The Green Question

An electric steam boiler emits no pollutants at the point of use but it may be responsible for off-site pollution, depending on the source of the electricity. It is also an inefficient way of using fossil fuels because a thermal power station typically converts only about one third of the fossil fuel energy into electricity.

However, if the power source is renewable and the electricity is generated via a wind turbine, solar heating, a hydro–electric plant or nuclear power station then an electric steam boiler is the only carbon-free boiler solution that exists in the commercial and industrial boiler market.

Moreover, the government has recently commissioned four Carbon Capture & Storage (CCS) power stations that will ultimately move the United Kingdom towards a completely carbon-free source of electricity generation. Over the next 20 years it is clear that many companies will be required to move towards Electric Boilers as the only realistic solution to reduce carbon emissions in the UK industrial boiler sector.

Electric Boilers versus Gas or Oil Boilers

Collins Walker Electric Boilers have distinct advantages over conventional oil and gas-fired solutions. The key benefits to our commercial and industrial customers are:

• No separate boiler house or chimney required
• Environmentally friendly and pollution free
• No fuel Storage requirement
• No special fire or health and safety precautions
• Instantaneous hot water and steam generation relative to gas and oil fired boilers
• Clean and quiet
• Compact, easy to install and can be located close to the point of use
• Low maintenance and years of trouble free operation
• High efficiency up to 98% even at partial load

Electrode Boilers versus Immersion Element Boilers

There are two methods of utilizing electric power to generate steam in an electric boiler or steam generator. One is to pass electric current through a metal resistance-heating element immersed in water. The metal element resists the passage of current and develops heat, which by contact is conducted to the water and finally generates steam. The other method is to utilize the water itself as the resistance element carrying alternating current between solid metal electrodes. The resistance of the water to the passage of current produces internal heat that results in rapid steam generation.

Collins Walker manufactures both Electrode and Immersion Element Steam Boilers and there are different benefits associated with each type of boiler. The boiler that is selected for a particular project will usually be based on the customer's specific requirements. Electrode Boilers are a simpler design and tend to be more physically robust and easier to maintain. They also tend to be more resistant to electrical supply fluctuations and spikes, so are popular in areas such as Africa and the Middle East. It is also possible to generate significantly more steam output from the same Electrode boiler by using a higher voltage electrical supply. For example, our largest Electrode Boiler, the ES240, will generate 3520 Kg/Hr of steam from a 3-phase 415 volt electrical supply. However, this can increase to 6000 Kg/Hr if a 690 volt electrical supply is used.

The Immersion Element Boilers are a more modern design which, with the use of elements, offers a greater flexibility in the range so the boiler can be tailored specifically to meet the customer's steam or hot water requirements. The use of elements also gives the capacity to upgrade boilers of the same model by adding elements to the flange assembly.

For example, our smaller ELV boiler can cover a steam output range of 19 Kg/Hr to 200 Kg/Hr simply via increasing the number of elements (& stages) in the boiler. The Immersion Element boilers also offer a more controlled electrical load regulation than the Electrode Boilers which can be improved further via the use of Thyristors rather than via staged contactors.