Afghan Energy, Chemical & Mining Industries
resource for Renewable Energies, Irrigation & Sustainable Industries.

An agricultural project to irrigate fruit trees required a minimum of 7 MW of electricity and we roughly estimate the costs of using different methods to produce this electritity.

- The power consumption is   for example :
If we consider solar:
We will require batteries if we decide to pump more than the required hours of sun available to us. In any case we will have to have redundant power sources at each of the 20 pumping stations. It would be better to do this at a 15 hour stretch at a Hydraulic power of 70-80KW which would reduce the price of the pumps and in turn compensate for the added redundancy power source. Fuel will be required for this added source out of the solar  time zone or cloudy conditions. The minimum cost of solar panel installation will be presently $1.5/Wp without backup power (est. 2015) which equates to (20 stations x   80KW x solar factor 1.2 / 0.8 eff. of pump  ) = 2.4MW for each of the 15 hours of pumping.
Also each of the 114 stations require solar installations of 10 KW each which equates to 1.14MW
Solar installation:
(2,400,000 + 1,140,000)  x ($0.7 per Wp panel + $0.8 for inverters, wiring, fixtures, electronics, wiring  etc) = $5.3m
Redundancy will be an added (20 x (100 kVA $15,000 ) + 114 x (15 kVA $3,000) )= $0.64m
Together solar will cost a minimum of $5.94m and will last at least 20 years with hardly any extra costs except for 7 hours daily generator power. Many variations of this is possible, however we have taken the minimum installation of solar. 7 hours generators at $0.22/kW (0.3633 l/kWh and $0.6/l)  is estimated to be per year 0.22 x 90kw x 7hours x 20 stations x 30  days x 7 months =      $0.6m/yr
The attached pdf file (0.05Mb) gives a more detailed calc. of the solar scenario. where at 12 hours daily watering one would require 4 hours of generator power. The total capital costs over 10 years is ($5.3/10 years plus $0.34m) equates to $0.9m
If we consider Natural Gas
We'll have to do a 3D seismic costing $3000/km2 for 100m2 costing $0.3m.
Drill down 3-4 km and case with well head will cost $4m with pipeline and
install a 10MW Deutz/Jenbacher used cogen plant costing $3m.
Filtering and separation and spares will cost $1m.  
Electrification substations and 50km line at 6MV will cost $2m with substations.
Total cost $10m
The energy factor for the Methane at an average volume of 85% is 37MJ/m3 which will produce at 35% efficiency electricity at a relatively low cost of $0.04c over the 10 year short life of the installation. ie $1.2m/yr ($1m costs and $0.2m interest and royalty) used for 7 months of:
12 hours daily 90kW at 20 stations and 4 hours of 144 stations at 10kw plus losses plus extras of 1.2 factor.
This equates to 6,000,000 kWh x $0.04 = $240,000.
The actual electricity will cost us: $1.2m/6,000,000= $0,20/kW or $1.2m/yr
therefore Estimated yearly costs is $1.2m per year.
If we consider coal (estimated)
A coal fired boiler will cost from china or europe  with turbine including installation  for 10Mw $3m.
Electrification substations and 50km line at 6MV will cost $2m with substations.
cost of purchase and delivery of coal / tonne is $60/tonne at 28GJ/tonne for black coal  which will produce $1.5/GJ or $1.5/GWs or $0.000015/kWs or $0.054/kWh
Taking the efficiencies into consideration the actual price will be about $0.07/kW.
Estimated yearly costs is ($70,000/GWh x 8GWh + (approx $0.5m capital costs over 10 years))= $1.06m/yr
If we consider Diesel
Generator and housing for an unused 6.2MW costs $1m. accessories and a possible co-gen $0.5m.
Electrification substations and 50km line at 6MV will cost $2m with substations.
Consumption 0.29 Liters/kWh and at $0.55/Liter diesel oil over 7 months will cost (0.29 x 0.55  x 6,200 kW  x 12hours x  30 days x 7 months) = $2.5m/yr
Estimated yearly costs is ($2.5m + (approx $0.35m capital costs over 10 years))= $2.85m/yr
Yearly cost for the following: all taken over 10 years, however solar installation is capable of 15 years, but has been considered for simplicity over 10 years.
Solar                                       $0.6m/year
Natural Gas               $1.2m/year
Coal                                          $1.06m/year
Diesel                                      $2.85m/year
Out of all the methods estimated, Coal fired electricity is the cheapest and the most "dirty".   The solar scenario estimates that we will eventually reach a discounted   $2/Wp for the quantity of panels that will order.
If we consider imported electricity, we have to rely on the importer and the government, and neither can be trusted to deliver on time for such a mission critical enterprise. All functions have to be kept in-house.
Solar 20 years lifetime and clean and reliable costs and easy installation with little maintenance will probably win the day.


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