“I’d put my money on the sun and solar energy. What a source
of power! I hope we don’t have to wait ’til oil and coal run out
before we tackle that.” Thomas Edison (1847–1931)
What is Energy?
We know it can’t be destroyed, only transformed from one form to another.
Oxford Dictionary says: ’ energy is power derived from physical or chemical
resources to provide light and heat, or to work machines’
Our body heat is living proof of energy.
Today as in primitive times if we felt cold, we would preserve body heat by
insulating our bodies with extra layers of clothing. That’s passive energy
management. Or by lighting a fire. That’s active.
The Eskom National Grid System
Today we have power stations that serve society. In a traditional coal-fired power
station Man lights an enormous fire that creates super-heated steam which,
through a turbine, drives a giant electrical generator. This electrical energy is
distributed country-wide through different sized cables and sub-stations until it
reaches your home and powers your electric geyser and all other appliances.
This is the national grid.Even when this technology is working efficiently, it creates a giant carbon
footprint that contributes to global warming as surely as your closed car gets
unbearably hot on a summers day. But this is only the beginning of our problems.
Eskom, for various reasons, is beginning to fail as a prime energy source.
Power outages are an early warning sign and it could take decades and
trillions of rands to solve.
This problem is forcing us into a new energy paradigm.
All of us, including architects and developers, are being forced to design
alternative energy solutions.
Alternative Energy Solutions: A Case Study
Take this fascinating case study.
Recently a group of property developers, who are planning a 42-home
development, were informed by Eskom that it would be unable to supply power to that complex.
I was involved in delivering a complete off the grid solution, and it involved
coordinating input from what I term an ‘energy brains trust’. These included
electrical and thermal engineers, architects, solar energy, lighting and gas
experts, and experts in the field of alternative energy solutions.
The team designed a decentralized ‘mini-grid’ energy system based on ten
houses (see diagram):
The Mini Grid: Power in your hands
At the risk of oversimplification, the system works as follows. Each house has many square metres of photovoltaic panels on their roofs. These convert sunlight into electrical energy. This DC energy is fed to a central battery room where a bank of over 100 large batteries will store the solar energy for use after sunset or during cloudy weather. This energy is returned to the homes through a high quality inverter which converts the DC current into 220 volts. Such an inverter delivers energy in true sine wave form, matching the same high quality of Eskom power. This AC current then powers all home appliances like the fridge, toaster, washing machine etc.
Like your car, each home will have its own highly effective LED 12 volt lighting
system, independent of the mini-grid. LED lights are not only highly effective but also very safe. They can be selected to give a warm light for internal use or intense for security use.
As the cable layout shows, it is an easy matter to rig high intensity, low wattage LED street lights around the complex.
Hot Water and Cooking
The large energy consumers such as hot water and cooking are solved by solar
water heating and gas or a combination of both. For off-grid applications, the
solar-gas hybrid system is an elegant solution for the supply of reliable, low cost hot water.
When the sun shines solar water heating presents no problem. But if there are
several days of rainy, cloudy weather, then the gas geyser senses the cooler
water temperature and simply fires up to deliver uninterrupted hot water.
Otherwise it remains dormant. Research has shown that the running costs for a
gas back-up system average at around R25 per person per month which is
There will also be a large, centralized gas tank. No more gas bottles outside
kitchen windows. The gas will be piped to each home through specialized pipes
designed for underground use. Clean, efficient and safe. The Managing Agent
could purchase the gas in bulk and re-sell it to the home-owners at a reasonable profit to cover costs.
And if the unusual happens and there is too much drain on the batteries, then the sophisticated inverter will send a signal to the generator which will start
automatically and run silently. It will not only re-charge the massive bank of
batteries but will supply power to all the homes for as long as is needed. If the energy system is well designed, the generator will seldom run.
The system is also fair, for it allows energy efficient home-owners to ‘sell back’ to the mini grid and build up an energy credit. But home owners who draw more energy than normal from the grid simply pay an energy premium. This is a balanced and democratic energy system.As one of our ‘green’ architects Chris Butters (Oslo) says: “…the best kind of energy is the kind you don’t use”.
In Europe solar energy is fast growing in popularity and costs are gradually
coming down. Here is a photo of a solar village in Freiburg, Germany.
Note the photovoltaic roofs which even in cloudy Europe generate enormous
amounts of electrical energy. In sunny South African this would be impractical. It would not only cost hundreds of thousands of rands but would be overkill. Note also the unusual roof overhang and large glass areas for efficient sun/heat management throughout both Winter and Summer. Feeding energy back into the grid is advanced in Europe and is a viable business option.
Improved Standard of Living:
The future has arrived and the sooner we start to think differently about energy and how we use it, the sooner we will reduce our expenditure and stress levels and improve our quality of lives.
As writer and environmentalist David R. Brower once said: “I believe that the
average guy in the street will give up a great deal, if he really understands
the cost of NOT giving it up. In fact, we may find that, while we’re
drastically cutting our energy consumption, we’re actually raising our
standard of living”.
Architects also need to get up to speed with latest developments like new glass technology which includes micro-coatings to influence thermal performance, and glass (currently being developed) which subtly integrates photovoltaic cells. Roof orientation and optimum pitch of around 35 degrees is also critical for future energy-efficient homes, especially for solar water heating.Architectural design is where the new energy age will be born.
OK so it does require a fairly hefty capital outlay for existing houses. But when it comes to new multiple housing developments, with a shared mini-grid energy system, the cost per house will only increase by 10% to 15%. It’s a no brainer for developers and future home-owners who deserve to reap the pleasures of living in greener, greater harmony with this beautiful planet.
After all it’s the only planet we’ve got!
Roger Metcalfe is a freelance journalist specializing in the environment,
technology and medicine. He is an ex-diplomat, and former TV producer and
currently runs his own alternative energy business “Solar Connect”. He also produces top end corporate films and is reading for his Masters in Filmic Communication. He can be contacted at firstname.lastname@example.org