Ambitious new climate change targets mean that power generation of all types is under greater scrutiny than ever before.
As part of their mission to enhance energy efficiency across plants, it is essential that operators undertake a thorough review of electrical systems, but how can they identify key areas of energy wastage and what are the best options for combating this?
The UK is taking serious steps to meet the terms of the Paris Agreement, with proposals in place to reduce emissions to ‘net zero’ by 2050. With the UK not currently on track to meet these targets and concerns that Brexit may trigger shortages in domestic energy supply, it is essential that any new power plants built are as efficient as possible, and that older plants tackle this through upgrades and re-thinks of electrical infrastructure.
However, with the need for operators to strike a balance between driving efficiency and ensuring plants are commercially viable, and uncertainty regarding the availability of relevant grants and subsidies in the future, this task is by no means straightforward.
When it comes to power plant optimisation, there is often a tendency for operators to focus on improving the performance of combustion and steam processes. However, considering the plant’s electrical systems as a whole can also achieve significant efficiency benefits. Where plants are generating their own power, electricity that would have been wasted can then be sold back to the grid instead.
No one-size-fits-all solution
A common pitfall for operators in the quest to drive efficiency is a failure to adopt a joined-up approach, which takes into account all areas of the plant. It is important to be aware that there is no one-size-fits-all solution to this, and an important first step is to assess whether intelligent monitoring systems are in place.
By measuring and monitoring heat flows across different parts of electrical systems, operators will be able to identify problem areas for energy wastage, allowing them to introduce targeted improvements through retrofitting or replacement of equipment.
One key area where there are often significant improvements to be made in terms of energy wastage is the restart process for motors. Compared to modern standards, older variable speed drives are often inefficient. Some are left running at a constant speed, regardless of load requirements. Allowing the frequency and speed of motors to be adjusted according to process requirements, switching to modern variable speed drives has the potential to reduce energy wastage by around 25 per cent.
Voltage management is another important technique which can help operators to optimise energy efficiency across their sites. In simple terms, this involves using electrical transformers to reduce or increase the voltage level from that of the incoming supply. In simple terms, the use of higher voltage equipment can reduce the electrical current drawn. This helps to ensure that electricity supplied to the site’s equipment is in line with its requirements, allowing energy wastage and excess costs to be kept down.
It is worth bearing in mind that operators are more likely to make significant energy savings using this technique if a high proportion of their equipment is large and involves high current. An analysis of the plant overall vs available voltage applicable equipment is advised. This will help to inform the decision about whether potential energy and cost savings outweigh the initial cost outlay involved in investing in voltage management technology.
Optimising the fuel burning process is another way in which plants can reduce their carbon emissions without compromising power output. This usually involves adjusting the site’s feed stock profile with a view to superheating steam in an efficient time, and then maintaining an optimum temperature. In some cases, a full burn may not be necessary to produce the required amount of energy, and ensuring the correct combustibles are used will therefore be key.
Industry is already coming under increasing pressure to modernise systems and support the UK in meeting its climate change commitments. Rather than automatically looking to build new plants, which are often delayed due to complications in securing planning permissions, operators should emulate several successful projects across Europe by investing in system upgrades.
By adopting an analytical and plant-wide approach to identifying key areas of energy wastage, and by taking advantage of the latest technological innovations, operators can bring their sites in line with new industry requirements whilst enjoying the positive impact to their bottom line.
Tim McNeilly is managing director at IC Electrical. IC Electrical is a UK-based electrical engineering contractor providing complete in-house electrical engineering solutions incorporating the design, build and installation of control panels, HV and LV electrical systems, communication and automation systems plus small power and lighting installations.