Summer has just started but the heat is becoming unbearable. Electricity costs -- at a record high of 4.72 baht per unit -- are set to soar further thanks to rising fuel costs. These two factors alone are enough to increase interest in solar rooftop systems among households.
Sunlight is plentiful in Thailand, after all. And it is free. Embracing renewable energy can also help battle climate change, which is another positive factor.
Clean is cool -- that is true. But a solar rooftop may not suit everyone. These are a few things to consider before you start shopping.
Financial investment
Sunlight is free, but photovoltaic panels are certainly not. Indeed, they are quite costly and no matter how efficient they may be, solar rooftops remain a long-term investment.
Depending on the type of solar panel, the installation cost and your rate of power consumption as well as behaviour, it can take an initial investment of around 200,000 baht and around five to 10 years to break even, depending on the current electricity tariff, before you start making a profit.
"Before, I would tell aspiring homeowners that it would not be worth it if they had to take out loans to install solar roofs," said Khomgrich Tantravanich, secretary-sgeneral of the Energy Regulator Commission (ERC).
But things have changed. Ten years ago, the cost of solar panels was much higher. There were no specific loans for the installation either. Those interested in solar energy thus had no choice but to take out normal loans with high interest.
At present, soft loans especially for solar rooftops -- some with an interest-free period and installation services -- are available which makes it easier for homeowners to consider the renewable energy option, Khomgrich said.
Objective
The next question is to determine what your objective is for installing a rooftop solar system.
While there are three types of solar rooftops -- on-grid that sells the power to the grid; on-grid which is mostly for self-consumption; and sale of excess power to the grid and off-grid -- Khomgrich suggested that homeowners consider only the on-grid system as it is the one being promoted by the government through the ERC's household solar rooftop campaign.
Under the scheme, homeowners can register to sell excess electricity to the government at the price of 2.20 baht per unit.
Although the resale rate is no match to the 4.72 baht electricity tariff, it is still better than wasting energy, Khomgrich said.
"I think the battery system is not worth investing in for on-grid households at present. However, by investing in household solar promotion, the government allows the sale of excess power to the grid so the grid can perform as a battery to provide power backup automatically. Additionally, the price of the storage system, its relatively short life span and high maintenance needs make it not cost-effective," Khomgrich said, adding that under the ERC's household solar rooftop programme, it is the grid that serves as the communal storage.
Power consumption behaviour
Households that will benefit from the rooftop solar system are those that use electricity during the daytime when the panels generate electricity.
"Check if you have people who stay at home during the day and use power -- the elderly, children or family members who work from home. If you have to use air-con during the day, it is more likely to be worth it. If it is just one refrigerator as every member of the household leaves for work in the morning and does not come back home until late, a solar system may not be the perfect answer," Khomgrich said.
If homeowners have checked all conditions and decided to go for the solar rooftop, Khomgrich recommends that they carefully calculate how much electricity they use and invest in just enough kilowatts of power.
"Although the government agrees to purchase up to 10kWp from households, the primary aim is for self-consumption. Also, the feed-in rate, albeit having been raised, is still much lower than the electricity tariffs so there is no incentive in having excess generating capacity," he said.
Roof structure
Once homeowners decided to install a solar rooftop system, they should contact a reliable provider and have an engineer do a thorough inspection of the site, according to Khomgrich.
For an initial assessment, the roof has to be wide and strong enough to support the solar panel. Roughly speaking, a 1kWp solar panel requires an area of about 7-8m² and weighs 10-12kg.
"Ceramic tile roofs usually come with strong enough structures to support the solar rooftop. For other types of roofings, or wooden houses, a supporting structure may be required," Khomgrich said.
But that is not all. The roof can be wide and strong, but if it is surrounded by tall buildings or trees and comes under shade most of the time, it is not an ideal candidate for the solar rooftop system.
Since solar panels can last up to 25 years, Khomgrich suggests that homeowners consider installing access to the roof for maintenance if possible.
"Although the rooftop solar system is among the easiest when it comes to maintenance, we still have to clean the panels from dust, oil stains and other pollutions from time to time otherwise they become less efficient. Access to the roof will make it easier," Khomgrich said.
He adds that for older houses, the owner may as well consider rewiring the house as the old wires are less energy-efficient and prone to damage.
Now, or later?
Although the price of solar panels has come down over the past decade, Khomgrich said it is not necessarily true that solar rooftops will become cheaper especially if the prospect is for only a few years in the future.
"It is up to demand and supply. China is the biggest producer of solar panels in the world. Prices thus vary according to its production. For example, a few years ago China produced a lot of panels so the prices dropped. But once the production slowed down, the prices have gone up. So it is not necessarily true that if one waits, the solar rooftop system will become cheaper," Khomgrich said.
Interested in installing a solar roof?
With UOB you can use credit card instalments to manage the initial cost.
UOB Loan Promotion:
When purchasing solar panel installation equipment with a UOB credit card, you are entitled to instalment payment with 0% interest for 10 months. Or pay your instalments using UOB Cash Plus card with 0% interest for 24 months.
This article is part of a 20-part series that explores what it takes to create and secure a sustainable future. In collaboration with UOB. You can view the whole series here.
