THE DC REVOLUTION - WAVE OF THE WORLD'S POWER FUTURE
In the world of power utilization we are about to experience a true paradigm shift. For the past hundred years AC power has been the standard and the norm at virtually every level of society. With the use of technologies developed in the recent electronics revolution, we are about to change that forever - to safer, cleaner, more efficient DC power.
Energy In Crisis
Power failures, power shortages, blackouts, escalating power costs, natural disasters, wars and terrorism are all contributing to energy crises worldwide, and are fast becoming a fact of our lives today. These energy crises have become a global catastrophe.
Insufficient generating capacity, peak demand deficits, outdated and inadequate power delivery infrastructure, inefficient power utilization, population growth, industrialization and increased consumer demand have all added to power shortages and escalating power costs.
The most viable solution – and also the most practical and economical – to overcome energy crises and power shortages is to convert power usage from alternating current (AC) to direct current (DC), and to provide transportable and portable power generating sources known as “Microgrids”.
Alternating current (AC) has many drawbacks. In the delivery of power from the generating source to the consumer, as much as 80% of the originating power is lost through transformers and power lines -- resulting in only 20% reaching the end users. In addition, the surges, transients and fluctuations present on today’s AC power lines produce “dirty” power. This “dirty” power is an enemy to critical equipment and appliances that require smooth, non-fluctuating current to operate efficiently and greatly increases equipment life.
Direct current (DC), in comparison, can reduce these power losses by as much as 60%, resulting in two to four times more power to end users from the same amount of power produced. A regulated DC is free from surges, transients, and fluctuations delivers “clean” power versus the “dirty” power typical of AC. Equipment utilizing DC power can last four times longer than AC equipment. DC can be stored in virtually any capacity by batteries, while AC cannot. This enables DC products to be portable as well as cordless, and allows operation during grid power outages.
The Second Electronics Revolution
The Electric Power Research Institute (EPRI) refers to the development of high power electronics and DC power distribution as the Second Electronics Revolution. (EPRI is an institution funded by the U.S. public utilities to conduct research and development for the advancement of the power industry.) EPRI’s DC microgrid project, now in design, calls for decentralized generation facilities distributing DC current to smaller “neighborhood” networks. All renewable energy sources - wind, solar, fuel cells, etc. - generate direct current. Distributed power sources in the future will all utilize one or more of these methods.
The DC Microgrid – Power Source Of The Future
A microgrid is a decentralized power generation and distribution network in which a generating facility produces and distributes power within a small area compared to the present system in which utilities build very large centralized generating facilities to deliver power over hundreds of miles to thousands of customers. A microgrid system would typically deliver power within a one to two-mile radius of the source; i.e., “distributed generation” instead of “centralized generation”.
The microgrid concept has the following advantages:
- Lower installation cost of power distribution network
- Reduction of distribution and voltage conversion losses – by 60-70%
- Ability to store power easily and cost-effectively
- Clean transient and distortion-free power
- Greater safety with lower distribution voltage
- Ability to quickly and easily provide power to remote areas
The Microgrid Program Overview
Micropower Corporation proposes to design and install DC microgrids throughout un- or under-electrified countries of to enable the major portion of the population that has never had electric power to receive it for the first time. Phase One of such a project is to install a microgrid in a village of approximately 300 homes within an area of one square mile (three square kilometers). The project would include the following:
- Comprehensive Energy Survey and Project Design – A thorough survey of the village will be conducted to collect data for the project. A comprehensive design will then be made for the project including a schedule of homes and buildings, internal layouts, and a complete Bill of Materials.
- Generation – Power will be generated from renewable and non-renewable sources including gas or propane fueled engine-driven generators, photovoltaic arrays, wind turbines, and fuel cells. Power will be generated and distributed at 280 volts DC with conversion to 48 volts DC for use within homes and other buildings. At this voltage, distribution will be within a three square kilometer (one square mile) area with the generator station centrally located.
- Storage – a central storage bank of batteries will be installed to allow uninterruptible power to be supplied to the grid with several hours backup. More than one type of batteries may be used including advanced lead-acid, lithium polymer, and nickel hydrogen.
- Homes – Each home will initially be allotted up to 250 watts of peak demand. A wiring harness will be provided for installation of four 20-watt fluorescent lamps driven by a single four-lamp Æon BB48-420 ballast. This ballast will power all four lamps with a draw of 54 watts. Two convenience outlets will be included that will provide 48VDC for other appliances such as a DC electric fan. The home will receive a 300W DC-DC converter to step the 280V distribution voltage of the grid down to 48VDC for use in the home. An optional, but recommended piece of equipment is a battery module with integral automatic charger that would provide 20 ampere-hour hours of storage. This would run the fluorescent ballast for approximately 18 hours in event of grid power failure, or up to four hours with a full 250-watt load.
- Village Center – It is expected that the village will have a central facility of some sort, which acts as a “town hall”, or perhaps a multi-purpose facility. This building would be provided with adequate lights to allow evening events including entertainment, worship, political meetings, education and other such activities. Refrigeration would be then able to be provided for medicines and other critical perishables. It may be expected that water pumping can also be provided at one or more locations.
- Controls and Monitoring – Micropower’s AutomatÆon automated energy metering, monitoring and control package will be installed at the Powerhouse to allow data gathering in real time from anywhere via the web, phone line, or satellite.
Phase One of the project can be operational within 6-9 months of initial funding, estimated at $500,000. Completion of Phase One of the Project will result in a template that may be easily duplicated in other locations around the country. The data gathered should clearly demonstrate the benefits of such a system in terms of safety, efficiency, security and reliability, and allow comparison of a variety of technologies for their applicability and practicality in a wide range of environments.
Electrification Issues And The DC Solution
Pressure for greater access to electricity and to its benefits continues to be felt throughout the world. From the steep, Æonced hillside slopes of Nepal and the dense, luxuriant jungles of Papua New Guinea, to the star, expansive desert regions of Tunisia and the forlorn, windswept plateaus of the Bolivian altiplano, rural populations are increasingly demanding electricity and the benefits commonly associated with it.
Clearly, there is a widespread desire for electricity in rural areas, and some villagers are willing to pay considerably for this commodity. Furthermore, few will dispute the fact that electricity is an intervention that plays a critical role in development. However, to increase its attractiveness to governments and financial institutions, which are usually responsible for initial capital investments in electrification; to encourage its broader replication; to permit a larger portion of the population to avail itself of the benefits customarily attributed to this form of energy; and to contribute to other rural development activities, reductions in the costs associated with distributing and using electricity are needed. Extending the national electricity grid into rural areas has generally been a costly exercise. To have a realistic chance of meeting the demand for electric service in these areas requires progress on two fronts:
- Reducing the costs associated with electrification, and
- Increasing the benefits and financial returns from the use of electricity.
Cost of Grid Extension. One reason that high costs are commonly associated with extending the grid into rural areas is that conventional designs used to supply densely populated, urban centers are also routinely adopted in remoter areas, without much thought as to their appropriateness. The total cost of materials and labor for a three-phase (three-wire) ACSR line with 70-meter spans supported by galvanized steel poles commonly encountered worldwide is $5-15,000 per kilometer. With grid extensions often requiring many kilometers of lines to reach rural villages, the cost of acquiring, transporting and erecting concrete or tubular steel poles – particularly in off-road locations, is very significant and often logistically difficult. Added to that is the cost of transformers.
DC Solution: Locating the generation centrally in the village itself with wire runs of no more than two kilometers in any direction results in a major reduction of distribution cost and eliminates the requirement for large transformers. The smaller number of poles required can usually be erected by roadsides or easy-to-access locations, and underground utilities become an option as well.
Cost of Meter, Meter Reading, and Billing. Besides the cost of electricity itself, the cost of an energy meter is an additional expense that dissuades poorer villagers with minimal disposable income from accessing electricity. Likewise, meter reading and billing costs can add significantly to the cost of electricity supply for small consumers.
DC Solution: The DC-DC converters in each home or building, which step the line voltage down to 48VDC for internal use, can simultaneously meter the power consumption without need of a separate power meter as with AC grid systems. This can be read onsite or remotely when adequate communications capability is available.
Limited Benefits of Electrification. Because of the costs normally incurred in electrification and the need to reduce subsidies, benefits attributable to electrification must be maximized. But experiences around the world have shown that initial benefits of rural electrification have been restricted to lighting.
DC Solution: Recognizing the need to increase the socio-economic impact of electrification on rural communities, significant thought has been focused on developing benefit and income-generating end uses. Experience has further confirmed the fact that numerous complementary inputs are necessary for this to occur. Æon has developed and is continuing to develop DC products and appliances with efficiencies that for the first time make this possible.
Management. Electric utilities hesitate to serve the more remote areas because of the logistical difficulties and costs they incur in constructing these systems and in maintaining staff to oversee operations. The low financial return for their efforts is a further deterrent.
DC Solution: By providing a grid totally within the service area the costs and logistical difficulties in maintaining the grid are totally minimized. Users’ organizations will also be formed to provide coordination between the villagers and the utility during project design and construction, to collect monthly fees from all consumers and deposit them in the utility’s local bank account, and to maintain liaison between consumers and the utility to resolve technical problems should they arise. By placing the responsibility for the financial success of the project on the villagers (to reduce operational costs, follow up with delinquent consumers, and ensure that theft of energy is minimized) the burden on the utility is thereby minimized.
Lack of Awareness of Electricity. Most villagers have seen electric lights; nevertheless, a general lack of awareness of electricity and its uses tends to prevent potential consumers from maximizing the benefits they might derive from it.
DC Solution: The utility will hire and train individuals on a full-time basis to familiarize villagers with all aspects of electrification – housewiring, safety, tariffs, and end uses. Consequently, a very high percentage of villagers in the service area may be expected to opt for access to electricity in spite of small disposable incomes. Through drama presentations, committee meetings and household visits, they will carry out the following activities:
- Increase awareness among villagers who will have access to electricity of potential uses to which this resource can be put
- Assist in deciding to what level of consumption consumers should subscribe
- Share ideas about how best to electrify their homes
- Respond to other questions potential consumers may have concerning this new commodity
It is clear from many studies that villagers are willing to spend more of their income on electricity than they previously spent on energy sources for which it serves as a substitute – specifically kerosene and batteries. They apparently place sufficient value on this commodity to be willing to incur this financial “loss”. The benefits the villagers themselves typically attribute to electrification are not cost savings but rather a sense of tranquility, prestige of the community, and simplified tasks around the house. The availability of adequate light allows more to be accomplished after nightfall, including reading and studies.
While these benefits may be meaningful to consumers, rural electrification must still generate additional revenues to encourage proliferation. To this end, focus must be on developing end uses that will permit consumers to generate income from the electricity to which they will now have access.
Establishment of a DC power company to undertake this effort may be expected to foster:
- New entrepreneurial opportunities for local citizens
- Creation of many new jobs
- Attraction of investments to the community
- Reduced pressure on the forests by substituting electricity for fuelwood
- Irrigation of crops and agro-processing to increase yield from existing land
The utility created by the project will also conduct training courses in enterprise creation to stimulate new ventures, which can make productive use of electricity to generate income and employment.
Reduction Of Deforestation
One of the largest energy needs in rural areas is for cooking. The heavy reliance on fuelwood and charcoal for this purpose – averaging around 150-200 kg per month per household -contributes to environmental degradation, especially in marginal areas already cleared for agriculture. Arresting and eventually reversing the resulting deterioration of the forest cover is a national priority. This destructive practice also places a growing burden on women and children, who spend an increasing number of daylight hours gathering fuelwood as it becomes more scarce and costly. Additionally, the smoke from indoor fires frequently contributes to health problems, and deposits soot on walls and throughout the household. Some of the likely initial such activities may be expected to be commercial cooking with electricity, displacing use of fuelwood. Since it can be demonstrated that electricity is more efficient than fuelwood for cooking, the consumer can save on his energy costs, the utility can increase revenues, and the negative environmental impact from extracting fuelwood from the dwindling forests can be reduced. Other food-processing activities can yield similar results.
If the objective is to provide electricity to rural households in the most cost-effective, sustainable, and environmentally benign manner, one must be equally receptive to all options, new technologies and designs, and new institutional approaches to implement and manage these systems. The implementation of inexpensive, efficient, low-maintenance DC grids enables unelectrified communities to quickly and painlessly step into the twenty-first century and begin to safely enjoy the benefits many of us take for granted.