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Quick Useful Information
Rules of Thumb (Singapore)
For 1 kWp installation:
What is Solar leasing and PPA ?
Frequently asked questions
1. How does solar technology work?
Today’s solar energy systems use three different types of technologies: PV panels, SHC and CSP. PV panels, usually made of semiconductors like silicon use photovoltaic cells to convert sunlight directly into electricity. Sunlight dislodges electrons in these semiconductors so they can flow freely. The electric field in each PV cell forces these freed electrons to flow, creating the electric current that powers the various devices in your home. The more direct sunlight each PV cell can absorb, the more power you get out of them.
Solar heating & cooling (SHC) systems consist of three main elements: a solar collector, insulated piping, and a hot water storage tank. These systems absorb the sun’s thermal energy to provide hot water and cooling (via thermal chillers)
Finally, there’s Concentrated Solar Power (CSP) technology, which uses a parabolic mirror to focus the sun’s energy to provide a more space efficient solar energy system. CSPs use dual-axis motors to accurately track the sun for maximum radiation collection up to temperatures of 300-600 C. CSP may not work very efficiently in Singapore as the sunlight is rather diffused due to the cloud cover rather being direct as required by the mirrors.
2. Do my solar panels still work at night or when it’s cloudy/rainy?
Photovoltaic panels will work in indirect sunlight, even when the light is reflected or partially blocked by clouds. Depending on cloud density, most solar panels will produce 10-25% of their rated capacity on overcast days. The same holds true for foggy days. There’s also the “edge of cloud” effect, which occurs when sunlight passes over the outer edges of scattered clouds, magnifying the sunlight to create a power boost that can offset a mostly cloudy day. The point to keep in mind when considering solar power is how much sunshine you get over an entire year, not just in the summer or sunny days. Incidentally, rain can keep your panels operating efficiently by washing off any dust, dirt and bird droppings.
3. How much will it cost to install solar?
The good news is that the cost of rooftop solar has seen a sharp drop in recent years. A recent Solar Power on the Rise report revealed that prices for household solar photovoltaic (PV) systems fell by nearly 30 percent from 2010 to 2013. With Solar, the fuel (sunlight) is free and there are however upfront costs involved to install the solar panels and other required components (such as inverters). These upfront costs are paid off easily by the savings due to electricity generated by the solar panels during its useful lifetime (solar systems can last for 25 years or longer).
The best way to compare cost of solar vs. other sources of energy is the Levelized Cost of Electricity (LCOE) as it factors in upfront investment costs and running costs. As solar has not much running costs, the LCOE largely depends on the cost of availability of upfront cash to invest in the solar system. The Solar Energy Research Institute of Singapore (SERIS) provides a comprehensive LCOE calculator for your own needs. The base case LCOE for solar systems in Singapore is seen to be around 12-15 cents/unit of power generated. You should compare this with the cost of electricity with your utility provider such as SP services or others.
Many solar system providers offer free installation and generous financing options with little or no upfront costs via leasing/financing agreements.
4. What is a solar lease/financing agreement?
There are a number of ways to pay for solar power. One is to finance the system and own it outright. Financing options for direct ownership often include a low or zero down payment. Another option is to enter into a Solar Power Purchase Agreement (PPA) with a third party, which provides electrical power without system ownership. The provider owns, operates, and maintains the system, and you agree to simply purchase the system's electric output for a predetermined period. The upside of this arrangement is no high upfront capital costs, and no system performance risk or complex design and permitting processes. You enjoy positive cash flow from the day the system is turned on! When your solar lease is over (usually 10 to 20 years), you can renew the lease, buy the system at fair market value, or ask the leasing company to remove the system.
5. How much of my home can I power through solar energy?
Today’s solar systems are extremely efficient, so much so that they can easily supply the power needs of most homes. In fact, once it’s installed and working, you’ll find there are times when your solar system produces more power than your household’s electrical needs. This typically occurs during the day when everyone’s at work or school and you’re not using your air conditioning or electric heating system. The excess power is pumped back to your electric company, and you’ll get credit for the overage.
If you are living in HDB apartments, the solar energy systems on the building rooftops installed by HDB are able to power common services in the building such as corridor lightings, lifts and pumps. Private apartment developments such as condominiums are also looking for similar schemes.
6. How easy is it to install solar panels?
Having your solar panels installed by professionals is a fairly seamless process that gets panels up and running in no time. It starts with an engineer’s site survey, which includes climbing on your roof, taking measurements, and determining the ideal location for the solar panels using a solar pathfinder device. The solar panels will most likely be installed on your roof, since it has the structural specifications today’s solar panels require. Each panel will be securely mounted using appropriate hardware and flashings.
7. How much maintenance will solar panels require?
Solar panels have no moving parts, so they don’t need a lot of maintenance. Depending on where you live, solar panels should be cleaned and inspected two or three times a year. Dirt, grime and bird droppings can reduce their efficiency. Today’s solar panels are built to take heavy rain and wind; what’s more, most solar panels sold in the Singapore are UL listed, which means they`ve gone through extensive testing to withstand hail. Many of today’s top solar providers offer regular maintenance in their contract agreements so you won’t have to worry about climbing up on your roof for inspections or cleaning.
8. What are some of the environmental benefits of solar energy?
Traditional electricity is generated from fossil fuels like oil and natural gas. When these fuels are burned to create energy, they produce toxic gases that lead to pollution and global warming. Solar power systems draw clean, pure energy from sunlight - an inexhaustible nature resource. As a result, installing solar panels helps to eliminate greenhouse gas emissions and global warming. It also reduces our collective dependence on fossil fuel
The average solar panel system can offset 30 tons of carbon dioxide over three decades, saving the equivalent of driving a car over 95,000 km and eliminating 300 cubic meters of water used to produce electricity (based on data collected from the Environmental Protection Agency).