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| Fig. 1: Local Scale: Author's home in Rhode Island. Source: Blake Crowe. |
In an age of increasing fossil fuel consumption and rising awareness of the industrial world's oil addiction, there is much talk of alternative energy sources that would replace fossil fuels. Numerous alternative energy options have been proposed by scientists and engineers as solutions that would allow human society to continue on as it currently operates. The issue arises however, that there exists no alternative that holds the same energy content as the millions of years of stored solar energy that humans have burned in the last 200 years. [1] Of the proposed energy solutions are more finite-fuel solutions such as coal, nuclear, or natural gas. On the other end of the spectrum lie the most developed renewable sources of energy such as hydroelectric, solar, and wind. Heroic attempts have been made over the last decade to develop these renewable energy technologies on the large scale to significantly offset fossil fuel power generation.
The term "large scale renewable energy" refers to the majority of government funded and large corporate energy projects of 100 KW or greater. The fundamental assumption at the core of these projects is that an integrated system of enough large wind farms, solar arrays, and hydroelectric dams will be able to largely contribute to our current energy needs. In 2008 the total global energy consumption was on the order of 132,000 TWh, approximately equal to 15 terawatts of power use. [2]
Hydroelectric provided 82% of all electricity form world renewable energy sources in 2012, increasing at an average rate of around 3% a year making it the largest player in the renewable field. [2] In the United States, 10% of electricity comes from around 2,200 different sites across the country, which hold around 80,000 MW of generating power. [1] The US Department of Energy has identified 5,677 undeveloped sites in the US, which would provide an additional 30,000 MW of generating power. [1] The conclusion here is that most of the hydro generating capacity has already been tapped into, and has been since the late 1800s. Even if we developed all of the untapped sites we would only boost the 10% capacity to roughly 15% of total US energy consumption.
In 2003 Denmark was generating 18% of its electricity from wind, making it the most per-capita wind energy generated per capita. [1] In 2005 the Germany was producing 18428 MW, Spain 10027 MW, United States 10027 MW, and India 4430 MW. [3] This amounts to a 676% growth from 1997 for total global wind generation. Although impressive, this growth still only amounts to less than 1% for total global electricity production. [3] 100KW and larger turbines and mega-watt scale wind farms account for most of this growth. Machinery and farms of this scale require a large amount of fossil fuels to manufacture as well as implement, making the construction of large-scale wind farms very much oil dependent. To grow to a point of significantly off setting coal, natural gas, or oil as an energy source would require massive amounts of fuel investment. The large turbines also require regular maintenance and upkeep, making them further reliant on fossil fuels.
Large scale solar runs into similar development problems that wind energy encounters. In 2011 there are 69 GW of photovoltaics installed worldwide capable of producing 85 TWh hours a year of electricity. [4] This amounts to approximately .06% of total world energy consumption for 2008. [5] The idea that we can replace the same gigantic systems currently producing the massive amounts of power with another gigantic infrastructure is shallow, especially with rising tensions worldwide surrounding oil. Without cheap fossil fuels it would not be possible to install industrial scale photovoltaics, especially on the magnitude that would be required to offset coal or natural gas.
The term local scale renewable refers to home, personal, and communal renewable energy harnessing systems. The largest differences between local scale and large scale are the magnitude of the energy harnessing systems, installation and maintenance costs, and energy storage capabilities.
The ecological term resilience is defined as the capacity of a system to absorb disturbance and still retain its basic function and structure. [6] Local systems have resilience that grid scale size systems lack. A small community with ay 5KW wind generating power, 5-10KW of photovoltaics, and perhaps a third supplement such as hydro or geothermal (if possible), would be able to respond to environmental changes much quicker than a large grid-tied system. [7] Small local scale systems supplying power to 10 or 15 frugal families can also take advantage of energy storage systems that large renewable energy systems cannot. Pump hydro and battery storage would work well for small- scale systems, whereas massive wind and solar farms have to feed directly into the grid, and are therefore reliant on the grid itself. [1] If the grid collapsed, large power generating sources would not be able to deliver electricity to power users.
The resilience of local systems is rooted in the proximity of the systems to the users and the potential for energy storage and independence. [7] Local renewable generation also has the advantage of developing systems that are appropriate foe the land. If there is an excess of wind energy, then a focus can be put on wind generation. If there are geo-thermal hot springs available locally, then those can be tapped through heat transfer systems. If there are fast flowing streams in the area then hydroelectric generation can be developed for that region specifically. Local systems can be more region specific since they exist on the small scale, and there exists more possibilities for integrated power generating systems of four or more different technologies, increasing the resilience of the systems.
The frenzy surrounding the development of large-scale renewable energy systems is a desperate attempt to continue the gigantic energy consuming lifestyle present across the globe. The problem lies in the fundamental idea that massive amounts of power can be generated in one place and transported to users hundreds of miles away. The infrastructure required for this large-scale grid system is expensive and fossil fuel dependent. Local systems have the potential to support small communities of people and be more appropriate for the immediate surrounding environment. As the tensions surrounding fossil fuels increase, local renewable energy power generation will become more valuable due decreased dependence on the systems of old.
© Jason Vidaurre. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] J. H. Kunstler, The Long Emergency (Grove Press, 2005).
[2] Energy Technology Perspectives 2012 (International Energy Agency, 2012).
[3] M. B. McElroy, Energy: Perspectives, Problems, and Prospects (Oxford,2009).
[4] G. Masson et al., "Global Market Outlook for Photovoltaics Until 2016, European Photovoltaic Industry Association, May 2012.
[3] P. O'Keefe, N. Pearsall and G. O'Brien, The Future of Energy Use (Routledge, 2010).
[6] B. Walker and D. Salt, Resilience Thinking (Island Press, 2006)
[7] R. Hopkins, The Transitions Handbook (Chelsea Green, 2008).