Mekong Eye

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Let the sunshine in

Reporters talk with two citizens who have installed solar panels in their homes — one off the grid, the other on the grid — about what one can expect from investing in renewable energy.

Workers install solar panels on Weeraboon Wisartsakul's house. Photo: Weeraboon Wisartsakul via Bangkok Post

By Apipar Norapoompipat

Bangkok, Thailand, August 24, 2017

Bangkok Post

Off the Grid with Rattana Sangcharern

Rattana Sangcharern, an energy technical officer at the Provincial Energy Office in Sa Kaeo, has been using the off-grid solar panel system for around five years. Off-grid means that the system is not connected to the main transmission line, only generating electricity when there is sunlight. Energy is instead stored in batteries, where it can be used later even when there’s no sunlight. Rattana had to design a system in order to store and generate enough power to meet her home’s requirements. For her house, she uses five 250W polycrystalline solar panels installed on the roof of her water tank, a 1,500W inverter and six deep-cycle 125A batteries to store the electricity, which generate 1,500W of power in her home to use constantly.

Why did you choose to install an off-grid system in your home?

I moved from Maha Sarakham to a piece of land in Nakhon Nayok, but it was far from any transmission lines. I tried to talk [with the energy authority], but they said 300,000 to 400,000 baht was needed to expand the line. I thought it was too expensive, so I decided to invest in solar panels. The system runs the electrics in my house normally like any other household — except for the air con.

How much did that cost you?

It was around 135,000 baht. It was just a coincidence that I was able to do everything myself. My partner is a solar-cell mechanic. Part of the equipment we used was second-hand, as we knew some companies. But the initial cost of the investment was 80,000 baht, as the system wasn’t that big.

How much money did you save by investing?

Compared to the cost of expanding the transmission line, it’s worth it. It’s instantly worth it once you install it. I don’t have to pay monthly for electricity bills. However, if the area has electricity already, the amount of time for you to break even would be about 40 years, as there’s also issues with maintenance. Every year, we have to wash, clean and refill distilled water in the batteries.

So that would mean that if you already have electricity in your area, it might not be worth installing?

People who already have electricity to use might say that installing the system will reduce the cost of electricity. But there’s actually the responsibility of these other factors, like the batteries. So I don’t recommend people who already have electricity to use to install this system. The system with batteries isn’t worth it. But if you do the on-grid version, where the panels are attached to the line and you use a lot of electricity during the day, it’s probably worth it.

What are some of the challenges in maintaining an off-grid system?

I installed an inverter of 1,500W. When I use electricity, I have to look at all the electronics in my house, of how many Watts each item uses. For example, the rice cooker eats up 600W, the boiler is 600W, the fridge is around 1,000W. If we use it all at the same time, it will cause damage to the inverter, as it’s over-capacitated.

The main aspect is the batteries. Because when solar cells charge, deep-cycle batteries have both distilled water and acid. When the batteries charge, they boil. Once they boil, the distilled water evaporates. If we don’t fill it up every two weeks, the batteries will break. If it’s about the panels, I can’t maintain them because they’re too high up. I let the rain do the work. And there’s nothing much about the inverter, because it depends on our usage. Everything revolves around the batteries and our usage.

If electricity finally makes it to your plot of land would you consider switching back to the line?

I don’t think I’d switch [laughs]. I see that I’m able to rely on myself, and it’s a charm of my house as well. People have asked this question and I tell them not yet — unless I run into another battery problem [laughs].

On the Grid with Weeraboon Wisartsakul

Prof Weeraboon Wisartsakul of Thammasat University’s Puey Ungphakorn School of Developmental Studies has been using the on-grid solar system for a little more than a year. As previously mentioned, the on-grid system is when solar panels are connected directly to the transmission line run by the Metropolitan Electric Authority. They generate power only when there is sunlight, and excess power can be generated back into the grid. Unlike Rattana, Weeraboon has installed the system to sell electricity. He invested around 270,000 baht in installing 14, 250W polycrystalline solar panels on his roof, a 3,680W inverter and a digital electricity meter to measure the power produced. From Feb 11 to Aug 15, he sold around 17,000 baht’s worth of electricity back to the government.

Why did you choose to install an on-grid system in your home?

When I first installed it, I just wanted to experiment and collect data. When I saw that the government was opening up and that we could sell power, I tried it out. So I only sell electricity. I don’t use it myself.

Do you think it’s worth the investment?

It’ll take eight to nine years to break even. It also depends on the rate that the Metropolitan Electricity Authority buys from us as well. Right now, it’s 6.85 baht per unit. What we use as consumers is around 4 baht. So they give us an incentive of 2 baht to invest. However, when I sell power, they have a set limit that they buy from us. So even if your system can produce a lot of electricity, the Metropolitan Electricity Authority can only buy a limited amount.

Are there any other incentives at all?

There’s not a lot of policies for households to install. But there’s policies to promote factories and farms. It’s a shame.

What was the process of installing an on-grid system to sell to the government?

It took around a year to install. The solar-cell company processes everything. I installed the system around May 2015, but I started selling electricity in February last year. It took around a year for the company to do the paperwork to ask for permission and send the Metropolitan Electricity Authority the blueprints of my system. Once the Metropolitan Electricity Authority approves, they will install the system. Once it’s installed, the Metropolitan Electricity Authority will come back, check, open the system, and will start buying.

Have you run into any problems?

I haven’t faced any problems. I have to clean the panels by spraying water and polishing them every three to four months, and with the electricity system, there’s no problems there as well.

Do you think the average household should install the on-grid system?

Within these last two years, the technology has become better and cheaper. If the starting price was lower than now, it would make the break-even period shorter, and I think that’s when it’s really good to install it. Especially with what I’ve mentioned before — housing communities and places where they use a lot of electricity during the day.

It’s a shame. Because if there’s a clear cut policy, then it’ll be of great use. Especially if there’s people looking to invest to not gain quick money, but to have a social impact as well. If the government supports this, homeowners could deal with electricity themselves after breaking even. They could send the money back to the government or get bank credit. I think it’ll make it more popular. But if no one invests in the long run, it’ll be troublesome.

Do you think you’ll switch to using the off-grid system to use your own electricity?

I’m not going to use my own electricity for now. There’s no one at home in the afternoons and I don’t want to invest in the batteries. If the technology for the batteries gets better, then it might be more interesting.


As our world continues to lose the war against climate change, Thailand is slowly joining the many countries planning to decrease fossil fuel usage and promote renewable energy sources, especially solar power.

Two years ago, the government announced Thailand’s Power Development Plan, aiming to increase renewable electricity generation capacity to 30% by 2036 and 40% soon after — compared to the 13% that we’ve used in this year’s first quarter so far. Though its strategy and policies are still unclear (like no incentives, subsidies, or loans for those interested in installing) energy policymakers will probably soon let individual households generate their own power through solar rooftop panels, and not only depend on solar farms. But many still ask whether it will be worth the investment.

Prof Decharut Sukkumnoed of Kasetsart University, and technical adviser to the Minister of Natural Resources and Environment, says that the lack of investment in solar panels in households results from the lack of government support in producing electricity to sell back into the system.

“The government does it intermittently,” he said. “So people aren’t sure which period they’ll be buying for and how much they’ll be buying. So it decreases the incentive to invest and sell into the system.”

His hope is for the government to open up projects where there exists stability and security within the policies.

“We should know at least three to four years in the future how much and at what price they’re willing to buy electricity,” he said.

“I also want them to consider creating a loan system for average people to invest in solar cells. It’s like when we build a house. We barely use our own money up front; we take out a loan and then we pay it back. Solar cells can create income instantly, but there’s no loan system in place. If there’s a loan system, I believe that people would take an interest in installing solar panels. Solar cells are an extremely important variable in reducing climate change. It’s the most important, after managing electricity demand.”


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