Ice from the sun: a day with Okra Solar

Written June 13, 2019

Yesterday I rode a long wooden boat through wetlands to the village of Prey Pdao in southern Cambodia. I was visiting the pilot site of Okra Solar, a tech start-up whose mission is to bring reliable electricity to the 1.1 billion people who still live without it.

The waterway between Prey Pdao and the mainland. Getting into the village requires a boat ride year-round.

Here in Prey Pdao, the main occupations are seasonal – tending rice paddies in the dry season, fishing in the wet. At the end of the annual rains, between September and November, the wetland floods into an expanse of open water, lapping at the village on all sides.

Prey Pdao is a four-hour drive straight south from Cambodia’s capital, Phnom Penh. Yet, it is not connected to the national electricity grid. The neighboring mainland villages have been connected for years. While the national grid is not entirely reliable, it gives families access to all sorts of appliances and electronics. Women can replace hours of drudgery with electric water kettles and washing machines, and children can study after dark. With a smartphone, charger and mobile data, everyone can access the knowledge and entertainment of the internet. It’s a huge step for families climbing out of poverty and achieving the comfort and income they want.

Until now, those opportunities have been largely absent from Prey Pdao. Utility companies consider hanging wires across the seasonally-flooded wetlands too expensive. Power lines that hang high above the water in the dry season would bump boaters’ heads in the wet season, and the shifting muck might make poles tilt, as I witnessed in coastal Louisiana in 2009.

A sideways pole in Louisiana, United States in 2009. One of the first photos I ever took! The shifting muck and seasonal floods of wetlands make utility poles expensive and high maintenance.

Okra Solar, a start-up social enterprise in Phnom Penh, brought electricity to Prey Pdao last year. This community is the pilot site for their unique style of solar energy. Okra Solar is a small team of passionate and brilliant engineers (including the one and only Nithya Menon) who’ve realized that the flaws in solar energy might be solved with some creative engineering.

Typical small-scale solar comes in two flavors. On the simple end, a single house installs a few panels and batteries and uses the electricity for its own needs. The problem is that to cover big loads, like a washing machine, or periods without sun (think nights and clouds) the system would need so many panels and batteries, it would be too expensive for most people. When it’s sunny, the solar panels quickly fill the battery to capacity and then sit there like inert hunks of metal. Many off-grid houses still manage to run a light bulb or radio from a small solar kit, but Okra Solar is trying to provide a step up in terms of energy quantity and reliability.

The other flavor of small-scale solar is the centralized microgrid. This system looks like a field of solar panels and batteries in the center of town, running wires out to participating houses. The downside here is that upfront cost can be prohibitive if households are required to buy the equipment. It’s also inflexible. Households need to predict their electricity use years in advance, a difficult task when they have no experience with an electricity bill. And they have to estimate based on rising needs, meaning much of the generated power will go unused at first. Once enough households begin using the full electrical output of the system, after a couple years, they will surpass the power output and need to overhaul the central system – leaving families in perpetual debt. Lastly, all batteries are hooked to each other, so if you want to add a few or replace ones that fail, the entire set has to be switched out at once.

James, Okra Solar’s community liaison for the Philippines, holds a first-generation Okra pod in Prey Pdao.

Okra Solar’s solution is to connect houses to one another in a mesh-like network, called an Okra grid. Each participating house has a solar panel or two on its roof, a battery inside, and an Okra Pod. Wires connect each house, so their solar panels and batteries communicate smoothly with all the other houses’.  There is no centralized panel field or battery bank. By sharing electricity and loads, the houses of a community can use the electricity they need, even at night and on cloudy days, without massively overstocking their personal inventory of panels and batteries. Surplus electricity from any one house flows out into the grid.

A local utility company owns and monitors the equipment, so families don’t have to invest a big up-front cost or manage their own repairs. This utility company bills each household for the amount of electricity it actually uses, and it can increase or decrease its consumption at any time.

The key to this system is a nifty bit of equipment called the Okra Pod. For engineers out there, it technically a controller. On the outside, it’s a plain white box with the cross-section of an okra stamped on it (yes, the vegetable). On the inside, it’s the masterful product of three years of the Okra engineering team’s sweat, tears and laughter.

The Okra Pod allows impressive flexibility. A household that initially opted out can join a nearby Okra grid at any time, or start a new one. Okra calls this system "plug and play." The minimum number of houses to start an Okra grid is two. Any number of households can join the grid, adding solar panels, batteries, and Okra Pods as they go.

Have you ever cut a pod of okra, that bitter green vegetable, in half? I bet it looked different on the inside than this Okra Pod!

Yesterday, I accompanied the Okra Solar team to Prey Pdao to see their pilot site and speak with customers. We started by crossing the watery gap in a long, wooden boat with a retrofitted tractor engine.

A young boy pretends to drive the boat across the wetland into Prey Pdao as we wait for its (adult) captain.

In Prey Pdao, I met Chaathy, a woman who has run a shop with her husband since 2009. She sells drinks, snacks, ingredients and fertilizer. During the two hours we visited Chaathy’s shop, she never paused in her work making fishing nets. She gathered the transparent threads in one hand and used pliers to clamp them in place with metal clips, so quickly her hands were a blur. An LED light bulb glowed blue-white over her head, and a standing fan cooled her with a constant breeze, both powered by the Okra grid.

Chaathy is a shop owner and fishing-net weaver in Prey Pdao. She uses the lights and fans powered by the Okra grid to make more nets in comfort and increase her income.

Chaathy’s husband, Sophal, has lived in Prey Pdao since 1987. He sells gasoline for members of his community to fuel their boats. The wetland that blocked the national grid from his village has also been an obstacle to his gasoline business, but now, with the electricity from the Okra grid, Sophal can rely on his phone to coordinate gasoline deliveries and sales. When he receives a call from his Vietnamese gasoline suppliers, he gets a boat ready to meet them and bring their gasoline back to Prey Pdao. On the sales side, many of Sophal’s customers pay him with “mobile money,” a digital currency common in Cambodia. Then Sophal can take his phone to a mobile money stall in the nearby town and convert it to cash, which he uses to pay household expenses or reinvest in his business.

Sophal uses his cellphone, charged by the Okra grid, to coordinate gasoline deliveries from his supplier and sell the fuel to his community using “mobile money,” a form of digital currency.

Before Okra, Chaathy and Sophal had a single solar panel from a local shop connected to their house. It powered one fan and two lightbulbs. As Sophal quickly added through a translator, “We could only use one light at a time.” They prioritized lighting the cooking area and the front porch from 6 to 10 pm. Chaathy could make six to eight fishing nets in a day, worth $10 to $12.50, limited by the intense heat of the day and darkness at night. When the sun shone and the battery filled, they could also power a television from one or two hours a day. If the sun didn’t shine, they cut out the fan and TV.

Now, with the Okra grid, the electricity is reliable and suffers less impact from weather. Chaathy can produce up to 20 nets a day, worth $32, more than doubling her workday with electric lights and fans. The household can power four lightbulbs, two fans, and four mobile phones, which Chaathy uses to stay in touch with her grown children who live on another river in the province. And the family can watch five hours of television a day.

TV might not sound like a productive activity, but Chaathy said it’s the most valuable benefit for her. She watches local and international news, as well as Cambodian and Thai dramas. It helps her relax and compare what’s going on in Cambodia with the rest of the world, she said.

When provided fairly, electricity can help improve education, income, and gender equity.

Two women accompanied our visit to Prey Pdao: Juliette, a gender consultant, and Charrya, a staff member from one of Okra Solar’s grantors. Together, we spoke with a circle of women gambling animatedly with cards, and the conversation went something like this.

Charrya: “Do you have a smartphone?”

Women playing cards: “No.” (without looking up from their hands)

Charrya: “Do your husbands have smartphones?”

Women: “Yes.”

Charrya: “Do you want a smartphone?”

Women: “Yes!” (looking from their cards for the first time, laughing)

Charrya: “Why don’t you have one?”

Women: “Too expensive! No money.” (absorbed again in the game)

Between rounds, they explained that while they manage the family’s finances – budgeting, calculating income and expense, making frugal purchases – the male head of the household has more control over using appliances.

The gambling women gave examples of what they’d seen on television, such as women in business and scenes of domestic violence. One woman said the TV made her more aware of domestic violence, what causes it, and what to do when it happens. She’d even talked to her husband about it. But, she concluded, it hadn’t changed his behavior.

A solar panel sits on the roof of a house in Prey Pdao, one of forty houses connected to Okra grids in this wetland-ringed community.

Chaathy and Sophal are testing out a freezer provided by Okra. The first model, a bulky rectangular box, sputtered out quickly, but a new model in the shape of a yellow cube is still chugging along. It’s the first freezer the community has owned. Both children and adults frequently slide back the lid to peek into its frosty depths. The peeking puts strain on the electrical system, but who can blame them? Here I am, surrounded by a flooded wetland in the tropical heat, peering into a potential source of non-carbon energy for the 1.1 billion people who still live without electricity. I was tempted to slide back the door of the freezer myself and marvel at the transparent chunks of frozen water inside, ice from the sun.

Post script: When I wrote this post in June, I was visiting my incredible friend from middle and high-school, Nithya Menon, now a firmware engineer. Check her blog, Off the Beaten Path, for more insights into the whirlwind life of a tech start-up in Phnom Penh!