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October 27, 2011 / Mike Piskur

The importance of distributed generation

A wonderful infographic, created by Solar Gaines and shared on Clean Technica, provides some very handy back-of-the-envelope calculations to support my post on the inevitability of solar power. To quote the infographic:

The sun strikes every square meter of our planet with more than 1,360 watts of power.
Half that energy is absorbed by the atmosphere or reflected back into space.
700 watts of power, on average, reaches Earth’s surface.
Summed across the half of the earth that the sun is shining on, that is 89 petawatts of power.
By comparison, all of human civilization uses around 15 terrawatts of power or one six-thousandth as much.
In 14 and a half seconds, the sun provides as much energy to Earth as humanity uses in a day. 

Now, plants and animals use some of that energy, and a huge portion of available solar power falls on oceans, deserts, forests, and other places where humans do not live in significant numbers. Despite unplanned growth and new highway construction, urban areas cover a relatively small land area. According to the USDA, urban areas cover nearly 60 million acres, or 3 percent of the approximately 1.9 billion acres of land in the contiguous 48 states (note that this amount doesn’t include certain roads and government facilities) . Approximately 80 percent of Americans live on that 3 percent of the nation’s land area.


When it comes to siting energy generation, we should focus on the 60 million acres of land already covered with buildings, streets, alleys, and sidewalks. Coal cannot be burned just anywhere, and nuclear reactors must remain far from urban centers. Energy from the sun, however, reaches every city and suburb. It only makes sense that electricity gets produced where it’s consumed. In Illinois, about 2.3 million acres, or 6 percent of total land, is paved or otherwise developed, and the vast majority is situated in the state’s northeastern corner, extending outward from the urban core of Chicago and the shores of Lake Michigan. Chicagoland is the nation’s third largest metropolitan area and is home to about 9.5 million people, while the city of Chicago is home to about 2.8 million people.

Chicago, like all cities, uses vast amounts of electricity. The residential and industrial sectors consume the bulk of this power, but as electric vehicles enter the market, the transportation sector’s consumption of electrical energy will increase. Despite energy efficiency gains, Illinois’ electricity consumption is projected to remain approximately constant until 2020. The Illinois Renewable Portfolio Standard (RPS) stipulates that renewables account for 16 percent of total electricity generation in 2020, with solar energy providing about 7 percent of that amount. In its current form, the Illinois RPS relies entirely on utility-scale renewable energy production and does not include an allocation specifically for distributed generation.

Coal and nuclear generation plants create massive environmental impacts and generally are sited far from densely populated areas. There are two coal-fired power plants in or near Chicago, but most of the city’s energy supply comes from plants located many miles away from the urban core. This model of electrical generation, while effective, is incredibly expensive and increasingly antiquated. Economies of scale dictate that utility-scale plants generate energy from coal and nuclear. These same economic drivers, however, show that solar and wind energy are best produced through small-scale, distributed generation. Widespread adoption of distributed generation and smart grid technology will create a democratized electricity system in the United States.

New Rules Project via European Commission

In Democratizing the Electricity System – A Vision for the 21st Century Grid, the New Rules Project lays out the economic, environmental, and political benefits of distributed generation:

A 21st century technological dynamic offers the possibility of a dramatically different electricity future: millions of widely dispersed renewable energy plants and storage systems tied into a smart grid. It’s a more democratic and participatory paradigm, with homes and businesses and communities becoming energy producers as well as consumers actively involved in designing the rules for the new electricity system…Most importantly, this vision represents a transformation in the ownership and control of the electricity system. Instead of a 20th century grid dominated by large, centralized utilities, the 21st century grid would be a democratized network of independently owned and widely dispersed renewable energy generators, with the economic benefits of electricity generation as widely dispersed as the ownership.

This is a decidedly post-industrial vision. Distributed production is replacing centralized production in many sectors, including food, art, and information, and the economics of renewable energy indicate that distributed generation is more efficient and dependable than centralized solar and wind generation. The report identifies four primary benefits of a distributed electricity system.

1. Vast potential and deployment speed. Nearly every state could meet 20 percent of its electricity needs with rooftop solar PV alone. Two-thirds of states have sufficient wind, solar and geothermal power to get 100 percent of their electricity from in-state (and distributed) sources.

2. Favorable economics. Some renewable energy technologies (with federal subsidies) already compete toe-to-toe with fossil fuel generation, and others – like solar – are rapidly becoming less expensive. Furthermore, the vast majority of economies of scale for renewable energy technologies are captured at a modest size, well within accepted size definitions of distributed generation.

3. Local ownership and political support. The economic impact of locally owned renewable energy projects can be several times greater than absentee owned ones, and distributed generation lends itself to ownership. Such local ownership also dramatically increases local acceptance of more renewable energy production. And because it’s a more efficient use of the electricity grid, distributed generation reduces the number of political fights over new high-voltage transmission lines.

4. Value to the grid. Distributed generation is more resilient to disruption, with power generation spread over thousands of generators and over a wide geographic area. This makes it harder for a large area to be without power and easier to maintain grid stability.

The report estimates that Illinois could meet 17 percent of electrical demand through rooftop solar generation alone. This doesn’t eliminate the need for utility-scale wind and solar generation, but the favorable economics (including decreasing cost of solar technologies), combined with potential savings from transmission and distribution infrastructure and energy loss, demand that distributed solar and wind provide a significant share of electrical generation in Illinois and the United States. It is entirely possible, given the correct regulatory framework, that distributed generation, particularly solar energy, could meet or exceed the target established by the RPS. This will come about through innovative financing sources, incentives for residential and small commercial consumers, and community supported generation facilities. The demands of life in the 21st century require a new electricity infrastructure. At this moment, as renewable energy technologies begin to challenge and replace fossil fuels, we are creating a new American power grid, and along with it the future source of American prosperity and stability.


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