Organic chocolate farmer Auxibio Sho irrigates his seedlings with a solar powered water pumping system.

work with the Toledo Cacao Growers Association (TCGA), Belize's only certified organic cooperative. TCGA is a democratically run organization established in 1986, and has been selling cacao to Green & Black's, a UK organic chocolate company, since 1993.

Theobroma cacao is a tropical subcanopy tree that produces seed-carrying pods. After harvesting the ripe pods and fermenting, drying, roasting, grinding, and processing the seeds, these seeds become cocoa, and cocoa makes chocolate. You may have seen Maya Gold, the dark chocolate with an orange flavor that Green & Black's makes from TCGA's cacao.

Catastrophe & Reconstruction

TCGA has about two hundred members, most of which are subsistence farmers who grow cacao for the export market. Our membership is 99 percent Kekchi Maya and Mopan Maya, spread out over seventeen villages. Of these villages, twelve were hit in 2001 by Hurricane Iris, the most ferocious storm Toledo has seen in more than sixty years. The damage to the economy of Toledo District, already the poorest district in the country, was catastrophic.

When the people of Toledo saw the rising sun the next day, they were confronted by broken and uprooted trees, a destroyed electricity grid, and damaged housing. Most of the traditional crops that Toledo's farmers subsist on—rice, beans, and corn—were laid down in the mud.

Foreign-currency-winning crops like citrus and cacao were also damaged, with a complete loss of the year's citrus crop, and severe damage to the cacao groves. Many farmers depend on the income they make from these crops. While the citrus only lost its fruit and flowers, the cacao needs a canopy of shade trees to protect it from sun. The shade trees also mine nutrients from the subsoil, dropping it to the forest floor in the form of leaves, flowers, fruit, and branches, where it is broken down and made available to the cacao plants. With much of the shade gone, the cacao was not sheltered. This important nutrient cycle, especially important for the organic cacao that TCGA's members grow, was broken.

When the hurricane hit Belize, the Toledo Cacao Growers Association was already working on a plan to establish five nurseries in various communities to expand the acreage of organic cacao in the district. The plan included valuable timber trees as an integral component. This proposal was being facilitated by an American NGO called Trees for the Future; its local partner, Trees Belize; and the Community Initiated Agricultural Development (CARD) Project.

Three Solar Water Pumping Systems

We were able to place two of the five nurseries in communities where there was piped water. This left three nurseries in need of water. Since our family farm has been using solar pumps for our irrigation and home water system for the last six years, I thought it would be neat if we could figure a way for these nurseries to be solar pumped.

Photovoltaic panels in the equatorial latitudes of Belize need only enough tilt to shed rain.

The home of TCGA chairman and cacao farmer Mr. Pablo in San Antonio Village,Toledo, Belize.

Photovoltaic panels in the equatorial latitudes of Belize need only enough tilt to shed rain.

Local and international funding enabled TCGA to pay for most of the equipment for two systems built around the Solar Force piston pump by Dankoff Solar Products. Plenty International donated a Shurflo submersible pump that had been on loan. A substantial grant made by the Unity Avenue Fund and a grant made available to TCGA by the UK-based Methodist Relief and Development Fund paid for the balance of the piston pump systems. Green & Black's donated some additional funds to assist TCGA in its efforts to rebuild, a portion of which was used to buy pipes, tanks, hose, and two solar-electric panels.

The three nurseries with solar powered water pumping are in the villages of San Antonio, San Pedro Columbia, and San Jose. These are all cacao producing villages that TCGA has targeted, where expansion is possible by both finding new members and encouraging existing members to expand their acreage.

Mr. Pablo's System, San Antonio Village

San Antonio Village is the largest Maya settlement in Toledo. It is predominantly a Mopan Maya village, and is the single largest cacao producing village in Toledo, with seventy producing members, and dozens of newer members who have not yet started reaping.

Mr. Pablo is TCGA's chairman. He is widely respected in the community as an honest and hard working farmer. He grows citrus organically, keeps bees, and grows vegetables, beans, and corn in addition to his cacao. His farm is at the end of a small road, 11/2 miles (2.4 km) from the village.

Mr. Pablo's nursery has a Shurflo submersible pump, powered by two Siemens SP75 panels wired in series for 24 VDC, with a controller. The panels are mounted on a rack made of sticks and bamboo. Mr. Pablo pumps his water from a "living spring" that never runs dry. He found it many years ago and has developed it. It is 120 feet (37 m) down the hill from his house, and before the days of the pump, he and his family collected water by bucket and carried it all the way to where his house is.

His system was originally a single panel system that I installed in 2001 while working with Plenty. When the pump arrived, it had been shipped with some skinny wire, and without thinking about it too much, I installed it using that wire. It never pumped as much water as expected, and when Ed Eaton of Solar Energy International (SEI) was down here, he looked at the system and fixed the poor job I did by installing properly sized wire.

Even though I have lived with solar electricity for years on our farm (see HP67), I wrongly assumed that the wire was sized for the pump and used it, even though in retrospect, it was obviously grossly undersized. This underscores the need for proper education in solar technology that groups like SEI can provide.

Mr. Pablo's Shurflo submersible pumps about 11/2 gallons (5.7 l) per minute up the hill. It has never needed any maintenance, and has proven very reliable in the year and a half it has been installed.

While we were waiting last year for the solar-electric panel for this original system to arrive, we decided to

Water from Mr. Pablo's spring used to be carried in buckets—now the sun does the work.

Water from Mr. Pablo's spring used to be carried in buckets—now the sun does the work.

Mr. Pablo, farmer and head of the Toledo Cacao Growers Association, is proud to use renewable energy and organic farming techniques.

use one of my extra panels, a Photowatt 75 watt panel. When the Siemens 75 watt panel finally arrived, Melanie at Plenty suggested that I just keep the Siemens panel and leave the Photowatt where it was. I figured a PV is a PV, right? Wrong, apparently. As Ed explained it to me, the voltage of all crystalline PVs drops as temperature increases. But single-crystalline PVs tend to be less affected by high temperatures than polycrystalline modules, like the Photowatt.

Two new Siemens panels arrived, and all I had to do was remove the Photowatt panel, and install the two 75 watt panels in series for 24 volts nominal. I configured the pump control to 24 volts, and presto, the pump was pumping double what it had at 12 volts on the single panel.

Mr. Pablo gets plenty of water to his house. This water kept his 8,000 seedling trees wet without a hitch. When the rainy season started again, all the trees went out for planting, and next year, TCGA will use this and the other nursery sites again.

Seeking Better Pumps

When I started looking into what sort of pumps we should use in the other two nurseries, I wanted efficient and trouble-free pumping. Mr. Pablo's Shurflo submersible pump has been trouble free, but we wanted something with more volume and longer projected lifespan for the rest of the nurseries. There is no UPS truck to deliver replacement parts in Belize, and shipping is expensive. In addition, everything that comes into Belize is charged duty. And the thought of having downtime while waiting for a part was troubling.

I did some research and contacted Windy Dankoff at Dankoff Solar, explaining what we needed. Windy suggested the Solar Force piston pump. I have actually been considering a Solar Force pump for a few years for our farm to replace the seemingly never-ending series of inexpensive Shurflo and Flojet diaphragm pumps that we have gone through—about one a year.

The folks at Dankoff designed two systems with Solar Force piston pumps and two 75 watt BP275 panels. One of them is at Ignacio Ash's farm in San Pedro Columbia, where he waters 10,000 trees in bags. The other is at Auxibio Sho's farm in San Jose and is used to irrigate the 8,000 trees in his nursery. The pumps themselves are heavy. They are solidly built and look as if they will easily last the 20 years that Windy says they can.

Taylor Steele at Dankoff Solar handled getting our order together. He took the time to find a less expensive air freight carrier that saved TCGA a few hundred dollars. In addition to this, a percentage of the equipment was donated to TCGA by Dankoff Solar.

A Dankoff Solar Force piston pump runs efficiently on 24 volts DC from a couple of PV panels.

Ignacio Ash's System, San Pedro Columbia Village

San Pedro Columbia is the largest Kekchi Maya settlement in Belize. It was established in the early 20th century by immigrant Kekchis fleeing forced labor and conscription in Guatemala. There are about twenty producing cacao farmers here, but roughly forty new farmers are planting cacao now. San Pedro Columbia is notable for having Belize's oldest producing cacao groves. Two, 20 acre cacao groves were planted around 1905.

Two BP275 photovoltaic modules directly power the Solar Force piston pumps for two identical pumping systems for organic cacao farmers Ignacio Ash (shown) and Auxibio Sho.

Two BP275 photovoltaic modules directly power the Solar Force piston pumps for two identical pumping systems for organic cacao farmers Ignacio Ash (shown) and Auxibio Sho.

Solar Water Pumping

Ignacio is the TCGA's extension officer and works parttime in other communities encouraging farmers to plant more cacao. His farm is 2 miles (3.2 km) up the river from the village. The only way to access his farm is by walking or by canoe. His farm is situated in a beautiful valley near where the river comes out of the ground. He is an industrious farmer, and a friend. My wife and I are lucky to have him as our neighbor across the river from our farm.

Ignacio Ash has two, BP275 panels mounted on a UniRac U-22-44M, top-of-pole PV rack. This is connected to a Dankoff pump controller (linear current booster) LCB-8A and then to a Dankoff Solar Force piston pump.

The system arrived in a small mountain of boxes, and I have to admit I was a wee bit intimidated on seeing them all. But the instructions were easy to understand, and with Plenty volunteer Mark Miller, it took us a few hours to set everything up, lay the pipes, and install the foot valve. When we turned the switches in the controller, the pump came to life.

Ignacio had already laid pipe into a pool in the river near where he ties his canoe. The river is clear and cold, since the source is only a few hundred meters up the valley from the pump site. We poured water in through the top of the pump, but it didn't pump. From reading the manual, we knew that this was because the leather piston seals needed to expand a bit. Lacking the tools to dismantle the pump and stretch the leathers manually, we left it for another day.

Two days later, I came over to Ignacio's farm, tool kit in hand, expecting to dismantle the pump. I was pleasantly surprised to see the pump quietly pumping away. Apparently the leathers needed only a bit of time and some water to expand on their own. Gushing out the end of the pipe was clear cold water. We filled a 5 gallon (19 l) bucket in about a minute.

Ignacio had set the two, 75 watt BP panels on a UniRac pole mount, but lacking a pole, he mounted the rack on a guava branch buried about 36 inches (91 cm) into the ground. Eventually he plans to get a pole and set it in concrete, but he likes his guava mount for now.

How Does a Solar Water Pump Work?

Windy Dankoff ©2003 Windy Dankoff

The TCGA project uses solar-electric panels to power a special type of pump. They are solar-direct, which means they have no batteries. They pump only during the day when there is sufficient sunlight. Like a traditional water pumping windmill, a solar-direct pump is typically used to fill a storage tank. The tank is sized to hold at least five days of water supply for use on cloudy days and at night. A water tank is cheaper and more durable than the equivalent energy storage in batteries.

The Dankoff Solar Force piston pump differs from a conventional electric pump in three fundamental ways.

The Dankoff Solar Force piston pump differs from a conventional electric pump in three fundamental ways.

Photovoltaic Panel:

Makes DC electricity

Photovoltaic Panel:

Makes DC electricity

1. It uses a DC (rather than AC) motor that varies its speed in response to the available solar power.

2. It uses a positive displacement mechanism that efficiently forces water up, even when running slowly. Other pumps use a centrifugal mechanism that loses its vertical lift capacity when the speed is reduced.

3. It uses less than half the energy of a centrifugal pump, thus minimizing the size and cost of the solar-electric array.

3. It uses less than half the energy of a centrifugal pump, thus minimizing the size and cost of the solar-electric array.

Pump Controller:

Adjusts voltage and current to optimize pump performance

Between the array and the pump is the controller. This is an electronic device that matches the power from the array to the demands of the pump motor. The pump forces water up as soon as it begins to turn, demanding full torque from the motor. In weak sunlight, the array supplies full voltage, but reduced current (amps). The current produces the torque in the motor. So, the controller reduces voltage and increases current so the motor can start and run even in weak sunlight. It's like starting your vehicle in low gear.

These systems represent one type of solar pump. Another option is to use a submersible pump. Another variation is to use a battery system. This has the advantage of pumping at any time, which is the key to keeping water pressurized. A pressure system eliminates the need for an elevated storage tank. Many remote homeowners choose a battery-based pumping system for that reason. They can run it on the same battery bank that supplies their lights and appliances.

Pump Controller:

Adjusts voltage and current to optimize pump performance

Solar Water Pumping

The author tends young shade trees.

Ignacio has since laid a few hundred feet of pipe up the hill to a 400 gallon (1,500 l) tank, which he uses to gravity feed the nursery site and his house. The nursery at his house handles 10,000 trees.

Auxibio Sho's System, San Jose Village

San Jose was established when San Antonio village subdivided and a percentage of the village moved there to look for new land. There are about seventy producing members there, and about thirty farmers who have young cacao that is not producing yet. (Cacao takes five years from planting to first harvest.) Cacao is the single

Healthy cacao seedlings thrive in the shade, drinking clean water pumped by the sun.

A Blatant Plug for Great Chocolate

Toledo Cacao Growers Association sells 100 percent of its cacao to a small, ethically minded, organic chocolate company in London called Green & Black's. This cacao is transformed into a fine, orange-flavored. organic dark chocolate called Maya Gold.

Green & Black's was the first company to sell certified organic chocolate, and Maya Gold was the first cocoa product to earn the Fairtrade mark. Fairtrade is a third party certifier that seeks to help ameliorate the inherent inequalities in North-South trade and buffer the effects of the highly volatile international market on pricing for cacao, coffee, sugar, tea, bananas, citrus, honey, and mangoes for producers in developing countries.

Green & Black's has a deep commitment to the producer groups that provide them with cacao. They have eight types of bar chocolate, all organic, ranging from organic milk chocolate to organic dark chocolate, and they are all very, very good.

By being certified organic and certified Fairtrade, the farmers at TCGA have a stable price that doesn't fluctuate like the extremely volatile world market price for cacao. A few years back, the world market price dropped significantly. The farmers at TCGA were getting three times the world market price for their cacao.

TCGA and Green & Black's have what is called a five-year rolling contract, which means that every morning when the sun rises, the farmers have a guaranteed market for 100 percent of their cacao at the third party Fairtrade mandated price for the next five years. This gives stability, and allows farmers to plan ahead. In the unlikely event that Green & Black's wanted to stop buying cacao from TCGA, they would have to give TCGA a five-year notice of their intentions. This would allow the cooperative five years to find another buyer.

If you see a Green & Black's product on the shelf—buy it! I am sure you will like it. If your local health food store or cooperative doesn't have it, ask them to carry it. By purchasing organic, Fairtrade chocolate, you are supporting small cooperatives, sustainable agriculture, and ethical trade. Eat Maya Gold!

Single Pumping System Costs


Cost (US$)

Dankoff Solar Force 3020-24PV pump


2 BP275 PV modules, 75 W

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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