When a production or manufacturing facility is built, everything is new and operating optimally. Over time, equipment deteriorates, or modifications are made with the best intentions, but not always with energy efficiency in mind. It is therefore good practice to do regular energy assessments to ensure, for example, that steam traps are working correctly, and there are no steam piping ‘dead legs’.
“Someone may move a machine, and the line, which used to provide steam energy, is not properly isolated but is still receiving energy. This is what we term a ‘dead leg’, and it is extremely inefficient,” explains Brenainn Cross, technical director at Associated Energy Services (AES).
Detail is in the data
AES engages clients regarding precisely what equipment is on site and how their steam process operates, which entails requesting data from their systems. Where reliable data cannot be provided, AES employs data capturing equipment to fill in the gaps.
Cross says that when it comes to doing an accurate energy assessment, understanding a company’s steam offtake is vital. “We want to know what their process looks like, how much energy they use, how they use it, and when they use it. Some companies have a very flat profile such as where there is a very consistent offtake, for example a tissue manufacturer. Others, such as a tyre or food manufacturer, have a batch-driven process with peaks and troughs throughout their steam offtake cycle.
“Many businesses do not realise that products use steam differently. They see steam used as a linear process, and do not appreciate that product type has a big impact. Once we have the correct data, there is great value for clients when they start understanding their own energy usage-related data and AES’ energy optimisation capabilities,” he adds. This information allows AES to estimate whether or not the client’s thermal energy plant is fit for purpose.
Finding the energy blind spots
Cross maintains that a lack of data and analysis around the conversion rate of fuel into energy is a substantial blind spot for many manufacturing or processing companies. Most focus on fuel consumption versus the quantity of product made – a process known as ‘fuel to product out’ costing − rather than monitoring how efficiently fuel is converted to steam energy, and thereafter how much steam energy is used to produce the product.
He admits, however, that there is no single ‘silver bullet’, and that energy assessments must be carried out on a case-by-case basis: “In instances where we see a mismatch between plant or equipment installed on site and the client’s energy usage profile, we will raise this. What we can achieve could be constrained by incorrect or inadequate equipment. We have to assess whether capital investment is required for us to meet our energy optimisation commitments accordingly.”
To this end, AES’ advice may extend beyond the boiler itself to issues such as water treatment and asset care: “One of our clients currently needs to consider additional feed water treatment to address a hard water challenge and remove total dissolved solids that can affect overall boiler energy efficiency, and in the worst case, damage equipment,” Cross adds.
While data collected regarding pressures, flow rates and temperatures is invaluable, it is often difficult to access and complete a full and detailed risk assessment of all equipment while it is operational. For this reason, boilers need to be taken offline for inspection. AES can then raise any problems with a client and discuss ongoing asset care and maintenance, and also the impact on the energy usage and optimisation process.
The power of change
Cross describes an energy assessment as a “conversation continuing throughout AES’ relationship with the client”. Ongoing assessments are also vital due to staff and management changes. “We know the baseline situation when we take over the boiler operations and maintenance. However, incoming staff and management may not. From a perception perspective, it is very important that the client is consistently made aware of the implications if no energy assessments or optimisation are done, and how pivotal these are to the long-term productivity and sustainability of their facility,” he says.
Energy savings speak for themselves. An example is the 21% and 38% improvement respectively registered at two food processing plants where AES is responsible for energy optimisation.
For Cross, initial assessments usually identify ‘low-hanging fruit’ or early energy saving gains. Take insulation: AES has countless examples of advising clients to insulate heated surfaces as a quick way to recover wasted energy.
“Uninsulated steam lines result in energy losses through radiation heat transfer. For a steam line with the specific parameters stated, insulating this piping would amount to a reduction in CO2 emissions of 620 tons per annum,” he says.
Assessments fuel change
“Over the past three years, we have seen increased pressure from larger clients requiring a more direct line of sight when it comes to their energy efficiencies, specifically with a view to environmental or carbon tax concerns,” Cross observes. He adds that AES has been asked to assess many unusual prospective fuel types, including the use of process byproduct streams as potential fuels. “An assessment often proves that the potential energy generation does not warrant the capital expenditure required to make the fuel change,” he explains.
He notes that the gamechanger is the baseline cost of the energy, citing a recent energy assessment where a fuel switch for a client has the potential to unlock significant operational savings.
“Throughout the process, input from specialist engineers allows us to fully assess and convey to the client the true value of fuel or other changes. In manufacturing or processing facilities, the focus is on the process but not on the conversion of energy – and often not sufficiently on its cost, quality or efficiency. Regular, accurate energy assessments really focus the client’s attention on powerful insights which AES can then use to make the changes required to achieve energy usage and cost savings, and also improved environmental and operational sustainability,” Cross concludes.
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