AU2016101350A4 - Distributed energy hub powered by reneweable ammonia - Google Patents

Abstract

A method for generating ammonia using renewable energy to power a distributed energy hub for zero carbon production of hydrogen and electricity for stationary and mobile use. The method comprising the steps of: (a) Using renewable energy to generate hydrogen and nitrogen and to power a synthesiser and liquefaction unit so as to produce renewable NH3; (b) Transporting this renewable NH3 via ship, road, rail or pipeline to a distributed energy hub; (c) Configuring equipment at this energy hub to consist of a tank to hold liquid NH3, an NH3 powered electricity generator such as an engine, gas turbine or fuel cell, a cracking unit to split H2 from NH3 and equipment to compress and dispense H2 for fuel cell vehicle use; (d) Additionally locating at or near the energy hub a fast charging electricity recharger for battery electric vehicles where the electricity is sourced from the energy hub's NH3 powered electricity generating unit, (e) Additionally locating at the energy hub connection equipment and wiring to enable the hub to supply to nearby customers or into the local electricity distribution grid electricity sourced from the energy hub's NH3 powered electricity generating unit, and (f) Efficiently configuring the energy hub's equipment such that waste heat from the electricity generating unit provides the heat requirements of the cracker unit whilst NH3 and H2 gases in the waste stream from the cracker unit are fed back as part of the fuel supply to the electricity generating unit. /7> /-7 Ky> Zr Zr 0 a, 41- Zr -42; w 4~ cm 1- ~#~< C) '4.3 Ita~ C) ~~ In cf-I r~ ~ 4$ +2 -C i~J) ,,, m -""---i 4' / U®'

Description

Distributed Energy Hub Powered by Renewable Ammonia FIELD OF THE INVENTION (01) The present invention relates broadly to a method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use.

BACKGROUND TO THE INVENTION (02) With increasing global concern about climate change there has been growing interest in the concept of generating energy for mobile and stationary use from renewable sources such as wind and solar so as to avoid the emission of harmful greenhouse gases such as carbon dioxide. (03) Concerns related to climate change have also fostered increasing interest in the distributed generation of energy which aims to closely locate the point of energy generation to the point of energy use so as to reduce efficiency losses and costs associated with long distance grid transmissions. (04) For mobile applications such as automobiles both renewably generated electricity and renewably generated hydrogen (H2) are seen as zero carbon energy sources. (05) Production of zero carbon H2 from water electrolysis powered by renewable energy is seen as a way of storing and transporting intermittent sources of renewable energy such as wind and solar. (06) Whilst H2 is potentially a zero carbon energy carrier, it is very hard to transport and compress into containers of convenient volumetric dimensions. (07) Of recent times there has been growing awareness that liquid ammonia (NH3) can be produced from renewable sources using renewably powered water electrolysis for H2 and renewably powered air separation units for nitrogen (N2) and renewably powered gas synthesis and liquefaction. (08) Because of its very high volumetric and gravimetric density of H2, liquid NH3 can act as an extremely efficient carrier of H2. (09) In terms of volumetric density, which is a crucial determinate for the economics of long distance transport, a 1 cubic meter tank of 700 bar H2 will contain 39.6 kgH2 and the same volume tank holding liquid H2 will hold 71 kgH2 but the same volume tank of liquid NH3 will hold 121 kgH2. (10) NH3 is also seen as a convenient carrier of H2 because the world currently produces, transports and consumes many millions of tonnes pa of NH3 which is handled by a vast existing infrastructure of ships, road and rail carriers and pipelines. (11) Whilst most of the world’s existing NH3 production is used for fertiliser, in recent years there have been advances in technologies which can harness NH3 for the stationary and mobile generation of energy. (12) Such technologies have included electricity generation via modified engines, gas turbines and stationary fuel cells, all of which can be powered by a feed of NH3 as fuel. (13) Still further technological advances have made it possible to efficiently split or crack NH3 back to its two constituent gases of nitrogen and hydrogen and thereby release the H2 for use in fuel cell vehicles such as the Toyota Mirai, the Hyundai Tucson or the Honda Clarity. (14) NH3 to H2 cracking technology requires a source of heat to generate the cracking process, so where the NH3 has been produced from renewable sources and the heat for the cracker is itself from a renewable source, the resulting cracked H2 can be described as being renewable and carbon free. (15) If the H2 used to power fuel cell vehicles has been sourced from renewable energy this enables such vehicles to be marketed as potentially a zero carbon means of transport. (16) Similarly battery electric vehicles, whose batteries have been charged from electricity powered from renewable sources, can also be marketed as potentially a zero carbon means of transport. (17) Renewably generated NH3 can be delivered to a distributed energy hub containing both an NH3 powered electricity generator and an NH3 to H2 cracker so as to provide both H2 and electricity to customers seeking zero carbon energy supplies from the hub. (18) The equipment components of such a distributed energy hub powered by renewable ammonia can be configured such that the waste heat from the electricity generating unit can be harnessed to provide the heat required to power the NH3 to H2 cracking unit, which thereby enhances overall energy efficiency and ensures that both the electricity and the H2 generated from the hub are carbon free. (19) Such a distributed energy hub with co-located electricity generating unit and cracking unit can further enhance efficiency by directing any un cracked NH3 and uncollected H2 in the cracker unit’s waste gas stream back into the NH3 powered electricity generating unit to thereby ensure utilization of such gases.

SUMMARY OF THE INVENTION (20) According to one aspect of the present invention there is provided a method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use, by: a. Using renewable energy to generate hydrogen and nitrogen and to power a synthesiser and liquefaction unit so as to produce renewable NH3; and b. Transporting this renewable NH3 via ship, road, rail or pipeline to a distributed energy hub; and c. Configuring equipment at this energy hub to consist of a tank to hold liquid NH3, an NH3 powered electricity generator such as an engine, gas turbine or fuel cell, a cracking unit to split H2 from NH3 and equipment to compress and dispense H2 for fuel cell vehicle use; and d. Additionally locating at or near the energy hub a fast charging electricity recharger for battery electric vehicles where the electricity is sourced from the energy hub’s NH3 powered electricity generating unit, and e. Additionally locating at the energy hub connection equipment and wiring to enable the hub to supply to nearby customers or into the local electricity distribution grid electricity sourced from the energy hub’s NH3 powered electricity generating unit, and f. Efficiently configuring the energy hub’s equipment such that waste heat from the electricity generating unit provides the heat requirements of the cracker unit whilst NH3 and H2 gases in the waste stream from the cracker unit are fed back as part of the fuel supply to the electricity generating unit.

BRIEF DESCRIPTION OF DRAWING (21) In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use will now be described, by way of example only, with reference to the accompanying drawing in Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIEMET (22) Figure 1 depicts a method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use, involving the following steps: a. Delivering renewably generated liquid NH3 to a distributed energy hub to be held in the hub’s holding tank 1 ; and b. Dispensing some of the NH3 from the holding tank to the hub’s NH3 powered electricity generating unit 2; and c. Transmitting some of the resulting electricity to an electric fast charging station 3 for recharging batteries in a battery electric vehicle 4; and d. Transmitting some of the electricity to the local electricity grid 5; and e. Dispensing some of the NH3 from the holding tank to the hub’s H2 cracking unit 6; and f. Delivering the cracked H2 from the cracking unit to a compressor 7 for delivery to the H2 refuelling unit 8 for dispensing into a hydrogen fuel cell electric vehicle 9; and g. Configuring the hub’s equipment such that waste heat from the electricity generating unit 2 is used to power the cracking unit 6 and the waste NH3 and H2 gases from the cracking unit are used to supplement the fuel for the electricity generating unit. (23) Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, some of the electricity generated from the hub, rather than being transmitted into the local electricity grid, might be delivered directly to a nearby customer in a behind the meter transaction. (24) All such variations are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description.

Claims (3)

1. Claims

   1. A method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use, said method comprising the steps of: Delivering renewably generated liquid ammonia to a distributed energy hub; and Holding the renewable ammonia at the hub in a liquid ammonia holding tank; and Dispensing ammonia from the tank to the hub’s ammonia powered electricity generator, which provides zero carbon electricity to the local distribution grid and which powers the hub’s fast charge electric charger to provide zero carbon energy for battery electric vehicles; and Dispensing from the tank ammonia to the hub’s hydrogen cracking unit to supply hydrogen gas to the hub’s compressor and hydrogen refuelling station to dispense zero carbon hydrogen for fuel cell electric vehicles.
2. 2. A method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use as described in claim 1, where: Some of the electricity generated by the hub’s ammonia powered electricity generator is provided directly to a nearby energy customer, bypassing the local distribution grid in a behind the meter transaction.
3. 3. A method of using renewably generated ammonia to power a distributed energy hub for the zero carbon production of hydrogen and electricity for stationary and mobile use as described in claim 1, where the electrical and thermal efficiency of the hub is enhanced by: Configuring the hub’s plant and equipment such that waste heat from the electricity generating unit provides the heat requirements of the cracker unit whilst NH3 and H2 gases in the waste stream from the cracker unit are fed back as part of the fuel supply to the electricity generating unit.