Solar Agroprocessing, Aug 2014

Making Energy Affordable

UN Target: "Access to Energy" for all by 2030

• Lighting + phone charging ≠ "access"

Need more than 2-10W solar lamps/kits

Possible "Access to Energy" package:

• Residential, mostly night-time needs:Lighting, phone charging, radio, fan and/or TV

• Community/business, mostly day-time needs: Refrigeration (especially for clinics), communications for market access, productive power for processing crops, carpentry, others?

= "Tier 2+" service package

= 75-150 kWh/year/house, or 25-50W/house

Why focus on solar agroprocessing?

Tiers of Energy Service

Current view of "access to energy" is still uncertain, and current thinking is based on tiers of services.

However, very focused on consumers / households

Does not account for • clinic needs for health• community mills• school equipment, comms• solar water pumping

and similar mostly community-scale needs.

Hence, "Tier 2+" suggested which includes these needs.Source: https://www.climateinvestmentfunds.org/

Reduced expenditure on diesel, which dominate offgrid milling now

Staple crops• Globally, it is mostly mostly women and children who currently spend 30-60

minutes per day manually processing food that is consumed each day by 250 million offgrid rural households that do not have electricity.

• Mechanized agro-processing reduces time spent on basic labour

• Saved time leads to more time spent in the fields increasing food security

• Saved time leads to non-agricultural income-generating activities/opportunities

• Saved time can also increase parents' contribution to childrens' education

Cash crops• Processing cash crops at the village level can earn more value for households

(eg. coconut oil produced instead of copra, edible rice instead of unhulled)

• Saved time leads to more time in fields growing/harvesting, increasing income

Agro-processing is commonly part of microhydro, grid and diesel rural electrification projects, but rarely part of solar electrification projects.

Benefits of solar agro-processing

Over 1 billion people lack electricity

15 crops make up 90% of all food consumed on the planet

3 crop groups make up 50-60% of all food consumed

• Rice

• Maize

• Wheat and other cereals (sorghum, millet, barley, rye, etc)

Other major crops are roots (cassava, yams, potato, taro) and in the Pacific, coconut

Meat is a larger food group for the rich than the poor.

Chicken and pork dominate the rural meat markets of poor countries.

Crops of the poorest 1 billion

World productionProcessing

required2008

Rank Crop (metric tons)

1 Maize/Corn 823 million thresh, grind, winnow

2 Wheat 690 million thresh, grind, winnow

3 Rice 685 millionthresh, hull, winnow,

(polish for white rice)

4 Potatoes 314 million wash, peel

5 Cassava 233 million peel, grate or slice

6 Soybeans 231 million thresh, dry, clean, press

7Sweet

potatoes110 million peel, sometimes slice

8 Sorghum 66 million thresh, grind, winnow

9 Yams 52 million peel, sometimes grate

10 Plantain 34 million peel

Average world yield

2010

(tons per hectare)

5.1

3.1

4.3

17.2

12.5

2.4

13.5

1.5

10.5

6.3

Staple Crops of the World

Source: Staple food - Wikipedia, the free encyclopedia.htm

threshing maize

grating cassava / yams

pounding = grinding corn/cassava or hulling rice

grinding flour

winnowing

grating coconut

Saving 1 hour per day for 250 million women globally that lack electricity

= 100 billion hours/year of productivity

= 50 million peoples' worth of 8-hour days

= entire workforce of the UK or France

by reducing time spent processing crops, fetching water and collecting firewood

Opportunity of Productivity

Mechanized offgrid agro-processing

Diesel2-20 kW engines directly driving mills via belts

Consume 1-7 L/hour of fuel, costing $1-7/hour, serves 200-2000 households at 200 kg/hr

1-4 hours/day operation means $300-3000/year on fuel

Solar0.2-2 kW solar systems drive mills directly or via batteries.

Panels $1-2/watt = $300-2000Batteries 0-300Ah = $0-2000Controllers, other = $100-500

Solutions can be delivered for $500-5000 for 25-250 kg/hour, but may be slower than diesel

2-5 year paybacks on diesel

Diesel mills are rarely found in small villages of < 50 households

One household eats 1-2 kg/day of staple food, so a 200 kg/hour mill can serve 100-200 households per hour of operation - this is the typical size of village in which mills are found (or in larger towns as well)

However, most rural villages are 20-50 households.

Many villagers travel 1-10 km to access a mill outside their village

This can cost $0.20-$1.00 for the return trip, with a 25-50 kg bag

The cost of milling is typicall $0.02-0.05/kg or $0.50-2.00 per bag

Thus, travel can increase agro-processing costs for small villages by 50-100% and so they tend to not use mills even if they could afford it. Small solar mills can penetrate these markets that diesel mills do not now reach.

Transport: the hidden cost

Base CaseManual flour grinders, used 30 mins/day, cost $30 and are bought by offgrid villagers in central / south America. These break every 6 months.

Solar solutionA 1/3 hp (250W) electric mill that can process 30 kg per hour and thus can serve 15-30 households with 1 hour of use per day. Assuming there are 3-4 hours of sun per day, the following system can serve this need.

1 x 100W solar panel for 1 hour/day use = $100-2001 x Nixtamatic mill = $250-4001 x 40Ah battery for 1 hour/day use = $ 80-1501 x 2000W Whistler Pro inverter = $150-250Controller, wires, other = $ 20-100TOTAL COST = $600-1100

Current annual cost: = $30 x 2 grinders/house/year x 15 houses = $900/year

1-2 year payback possible

Case Study - Maize flour grinding

Case Study - Rice hulling

Base CaseRice hulling costs $0.50 to process a 25 kg ($0.02/kg) bag which lasts 12-25 days. Once transport costs are added, this can be $1/bag or $0.04/kg. A small village wishes to have a solar mill installed instead of traveling to the large rice mill in a nearby town.

Solar solutionA 1/2 hp (375W) micro rice mill can process 40 kg/hr, so serve 40-80 households with 2 hours/day of use.

2 x 150W solar panel for 2 hours use = $300-5001 x micro rice mill without polisher = $500-7001 x 80Ah battery for 1 hour/day backup = $150-2501 x 2000W Whistler Pro inverter = $150-250Controller, wires, other = $ 50-100TOTAL COST = $1150-1800

The micro rice mill can process 80 kg/day, or 400-500 kg/week (8-10 bags). More panels = more households.

Revenue = $10/week, or $500-2000 per year.

2-4 year payback possible, or 3-6 years if a small operator salary is drawn from gross revenue.

Case Study - Coconut Grating

Base CaseIn South-East Asia, freshly grated coconut is available in local markets as well as whole coconuts, whereas in the Pacific, only whole coconuts are available. Peri-urban households can grate coconut for time-poor urban housewives or restaurants.

Solar solutionA 1/4 hp (175W) electric coconut grater can process up to 50 nuts per hour (typically 10-20 nut), producing 250g of grated meat per nut or 2.5-10 kg per hour.

1 x 80W solar panel for 1 hour/day use = $100-1501 x 175W coconut grater with DC motor = $100-2001 x 24Ah battery for 1 hour/day use = $ 50-100Controller, wires, other = $ 0-50TOTAL COST = $250-500

Whole coconuts sell for $0.10 each while one 500g of coconut milk (1 nut worth) sells for $1, so the selling price of grated coconut is set at $0.25 per nut (250g).

Profit = $0.15 x 20 nuts/day = $3/day = $1000/yearOf this, $0.05/nut is charged for mill use = $1/dayHence, 1-2 year payback possible

Case Study - Coconut Oil

Base CaseCoconut oil can be used to displace fuel in remote islands, or as a cooking oil, or for other uses. It is usually made in centralized mills, and villagers supply dried coconut meat (copra). Small scale oil expelling may also be possible to add local value to this crop.

Solar solutionA 1/4 hp (175W) electric coconut grater can process up to 50 nuts per hour (typically 10-20 nut), and a 150-500W oil expeller can produce 3-5 L/hour.

1 x 150W solar panel for 1 hour/day use = $150-2501 x 175W coconut grater = $100-2001 x 150W electric cold oil press = $400-6001 x 40Ah battery for 1 hour/day use = $ 80-1501 x 2000W Whistler Pro inverter = $150-250Controller, wires, other = $ 20-50TOTAL COST = $900-1500

Coconut oil value $1-5/litre, depending on use.Production = 4 L/day x 250 days/year = 1000 L/yearGross revenue $1000-5000, payback period <2 years

Base CaseManual cassava and yam graters are used 15-30 mins/day are used across the Pacific, at a rate of around 5 kg/hour. During large festivals, up to 30 women process 200-500 kg over many hours.

Solar solutionA 2/3 hp (500W) electric drill has a grating attachment added, or more sophisticated graters can be purchased, that can process up to 150 kg / hour serving 75-150 households with 1 hour of use per day.

3 x 80W solar panel for 1 hour/day use = $250-3501 x electric grating machine = $100-2001 x 40Ah battery for 1 hour/day use = $ 80-1501 x 2000W Whistler Pro inverter = $150-250Controller, wires, other = $ 20-50TOTAL COST = $600-1000

If paid in cash, $0.05/kg generates $7-8/hour revenueIf paid in kind, one $10/house/month local handicraft can be exchanged for supply of the service, and sold

Revenue = $1000/year, 1-2 year payback possible

Case Study - Cassava grating