Friday, July 15, 2011

Producing electricity where it’s needed the way to go

A good article on decentralizing our energy supply. (includes this bit on hydro: "Many African countries rely largely on hydropower, which is not good news. Why not? Well, for starters, they have to put the power station where the power is – at the river or dam. Mostly, that turns out to not be the place where they actually need the power, so they have to start constructing a power transmission grid. Some of these African countries are very big, and even the smaller ones are still big by European standards. This tends to immediately imply that there is major cost and complexity that naturally go with the development of a significant transmission grid. This is expensive, takes time and demands constant complex maintenance.")

-----------------


 Producing electricity where it's needed the way to go
  
 
15th July 2011
 We have now passed midwinter, the longest night of the year, and we are heading towards summer.

Geographically speaking, this is true, but the nights will still be rather cold for about a month, before we start to really feel the returning warmth of summer. This time of the year puts real pressure on the country's electricity supply system – many thousands of people dive into hot baths and turn on their household heaters, all at about the same time, each evening. Cooking starts in the homes of the nation and electrical switches are flicked on stoves and other electrical gear in kitchens. Even opening the fridge door tends to cause the fridge motor to switch on to remove the bit of heat that would have migrated into the fridge while the door was open.

So the large electrical power lines that crisscross the country hum as they transmit power across vast distances, and we South Africans do this electrical transmission in a rather spectacular fashion.

South Africa is blessed with abundant coal, so we burn coal to produce most of our electricity. One snag is that the coal is essentially all clustered in the north-eastern part of the country. The result is that we have to move the electricity over great distances. Building all those major power lines, which are actually world-leading technology, was expensive but such long-distance transmission also results in a significant loss of power.

As electricity is transported over long distances, some of it is lost into the atmosphere in accordance with the laws of physics.

The South African distribution grid works rather well but it is a major piece of complex tech- nology. Now let us turn some attention to other African countries, of which there are more than 50, covering a major surface area. Africa is larger in area than China, the US and Europe put together – that is a lot of ground to cover.

Most African countries are not blessed with huge deposits of coal – some have some oil, but it is not a great idea to burn this oil to make electricity. It is much better to turn the oil into fuel for cars, trains and aircraft.

Many African countries rely largely on hydropower, which is not good news. Why not? Well, for starters, they have to put the power station where the power is – at the river or dam. Mostly, that turns out to not be the place where they actually need the power, so they have to start constructing a power transmission grid. Some of these African countries are very big, and even the smaller ones are still big by European standards. This tends to immediately imply that there is major cost and complexity that naturally go with the development of a significant transmission grid. This is expensive, takes time and demands constant complex maintenance.

In South Africa, we carry out live-line maintenance. We drop technicians onto live power lines from a helicopter. There, they sit on a live line at about 700 000 V and repair the line. They tell me that their hair stands on end from the huge electric field. As long as they make no earth contact, like coming close to a pylon, then the technician will not explode in a ball of flame.

Although the major South African grid is a huge technological achievement that South Africa should be proud of, is this the way to go for other African countries? In fact, is it the way to go for any country in the society of the future?

The answer is clear and definite – maybe. If any country has a major source of fuel, such as South Africa's coal reserves, then, perhaps, it is profitable to move the power over long distances. If, on the other hand, a country does not have a major fuel source, then why build a huge grid?

For most of Africa, and, for that matter, the rest of the world, the answer seems to be producing the electricity where you want it in order to minimise the need for long power lines. Rather have multiple sets of smaller distribution grids than one large national one.

Okay, great philosophy, but how do we do it? The answer lies in producing small power plants that can be placed where you want them. Take the point of production to where you need the power. In other words, build small nuclear power plants in Richards Bay, Port Elizabeth, Carltonville . . . In other African countries, do the same. It is easy to take nuclear fuel to the power station because so little nuclear fuel is used.

Building large-scale nuclear power plants of 2 000 MW on the Cape coast is fine – we need that to power the Cape, but we also need independent nuclear plants to power the inland goldfields, iron-ore mines and copper mines.

Great strides have been made in producing smaller power plants that are cost effective, easy to operate and inherently safe. This is the way of the future and we are going to see a number of such designs emerge.

There is much more technological innovation about to unleash itself in the world of nuclear power than there is in the fields of solar and wind power. A range of nuclear power plant types and sizes is the future.

This philosophy is spreading across Africa. Distributed small power plants, placed strategically – near points of consumption – will be the way to rapidly advance our vast continent. Further, such a strategy lends itself to the private ownership of the production of electricity, leading to healthy market competition.

Edited by: Martin Zhuwakinyu

No comments:

Post a Comment