GREEN Information 04 – Solar Panels
Solar energy classified into Thermal and Light, is the cleanest and most inexhaustible of all known energy sources. Photovoltaic System (PV System) sometimes known as Solar Panels are usually installed on roofs of houses or on top of street lamps. Its function is to convert solar power (sunlight) into electricity. Such system can be made up of one or more Photovoltaic (PV) solar panels with an inverter or other devices which is used to store the solar energy.
The disadvantage of PV solar panels is their high cost and relatively low energy conversion rate (only 13-15%). Thermal solar on the other hand has average efficiency levels 4-5 times that of PV solar panels, and is therefore much cheaper per unit of energy produced.
Energy Management Software(s) or Maximum Power Point Tracker (MPPT) is sometimes included in the Solar Panels system as well. These serves as control panel to the energy received from the sunlight as it allows the user to adjust the amount of energy to be use for certain appliances.
Solar system produce electricity in day time, batteries can be installed to store the energy for the heavy usage of electricity at night. But this method is quite expensive and requires a lot of maintenance. Solar energy stored may also be transferred to electricity grids or combined with electricity generators to power hybrid electricity plants.
Selling collected electricity back to Power Grid
From the year 2010, Government of Singapore allows private house owners to build their owner solar power generation system and connect to Power Grid. As there’s more production in day time than usage, the extra portion will be exported back to Singapore Power Grid. Your meter will be changed to a 2 way meter, which has 2 readings: how much you use, and how much you already exported to Power Grid. At the end of the month, the amount you exported to Power Grid will offset your PUB bill, including water, gas, etc. Application submission to SP Services will be around 8 weeks.
Calculation for the size of a Solar Power Generation System, depend on:
i) consumption requirements (average monthly utility bill for electricity is around $150, therefore the consumption is around 560kWh)
ii) available installation area above roof surface with very good sunshine position (therefore, for a production of around 560kWh electricity, it is calculated the installation area will be around 50sqm, about 20 Nos of Solar Panels)
iii) budget (installation of 20 Nos of Solar Panels will cost about $17,000)
Solar Water Heater
A solar water heater basically consists of solar collector (collecting the solar energy), storage tank (store the heat), backup heating system and controller. The heat collected in daytime will be stored in the tank, so you can still use the hot water at night. During raining season, the water temperature in the storage tank is lower than preset value of 40 Celsius Degree, the backup heater will switch on automatically to ensure continuous hot water supply.
How does using solar panels help the Environment?
1kWh of electricity will produce about 1kg of CO2 emission, which will resulted in global warming or “GREEN House Effect.” Burning fossil fuels such as coal for electricity production, and gas for water heating both release large amounts of CO2 into the atmosphere, thus contributing to this environmentally harmful phenomenon. Using solar and other forms of renewable energy reduces reliance on fossil fuels for energy production, thus directly reducing CO2 emissions. CO2 emissions contribute to global warming, an environmental issue which is now of great concern. The average household can reduce CO2 emissions by as much as 20% by installing solar panels.
By using renewable energy sources such a Solar Thermal, Solar PV, Wind, Hydro and Geothermal, reliance on fossil fuels can be minimized. In the average household, water heating accounts for around 30% of CO2 emissions. By installing a solar water heater, which can provide between 50-70% of your hot water heating energy needs, you can reduce your total CO2 emissions by more than 20%.