Two weeks ago (April 15, 2014), I discussed some of the changes necessary in the electrical grid to accommodate sustainable power sources. To a major extent, the blog was based on an MIT report titled “The Future of the Electrical Grid.” Appendix B.2 of this report provides a brief tutorial on the “Fundamentals of Electrical Power.” Two key sentences in this Appendix describe the origin of the two most fundamental terms – voltage and current:
Voltage can be considered analogous to the pressure in a water pipe. Voltage is measured in volts (V), and for large values expressed in kilovolts (kV) or megavolts (MV).
Current is a measure of the rate of flow of charge through a conductor. It is measured in amperes. Current can be considered analogous to the rate of flow of water through a pipe.
Water infrastructure is intimately connected to that of electrical distribution – and not only through terminology. As President Obama’s comment during his visit to California (April 1, 2014 blog) and the MIT report clearly indicate, both distribution systems need major upgrades. This need of an upgrade is not confined to the US; it is global. But there are some major differences – both between the distribution systems of water and electricity – and the upgrade requirements of developed and developing countries. I will discuss the needed modifications to the water infrastructure and the interconnections between the water and energy infrastructures in future blogs. Right now, I would like to focus on some specific aspects of the electrical grid.
The MIT report describes the early history of the electrical grid in the United States in these words:
Thomas Edison introduced the first electric power system in New York City in 1882. This direct current (dc) system initially served 59 customers in the Wall Street area at a price of about $5 per kilowatt hour (kWh). It operated at 100 volts and mainly supplied electric lights. By the end of the 1880s, many cities had similar small central stations that each served only a few city blocks.
To the extent that the industry was regulated, city governments performed this function. City governments also became major customers for street lighting and trolley services and could extract various concessions in exchange for the right to string wires. Soon, they also became owners. By 1900, municipally owned utilities accounted for about 8% of total U.S. generation. Vigorous debates about the relative merits of government- and investor-owned utilities continued in the U.S. through the 1930s, when federal policies were established that today still favor government-owned and cooperative utilities.
Today, this description fits the definition of a microgrid, which – according to Wikipedia– is an example of distributed generation of electricity:
A microgrid is a localized grouping of electricity generation, energy storage, and loads that normally operates connected to a traditional centralized grid (macrogrid). This single point of common coupling with the macrogrid can be disconnected. The microgrid can then function autonomously. Generation and loads in a microgrid are usually interconnected at low voltage. From the point of view of the grid operator, a connected microgrid can be controlled as if it were one entity.
Microgrid generation resources can include fuel cells, wind, solar, or other energy sources. The multiple dispersed generation sources and ability to isolate the microgrid from a larger network would provide highly reliable electric power. Produced heat from generation sources such as microturbines could be used for local process heating or space heating, allowing flexible tradeoff between the needs for heat and electric power
The early grid fits this definition except for the aspect regarding connectivity. There was no main grid – this was the only grid.
Recently, microgrids have started to become very popular – both in the US and other developed countries. Next week, Elisa Wood, of EnergyEfficiencyMarkets.com will present a guest blog on the current interest in microgrids in the US.
My own interest in microgrids started in a different place. In a previous blog (September 3, 2012), I wrote about “Three Shades of Deniers.” For me the most disturbing shade was the “Fatalists”:
This group fully agrees with both the science and its predicted impact, but believes that since the task of preventing it is so enormous as to be practically undoable, they might as well enjoy life for as long as it lasts. Unfortunately, many in this group are good scientists.
The usual example that this group provides is India, citing that with more than one billion people – approximately 25% of them without electrical power – it will be impossible to prevent major increases in global greenhouse concentrations. I decided to travel there – to see for myself and, hopefully, try to do something about it. I fully realize that the issue is global, not unique to India. As I mentioned in a previous blog (April 15, 2014) close to 1.5 billion people do not have access to electricity, yet in large part due to the recent, much better, global access to phones, they are fully aware of how access to electricity can improve quality of life.
So the question is what they are doing to gain such access, and whether these measures justify the skepticism of the fatalists. I was able to interest a colleague of mine, Prof. Vinit Parmar from our film department, and we went exploring. We went to a region of India called the Sundarbans, which is part of the West Bengal State, near the city of Kolkata (Calcutta). The region is shared by India and Bangladesh and is the home of one of the world’s largest deltas, formed by the outlets of the Ganges, the Brahmaphutra and the Meghna rivers into the Bay of Bengal. About 4 million people live on the Indian side of the border. The land’s topography has made it difficult to extend the Indian electrical grid, and until 1995 most of the inhabitants lived a Hunter-Gatherer way of life: “hunting” fish and gathering honey in the Mangrove forest. Around 1995, the Indian government (with some help from the US government) decided to do something about it and try to deliver electricity to the region. They decided to do it by skipping the coal stage, instead delivering the electricity in the most sustainable way that the budget would allow.
We tried to monitor this process through a documentary film; to accomplish this we needed some help but the result, along with the full list of contributors, can be seen in the short film “Quest for Energy.”
The film illustrates the initial delivery of electricity in the small town of Gosaba. This delivery comes by way of a microgrid that runs through some of the main streets in town. Here, the microgrid doesn’t function as an additional, supplemental aspect of the main grid. In fact, since in this case, the microgrid is the only grid, in a sense, it resembles the main grid in the US more than 100 years ago. The proliferation of microgrids in rich countries is a boon to developing countries like India because it promotes further exploration and improvement of such technology. Hopefully these innovations will continue to be applicable not only in rich countries, where the microgrids function mostly as a form of adaptation, but also in poor countries where in many regions they are the only game in town.