Land Use Benefits
DE can reduce the environmental footprint of providing society energy.
The centralized electricity system uses vast amounts of resources including land. Large amounts of land are required for mining the fuels used in both centralized and decentralized energy systems. For example large tracts of land are used for strip mining coal, and total deforestation from siesmic lines used for locating oil and gas reserves underground is comparible to that of the forestry sector in some areas. Because DE uses less fuel to provide the same energy services DE is one way of slowing or postponing resource extraction and can thereby releive land use pressure.
Another way DE can reduce land use pressure is by reducing the amount of land required for electricity generating facilities and rights-of-way for transmission and distribution infrastructure.
In many cases DE capacity, unlike central generation, can be sited without incremental land use which can reduce the not-in-my-back-yard phenomenon which often plagues the development of larger central generation projects. The basic idea of DE is that it generates power at the point of use. Solar panels are added to rooftops that already exist. Fossil fueled CHP units replace existing boliers or are installed as the heart of community energy systems or on the premises of exisitng factories. Because DE is used at the end user site no extra land is required to house the capacity. The table below presents the results of a study which compared typical land use required for centralized and decentralized plant. As you can see it is estimated that land-use savings resultant from using DE rather than central generation to meet the same demand range between 66 to 400 acres. Of course this reduced land requirement would also translate into savings for the developer.
| Estimated land use requirments for decentralized and centralized generating capacity|
| ||technology||land required |
|total land use|
|DE|| building integrated PV||0||12||0|
|DE|| residential CHP||0.14||50||0.16|
|DE|| industrial CHP||0.61||98||1.37|
|DE|| commercial CHP||0.38||100||0.86|
| DE subtotal||250||2.39|
|CG|| natural gas||11||250||66|
| Source: Spitzley and Keolian|
Increased DE use can also reduce or eliminate the need for expensive and unsightly high voltage transimission expansions. When fossil fuels are the primary fuel it is much more efficient (and less land intensive) to transport the fuel itself and then burn it in DE applications than to transport electrical energy. The below images illustrate two different energy transportation technologies which cost approximately the same to build and operate.
|For the same price much more energy can be moved through a pipeline than electrical wires.|
|25,000MW capacity gas pipeline|| 500MW capacity transmission line|
|Source: Klimstra 2006|
If new electricity is generated where it is required there is no need to transport it over large distances. If the DE can be sited in areas with existing transmission bottlenecks the need for new transmission capacity could be avoided all together.