Fertile demand

UK-based deep mining company Cleveland Potash has selected KiWi Power to develop a pilot demand response (DR) programme at its potash and rock salt mine near Middlesbrough, UK.

KiWi Power is a smart grid company that specialises in managing the demand side of energy consumption for large industrial and commercial consumers of electricity.

Cleveland Potash, a business unit of ICL Fertilizers, operates the UK’s only potash and rock salt mine, which can produce nearly a million tonnes of potash and more than half a million tonnes of Polyhalite salt each year.

Polyhalite, which Cleveland Potash markets under the product name Polysulphate, is a complex salt comprising sulphur, potassium, magnesium and calcium which are all essential nutrients for crop production.

This salt has the additional benefit of being low in chlorides and can be used as a specialty fertiliser suitable for fertilising crops and agricultural land that are sensitive to chlorine.

In addition to fertiliser production, Cleveland Potash’s products are also used in glass making and applications in the chemical and pharmaceutical industries.

Due to the energy intensiveness of the company’s systems - lifting machinery, pumps, fans systems and rock shafts - a private Combined Heat and Power (CHP) plant is on site to provide the heat required for operations and drying.

Working closely with the CHP operator, KiWi Power designed and installed a high-voltage (HV) monitoring solution to be able to monitor each on-site gas engine independently, allowing the cycle of engines to continue to ensure a fair split of running hours on each engine.

Each gas engine is now monitored in real time, minute by minute, allowing flexibility on which engine is used for all DR.

To date, the site has achieved successful DR capacity of 3MW.

KiWi Power process engineers visited the Cleveland site to meet with the engineering and operations team and identify the main opportunities for DR.

A DR strategy was then drawn up by KiWi Power, reviewed with key site personnel and agreed upon.

To ensure the opportunity was utilised to its maximum by Cleveland Potash, a minor request was made to alter existing CHP manning hours to ensure adequate coverage by authorised staff.

This change resulted in a significant increase in both revenue and site availability.

Following thorough testing, KiWi Power installed smart metering across the HV engines at the site in line with National Grid’s specifications.

This was a non-invasive procedure and installed outside operating windows to avoid any potential interruption to site.

Following the installation, KiWi Power engineers delivered training to Cleveland Potash’s CHP partner for the programme, including the DR strategy and their role in executing it.

Prior to going live, a series of tests were carried out by KiWi Power and Cleveland Potash together to ensure both the operational remit and local risk management strategies were adhered to.

In addition to benefitting from KiWi Power’s various DR schemes, the project was also designed to reap the benefits of avoiding heavy energy usage during National Grid’s benefit Triad periods.

Triad demand is measured as the average demand on the system over three half hours between November and February (inclusive) in a financial year.

In April of each year, each licensed electricity supplier is charged a fee by National Grid for the peak load it imposed on the grid during those times of the previous winter.

They then pass this cost on to customers with energy intensive users charged a higher rate than usual for the electricity used during a Triad period.

The periods are not known in advance, but electricity suppliers will issue customers between 20 & 30 warnings each winter of when they think a Triad period may occur.

Such energy-saving benefits will become even more important for Cleveland Potash following its announcement that the government has approved a grant of £4.9 million for the company’s polyahite expansion project.

Geological studies conducted by parent company ICL Fertilizers indicate that there are deposits amounting to more than one billion tonnes of polyhalite under the company’s potash mine.

ICL Fertilizers chief operating officer Nissim Adar said: “We see significant potential in increasing our production capacity and marketing of Polysulphate from [the] Cleveland Potash mine. We are very grateful to the British government for their faith in ICL and in this project.”