EL CASO PINOCHET BAJO EL DISEÑO TRANSICIONAL

The economic feasibility of developing an on-farm pressurized irrigation system is highly site dependent; therefore it is difficult to make any broad conclusions regarding the economic feasibility of installing on-farm pressurized irrigation systems on the lands where potential was identified. However, we believe that the achievability of these projects is very high and the opportunity may be significant, as shown by recent development and available grant programs through the NRCS.

Conditions Necessary for a Feasible Project

The conditions necessary for a feasible on-farm pressurized irrigation system project will depend on whether it is a new sprinkler installation or a retrofit of an existing sprinkler installation.

Newly Installed System

If the goal is to produce power in addition to pressurizing the sprinkler system, then excess pressure and/or flow is needed. If there is an excess of pressure, and inline turbine can be used to burn some of the pressure in the production of electrical or mechanical energy. If there is an

excess of flow, some of the water can be diverted to the turbine while the remaining flow goes to the sprinkler. Any water run through the turbine can either be returned to the stream system or used to flood irrigate other areas.

Proximity to the grid is not required. Locations remote from the grid can covert hydropower into mechanical energy to drive the sprinkler system, which could result in much less cost than extending electricity service to the location. If a connection to the grid is available, hydropower generated at the site could be used to offset other nearby electrical loads.

If electricity is produced, then a net metering arrangement maximizes the savings provided by the system since power is offset at the retail rate. Because electrical loads may not be in close proximity to the location of hydropower generation, the ideal situation is for a utility to allow net metering across several interconnection points, although this is not yet allowed in Colorado. If used to net meter other electrical loads, the timing of the loads should be well aligned with the timing of hydropower generation. In the case of pressurized irrigation systems, this means electrical loads should have the highest demand during the irrigation season.

Retrofit Existing Sprinkler Systems

The upfront cost of replacing flood irrigation methods with a sprinkler system is a common barrier to development. The addition of hydropower (for instance, to offset the fuel or electricity costs associated with a sprinkler system) may be sufficient to entice a previously reluctant irrigator to make the investment, but this is not guaranteed. Retrofitting an existing sprinkler system is an attractive option since the irrigator has already made the decision to convert to sprinkler irrigation, thus removing this barrier to development.

If the existing system received funding from the NRCS for system installation, then the NRCS may not provide additional funding for retrofitting the system. For instance, the NRCS

Environmental Quality Incentives Program (EQIP), which funds projects that conserve water and energy, limits applicants to $300,000 in funding during any six year period unless the project is found to have “special environmental significance”, in which case the a petition can be submitted to raise the six-year funding cap to $450,000.2 Also, if a pipeline is already in place but a new pipeline is required due to a change in pressure or flow requirements to support hydropower generation, the NRCS may not provide funds to replace it.

An existing sprinkler system which currently uses an open ditch to deliver water would be a favorable retrofit because the NRCS may pay for the piping under its EQIP program due to the water conservation benefits of reduced seepage. If a pipeline already exists to deliver water to the sprinkler system, the site would be unfavorable if the pipe was designed such to burn off excess pressure via friction. In this case, a hydropower retrofit would require replacing the existing pipeline. The site would be favorable if the excess pressure is not burned off but is instead reduced through a pressure-reducing valve (PRV). The PRV can be replaced with a turbine to accomplish the same pressure reduction, but with the benefit of hydropower generation.

2_{http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/financial/eqip/, accessed November 4,}

If the existing pivot is fuel-operated (i.e. diesel), then this likely means electrical service is not available at the site since, if given a choice, a pivot operator would likely chose electricity instead of diesel since it is the least expensive option over the long term. Since electrical service is not available without a large investment, these fuel-operated pivots are probably candidates only for hydromechanical systems. Therefore, the retrofit can only proceed if the existing pivot was manufactured by TL. This decision tree would quickly weed out retrofits on fuel-operated pivots that are infeasible. If the existing pivot is electricity-operated, then the retrofit can be hydroelectric or hydromechanical. Thus, it is irrelevant who manufactured the existing pivot. A cost-effective retrofit is one that is favorable in all of the above conditions. However, a site that is highly favorable in a few conditions may outweigh the fact that it is unfavorable in other conditions. This is a site-specific determination.