The power of cold

Diesel generators – or gensets – have long been the choice for backup power in emergencies, particularly among companies running critical operations within industry.

Electricity is vital to remaining operational. Lighting, ventilation, heating and cooling systems, and the ever-growing range of technologies on which we rely, all need a constant supply of power.

Because burning diesel produces particulate matter, nitrogen oxides (NOx) and CO2, some environmental officials are considering ways to restrict their use.

The capacity to meet the very highest demand peaks has typically been provided by a fleet of distributed diesel generators. These are used to generate backup power in the event of a power cut, reduce consumption of grid electricity when power is most expensive, and earn revenue by providing reserve capacity to network operators.

Diesel gensets are most commonly used because they provide a relatively cheap and reliable solution. Many people, however, do not realise that diesel power generation is also used as a safety net against nationwide grid electricity disruption.

Last month it came to light that a number of ‘diesel farms’ in the UK were being subsidised by the Government to provide additional power to the grid. Typically, these ‘mini power plants’ operate during periods of peak demand, often coinciding with major televised events, such as the World Cup.

Part of the reason for this is that sources of renewable energy are increasingly present on the grid, creating issues around their intermittency.

The net effect is that consumers of significant quantities of grid electricity are exposed to an increasingly ‘peaky’ power supply, which is reflected in fluctuating prices.

The result of this, combined with changing demand profiles, is that National Grid must work with electricity users to match peaks and troughs in power production and consumption.

In a bid to avoid using this more expensive power at peak times, backup gensets are increasingly being deployed across a wide range of industries.

Known as ‘peak shaving’, this is a common practice – using an alternative power supply when grid electricity is most costly – and even selling excess power back to the grid at times of peak demand.

Backup gensets do provide a resilient power source to protect vital processes, but they are not sustainable in their current form because of their contribution to worsening air quality.

Because burning diesel produces particulate matter, nitrogen oxides (NOx) and CO2, some environmental officials are considering ways to restrict their use.

The City of London recently issued planning guidance to discourage the use of diesel-powered backup gensets, particularly when they are used at times other than in an emergency.

Additionally, it is developing a policy on the use of generators outside of emergencies, and encouraging action to reduce emissions and raise awareness of air quality.

This all goes to highlight the urgent need to replace the diesel genset with a cleaner, more environmental alternative. A long-term solution must provide real energy security to end users, and be economically viable as well.

The Dearman engine, which uses the expansion of liquid nitrogen to provide power and cooling, is currently being developed for use as a zero-emission backup generator.

The extremely cold nitrogen gas within the engine can also be used directly in a heat exchanger to provide ‘free’ cooling to the building or its essential services.

An alternative that delivers both power and cooling is not only a sustainable solution, but would offer an economically sound business case suited to plant operators in all sectors. 

This ‘free cooling’ also offers a dividend for warmer climates where peak electricity demand and power cuts are often caused by an intense air conditioning load.

Even in mild climates the need for additional cooling is expected to climb sharply. Cooling demand in buildings in Europe is forecast to rise by 72% by 2030, according to the European Commission.

With air quality high on the policy agenda, and energy security a priority for manufacturing industry, we see an exciting opportunity for innovative technologies to contribute to the future of cleaner, cooler process plants.

Dearman is a global technology company delivering clean ‘cold and power’. Its cutting-edge technology uniquely harnesses liquid air to deliver zero-emission power and cooling. 

The first application of Dearman technology, to provide sustainable and efficient zero-emission transport refrigeration, is currently undergoing trials at UK engineering and test centre, MIRA. It is also developing a portfolio of proprietary technologies, products and services, which deliver significant reductions in operating cost, fuel usage and emissions, at low capital cost.