Archive for the ‘solar power’ Category

After 18 months of promoting solar energy, I finally got my own solar power system installed. The first full day of it running produced 11.1kWh. My mind jumped ahead: “11.1kWh in a day multiplied by 365 is 4,051.5kWh. We are with Origin, so we receive 50c per kWh that goes back into the grid. That means, if we achieved a 100% feed-in rate, we’d receive $2,025.75 per year!

How quickly can I get more panels on my roof?”

Then I looked at my meter. And as so many of our clients had told me, it was really running backwards:

Assumptions are Exciting but Wrong

Of course, the calculation is not correct. Firstly, this first day was a beautiful cloudless day, not too hot, so the solar power system would have produced close to capacity. On cloudy days it is going to be significantly less. In winter with shorter days it is also going to be less. It might be a little more as the days get longer, but extrapolating from one day is just not realistic.

The next wrong assumption is that we can feed 100% of the produced power back into the grid. For Queensland with its net feed-in tariff that will not happen. When we have out new meter from Energex, I’ll update you on what is realistic for us.

The other thing is that we have a 2kW system, so it is larger than the 1.08kWh or 1.6kW that most people have. However, our roof is East facing, rather than the ideal North. We had to go for that as it is the roof with the least shade (it hits about 2.30pm in the afternoon, but by then, the angle of the sun is not producing much power anymore anyway).

It is so worth it!

We also have one of the Climate Smart home meters. From that I know that our average daily consumption is 5.5kWh – less than half of that during the day. So we should be able to export two thirds back into the grid. That would still be over $1,000. Plus the savings of our own electricity.

We got the old $8,000 Federal Solar Rebate, so our return would be close to 20%. This would be one of the best returns on any investments we’ve made. Without this rebate, it should still be over 10% return, better than any bank offers.

What the actual financial outcome will be, I won’t know until in a year. But the joy and excitement of having our own power produced on site, clean and green that is great. And it has really renewed my excitement about what we are offering.

The most common type of solar, and the one you are most likely to see on roofs around your suburb, is photovoltaic, or solar PV. But solar PV is not the only type of system that can be used to transfer the sun’s energy into electricity.

There are several types of power generation methods being researched and developed but the most tried and tested methods are Concentrated Photovoltaic, Solar Thermal and Solar Ponds.

Concentrated PV

Concentrated PV works on the same premise as normal PV however it involves using mirrors to reflect rays onto either a solar cell or a solar tower.  This concentrates more rays onto the same solar cell than what would be acquired through using a flat PV module.

Solar Thermal

Solar Thermal again uses the technology of flat panel collectors however it uses these to heat water to produce high pressure steam. This steam then moves a turbine that generates an electrical current through a generator.

Solar Ponds

Solar ponds differ from the PV, Concentrated PV and Solar Thermal which all use some form of collector. They instead use salt-water lakes lined with black plastic. The plastic acts as an absorber of the solar radiation. The top of the lake is maintained with fresh water while the denser salt water collects at the bottom of the pond. Combined with the solar radiation, the dense salt water can increase up to temperatures of 85-90°C, thus creating steam to drive a turbine and again create an electrical current through a generator.

Each of these are developing technologies and therefore have their own challenges, further emphasising that PV is the best proven technology so far on the market

So you’ve done the research, selected your system, placed your order and now it’s time for your solar power system to be installed. The installation should create little disruption to the household but it is important to know how you will be affected.

Pre-Install Inspection

First off, the installer should do a pre-install inspection. This allows them to check the proposed location for the solar power system for any trees, buildings or other obstructions that may be shading the roof, as well as to ensure the roof is suitable and stable.

They will also use this opportunity to check that the switchboard doesn’t need upgrading. If they find it does, you may be required to have this completed prior to the installation. This could throw out the installation timeframe as well as cost you additional money. To avoid this inconvenience it is best that you establish when ordering your system whether or not your switchboard is suitable.

If the location and switchboard are suitable, the installation will then proceed.

Installation

While you don’t need to be home while the installation is taking place, the main power does need to be shut off for approximately 10 minutes. Given this, you need to notify the installer if you have a critical appliance that needs power.

Post Installation

The final step in the installation process in the changing of the meter. This will be carried out by the utility and again will mean the main power will be shut down for a short period of time, so it is important that you also let them know if you have something critically needing power.

If you have seen anything about solar energy in the news it is more than likely you have come across the term feed-in-tariff or FiT.

Feed-in-Tariffs

A feed-in tariff comes in two forms, gross and net. A gross feed-in-tariff means that homeowners will be paid for every kilowatt hour of energy generated off their solar power system, whereas a net feed-in tariff will see the homeowner only be paid for the surplus kilowatt hours it puts back onto the grid after household usage.

Increase Money Earned

Both of these methods can potentially mean cost savings for the home owners. While the gross FiT is by far the more attractive option, the net FiT can still help pay off the system and eventually make money for the home owner.

How? By decreasing your household usage, you will increase the amount available for you to feed back in the grid. This will work best if energy usage throughout the day (when the panels are producing their power) is kept to a minimum so maximum power is fed into the grid, then at night you buy from the grid at a cheaper rate. If you are subsidising some of your traditional power with solar power, then reducing your usage will decrease your reliance on the grid power and will again save you money.

Reducing Usage

Here are some tips on reducing your household energy consumption:

• Install Insulation. This will reduce your requirements for cooling and heating appliances, which can be big energy users.
• Section off rooms of your house when using cooling/heating to ensure you are not wasting energy trying to heat/cool unused rooms.
• Install energy efficient lighting.
• Consider having an energy audit conducted. This can identify appliances that are draining your power.
• Unplug/switch off appliances when not in use.
• Ensure new appliances have high efficiency energy ratings.
• Replace electric hot water system with solar hot water or a heat pump.

There are two factors that determine the size of solar systems: the number of panels and the watt capacity of each panel.

Output

The maximum output of the panel per hour is calculated by multiplying the number of panels by their watt capacity. For example, a system with nine 175 watt panels will produce 1.5kW per hour in sunlight.  In order to determine what size system would be best for your home, it is crucial you first identify how much electricity you are currently consuming and secondly what your energy goals are. Your current electricity usage will be found on your most recent utility statement.

Your Goals

If you are looking to only substitute some of your traditional energy with solar energy, you will need to establish how much you wish to substitute and select a system that will produce the required amount of energy.

If your goal is for your home to be 100% powered by solar, you will need to select a system that will produce enough energy to cover your entire usage.

Those who are motivated by environmental benefits as a core reason for going solar, often aim to produce enough energy to feed the surplus back onto the grid. Governments make this an attractive option through feed-in-tariffs (FiT). The use of feed-in tariffs varies across the states, (link to rebates) however most involve homeowners being paid for every kilowatt hour of surplus energy they put back onto the grid: this is called a net feed-in-tariff. The ACT, however, has a gross feed-in tariff which means homeowners will receive payment for every kilowatt hour produced off their system, regardless of whether or not it was used by that household or put back onto the grid. Both of these set-ups make the economics of a solar system more attractive, as it contributes to recouping the costs of the system.

Ability to Upgrade

It is important that your goals are considered early on in the decision making process as the size of your system may restrict your ability to reach your specific requirements, should they change down the track. If, for example, you start off just wanting to subsidise your traditional energy usage but later on want to be 100% solar sufficient, your inverter may not be large enough to convert the energy from any additional panels.

Given this, one of the most important factors to consider is the capacity of the inverter. If the inverter you choose is too small, it will need to be replaced if you decide to upgrade the system and add new panels.