Solar Power & PV Systems

Solar Power Systems & PV Panels

We have been in the trade services of Electrical and Plumbing which go hand in hand with solar power, after all where are you going to use that power, for almost 40 years. And we really like solar power. We have had the pleasure of removing electric power meters. Its a nice change from repairing building systems. Its the only time the installation we do saves money. Solar power has a return on the investment.

We repair, and install solar power systems and solar hot water systems throughout the Wellington region, either as grid-connected or stand-alone systems.

Solar Power Viability

The solar power industry has seen gradual price reductions of the panels while the price of power has continued to rise and the tipping point has crossed over for many where it is now a better investment to get power from your own panels rather than the power company.

Some typical solar power installations, where bigger savings can be made, are rural stand alone or beach houses – buildings where you are not there often, but are still paying a line charge.

Over a ten year period, line charges can mount up to $4000 at today’s prices. The catch is, you need to have a north facing roof and sufficient area to install the panels. The installation is fairly simple just requiring a connection to the fuse board.  Any surplus power can be sold back to the supplier at a set rate.

It is best to reduce your power consumption

Rather than having to produce a lot of power its better to reduce your power consumption specially at night. This saves a lot on panels and the electrical equipment to manage it. So the installation price of solar power goes down. Now we are generating it what do we do with it. Most of the solar installers recommend selling it back to the grid. But during the day its better to try and use it somewhere like the hot water heater. If your tank needs replacement its better to get a solar tank and fit a solar water heater collector as its currently cheaper to generate heat that it is power. Although that is changing fast. If you have a large tank then heat that rather than sell the power to the power company at a very low rate. If you have a larger set of panels say around 5kW then consider getting a battery and store some power.

Design of Solar Power and PV Systems

Use gas for the hob as that will reduce the size of the inverter. The hob draws a lot of power in a short burst.  I would not get a solar panel set smaller than 5kW for a 3 bedroom house with a battery and put the hot water on solar water heating. This effectively gives you 7kW of energy collection.

We can do a $99.00 electrical energy audit which should save you money and pay for it self in a very short time.

If hot water is something you want to save on but dont want to spend lots on solar panels or solar water heating then a Heat Pump water heater is an option too.

Most domestic installations are straight forward. We do have some more complex systems that can turn off outlets in the building that are not likely to be required. Eg TV outlets are usually not required 1am through to say 6am and so the usual standby power is saved.

Take care with solar sellers as most want you to sell it all back to the grid and low rates as there is nothing to use the power on. That is not an efficient way to install pv power.

Car Charging

Car charging is going to be big. So up the size of your collectors. I would consider 7 to 10 kW going forward and put the excess into your car and sell nothing back to the grid. Bi directional charging is now available so at times you can use your car to power the house at night. So you charge your car during the day with solar power and use the power from your car at night.

Winter Loads

This is the million dollar problem. In winter we want heating and this is where we have the least sun. Consider gas heating. I think its going to be a long way off before we see panels and batteries come down enough or there is enough roof area and battery storage to run heaters. Another thing to do is install R 2.7 insulation in all walls and double glaze windows using pvc frames. Go big on ceiling insulation and under floor insulation also and minimise the heating required. You may just get away with solar power using large window and perhaps a little thermal mass heating and heat pumps. Night store heaters are a form of energy storage too. If the house has a high insulation value and you can store some heat in thermal mass you can release that on winter days. Another option is to install a potbelly with a wet back and burn all rubbish heating water and discharging heat for spacing heating also.

solar hot water heating image of evacuated tubes installation in Wellington

Back Up Solar Power

These systems are not standard as they require batteries.

We can set up systems to provide backup power in the event of power cut. These systems can switch over automatically in less than a second to provide power from  batteries.

Going It Alone with Solar Power

For those requiring a standalone system from the grid then batteries are required. For example rural systems where the cost of running cables to the grid is excessive or too hard. Or you just want to be independent.

Is Wellington Suitable for PV Panels?

Power is generated from the conversion of Ultra Violet light into electricity. Germany is considered the leader  with a higher uptake than most other countries with some days producing half their power using solar panels and Italy not far behind. Wellington is considered to have more Ultra Violet light than most parts of Germany.

What’s an Ideal Situation?

For solar power if you have a low line charge or daily charge and a high per kW hour charge and we can replace some of that expensive electricity with a PV Solar panel the return will be fairly high.  It depends on the power plan that you have.  Some Wellington account holders are paying over 50c per kilo Watt on some power plans. So picking an ideal power plan is essential for solar power if grid connected.

You have spare cash earning interest at the bank on which you are being taxed. Solar panels have the effect of earning money with no tax. That’s no PAYE and no GST tax.

What’s Not Ideal?

A building with a small roof area, a shaded roof,  not facing north, a low power rate. You dont use any power during the day. Your roof is very high off the ground. Its extremely windy or pummeled by the sea.