Go for gas: why natural gas-powered generators have come of age
Craig Wilkins, Director of Prime Power at Cummins, argues how, for the foreseeable future at least, natural gas-powered generators will continue to be key to meeting the power needs of the utilities sector in the Middle East and across the globe
We live in interesting times. Energy generation via fossil fuels is gradually being challenged as emissions reduction, carbon reduction and environmental drivers become a key factor in power generation. It is also an increasing trend that modular power networks – made up of renewables as well as batteries for storage – will be the future of power generation for society and industry.
The concept is scalable, able to power entire cities, as well as remote off-grid installations, and will have wide reaching implications for the utilities sector. In the Middle East, the sector is leading the way in investment into renewables, with Saudi Arabia and Dubai both recently announcing plans to build vast solar-powered desalination plants.
So where does the ‘traditional’ fossil fuel powered generator sit in the coming new age of power? Well, battery technology is advancing, but for the foreseeable future at least, it is unable to provide necessary power for intensive use demanded by utilities operations. It is natural gas that is emerging as the ideal fuel source to supplement renewable power networks. Cloud cover or wind changes can suddenly impact the efficiency of renewable energy generation, and for that reason natural gas generators that can respond quickly to maintain voltage, frequency and kW output are a key ingredient to these new power networks.
This emerging market trend has manufacturers racing to develop even cleaner, more efficient and intelligent gas generators. For that reason, Cummins, launched the HSK78G gas generator series. Designed from the skids up, this generator series will satisfy increasing demand from urban-sites through to heavy-industrial installations, including utilities such as desalination and water-treatment plants.
The benefits of gas power
An un-interruptible supply of fuel, clean technology and an excellent total-cost-of-ownership, all combine to present clear benefits for gas-power.
In the context of progressively stringent global emissions standards, modern gas-powered generators, such as the lean-burn HSK78G, are cleaner than their diesel counterparts. Air pollutant outputs are lower, including NOx, hydrocarbons, carbon monoxide and particulate matter, allowing the machine to operate in urban environments with tight emissions regulations.
Lean burn levels for NOx, without aftertreatment, are as low as 250 mg/Nm³ compared to 2500-3000 mg/Nm³ for diesel. Particulate matter levels are also almost zero. This is achieved because lean burn gas generators use twice as much air in the air/fuel mix than is required for total burn, which reduces burn temperature and NOx output.
Emissions aside, gas-powered generators offer operational advantages for the utilities sector. Having access to a continuous, un-interruptible fuel supply via a gas pipeline is an obvious benefit for use in prime-power or backup power configurations.
It also negates the need to store very large quantities of diesel on-site which require costly efforts to maintain the quality of the fuel. In addition, considering that the typical fuel cost ratio for diesel vs natural gas is 6:1, then some operators can look to achieve a significant Opex saving.
The next generation of gas-powered generators will also be able to use fuel effectively in varying qualities – ranging from pipeline natural gas to flare gas, biogas and lowest BTU (British Thermal Unit) fuels with very aggressive contaminant levels.
Its fuel flexibility gives operators around the Middle East confidence that their generators can burn a variety of local gas energy sources, even utilising what would otherwise be considered waste products. Oil refineries can burn their flare gas, generating power for operations, storing energy in batteries for use later, or selling it back to the local grid.
Reliability and extreme engineering
Running utilities such as water plants require power generation that simply cannot fail, but the climate in the Middle East places enormous strain on power systems. Technological advances are producing generators that can work effectively in the worst possible environments on earth.
For example, the HSK78G can operate effectively in temperatures up to 55°C. In the past natural gas generators have required higher levels of maintenance when compared to their diesel counterparts, but technological advances have overcome these issues, resulting in extremely reliable and robust generators. This is demonstrated by the HSK78G, which has one of the longest service cycles in the industry – an 80,000-hour full overhaul.
Energy markets continue to evolve with renewables and battery technology advancing at pace. However, as with the diversity of the utilities sector, no single technology is likely to be the only choice. Rather, most utilities operations will require a mix of energy technologies that suit their environment, power needs, location and emission zones.
What is for certain is that gas-power has undoubtedly come of age. It offers operators of utilities installations an efficient, proven and future-proof power solution, perfectly complementing renewable power and batteries. An added bonus, as demonstrated by the HSK78G, is its utility in the Middle Eastern market, with the widespread availability of natural gas (both pipeline and non-pipeline quality fuels) and ability to work at blisteringly high ambient temperatures.