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Availability, Reactive Power & Power Factors

Availability

What is it?

Availability , or Available Supply Capacity is in simple terms the size of the wire through which electricity can enter a premise.

It is not charged to all customers but is limited to those with maximum demand metering or in other words those with the largest load requirements.

Energy suppliers charge availability on a p/kVA basis

The higher the Availability the larger the ‘wire’ and therefore the greater the peak or continuous demand level a business can draw through their meter.

The distribution network will hold records of the Available Supply Capacity at each premise and will charge suppliers based on their knowledge of the metering system in place

Suppliers will pass this charge directly on to the customer.

How can it be changed?

The Available Supply Capacity of a meter connection can be increased or decreased via groundworks undertaken by or on behalf of your distribution company.

Whilst an increase in Available Supply Capacity will boost the volume of energy available through your network at any one time, it is a chargeable item for the physical works

In addition it will carry an on-going and size dependent kVA rating and charge, inevitably the higher the available capacity, the higher the p/kVA charge that will be applicable.

A reduction will similarly carry a cost for physical works but should result in a lower p/kVA charge

How can Business Juice help?

We can work with your current supplier, or your chosen supplier if you are transferring your contract, and can organise for the relevant distribution business and groundwork specialists to deliver the changes needed at your business premise.

Reactive Power

What is it?

Put simply, Reactive Power, or Apparent Power is the inefficiency caused where current and voltage are not in phase.

This is not charged to all customers but is limited to those who’s current and voltage is actually not in phase within the metering system and preceding network.

Energy suppliers charge Reactive Power on a p/kVAr basis.

This circumstance is also known as Apparent Power.

This is as opposed to Real Power, which is the optimal theoretical capacity for a circuit to perform work in a particular time.

As it is a measure of the inefficiency of the metering and transportation system suppliers will levy the charge on customers who are deemed or known to have an inefficient system.

The distribution network will hold records and charge suppliers based on their knowledge of the metering system in place at each premise, the suppliers will then pass this cost directly on to the customer.

How can it be changed?

The Reactive Power rate within a metering system and the network leading to the supply point can only be changed by the Distribution business that owns the relevant wires.

The Reactive Power, which occurs within a premise, within the electrical components and facilitates installed can be improved by installing more efficient systems that do not lend themselves to a mismatch between current and voltage and which therefore deliver a sub-optimal performance when compared to Real Power.

Power Factor

Power Factor is the ratio between the Real Power flowing to the load and the Apparent Power in the circuit.

In effect, the Power Factor is the outturn of the impact of Reactive Power in a system.

Where Reactive Power isn’t an issue and therefore inefficiency in the system isn’t a problem the Power Factor will be high.

Conversely where Reactive or Apparent Power is an issue, caused by the mismatch between current and voltage then inefficiency will be a problem and the Power Factor will be low.

A low Power Factor therefore indicates an inefficient system.

A load with a low Power Factor has to draw more current to deliver the same amount of Real Power being transferred.

In effect more energy needs to be put in to deliver the same performance as a more efficient system.

Because the system is inefficient, higher current is needed to compensate for the energy lost in the distribution system, to cope with this higher ‘input’ larger wires and other equipment are needed.

The cost of the larger equipment AND the wasted energy results in additional charges being levied on the customer via kVA and kVAr charges as well as increased kWh usage.

How can it be changed?

The Power Factor within a metering system and the network leading to the supply point can only be changed by the Distribution business that owns the relevant wires. This would necessarily involve the installation of capacitors and inductors along the distribution network and in sub-stations.

The Metering system installed on the premise will be agnostic as to the level of power factor of the equipment in the premise itself, It will simply see the load that is being called for and will facilitate that level of load up to its Available Supply Capacity.

The customer will, as a result, pay for this inefficiency through the greater energy demand and therefore higher kWh usage.

Within the premise itself, as with the distribution network, a low power factor can be addressed by the installation of capacitors and inductors built into power consuming equipment.

What are the realistic options?

An individual customer will have little opportunity, unless they are a major energy user directly connected to the grid, to engage with the distribution network to improve the Reactive or Apparent Power rating of the network leading to their supply point and likewise will have little influence over the Power Factor rating.

As a result it will be a case of waiting for cyclical renewal and improvement in the local distribution network for any material changes to be made.

Within the premises itself however, the machinery on site may be creating a Reactive or Apparent Power rating and Low Power Factor rating itself. This can be addressed but requires careful consideration as it involves potentially significant investment.

The drawback of acting is cost and disruption, however the benefits include:

  • Reducing the energy demanded from the meter, reducing the kWh consumed at the premise and therefore lowering the bills;
  • Reducing the energy demanded from the meter, whilst inefficiency will still exist ‘outside’ of the premise, the requirement for a compensatory large cable (and therefore a high Available Supply Capacity) will be reduced by the demand efficiencies made internally;
  • As cable size is reduced through the demand efficiencies made, the level of losses can be reduced, therefore reducing the overall level of demand and cost further;
  • Enabling a business to better meet efficiency targets including Corporate Social Responsibility initiatives;
  • Extending the life of equipment and reducing maintenance costs as it is being run less intensively and at a cooler rate through the lower energy levels being called

Each case however will need to be taken on its individual merits with particular focus on the ultimate payback and initial outlay required. The benefit can outweigh the cost and will be entirely site specific in its application.

What must also be borne in mind is that whilst optimum efficiencies can be achieved within the premise, still the network that delivers the energy could be deeply inefficient requiring the customer to pay for excessive Available Supply Capacity as well as Reactive Power through the inefficiencies of the distribution network regardless of the work undertaken internally.