Supergrid Information

Advantages / Disadvantages

The advantages of having a D.C supergrid are remarkable. Save that Governments are understandably worried about the present economic demands, it is hard to understand why this vital asset is not placed at the top of every Nation's agenda. The threat from Climate Change although somewhat more distant (but may be closer than people realise) is so much larger than the credit crunch.

The need for a Supergrid needs to be addressed now.

Advantages

1. The Supergrid is much more efficient than the present AC grid. It will transport electricity at a loss of perhaps 4% per 1,000 km. Incontrast, the A.C. grids that we use to distribute electricity within countries,would lose perhaps 45% over the same distance. Renewable energy sources are often far away from the need (unlike present generative capacity). In contrast the fossil/nuclear economy we presently rely on brings fuel to local power stations and transmits the power over in general "tens" or very low "hundreds" of miles

   It is quite clear that the new sources of energy demand a new transmission system.
2. DC supergrids are also third of the size of AC systems for the same load. Pylons (where needed- much can be underground or undersea) are much smaller. Mile for mile the system gets cheaper over longer distances.
3. AC grids from different systems are hard to connect because they need to be synchronised, have the same frequency and voltages. DC stabilises grids by allowing interconnection and rapid support for variations in capacity. With increasing demand (air con, computers,transport) stress on grids increases as does the threat of major outages.
4. New areas of resources such as geothermal from Iceland or Turkey come within range.
5. Evidence is emerging that certain resources when matched over long distances may provide a reliable source of power for a large part of the time. Put (very) simply, if the Summer wind is blowing in Morocco it may be calm in in Britain and if the winter wind is blowing in Britain it may be calm in Morocco - averaged out the supply is far more reliable. See Gregor Czisch paper
6. Demand over the next thirty years is likely to increase over present estimates (by perhaps 35%) with the transport sector (and other unforseen new loads) becoming electrically based. Infrastructure needs to be improved and DC is the obvious candidate.
7. All of the above facilitate a free market in electricity and allow people and industry to obtain energy at the most economical price. There is a strong suspicion today that the electricity industry has a veted interest in not having competition and therefore charging more is justified.

Disadvantages

Conversion at each end of the system is expensive and takes a large area of land.

DC is not suited for end users so needs conversion.

Conclusion

DC is suitable to be used as the electrical equivalent of a motorway or "superhighway" with occasional intersections with National Grids. Local AC grids are ideal for local transmission, but urgently need the "backbone" of a strong D.C network.

If you believe in the environment and the need to change - help this to happen by supporting us.