Dave's Solar Snapshot

How to Enjoy Solar – Without Buying a Solar System

March 31st, 2016
Guest post by Sheena Ong

It’s not a lease, and it’s not a fleece. That’s right, there’s a legitimate way to install and enjoy the benefits of solar PV without paying for or owning a PV system: a model called a Power Purchase Agreement (PPA) in which the panels sit on your roof but are owned by a third party, supplying you with clean energy and none of the responsibilities of ownership.

Businesses are increasingly seeing the benefits of “going solar” but not everyone wants to rush in and buy off the shelf. Concerns about raising capital or managing risk might be barriers, but an alternative arrangement known as a Power Purchase Agreement is a model deployed successfully throughout the world that might work for you.

In a PPA, a third party provides a renewable energy system at the site of a client, who wouldn’t own it themselves but simply enter into an agreement to purchase the electricity that their business uses from it. The company who built the system – or a third party – would then operate and maintain the system, acting as a mini retailer by selling the solar electricity to the business owner at an agreed rate, designed to be lower than the grid electricity price.

PPAs have attracted client companies such as Walmart and operators such as Solar City in the US (you know, the one pioneered by Elon Musk). Uptake in Australia is a bit slower, but we’re getting there.

Enigin’s PPA is flexible, allowing our clients to purchase the system outright at any time at the depreciated system value. By Enigin owning and operating the PV system, risks and costs of ownership to the client are removed while providing benefits of lower electricity costs.

Each deal is tailored to your business needs, but one thing is always the same: you lower your costs and get clean renewable energy. Plus, our PPAs live harmoniously alongside your existing grid electricity supply contracts with Synergy and the other retailers.

Alternatively, Enigin may lease the roof space from landlords – effectively making the sun an additional tenant! That can be a massive boon for property developers and owners.

As a cost-competitive clean energy option, why not consider a PPA for your business?

Sky’s the limit: A PPA can allow you to benefit from solar while managing finance and risks.
(image adapted from Asia Chang, Unsplash)

Batteries Demystified, Part 1: What is a Battery and How Do We Use Them?

February 29th, 2016

Batteries have been around for ages, but with applications ranging from renewable energy storage to consumer devices, it’s the technology that is on everyone’s lips today. But don’t dive in blind – arm yourself with this basic intro into battery technology, and you’ll have the confidence to make the right choice for your organisation.

What is a battery?

A battery is an energy storage device that uses chemicals for storing energy. Batteries can be single use or rechargeable and are constructed using various chemistries. Energy storage for solar power systems is what we will be focussing on, which necessarily requires rechargeable-type batteries.

What types are there?

There are many different types. Lead Acid (such as in car batteries), Lithium Ion (such as in consumer devices like phones and laptops), Nickel Cadmium, Saltwater and Redox Flow are just a few of the main chemistry groups. Even within the classic Lead Acid range, there are three main types – Flooded, Gel and Absorptive Glass Mat (AGM) – depending on whether the chemical is in a liquid, gel or material-soaked state. And then, these types can be further differentiated by the structure of the battery and any additives used to improve performance.

For example, a starter battery in a car is great for the high initial current needed to turn the engine over and get it going, all within a relatively compact size, but is terrible for discharging slowly and continuously over many cycles, with the deep cycle batteries used for golf carts. This is due to the structure of the lead plates, which are thin but have a high surface area allowing for a quick burst of energy.

What's available now?

At the moment the primary types of battery for solar energy storage systems are Lead Acid Gel and Lithium Ion, like the Tesla Powerwall. Emerging technologies such as Saltwater and Redox Flow batteries are starting to be taken up but relatively rare at the moment.

Generally the price of a battery alone is around $900-$1,000 per kWh for Lithium Ion, and around $250-$400 per kWh for Lead Acid Gel. The price of batteries is slowly starting to decrease – though still currently more expensive than many consumers think, when you consider the supporting equipment like control devices that need to go with them!

Solar battery bank for an off-grid community in the Northern Territory, Banthula, using German-made Sonnenschein Lead Acid batteries

The main difference is the Lithium Ion can be discharged almostly completely then recharged and still retain a long life, whereas you should only discharge the Lead Acid 30-50% to retain a similarly long life. The size and weight of the two types also differs markedly, with Lithium Ion being far lighter and more compact, especially if you only need half the size of an equivalent Lead Acid.

There’s plenty to say about these different types of batteries – toxicity, temperature threshold, sustainability and more – but we’ll delve further into battery types in next month’s article!

How are they used?

There are three main uses for batteries in solar energy storage. The first is if you are off grid, completely isolated from mains power. Here the batteries are crucial as they keep the lights on at night and the food in your fridge cold. They need to ride through periods of cloudy weather when the solar is not producing much energy.

But if you’re connected to the power grid, the battery could provide energy during those times that the grid goes down – or simply for owners that want to reduce their grid dependence. It’s important in many cases: for sites where blackouts occur several times a year; for essential loads such as computer servers, vaccine fridges or dialysis machines; or for organisations and property developers that see the value in reducing their dependency on the grid. This grid-connected/battery scenario can even be an interim step to your ultimate goal of complete grid independence.

The battery could also be used to store energy produced by a home or commercial solar PV system during the day when occupants are out or the evening-based business is closed, and discharge during the evening and overnight when most energy is used within the house or business.

Batteries for YOUR organisation?

The reduced dependency on the mains grid is, we believe, a particularly exciting growth area. A future of “micro-grids” where clusters of buildings generate and consume their own solar power, any time of the day, is not so far away!

Batteries can also create a smoother power supply for you, therefore having a “peak lopping” effect: reducing your peak power demand and costs, depending on your load profile.

Could batteries work for you?


Top 5 Solar PV Projects of 2015

January 29th, 2016

2015 saw a substantial increase in both number and size of our commercial solar PV projects. We think it's because of low risk purchasing models, low funding costs and increased benefits. These are our top five for the year.

Corpus Christi College – 168 kWp

A Western Australian Catholic college will now access about 30% of its energy needs from rooftop solar, showing how solar makes good savings sense for schools across Australia.

Corpus Christi College will save more than $1.5 million on its energy bills over the 25-year life of its 168 kWP solar PV system. In addition to business case development and engineering, procurement and construction (EPC) Enigin negotiated cash flow positive funding for the upfront cost of installation through an Energy Efficient Loan, a joint initiative of the Commonwealth Bank and Clean Energy Finance Corporation (CEFC).

We used custom in-house designed and built grid protection equipment to comply with Western Power network requirements and ensure that the system operates at all times to maximise yield.

Check out our awesome aerial shot taken with a Go Pro!

Gilbert’s Fresh Market, Mandurah – 99 kWp

Following on from the success of our solar and energy efficiency program for Gilbert’s Markets Midland in 2012, which had a whole of program ROI of less than 3 years; the owner asked us for a fixed price EPC 99 kWp system on his newest innovative retail food outlet in Mandurah.

396 Canadian Solar modules were deployed to just squeeze onto the available roof space. This was combined with six SMA Sunny Tripower inverters, and a transformer was also used to filter out all DC produced by the transformer-less inverters. 

Winthrop IGA – 100 kWp

Speaking of return customers, this was a 70 kWp expansion to a 30 kWp system we installed on the Winthrop IGA supermarket in 2013.

This project had an additional challenge to the regular grid protection requirements from Western Power’s requiring zero DC injection onto the electricity network. As a result, a German-manufactured power transformer with 125 kVA capacity was imported and deployed to filter all DC from the PV system. The DC injection ruling has since been amended and systems rarely need transformers to filter out the DC.

Beta Spuds – 99 kWp

Our partner business Solarmatrix and friends at Renewable Energy International delivered a complete 99 kWp PV system for the Beta Spuds warehouse in Mandogalup.

Unique to this project was a Cluster Controller that allowed the system to provide load following so that no power is exported, preventing the grid protection from isolating the system due to the anti-exporting requirement of Western Power. This ensures the system is operating at all times to maximise yield. 

Chamber of Commerce and Industry – 40 kWp

Following our success with a 38 kWp installation on top of the CCI building in the Perth CBD, the Chamber of Commerce and Industry engaged our partner business Solarmatrix to install a 40 kWp PV system on their Kwinana Industrial Training Facility.

It features 160 premium German-manufactured glass-glass modules from Solarworld, two SMA Sunny Tripower inverters and ongoing performance monitoring via Sunny Portal. 

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