generated by the cell which can be used.
When the battery is recharged, the lead sulphate in each cell is broken down resulting in lead dioxide being redeposited on the positive electrode, and lead being replaced on the negative electrode.

When batteries are frequently deeply discharged then sulphation build up occurs. Sulphur molecules from the battery acid (electrolyte) start to coat the lead of the plates. Once the lead is coverered in sulphur the battery is dead and cannot be recharged. Sulphation starts occuring once the charge of a starting battery descends below 75%. Therefore lead acid batteries do need to be looked after well if they are to remain useable for a long time, and monitoring humidity and charging levels are key to achieving this for any energy storage appliance system. 

Supercapacitor systems are interesting and have potential, perhaps not replacing batteries but almost certainly complimenting them. The fast speed at which supercapacitors charge is an important compliment to the slow charging time but large volumetric power capacity of batteries. Solar and wind in particular are also subject to bursts and lags of energy in fast fluctuations, something which charging supercapacitors could deal with much better than batteries due to the speed of charging and discharging which could allow for an intermediate step in the process of power storage to allow for a way to combat losses.

Production of supercapacitors has gotten much more easier in recent years and probably the greatest development has been the use of graphene to produce cheap supercapacitor arrays from graphite on conventional surfaces such as glass or plastic with aluminium and a suitable spacer + electrolyte 

Energy storage is still a huge issue and is evolving all the time as new developments are made at research and industry levels. As we have seen in the comparative chart, Hydrogen, although seemingly good in terms of fuel cell efficiency is currently expensive, notorious to store and requires non-trivial liquid and gas plumbing and compression technologies which often consume the energy you wish to produce and store. However, increased research in the fuel of hydrogen production and, most importantly, storage may create a change in how we store electricity. For the moment however, batteries and supercapacitors seems key to having cheap and easily replicable means to store energy in a decentralized infrastructure.

Future-Proofing the Smart Grid 

In the concept of an energy internet, the power generation and energy storage of every building, acting as a node in a network, will be monitored by a machine-to-machine (abbreviated to M2M) system which will use smart meters to measure the amount of electricity used, and report that information electronically to a power provider for billing purposes. 

A smart meter is a good example of an enabling technology that makes it possible to extract value from two-way communication in support of distributed technologies and consumer participation in energy production.

At a basic level, smart meters will permit utilities to collect, measure, and analyze energy consumption data for grid management, outage notification, and billing purposes. The meters may increase energy efficiency by giving consumers greater control over their use of electricity, as well as permitting better integration of plug-in electric vehicles and renewable energy sources such as integrated solar and wind power generators in buildings. They may also aid in the development of a more reliable electricity grid that is better equipped to withstand cyber attacks and natural disasters, and help to decrease the overall peak demand for electricity.

The smart meters' essential functions include

(1) recording near-real time data on consumer electricity usage
(2) transmitting this data to the smart grid using a variety of communications technologies
(3) receiving communications from the smart grid, such as real-time energy prices or remote 
commands that can alter a consumer’s electricity usage to facilitate demand response

Smart meters identify consumption in greater detail than a conventional power meter and communicate that information back to the electrical utility for monitoring and billing purposes. Smart meters will range in terms of interaction with the utility and the distribution component of the grid, from relaying information on a daily, hourly or real-time basis. Smart meters are more tamper-resistant, can be remotely connected or disconnected, help with the detection of outages, as well as unauthorized removal and meter bypass.

Smart meters can be designed to transmit data wirelessly to locally installed receivers, some to roving receivers in vehicles, and some via wired communication lines.
Smart meters are already being installed to help power companies to locate and route around failures in the electrical grid, providing faster, sometimes almost immediate restoration of power to consumers. In system of user production as well as consumption power companies would be able to use these smart meters to reduce the amount of power sent to a particular region that is sustaining itself and provide financial support to those regions in the form of charging customers different electrical rates for different times of day or for different uses. Companies could easily allow customers to track their own electricity use through web or mobile phone interfaces.

The inclusion of smart meters and M2M systems would begin to set up the power generation aspect of the energy internet in just the same way as the inclusion of modems in the home set up the communication infrastructure of the first internet, replacing the notion that it would require transmission towers in every city and neighborhood as was the case with earlier mobile communications. The forecasts for M2M connectivity identify tens-of-billions of devices exchanging data in medical, industrial, home, smart grid, and, as-yet-undefined, markets. Due to location, legacy retrofits, and geography, most M2M connections will be wireless, rely on IP packets and IPV6 addressing, and will take place over WLAN Wi-Fi networks. 

This is of course related to the “Internet of Things” concept which describes a future where all manner of devices connect with each other and exchange meaningful data, increasingly with no human intervention. Assigning an address to every microcontroller-based subsystem will result in more uniquely connected nodes than anyone can count, but it’s surely in the billions in the next few years. A large percentage of these so-called M2M transactions will be IP-based and will occur in loosely-coupled, relatively close proximity 2.4 GHz WLAN networks dominated by Wi-Fi, the most widely used wireless protocol. WiFi is the wireless equivalent of the wired Ethernet protocol that forms the backbone of today’s internet. Typically, Wi-Fi operates on high performance computers, which can handle data-intensive applications. Compared to traditional Wi-Fi, Embedded Wi-Fi performs a single or very limited number of functions, such as transmitting static images, but at relatively lower data rates.

Embedded Wi-Fi offers clear advantages in that any Wi-Fi enabled smart device is able to readily communicate over the Web. Typical data rates of 1-5 Mbps are supported, which make it suitable for control and monitoring applications. Embedded Wi-Fi operates in the universally available 2.4 GHz spectrum. This spectrum is an open and unlicensed frequency band and, as a consequence, is being used by a plethora of wireless technologies.

In order for manufacturers to be able to bring wirelessly enabled smart appliances quickly to the marketplace that will make up this "Internet of Things" that will work within the energy internet they will need to integrate two key building blocks into their products — wireless technology and advanced microcontrollers. 

The first building block is an easy challenge, with applications for smart appliances already beginning to emerge that are centered around energy usage and monitoring by means of wireless monitoring. Services such as Google PowerMeter have enabled consumers to gain instant access to their energy usage data. This is a service which does not even require a conventional smart meter and instead works with devices such as the TED 5000,The PowerCost Monitor Microsoft Hohm and other open source energy monitor technologies, which use microcomputers such as WiFi-enabled Arduino boards and others, aimed at giving consumers more detailed information so they can find ways to reduce energy use. 

                             Google's PowerMeter energy monitor working on a smart phone.

In essence these technologies are monitors that provides a real-time read-out of home electricity use to a WiFi enabled device such as a smartphone or PC.

In turn, having this information will provide consumers with some impetus to undertake active measures such as signing up for cost-saving energy usage plans if they are offered by their utility companies. Utility companies themselves are rapidly deploying wireless-enabled smart meters to enable this choice. The second building block  is the more difficult step, namely allowing smart meters and M2M systems integrated in the home, forming a Home Area Network, or HAN, to provide load-control features to individual appliances using microcontrollers, hence creating "smart appliances" and "smart buildings/homes".

Wireless smart appliances are generally built upon a platform that includes three major subsystems: the microcontroller, which acts as the brain of the appliance; the wireless protocol stack, which defines the logical connections amongst devices in a network; and the RF transceiver, which handles the transmission of packets over the air.

Today’s manufacturers have a wide selection of microcontrollers around which to design their smart appliance platforms. One of the major selection criteria is the cost of the microcontroller. Additional criteria are the size of its program and data memory, its power consumption, the availability of peripherals, and its processing speed.

The Open Energy Monitor Project is a project which enables smart-appliance developers to create their own monitor system to monitor all sorts of energy inputs, analyze the data, and force outputs as a result of the data. These tasks can be achieved using a low cost, modular, open source microcontroller system, such as an Arduino,  that are powerful and flexible enough to form the basis of a wide range of systems.

PV installation monitors, solar hot water controllers, household energy monitors etc, can be assembled from a selection of modules linked together with an Arduino and configured using simple to use software libraries.

The diagram below gives an overview of how these applications can fit together:

At the heart of the Open Energy Monitor is Arduino, allowing for for making a computer specifically designed to sense and control the energy production and consumption of an appliance. To anyone unfamiliar with the concept, an Arduino itself is one of many open-source physical computing platforms based on a simple microcontroller board, and a development environment for writing software for the board.

The potential advantage of a modular system such as Arduino is that it allows users to customize their energy systems.  For example dynamically linking a variety of energy sources with their demand enabling all sorts of interesting increases in functionality while also economizing on parts. 

Another important subsystem of the smart appliance platform is the wireless protocol stack. Its operation determines how the devices communicate, how many devices may be on a single Home Area Network (HAN), and the maximum data throughput. The protocol stack is often the most complex software module in the application firmware. The development time of the smart appliance can be greatly reduced, if software for the stack is already available. Moreover, the portability of a vendor’s stack across all of its microcontroller families is of primary importance. This gives the developer the flexibility to choose the 8-, 16- or 32-bit microcontroller that is most appropriate for a given platform, while maintaining the same protocol stack functionality and features.

The RF transceiver completes the major components of the smart appliance platform, handling the duties of transmitting the packets over the air. The choice of RF transceiver together with the wireless protocol determines the environment in which the smart appliance can operate. If a low-power application requires wireless communication through obstructions such as walls, then a Sub-GHz transceiver may be more suitable. By contrast, higher-frequency bands such as 2.4 GHz make for a better choice in applications requiring higher data throughput.

Traditionally, RF transceiver design is a very complex undertaking. To help alleviate this complexity, manufacturers have designed fully integrated and FCC/ETSI certified RF modules. These modules include the RF transceiver, the functional antenna, and the supporting RF circuitry. Appliance manufacturers may simply include these modules in their designs, rather than acquiring the RF expertise to design the transceiver from the bottom up. Using modules reduces the time-to-market, risk, and development costs and will ultimately make the appliances cheaper and more universally integrated.

It is crucial to remember that at the core of the energy system being set up, the "smart appliances" will not be limited to the appliances that consume power but also the ones that will generate power such as the solar panels and wind turbines installed on rooftops of buildings and homes and will be designed to balance energy consumption and utility rates by communicating between the wirelessly connected smart appliances and smart meter technology. 

Wi-Fi enabled "Smart Home" where energy loads are controlled and utility rates balanced via Smart Meter communication (Image Courtesy of Microchip Technology Inc).

For example, when electricity demand in the building is high and power production in the same building is high the smart meter should be programmed to be able send power from the source, the solar panels and wind turbines, to the appliances demanding power over sending the power out to an external storage battery bank or transmission cable to the electricity grid to nearby buildings. At a different instance, say when the building is producing power but no appliances are running, the smart meter could be programmed to send the surplus power to either the storage battery or through a transmission cable which would be monitored over time such that the owner of the building would get some financial reward, perhaps in the form of a premium on energy bills, at a rate determined by the energy provider that owns the transmission infrastructure.

On such a transmission infrastructure, no one will know, or should know, exactly what individual systems or devices will be interconnected, or what kind of data will be exchanged. New systems and ideas are rapidly emerging, which favor modular approaches to chipset implementations. RF standards like 802.11ac (Wi-Fi) continue to evolve by adding channels, bandwidth, and security to become more and more application-specific.

Moreover, the installation of the core node of the M2M systems, the smart meters and the communications technologies that accompany them may have unforeseen legal consequences for those who generate, seek, or use the data recorded by the meters. These consequences may arise under existing federal laws or constitutional provisions governing the privacy of electronic communications, data retention, computer misuse, surveillance, and consumer protection.

Network data security is of primary importance because of the sensitive nature of the information that may be transmitted between devices. Security for Wi-Fi is based on a robust AES-128 algorithm, and operates within the framework that is described in the IEEE 802.15.4 specifications, respectively. The methodology for establishing and transporting security keys, and the authentication of devices are all defined by each of the specifications. Smart appliance manufacturers who choose a proprietary wireless protocol will have the added challenge of selecting the appropriate security algorithm and services.

Independent of the encryption algorithm chosen, there are two important security-related factors that manufacturers must be aware of. The first is whether the encryption algorithm is subject to export control laws. Products containing software or hardware algorithms must either restrict their key lengths or obtain specific export authorizations. Regardless of whether they are based in hardware or software, encryption algorithms have the same restrictions and must adhere to all export control laws. Secondly, regardless of the robustness of the encryption algorithm, data integrity will be severely compromised if the keys are compromised. Therefore, protection of the keys themselves is of vital importance. So it will ultimately be up to device manufacturers to devise an appropriate method of key protection, in effect they will choose how vulnerable the device is to surveillance and how protected the consumer is.


The growth of the energy internet is therefore characterized by this key fact: interdependent evolution. The inclusion of smart meters in the home will induce energy saving strategies which will then see the evolution of smart appliances in the home that will be connected to a continuously monitored electricity grid. Meanwhile, the smart appliances in the home will begin to include solar panel, wind turbine and energy storage technology that will be installed by active consumers and under initiatives that need to be assisted by both government and business to create demand by means of state procurement and development and by encouraging private investment for a strategy that is not going to create profit right away but which will create profits in the not-too-distant future.

Today, everywhere in the world, the transmission electricity grid is servo mechanical and it's 60 years old at least and largely non-digitalized. It's designed to be centralized and go in one direction. Where the power is generated, be it fossil  fuel power or nuclear, then you send it to the passive consumer at the end of the line. So this old transmission grid wasn't designed to handle millions of small players generating green electricity on site, solar wind, et cetera, and sending it back and then controlling the peak and base flows. So in the development of an energy internet you don't have to go too far into the subject matter to realize that it is a radical development and the natural questions to ask are "are governments and big corporations going to tolerate and allow such radical measures or are they going to fight it?"

The great economic revolutions in history occur when new energy regimes emerge and new communication revolutions emerged to organize them. In the 19th century as we said you had to have steam power printing to come together with coal and steam power and the locomotive. In the 20th century we had to have centralized electricity and the telephone to manage the complexities of an oil, auto and suburban era, which were all revolutionary forces often guided by corporate capitalism and state intervention. 

So here in the 21st century we have the distributive and collaborative peer-to-peer Internet communication combined with a growing demand for renewable energy but they are still in small amounts. Less than half of the world's population have access to the internet and the development of an sustainable energy infrastructure, while we still have the luxury of using non-renewable sources before they run out, is too slow in the context of peak oil and the movement away from manufacturing, research and development and towards financialisation and short-term profit in many economies. 

It will be crucial to create critical mass by collaborating across entire continents to organize the energy internet into the dominant system by which we obtain the renewable electricity we need to power our lives and civilization, and ultimately removing it from the confines of the fossil fuel industry. Combining the concept of the decentralized communication system that is the internet with a decentralized renewable energy infrastructure will allow for  a distributive power grid that can be easily installed and utilized anywhere on the planet, from the most remote village to the tallest skyscraper. Just as the communication internet has created a real change in social organisation, the energy internet will create a huge change in our organisation of infrastructure and how we utilize energy in our technology, allowing the other half of the world to not only have internet access but the whole planet to have cheap, affordable and abundant energy with responsibility and care for the environment so that our civilization can provide future generations with the energy and information needed to continue advancing our species to new frontiers.