Establishing Clean 'Power and Cooling' As a Cold Chain System Solution
The cryogen required to begin creating a clean ‘power and cooling’ based cold chain system, by starting the process of local capability and capacity building with cryogen fuelled refrigeration units for the transport step, is often already available in many developing nations. In this regard, although liquid air is not yet produced commercially, throughout the industrialised world nitrogen is as a standard output from the air separation process. The industrial gas companies potentially have large amounts of spare nitrogen production capacity available for the simple reason that the gas is more prevalent as a component of air than oxygen (78% of air by volume is nitrogen compared with only 21% oxygen) but there is significantly less commercial demand for it. Consequently the potential for nitrogen production in an ASU is often simply not utilised and the amount of this latent capacity is set to increase across the developing world as industrial gas production grows along with widespread industrialisation. This surplus could in many cases be employed to support early deployment of the refrigerated transport solution, in the emerging industrial centres of developing economies. Initial, conservative cost modelling presented in the Tanzanian case study of this report shows that replacing diesel with cryogen fuelled refrigeration units on cold chain road transport reefers can lead to considerable cost savings.
IN ASIA, THE INDUSTRIAL GAS SECTOR IS GROWING FAST, AND RECENT INVESTMENT HAS LED TO THE EMERGENCE OF SIGNIFICANT SPARE NITROGEN CAPACITY.
In Asia, the industrial gas sector is growing fast, and recent investment has led to the emergence of significant spare nitrogen capacity. For example, analysts at gasworld estimate current spare nitrogen liquefaction capacity in the ‘merchant’ and ‘onsite’ trade is about 3, 500 tonnes per day in India alone. In principle, this amount of surplus nitrogen would be enough to fuel refrigeration units on about 29, 000 delivery trucks. Additionally, many of these countries have established, or are in the process of establishing, facilities to enable the import of LNG to meet growing energy needs. The regasification of LNG provides surplus cold which in most cases is currently not used but could be recycled to help drive a liquid air plant. By 2015China is expected to have LNG import capacity of 47 million tonnes per year, and the waste cold from this amount of regasification could theoretically be used to help produce 17 million tonnes of liquid air, which would be enough to fuel 390, 000 cryogen fuelled refrigerated truck units. In other words, in a simple calculation, China will have the potential of wasting more cold than would be required to support the entire refrigerated fleet projected to be in place within a decade (365, 000).
Recycling unpacked cold from LNG
LNG is natural gas (typically methane) which has been shrunk about 600 times in volume for ease of transport and storage by chilling to about -162°C at atmospheric pressure. This is an energy intensive process. Regasification of this cryogen requires significant amounts of energy to heat the LNG to a temperature above0°C and this is generally achieved through a series of heat exchangers with sea water on the ‘hot’ (ie warm) side. In cases where the water is not of sufficient quality the heat is often supplied by burning some of the gas itself. The process of regasification gives off substantial amounts of cold that is usually rejected to the sea or vented to the environment, both of which effectively ‘waste’ this cold resource. In a sense, LNG is natural gas packed in cold, but that packaging is currently discarded, rather like the polystyrene in the box of a new TV set. However, this cold can be recycled and where this approach has been adopted at LNG terminals in Japan and Korea for nitrogen production the liquefier requires two thirds less electricity than a conventional unit, thereby both capturing the otherwise wasted cold and reducing the cost and carbon intensity of the cryogen product by a similar margin.
Figure 3: Artists impression of a local cold economy based on a cryogenic cold chain system building capacity in an emerging industrial centre. (Reproduced with permission of the Liquid Air Energy Network).
In such a capability and capacity building scenario, what starts initially as a zero emissions at point of use transport solution for the cold chain will evolve and extend to become a wide ranging cleantech leapfrog to a sustainable cold chain approach, incorporating surplus nitrogen production capacity, waste cold from LNG regasification and local production in energy storage facilities of liquid air for use as transport refrigeration unit fuel (Figure 3). A case study on India is provided elsewhere in this report as an example to give further details of the capabilities, capacities and opportunities available in a rapidly industrialising country to implement this scenario in practice on the ground. The study also provides an early initial cost comparison for the cleantech solution against those that would be incurred in taking a traditional fossil fuelled ‘business-as-usual’ infrastructure approach.
In the newly emerging economies, such as those of sub-Saharan Africa, the situation is somewhat different. Here, depending on the stage of industrial development, there may be small but increasing amounts of surplus liquid nitrogen production available from industrial gas production to begin local capability and capacity building. In some cases also, depending on the individual country’s emerging energy infrastructure, there might be some LNG regasification infrastructure to enable exploitation of waste cold. However, in many locations, particularly those that are rural and remote, a different capability and capacity building scenario will need to be followed. The opportunity here is to establish cryogenic energy storage as the technology of choice for off-grid and micro-grid renewable energy projects at local agricultural ‘hubs’; thereby providing the potential for local liquid air production to fuel cryogen TRUs as well as delivering reliable electricity supply to cold stores and the broader community. Capacity and capability building in this scenario will open up the possibility of providing a broad range of additional local ‘power and cooling’ services based on a tank of cold: in effect creating a ‘cold economy’ from the bottom up. The Tanzanian case study included in this report explores the practical in-country potential for such an approach in a sub-Saharan Africa context and provides an early initial indication of the economics of implementation.