The case for e-drives [LNG2023]
What is your view on the energy trilemma? In a time of volatile and high energy prices, how can we balance energy security and affordability with sustainability?
We understand the Energy Trilemma is the need to find balance between energy reliability, affordability, and sustainability and its impact on everyday lives. If we address the prime sources of energy, i.e., oil, coal, piped gas, LNG, renewables and nuclear, none can satisfy all three criteria. Renewable energy is clearly best-in-class with respect to sustainability. Although, one must not omit the lifecycle footprint through the renewable value chain, i.e., from raw material extraction through to production and operation. Renewable energy is affordable and increasingly so. But currently, it cannot meet the world energy demands and still needs major investment and scale up of infrastructure to improve the reliability and consistency in supply.
|
Advertisement: The National Gas Company of Trinidad and Tobago Limited (NGC) NGC’s HSSE strategy is reflective and supportive of the organisational vision to become a leader in the global energy business. |
In the short- to medium-term, it is necessary to provide both energy security and affordability through non-renewable sources, notwithstanding public objection to using hydrocarbons (and/or nuclear).
Energy supply from hydrocarbons is affordable and reliable, but has higher emissions throughout its value chain, particularly in the transportation sector. There are many opportunities to abate these emissions, but these techniques come at a cost, particularly for energy provided through coal or oil.
Piped gas and by inference LNG, is affordable, and have relatively lower emissions than coal and oil, with opportunities for further abatement. As such, natural gas and LNG are well positioned to be the energy source of choice in the short- to medium-term, to satisfy the shortfall from renewable sources.
Natural gas and LNG provide proven and cost-effective solutions to energy security, can displace some of the energy supply of higher-emission sources – replacement of coal in power stations for example – and can provide the security of energy supply that is necessary as emerging technologies, together with the renewables industry, strive to meet the world’s energy demand.
What role does LNG have on the road to net zero, and how can LNG best maintain its social licence to operate?
Natural gas and LNG can contribute in a significant way to the reduction of emissions in the energy industry in the near term. Use of natural gas is constrained by its availability in areas of high energy demand and by constraints in infrastructure to move the gas in sufficient quantities to the end user. In these instances, LNG provides a valuable opportunity to support an increase in use of natural gas, which can then be utilised to displace higher emitting fuel sources, such as use of coal for power generation.
Additionally, LNG has a high energy content per unit volume and can be stored in large quantities. Therefore, it provides an ideal way to provide energy security and reliability, and enable supply of energy at peak demands, whether diurnal or annual. Importantly, LNG can also provide much needed energy security for events, whether geopolitical or climatic, that are outside the control of a natural gas consuming nation.
Use of natural gas, and by inference LNG, generates higher emissions than renewable sources of energy. Therefore, to maintain support for LNG, there is a necessity to show pathways to reduce emissions and implement emission reduction technologies on new and existing natural gas and LNG facilities. Many emission reduction concepts can be implemented at a relatively low cost, particularly if combined with use of renewable energy, but others do incur an increase in cost, such as sequestration of the CO2 that is already captured as part of the processing of the natural gas or LNG and then generally emitted.
We’ve seen increased adoption of e-drives as a low-carbon power solution for LNG facilities. How significant an impact do they have on emissions versus gas turbines and what do they add in terms of extra cost?
The use of e-drive as a low-carbon power solution for LNG facilities must be considered with both Scope 1 and Scope 2 emissions in mind: emissions associated with the operation of the LNG facility (Scope 1); and the emissions associated with the generation of the power that supplies the LNG facility (Scope 2).
A good example of a low-carbon solution is the Woodfibre LNG project where the imported power to the LNG facility is primarily from a renewable source, in this case hydroelectric. It would be unrealistic to categorise an e-drive LNG plant as low carbon if the power to drive the facility is sourced from an open cycle or coal fired power plant. Power sourced from a natural gas fired combined cycle power plant has some potential to enable a lower carbon LNG facility but this improvement in emissions can be negated, if not completely lost, due to the process heating requirements of an LNG facility.
By using e-drive in conjunction with renewable power, the GHG emissions could be reduced by 80%-90% when compared to a traditional industrial gas turbine driver configuration utilised by most of the world’s LNG facilities. When considering auxiliary systems required to operate gas turbines and e-drive compressors, the cost difference between the two solutions is not significant although the cost of power supplied through renewable sources is transferred from a capital cost to an operating cost.
What kind of innovations are we seeing regarding e-drives and what is the potential for those innovations to drive down costs?
One of the innovations we are seeing with e-drives is the development of an increasingly standard and modular design approach to the liquefaction and refrigeration units of an LNG facility. This should provide an opportunity to drive down cost and result in a reduced testing program and shorter delivery times.
This interview was originally published in the LNG2023 Daily, produced by NGW during the LNG2023 conference in Vancouver July 10-13.