We offer a global view of reciprocating engines in remote communities in this excerpt from the Microgrid Knowledge guide, Reciprocating Engine Generators and Microgrids: The Last Defense Against a Power Outage.
In a land where winter can bring only a few hours of sunlight daily—or none at all for 67 days in Barrow, Alaska the northern most inhabited place in the United States—solar energy is not a practical resource.
Such Alaskan communities rely instead on reciprocating engine generators to keep the dark at bay.
In fact, according to the Alaska Energy Authority, 94 percent of electrical generation in rural Alaska comes from diesel generators, and this is not likely to change significantly in the immediate future.
Of course, Alaska is not the only place where generation options are limited. About 1.2 billion people worldwide currently lack access to electricity. And if the pace of new connections made during 2000–2010 continues for the next 15 years, and population growth is taken into account, the number will rise by an additional 40 percent by 2030.
Like Alaska, most remote areas of the world use reciprocating engines powered primarily by diesel fuel. Reciprocating engines have many advantages for these communities, whether they are used in a home or for a village. They are simple in design and easy to install, are low maintenance, have a long engine lifespan, and can be combined with other systems.
Increasingly, diesel generators are paired with renewable energy sources, particularly solar where practical. Called hybrids, or hybrid gensets, these systems often are made up of a conventional fuel (diesel) generator, a renewable energy resource (often solar), and sometimes with energy storage, such as batteries. It’s not unusual to find such pairings within microgrids.
The pairing increases system efficiency because:
▶▶When the sun is shining and the solar panels are producing electricity, the fossil fuel generators do not need to run. This reduces fuel costs, emissions, and generator maintenance needs.
▶▶When the sun is not shining, the customer has an alternative source of energy to ensure reliability. The reciprocating engines are flexible; can run anytime on fuel and are not limited to daylight hours when the sun shines.
However, hybrids are significantly more complex than simple gensets, especially when paired with cycling rechargeable batteries. So, often the hybrid still needs to be subsidized for rural electrification.
Campaigns are now underway to bring electrification to remote areas of the world, particularly in Africa and India. Reciprocating engines are expected to become increasingly important to this effort, given the difficulty and expense of connecting many remote regions to a central grid. In fact, the 2011 World Energy Outlook, produced by the International Energy Association (IEA), found that in 70 percent of rural areas distributed generation was a more efficient option to achieve universal energy access than the expansion of centralized electric grids.
Below is a look at distributed generation, in the form of reciprocating engines, in the less developed areas of sub-Saharan Africa, India and South America, where the central grid tends to be unreliable—if one exists at all. It shows why these reciprocating generators are in strong demand in these regions—and are likely to continue to be so.
Sub-Saharan Africa has seen rapid economic growth and energy use has risen by 45 percent since 2000. Efforts to promote electrification in the region are gaining momentum, according to the IEA, but only 290 million out of 915 million people have access to electricity. And the total number without access is rising due to population growth.
Demand for diesel fuel is expected to grow by 2.7 percent by year 2040, a rate greater than kerosene and gasoline in African countries such as Nigeria and Ethiopia. Overall, the demand for reciprocating engines in rural and peri-urban areas of sub-Saharan Africa is expected to grow in the next few decades. Also, diesel hybrid systems may provide the largest share of electricity in both microgrids and off-grid systems in these areas by 2040, according to the IEA.
India is the world’s second most populous country, but it is fifth in regional electricity consumed, barely coming ahead of Japan which has about 1 billion fewer people.
Energy use in India has almost doubled since 2000, but energy consumption per capita is still only around one-third of the global average and some 240 million out of 1.3 billion people have no access to electricity.
Millions of diesel generator sets—or about 90,000 MW— meet the shortfall in industrial and commercial energy production, with capacity growing at a rate of 5,000 MW to 8,000 MW annually. This annual capacity is higher than the cumulative nuclear and solar capacities being added each year. Genset capacity is also increasing annually at the consumer level—most commercial businesses, mid-to-large sized factories, and apartment complexes are equipped with diesel back-up power.
Of the top five electricity-generating countries in Central and South America, three—Brazil, Venezuela and Paraguay—generate more than 70 percent of their total electricity from hydropower.
Still, about 75 million people overall in Latin America live without access to electricity and about 31 million people—seven percent of the regional population — live without grid-connected electricity. In Nicaragua, for example, only about 52 percent of the population has access to electricity, one of the lowest rates of electricity coverage in Latin America. Peru, which fares better, still has around six million people without access. While Brazilians have the highest overall levels of access to electricity, in poor rural areas 30 percent of households have no electricity.
Expansion of the electric grid may take decades to reach areas such as the Amazon jungles of Brazil and Columbia, and the mountainous Andes area in Venezuela and Chile—if it comes at all. While hydropower has long been the workhorse of the region’s energy sector, recurring droughts have forced countries such as Chile to change their energy focus from hydropower to natural gas and other fuel sources.
Rural communities, then, tend to rely on simple reciprocating engines to provide power to their households. For example, many of the 12,000 communities located on the banks of the Amazon meet their energy needs through small diesel generators. Higher income families in these areas tend to consume more energy and usually supplement their diesel gensets with one or two solar arrays.
Watch for our next installment in this series where we profile real world uses of reciprocating engine generators. Or read more in Reciprocating Engine Generators and Microgrids: The Last Defense Against a Power Outage, available for free download courtesy of Fairbanks Morse Engine.