THE PRINCIPLE OF LOAD MANAGEMENT BY RIPPLE CONTROL

Farad (Pty) Ltd is a specialist load management company dealing with the control and management of the electricity accounts of any bulk purchaser of electricity. We supply and install the whole range of Enermet Ripple Control equipment imported from Switzerland. Our core strengths are:

1. More systems operating in South Africa than any other supplier.

2. Uninterrupted participation in the Ripple Control field, in South Africa working in close co-operation with Enermet AG since 1956.

3. Complete range of spares, valued at over R600'000.

The Nature of Electricity Costs
Two quantities are of supreme importance in electricity supply costs, namely, the energy taken by the consumer and the power at which the energy is taken.

The largest power at one time is equivalent to the highest peak of the load curve and determines the size of equipment to a large extent. It is therefore evident that in two networks whose consumers require the same amount of energy, the actual supply costs will still be considerably different, if the maximum power requirements are different.

The Municipality - Buyer, Distributor & Seller of Electricity
In most cases, the municipality buys the electricity from ESKOM and is charged for the energy as well as for the maximum demand. The electricity is then distributed to the consumers who are invoiced an average price for each kWh consumed.
Studies show that the energy which is consumed within a certain period (i.e. one month) is not subject to large variations. Hence, the revenue of the municipality is more or less predictable and constant.

However, the expenses are not. One short cold spell or a particular social event can cause a demand peak and boost the ESKOM maximum demand charges drastically. Furthermore, the municipality itself has to take precautions to provide adequately dimensioned equipment capable of coping with the demand peak. Network re-enforcement is required, transformers must be added and new substations must be built at a faster rate than the growth rate of the energy consumption would suggest.

Load management by Load Control
The prime objective of a Load Control scheme is to avoid demand peaks. Cutting the demand peaks therefore means the demand charges as well as the M.D. related investments that have to be made by the Municipality are kept as low as possible.

Load control basically means that certain devices are switched off during peak periods. It can be differentiated between imposed load control and induced load control.
In the past only imposed load control has been used. Appliances which exhibit storage characteristics such as water heaters, air conditioning, storage heating, etc. are particularly suitable for load control.

Induced load control is applied where consumers pay different energy rates depending on the time of the day. By charging more during ON peak times, the consumer is induced to consume energy during STANDARD and OFF-peak hours.

Ripple control and Megaflex
The principle of using Ripple Control with the Megaflex tariff is to defer the purchase of units from the Peak period to the Standard period and from Standard to Off-peak period.

To fulfil the long-term benefit of a Load Control scheme, the needs of the Local Municipality as well as of the consumers must be satisfied.

This requires the reconciliation of basically opposing interests: on the one hand, the demand should be kept as low as possible and, on the other hand, the consumers should be inconvenienced as little as possible.

Conclusion
For typical cash flow projections based on a loan period of 10 years, the rate of return on a Ripple Control system is such that the initial investment is re-couped within the first few years and the remaining surpluses which are accumulated over the 30 to 40 year life span of the equipment are a net profit to the council. Ripple Control is a well-proven management tool with an excellent track record, utilised throughout the world and recognised by banks as low risk projects, which they are willing to finance.