Paul Polak, SunPower and good news for poor farmers
Paul Polak is an accomplished man and a very busy man. After spending a few decades researching and trying out various innovations to lift poor farmers out of poverty, he wrote Out of Poverty in 2008. Making the treadle pump affordable to low income farmers was among his earliest invention. IDE (International Development Enterprises) is possibly the first organization Polak created — as far back as 1982. From donkey carts in Somalia to treadle pumps in Bangladesh to coconut processing plants in Vietnam to drip irrigation systems in Nepal and India, the range of innovations is pretty diverse. We wrote about one of IDE’s for-profit spinoffs – Global Easy Water Products (GEWP) – here.
More recently, Polak started Spring Health – a social enterprise that sells safe drinking water in Eastern India. In this interview, he says “Spring Health is starting its commercial rollout phase, which aims to reach 50 new villages a month in the fourth month. We’ve learned a lot in the 35 village beta test, and while we face considerable risks, I believe we have a strong chance of achieving both scale and profitability in selling safe drinking water to poor rural customers within 3 years.”
Some people never tire. Or retire. Paul Polak is one of them.
He has started yet another initiative. SunPower is a 2,000-watt solar pumping system that is affordable for farmers who make $3 to $5 a day. Polak’s team is running an Indiego campaign to raise $50,000 to complete building the prototype, in partnership with Ball Aerospace engineers. The campaign’s already reached the halfway mark.
Cutting cost from $7000 to $2500
The SunWater team has defined the problem as cutting the cost of an installed 2-kilowatt solar PhotoVoltaic (PV) powered pumping system to $2,500 – price of controller, pump and motor at less than $1,100 and 70 cents a watt ($1,400 for a 2-kilowatt system). Replacing solar panels with mirrors is another unique aspect of what they are attempting – more details on the Paul Polak blog. If they get anywhere close to these numbers, they’d would be economically competitive with diesel-powered pumps.
In this NYTimes article, Polak talks about the SunPower system in a fair bit of detail – excerpts below.
The breakthrough in affordability is based on a total systems design approach, in which the cost of the photovoltaic electricity generation system is an important component. Many of the affordability breakthroughs are based on other parts of the system- the controller, the inverter, the motor, the pump, the water conveyance from the well to the crop, the water application system, the selection of high value diversified crops to be grown, and optimization of farmer production methods and access to market. For example, we can provide a drip irrigation system that costs $1,400 for one hectare, less than half the cost of conventional systems. Replacing earth channels by lay-flat hose and conventional surface irrigation by low cost drip at least doubles crop/drop efficiency. Fine tuning impellers to the exact vertical lift improves efficiency by as much as 40 percent.
This project is market driven. There are approximately 20 million diesel pumps producing irrigation water just in India now. Most of them are 5 horsepower with vertical lifts in the suction range. We are designing a radically affordable 2 kilowatt solar pumping system capable of drip irrigating one hectare of high value diversified off-season fruits, vegetables and spices at a retail price 80 percent lower than the existing price of $7,000 for an installed 2 kilowatt solar pumping system in India today. To irrigate 1 hectare (2.5 acres), Jack’s calculations assume we need to apply 5mm/day, which we will deliver through a low cost drip irrigation system. Since it is capable of irrigating 1 hectare of land, this system will be attractive for a very large population of farmers, first in India and then in other developing countries.
Since PV is costly, we start by lowering the cost of the PV system through the use of concentrators. The basic idea is that its cheaper to build flat plate mirrors with a simple tracking devices than it is to invest in larger solar panels. With an efficiency of about 70 percent in mirror-reflected light, our pilot tests with miniaturized models indicate we can obtain an output of about seven suns from 10 mirrors on which 10 suns of light fall when the sunlight is concentrated on a solar panel. This means that in full scale models, we should be able to get approximately 2000 watts output from a 300 watt panel on which 10 mirrors concentrate light.
The problem of overheating of the panels is addressed by attaching a simple water based heat exchanger to the back of the panel through which a small portion of the groundwater we are lifting is pumped. We are using flat plate mirrors because they are one-third the cost of parabolic mirrors, and because flat plate mirrors can be obtained just about anywhere comparatively cheaply in rural areas in developing countries.
[Closing Note: Hat tip to Gaurav Makkar for alerting me to SunPower.]