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Here’s why you should consider a battery-powered home

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The solar-powered home and electric car is not the way of the future anymore; it’s a reality. This is according to Cape Town-based Perpetual Power Systems Africa director, Mark van Heerden, a systems engineer, who says a grid-tied solar power system is the best investment in South Africa today.

“In most parts of South Africa we need half the size of the systems installed in other parts of the world for the same amount of power,” he says, noting that this provides buyers with greater returns than any savings or pension over the same amount of time. “The difference between those buying solar power systems and those who are not is only a question of time.”

Investment into renewable technology is also reflecting this reality. For the first time ever, global investment into renewable power (which includes solar and wind) exceeded fossil fuel technologies in 2015. And this was on the back of historically low fossil fuel prices.

“The numbers demonstrated in the Bloomberg article that renewables received $134bn of investment, while coal and gas only received $80bn,” says Jay Urban, director of Power Generation at WSP Parsons Brinckerhoff Africa, explaining that while this is a significant development in especially emerging markets, the question of base load power also needs to be answered. “Solar energy currently can’t compete with base-load solutions because, while a solar energy plant can feed into the grid during off-peak times (during the day), due to storage capacity challenges these solutions often don’t prove efficient for peak time. Although this is slowly changing with new developments for improved concentrated solar power storage.”

First things first

Solar plant at Val de Vie (1)

An aerial view of the solar plant at Val de Vie Estate in the Cape Winelands.

Implementing the first stage of the road map to complete self-sufficient homes are basic grid-tied systems with smart home solutions, and then partial- to off-grid applications.

“The prospect of battery-powered homes to improve self-consumption is real and those who understand it and have the money are implementing it,” says van Heerden, whose company supplies German-manufactured solar power systems for commercial and residential use. “Solar power is becoming one of the largest drivers of electricity in the world today, with the sun being the cheapest resource.

“Essentially it entails the storage of the free energy created and its use from early evening to early morning until the sun rises to recharge the batteries throughout the day for the next evening and/or cover any premature mains supply outages.”

Solar-powered batteries are frequently sought by developers of new suburbs, estates and large-scale residential applications, with developers seeing them as a major selling point in keeping power supply costs down.

New residential developments such as Val de Vie Estate in the Western Cape Winelands, Baronetcy Estate in Plattekloof in Cape Town’s Northern Suburbs, and Steyn City in Fourways, Gauteng, are frequently being equipped with a host of features incorporated into their design. These range from solar heating, water saving and recycling, water-wise gardens with indigenous plants, LED lighting with time switches and sensory capabilities and insulation to conserve heat or for cooling, to back-up power solutions such as invertors or generators.

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“Some two years ago the South African National Standard 01400-XA regulation for energy efficiency was implemented with all new homes in the country required to comply,” says Phillippe Fouché, a director of SAOTA. “Baronetcy Estate homes are already designed to these specifications. For example, most windows need to be double glazed or incorporate a special tint which ensures that the home is cool in the summer and warm in the winter by regulating the temperature within the home, thereby reducing energy usage for air conditioning or heating. There is much taken into account when the properties are designed, including window size, wall cavities and orientation or positioning of the home. With ever-increasing electricity and water tariffs, fully off-grid homes are becoming more and more appealing for residents on the estate.”

Starting out

For homeowners, the most popular choice is to start out with a basic, grid-tied system with partial to off-grid battery options that consist of lead acid or lithium batteries; the grid or utility system is used to top up batteries if needed. The solar-powered system can be expanded or changed on a modular basis at any time to convert to completely off-grid applications.

So, how does solar power benefit a home? In brief, solar panels are made up of photovoltaic (PV) cells that convert sunlight into direct current (DC) electricity during the day. An inverter converts the DC electricity into alternating current (AC) to power your lights and appliances at night.

A completely self-contained, off-grid system will require one or more battery banks to store excess power for use at night or during the days in the winter months.

A question of cost

Signature SIBAYA gated estate house 2A (2) (resized)

Homes to be built in the new Signature Sibaya luxury residential development on the KwaZulu-Natal North Coast will incorporate eco-friendly principles, including solar panels, water conservation tanks and invertors.

Is solar power more expensive than traditional power systems? “There is an initial outlay, typically ranging from R60,000 to R1,3m for a single, free-standing home using a grid-tied system, but you can see a return on your investment in as little as five to 10 years,” says van Heerden. “An immediate reduction in power bills is visible, up to 60% on average, depending on your location, requirements and systems set-up.

“New-build homeowners who are currently planning their homes must request their architects to design to accommodate solar power generators and battery storage systems, as well as future battery chargers to charge electric cars. Specifically, the roof structure and elevations must preferably be angled to north, east and west in the Southern Hemisphere. Flat-roof applications and carports are very useful and easy to work on. While these systems do not require much space, however, allow for a minimum space of approximately 300mm along the length of a typical garage wall to accommodate the inverter and charger equipment, and battery racks indoors or outdoors.

“For electrical reticulation planning, allow for wire ways to connect the roof to the garage or a battery storage compartment or a separate, properly ventilated room as well as main distribution boards with dedicated circuits.”

Future-proofing the future

Baronetcy Estate home

The owner of this residence in Baronetcy Estate wanted a house that competes on the international market. Glass with a solar shield protects against the sun as well as a double glazing component. The overhang of the concrete roof curbs the influx of early afternoon sun, while the sides of the windows are protected with a vertical sloping box element. In the middle section of the house sliding louvres can be positioned to screen the sun. Provision is made to insulate the floors, walls and roofs with polystyrene sheeting while the heating system will be driven by a solar system to further reduce the carbon footprint. Light fittings as well as appliances are specified to be of low energy consumption type and the articulation of the electrics is planned to be intelligent and switches off by itself should it not be needed. A fully integrated smart home will alleviate a lot of the consumption. In general a footprint is created that is easily manageable and uses as little power as possible.

What is certain is that homes will need to adapt to changing requirements and climatic and socioeconomic requirements, says Louise Varga, project manager for Pam Golding Properties in the Boland and Overberg regions.

Partnered with the Green Building Council of South Africa (GBCSA), Pam Golding Properties is actively driving a better understanding of value in the residential property market with regard to a home’s green credentials.

In helping empower the residential property market to design and build resource-efficient buildings, the GBCSA has implemented a new green building certification programme called EDGE (Excellence in Design for Greater Efficiencies). Available via a free online software platform, the green rating tool aims to achieve a minimum saving of 20% in energy, water and embodied energy in materials. Smart, fast and affordable, it calculates the upfront cost and potential operational savings of green buildings.

“As South Africa is becoming ever more environmentally conscious, the urge to protect the environment and reduce one’s carbon footprint has expanded into the world of architecture and construction, making energy-efficient design of ever-increasing relevance,” says Varga, with her Durban compatriot, Carol Reynolds, Pam Golding Properties area principal for Durban Coastal, saying an increasing number of people are looking at sustainable residential developments.

“A global network has been developed around the concept of eco-villages and this is indeed the way of the future,” she says. “Communities of like-minded people are living together in self-sufficient eco-estates with boreholes, solar heating and solar- and wind-generated power, and water tanks and underground systems to conserve the environment.

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“From a design perspective we are seeing a shift away from big double-storey blocks to modular homes with different levels, cantilevered platforms and the use of wood, glass and steel. The general look is one of simple, understated elegance that complements the environment, while homes are now seen as an integral component of their surrounds rather than separate from it.”

Laurie Wener of Pam Golding Properties in the Western Cape says realistically, we need to have smaller and more manageable low-maintenance homes which conserve energy, reduce utility costs and are close to good public transport. “Self-cleaning, labour-saving devices will be of primary importance while recharging of electrically operated vehicles may become the norm.”

At Baronetcy Estate in Cape Town’s Northern Suburbs, homeowners are prioritising energy-efficient homes or even going completely off-grid, according to Pierre Nel, area principal for Pam Golding Properties Plattekloof.

“Load shedding prompted many homeowners to install battery-powered systems that work off solar panels, and run all the necessary, lights, ADSL lines, telephones, TV and small appliances,” says Nel. “On this estate, most homes have solar geysers or heat pumps to further enhance energy efficiency, while some include electric swimming pool covers to reduce water evaporation.”

Fouché says the relationship between buildings and the environment is as old as architecture itself. “Great buildings have always responded to the landscape, the environment and the climate in which they are sited,” says Fouché. “The great buildings of the future will continue that relationship.

“By their very nature buildings are long-term and should therefore be forward-looking in their conception, and so ‘future proofing’ can massively enhance their long-term sustainability. It’s an oft-repeated statistic that buildings generate an astonishing one out of every three tons of carbon dioxide emissions. Hence, architects, designers and builders have a key role to play in providing a sustainable future in our cities and landscapes.”

Additional reporting by David A Steynberg


Alison Goldberg is the former property editor of Business Day (1985) and the Financial Mail (1991-99). In 1995 she won the Sanlam Financial Journalist of the Year Award. She has edited such titles as National Constructor and The Miner in Australia and has freelanced for The Star, The South African Jewish Report and The Jerusalem Post.

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