New Builds/Renovations and Solar

I get a lot of enquiries from clients who are looking to install solar on a new house or renovation. It’s a great idea to consider solar when you have the skeleton of the house exposed as it means that the wiring can be done as efficiently and neatly as possible; some houses can be very difficult to run concealed wiring from the panels to the inverter to the switchboard and surface wiring may be inevitable. By taking the shortest possible route between the components we can also reduce losses in the cables and increase the efficiency of the system (it’s likely a minor gain, but a gain none-the-less).

The problem with designing a system for a new house (or renovation) however, is that the historical data showing energy usage is not available (or not relevant). Typically I look at how much power is historically used throughout an average day (for a few seasonal variances) and overlay that with a estimated solar output; coming up with a suitably sized system for your needs. Given that the price of solar is still dropping and feed in tariffs (in Victoria) have recently risen, it’s not such a big deal to oversize the system any more.

The other way to size the system is to base it on both the available roof space and the the average consumption for the house/family size. This gives a good ball park figure to work with, and any local variances that may increase or decrease from this average can be factored in.

Something else that you may want to consider is integration of batteries and backup systems into your house. If your power and lighting circuits are carefully planned, then you can select which appliances you might wish to keep running if the grid was to go down (and you have a hybrid system with backup functionality). Most current hybrid systems can’t just power the whole house in the event of a grid failure, so you have to choose what you want to connect to the emergency output, which is best done whilst the plaster is off the walls.

The main thing I want to convey from this post is that whether or not you intend to put on solar at the time of building, it is highly worthwhile talking to a local solar contractor about pre-wiring the house for solar. It will likely give you a cost saving as the job is done quicker, and will also result in a cleaner installation.

-Ryan Akers


I have been asked now on a few occasions about the authenticity of my pledge to donate a large percentage of profits to environmental conservation. I’ve always enjoyed getting out into our natural environment through freediving, mountain biking and hiking, and have a great respect for its fragility and need for protection. In my last job as a junior engineer I found myself doing a lot of international travel and this huge carbon footprint inspired me to think about ways that I could make a positive impact on the planet.
After looking for effective ways to make this difference, and having been inspired by the business model behind Who Gives A Crap I came to the conclusion that the best way to make this contribution was to start my own small business. I had been in an electrical business development role previously too, so I knew what I was getting myself in for.
The hard part about this business model is determining the right level of financial transparency to give; too much makes the business noncompetitive, too little makes prospective clients think that the pledge is false. For the record I have stated that I will donate 60% of profits to Trust for Nature. Profits are the proceeds left after paying for materials, wages, loan repayments, etc, etc.
As I was happy with my wages as a junior engineer, I have set my own salary at the same value; no exorbitant wages or tricky accounting to ensure that there are no profits to donate.
There’s no hiding that this is a new business, and there were large start up costs that we paid from our savings; these will be re-payed before we start generating profits; the first year will probably not see us make any contributions to Trust for Nature.
If you want to know more, or talk about this in depth, I’d be happy to answer any questions during a solar consultation.

Ryan Akers


A Bit About Batteries

The solar industry is facing a big wave of battery installations with all the talk over the past couple of years starting to turn to action; the introduction of the Powerwall, and its imminent successor, the Powerwall2 being the main marketing catalyst. There are far more options out there than the Powerwall variants though.

The topic of batteries is massive, and is something that I’ll be covering here ongoing for many years to come as technologies emerge and mature.
Batteries have been around for some time in off-grid homes, mainly in large Lead-Acid banks which have a good life span if used and managed correctly. Recently however, the introduction of nicely packaged Lithium Ion batteries has reduced the space required and improved the aesthetics of batteries.

One of the key philosophies at Greenhouse Electrical Services is to promote and provide the most environmentally friendly option. With the range and complexity of batteries available it becomes quite difficult to conclude on the best battery chemistry to recommend, and different circumstances will yield a different answer.

As far as the technologies go I will briefly discuss the environmental aspects of the main battery types:

Lithium Ion – These are the batteries that you will hear the most about as they are found in Tesla Powerwalls (both variants), LG Chem and a host of smaller name brands. These batteries are currently at the front of the cost per kilowatt-hour race, however their chemistry isn’t as clean as I would like; they contain cobalt which from my research is difficult to recycle, is toxic, and requires substantial mining operations to acquire. Lithium Ion batteries are also prone to thermal runaway if damaged sufficiently; thermal runaway results in some very high energy fires. That being said, I have read that the aforementioned products have been packaged so as to minimise the risks of damage.

Lithium Iron Phosphate – Slightly more expensive than Lithium Ion, and offering similar characteristics, this type of battery does not have a nickel component. It is also much safer in terms of fire risks. It is pleasing that this chemistry is becoming more prevalent and prices are dropping. Some examples of this type of battery are the Enphase battery, SimpliPhi, and the Ampetus Super Lithium, to name a few.

Zinc Bromine: These type of batteries actually use a flow of liquids from one tank to another to generate charge. They are a little more bulky, more expensive and also have a lower peak power output, however they make up for this by being very safe (they claim that the fluids are actually fire retardants) and having a long lifespan. They are also highly recyclable. Check out the Z-Cell for an example.

Salt-Water Batteries (Sodium-Ion): This type of battery is also very safe and environmentally friendly (as friendly as a battery can be). One example is the battery from Aquion Energy. This battery technology is static (unlike the flow battery above) like a “normal” battery. Salt-water batteries do have some draw backs however: they can be very heavy and at the time of writing were priced in the mid-range of options.

Sealed Lead-Acid: This type of battery has been used in off-grid homes for over 40 years and there is no reason that it can’t continue to be used as such. They do require regular maintenance to achieve a long lifespan which most people may prefer not to do; you can’t just bolt them to the wall and admire them like modern battery variants. They also take up a lot of room and weigh a substantial amount. Due to the fact that they have been around a long time, there are recycling facilities set up to recover a lot of the components used in the batteries, however these components do include lead and sulfuric acid, so if they aren’t disposed of correctly they can become an environmental hazard.

As far as recycling the newer battery technologies (Lithium Ion, Lithium Iron Phosphate, etc.), many companies say there is no reason that their batteries can’t be recycled. Because these types of batteries are only new and are still in service, there isn’t a call for a large scale recycling facility. Theoretically they can be recycled, but as far as I can tell it’s not yet happening (due to a lack of demand). It’s hard to say just how well they can be recycled without real-world experience.

For a good comparison of the batteries that are currently available, I recommend taking a look at the SolarQuotes Storage comparison.



About Tariffs and Rebates

There has been a fair bit of media coverage about feed-in-tariffs and rebates ending unfairly lately, as well as some dubious scare-campaign marketing from the big solar retailers. I’d like to discuss the details of the money side of a solar installation here:

There are two ways that you will be paid for your panels, the government rebate (also known as Small-scale Technology Certificates, or STCs).

STCs are based on the kW output of the panels multiplied by the number of years until 2030, and are paid upfront at the completion of the installation. Each year, this rebate reduces, as there are less years until 2030. This year (2017) it is multiplied by 14, next year it will be 13. It may seem like you need to rush to install a system before the rebate reduces on the change of the year, however the truth is that the reduction is fairly insignificant and is often covered by the ever reducing cost of panels; you mightn’t be getting as much of a rebate, but the panels cost less, so you break even.

The STC rebate is often factored into the installation quote and is paid directly to the installer. It can be arranged that you can be paid for these STCs directly, but you will be paying more upfront at the beginning and it will take a while to get all the paperwork through if it’s your first time. There really is little point or gain in claiming STCs yourself, just let your installer handle it for you.

The other way that you might get some money out of your panels is through the feed-in-tariff. This is the money paid for each kWh of power that you feed back into the grid. Only the excess power that you generate will be fed into the grid. As an example, if you are generating 3kW of power and using 2kW at the time, then 1kW of power will be fed into the grid. If you do this for one hour, you will have fed in 1kWh and be credited for that.
Currently the standard feed-in-tariff is set by the State Government at a minimum of 5c per kWh, and your electricity retailer can choose to pay more than this minimum (be careful when selecting energy retailers as they may look to pay more for solar, but charge more for power consumed from the grid – more on that in a future blog).
Back in the day a premium feed in tariff (PFIT) of 60c per kilowatt hour was offered, and will continue to be paid to those customers until 2024. This was due to the high cost of panels and inverters at the time, however most of the people who took up solar at this time will well and truly have paid off their systems and will likely be making good profit. Then there was a 25c per kWh feed in tariff which recently ended, with those customers reverting to the current rate.

Whether or not these rates are fair is beyond the discussion here; I’ll leave that to the people on the online forums to fight out. My advice though, is to install a system that has been sized to your consumption. By using solar generated power, rather than paying for it from the grid, you will save more than you will make by exporting it. Think of it in terms of savings, rather than the profits.

More info about feed-in-tariffs in Victoria can be found here.


Why installing high efficiency panels will save you money in the long run.

When it comes time to install solar on your premises, there are going to be a lot of variables to consider with regard to selection of a solar panel. There is a large variance in the quality of a panel, the ethics of the manufacturing process, the price of the panel, the size and the aesthetics of the panel. Today I’m going to write about the efficiency of the panel and cells.
Efficiency is the amount of power you will be able to get out of a set area. The common sized panel that you will see on your suburban roof is around 1m wide, by 1600mm tall. For the past couple of years, the most common output of these panels was 250 Watts (W). Technology has been improving though and you can now get more Watts out of the same panel area. At the time of writing Sunpower have a 345W panel and LG have a 320Watt panel, with 350W due soon and even a 400W panel reportedly available in 2018. Other panel manufacturers are not too far behind.
The advantages of a high efficiency panel are not immediately obvious though, as they are more expensive. As we see the cost of grid sourced power rising, and the cost of LPG on a steady increase, there is a clear incentive to producing and using as much of your own power as possible. There is growing talk of “all electric” houses, and people are defecting from their gas connection to eliminate the extra service charge for running only one or two appliances. The are also the environmental benefits to not burning a fossil fuel which may have been sourced by some very environmentally controversial mining methods.
Another consideration is that Electric Cars are starting to gain traction and home storage batteries are getting closer to becoming financially and environmentally viable. All of these forecasts lead to a house using more electricity (though net energy consuption may remain the same or potentially shrink).
This increase in electricity consumption inevitably leads to the homeowner considering how they can produce more electricity on-site, through an expansion of their solar power system. Once we start talking about this size system, the main limitation we come across is rooftop real estate.
There is a finite amount of usable space on your rooftop, and if you fill it upĀ  now with low efficiency panels, when it comes time to consider an expansion, then you will run into a problem; there’s no room for the panels.
It is therefore in your best interests to install the highest efficiency panels that you can afford, and keep that space for future expansion.
I still recommend only installing as big a system as you need to service your current usage patterns, but don’t blow your valuable roof space all at once on cheaper low efficiency panels, because that’s all you need right now.