Guyana will still have to import heavy fuel for gas plant

Sep 14, 2021 News

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….viability of project also requires GPL maintained at all times—Cabinet Papers

Kaieteur News – The Government of Guyana has been steadfastly propagating the idea of a gas-to-energy project that is supposed to reduce not only the nation’s fuel import bill but significantly reduce the country’s greenhouse gas emissions, as a transition fuel towards the goal of 100 percent renewable at some point in the future.
What has however been lost in the public debate over the pros, cons and feasibility of setting up a Natural gas electricity plant is the fact that it was never intended to be a Natural gas plant alone but in fact a dual powered plant, using both Natural gas and Heavy Fuel Oil (HFO).

This much is documented in a Cabinet Paper back in 2018 where the Executive was being asked to finalise a landing site for the gas pipeline that is expected to pipe the associated gases to shore.
The use of a dual powered plant has also been the basis of the 2017 Energy Narrative Inter-American Development Bank (IDB)-financed study which in large part also served as the basis for the gas-to-shore project being peddled by both the incumbent and recently ousted administrations.
In the Cabinet Paper seen by this publication, it was firstly noted that it was a request for Cabinet to review and endorse the recommended site as the proposed landing site location for the offshore pipeline, and development of “a Natural gas power generation facility (200MW dual fuel) with associated substation, liquid fuel storage and related facilities.”
In that document it was noted that as a national objective and commitment, Guyana has committed to 100 percent Renewable by 2025, conditional on appropriate support and adequate resources.
As such, Natural Gas “may therefore provide a new transition fuel opportunity that could reduce electricity costs and promote stronger economic growth, before hydropower is on stream and one which can coexist with hydropower as a clean energy source. Further, LNG can be used to supply off grid generation capacity in the hinterland and other locations for domestic use and industrial development thereby fitting within Guyana’s strategy to support economic development.”
In the document it was clearly spelt out that the new Natural gas-fired generation capacity should be dual-fuel and a new power plant should be located at the Natural gas landing point.
Additionally, it was noted that in 2017 during a site selection process that was being undertaken with the help of ExxonMobil Guyana, it was outlined that under the Terms of Reference the team was appointed to identify a suitable site(s) for associated infrastructure, specifically the installation of a 200MW dual fuel (natural gas and heavy fuel oil) generation plant along with associated substation, transmission network, liquid fuel storage and related facilities.
It was noted in the 2017 Energy Narrative report that at each point in time during the study, reference was made either for the conversion of existing generating sets to use Natural gas or in installing dual powered facilities given the aged equipment currently supplying the country with electricity.
According to that report, it was noted that in the initial inspection, it was determined that converting existing generation units to use Natural gas as dual fuel generators would minimise initial capital costs, take advantage of their strategic locations across the current transmission system, and potentially eliminate the need for Natural gas storage at the generation sites. It was found too that Natural gas storage may be advantageous to better match Natural gas supply with the electricity load shape, but further detail on Guyana’s load shape is required for this more detailed analysis.
Additionally, the Energy narrative report said new Natural gas-fired generation capacity should also be dual fuel and that a new power plant should be located at the Natural gas landing point, but additional power generation capacity should also be located at the existing generation sites where feasible to optimise the use of onshore Natural gas distribution infrastructure.
As it relates to the Guyana Power and Light’s (GPL) capacity, the report said all of the utility company’s listed generation units are reciprocating engines, burning either heavy fuel oil (HFO) or light fuel oil (LFO), with the exception of Skeldon-GuySuCo 2 which consists of two 15 MW gas turbines fueled by sugarcane bagasse.
As such, virtually all of GPL’s current installed capacity is suitable to be converted to use Natural gas as a fuel.
It was noted however that the current engines are a mix of new installations (within the past 10 years) and much older units ranging from 20-40 years old.
“While newer units could be adapted to become dual fuel (Natural gas and HFO), it is likely more cost effective to replace units that are more than 30 years old.”
It was noted that in GPL’s existing generating fleet both the Wartsila and Caterpillar manufacture dual fuel engines capable of burning liquid fuels and Natural gas and that existing single fuel units can also be converted to become dual fuel at an estimated cost of US$100 per kW of capacity.
The report said too as dual fuel units, the power plants can rely on liquid fuels as a back-up in the event of disruptions to the Natural gas supply and that each existing gas power plant already has a storage tank for liquid fuels, removing the need to build additional fuel storage and relieve a potential constraint, given the limited availability of additional space at some locations.
The study found that the analysis also suggests that the Natural gas supply will be most cost effective if new generation units are co-located with the existing units that are converted to Natural gas.
Additionally, in its report it was assumed that there was no need for Natural gas storage at the landing site or the individual power plants.
According to the report, the new and converted power plants are expected to be dual fuel, and existing power plants already have liquid fuel storage tanks and this will allow them to use liquid fuels in the event of a disruption in Natural gas supply.
Further compounding the viability of the gas-to-energy project, the report had found that putting the full power plant in a single location would also put Guyana’s electricity grid at greater risk of an outage.
A fault at the station itself (mitigated by the fact that it is many smaller engines together, rather than one big turbine), or a downed transmission line between the station and the rest of the system could disrupt electricity supply to the entire grid.
The report said that having generation at multiple locations helps mitigate this problem by locating generation nearer to the load. In this way, not all electricity supply is then lost if a transmission line goes down.
Importantly, the report noted that if the single 200MW plant were built, it would be advisable to maintain GPL’s current power plants as back-up power in the event of an outage.
In addition, GPLs capacity margin requirements state that the margin must be at least as large as the two largest units in the system, as such, adding a single large power plant would increase that capacity margin requirement, potentially requiring further investment in smaller plants elsewhere to mitigate its impact on system reliability.

 

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