A good look at the economics of solar PV and storage

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Let’s remove the emotion for a minute and take a close look at the economics of the decision whether or not to get a solar PV and battery system.

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One Step Off The Grid
Interest in energy storage is heating up across Australia, and thanks mainly to Tesla’s Elon Musk, the prospect of installing a battery at your home and having it provide power to your household equipment has become fashionable.

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  1. Tim Forcey 4 years ago

    Another step along the way: Store your solar energy as hot water. See article here: https://theconversation.com/get-more-out-of-your-solar-power-system-by-using-water-as-a-battery-37807

    • Brunel 4 years ago

      What if the house has 3 people who shower at 5am.

      • Tim Forcey 4 years ago

        Brunel: The storage tank stores the hot water for when it is needed. By the way, there are some excellent shower heads on the Australian market, those that use the double-impingeing jet technology, that give a good shower at a hot water consumption rate down to 4 litres a minute. At that low rate of water use, many showers can be had before the hot water in the tank is depleted. Of course, with a heat pump, should the hot water deplete before the sun comes up, the heat pump will come on to create more hot water, but that just means you are not using your own solar-PV produced electricity for that particular shower. Does that help? Cheers, Tim Forcey

      • Tim Forcey 4 years ago

        Many people have used “off-peak” hot water systems in Australia for ‘yonks’. Tank capacity can range to over 300 litres.

        If you get close to using up all the stored energy, just allow the heat pump to kick on, no drama. Heat pump hot water systems are quite powerful and can rapidly heat water. (And by the way, electricity prices at 5 am can be quite cheap.)

        To use up 300 litres, let’s see, 3 people x 5 litres per minute shower head x 20 minutes = 300 litres. 20 minutes is quite a long shower.

        • Brunel 4 years ago

          Mid-day will be the new off-peak. With solar panels in Dubai smashing the price of daytime electrons.

          If a heat pump can heat water at a rate of 10L/min, that would be good for a house.

  2. BasM 4 years ago

    The smart way is to:
    – change to cheaper electricity provider
    – install a solar installation with the option to install battery later on.

    As the costs of batteres are widely predicted to follow similar price decrease path as solar. So big chance it will be highly profitable to do in e.g. 2020.

  3. MaxG 4 years ago

    Actually, I would add:
    1. review power use, by switching off what is not required; e.g. PCs off over night.
    2. install efficient devices
    3. get cheapest tariff
    4. then calculate feasibility of solar
    5. then battery

    I took a similar approach, but took my power bill at present cost and paid it forward for 15 years. This paid for the off-grid system. If the energy prices rise (which they have been year after year), the payback period (discussed here) is even further reduced.

    However, what actually happened, I increased my power consumption; switching to electric/battery operated devices, installing irrigation (which I wouldn’t have done if I’d to pay for the kWh used).
    In essence: I have more freedom, blow (excess PV) energy as I see fit, and no worries about the energy market or its future pricing structure.
    The other argument: I rather buy a car for 20k$ instrad of 50, and whack the 30 into an off-grid system.
    I admit: it requires a more radical mind 🙂

  4. TweedCAN 4 years ago

    There are 146,000 households in NSW who already have solar panels but lose their fixed feed in tariff this December. For a typical household, power bills will go up by $1000/year so the economics of batteries look pretty attractive and the group is big enough to make a real impact on the market.

  5. AnumakondaJagadeesh 3 years ago

    The challenge for wider use of Renewables is storage. Now that PV cost has come down considerably(the quality of solar panels in developing countries questionable) in India there is mad rush to go for solar PV. There is the world’s largest Solar PV Park in the world 1000 MW at a cost of Rs 7000 Crore(1 US $ = about Rs 65 ; 1 Crore= 10 million) in Kurnool, Andhra Pradesh the panels were blown away in normal rain and gale within inauguration of a Month. In US the solar panels are designed to have survival wind speed of 145 miles/hour(about 233 km/hr). Another problem is dust in Rajasthan desert and water availability to clean the solar panels. There is LOO(Sand particles) which travel at terrific speed even up to Delhi. Did anybody studied the effect of fast travelling LOO on the smooth surface of Solar Panels? The solar panels life is about 25 years. Loo may create dips on the solar panels which may lower the efficiency.

    In Andhra Pradesh TESLA storage system will be promoted according to official sources. While one appreciates this, if storage besides efficiency increase(solar PV efficiency is poor) is needed ,the Government of India and State Governments can promote Concentrated Solar Power(CSP).TESLA Solar Battery system is very expensive that too for Developing countries.

    One of the points, which could be seen as an advantage for the CSP system, is possibly of heat storage. In power plant projects, supplying power during the peak time is a critical and challenging point. Currently in PV systems, electrical storage is not feasible, so they usually can only cover the daytime demand. However, the CSP System provides the ability to incorporate simple, efficient, and cost-effective thermal energy storage by virtue of converting sunlight to heat as an intermediate step to generating electricity during the peak time. Thermal energy storage for use in CSP systems is achievable by different technologies. It could be one of sensible heat storage, latent heat storage using phase change materials (PCMs) or thermochemical storage. The possibility of heat storage in CSP plants categorises this system among “Dispatchable generation” technologies.

    The mass-manufacture of PV system and government subsidy schemes have resulted in the development of low cost high-efficiency multifunction cells. For CSP systems, the cost of mirrors, vacuum receiver, lenses, support structure, high-efficiency heat transfer fluid and turbine have affected the initial and operational costs of the CSP project significantly and a result uncompetitive in most scenarios. In the most optimistic scenarios, CSP systems could supply around 10 % of global electricity.

    Also in India only big industries are setting up Renewable Energy Projects in India. Solar Co-operatives on the lines of those in US and Wind Farm Co-operatives in Europe will make Renewable Energy Projects in India mass based.

    Also Roof top solar and wind hybrid systems make sense in India as rising buildings Apartment culture is growing.

    Dr.A.Jagadeesh Nellore(AP)

    Renewable Energy Expert


    Margaret Nobel Foundation Seattle Award in Energy Technology.

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