The use of gas engines is continually increasing as the capabilities of these machines become more cutting edge.
In the new energy landscape the buzzword is flexibility, and gas engines are fulfilling that need, winning new devotees because of the speed at which they can be transported and installed compared to their gas turbine counterparts.
One of the key trends of recent years is the development of gas engines running on alternative fuels.
|Round table panellists debate the future of gas engines running on alternative fuels|
I recently moderated a round table discussion which assessed the current and future challenges and opportunities that the alternative fuel gas engine market is facing.
Pritil Gunjan, Energy & Environment Industry Analyst for Europe at consultancy Frost & Sullivan, began the session by setting the scene. She said that while clean energy and energy sufficiency/efficiency will in future drive the market for alternative fuels, the current biogas market has “somewhat slowed down”.
“There was talk three to four years ago about renewables and alternative fuels taking over the market, but the recession put a brake on that.”
She said Frost & Sullivan believes that, for the European market, there is 40 GW of installed capacity, and added that globally “a few pockets are growing” – Germany, central and Eastern Europe, India and China.
|Gunjan: waste-to-fuel technology “comes at a price”|
Gunjan said that the key drivers of the market were “cost/benefit, regulations, political stability and energy consciousness”.
Of those developing “pockets”, she said Germany is taking a lead because it “is a very open-minded country. They are aware that greenhouse gases will cause huge havoc for future generations – it is a commendable thing that the country is doing”.
In India, she said the needs and requirements are very basic: “They need energy, and they just want to meet demand. There is a growing rise in interest in clean fuels – the Indian government is focused on renewable energy.”
She said that for an emerging market like India which has a desperate need for power, the reason for looking to waste gas was obvious: “There is a lot of waste, and they need to use it.”
But she cautioned that the availability of waste-to-fuel technology “comes at a cost. If enough subsidies are not provided to help, they are not going to meet their needs.”
|Klimstra: “AD, syngas, landfill – all have different qualities, problems and challenges”|
Energy and engine consultant Jacob Klimstra said that the market potential of biogas rather depends on just what you mean by ‘biogas’: “AD, syngas, landfill gas all have different qualities and problems and challenges.
“Looking at low electricity prices in Europe at the moment, it’s very difficult to compete.” He said that in the Netherlands there were “a lot of big farmers using biogas from their manure and waste, but the problem was that the scale was too small – only 350-500 kW. When you look at the processing of gas to get it clean enough to put into an engine, it is too expensive. Biogas may be possible on the municipal level, but on a smaller scale it’s very, very difficult to compete in the long run.”
Dr Tilman Tütken, vice-president of MAN Diesel & Turbo, was keen to highlight the German “success story of 4000 MW of biogas”.
“We have subsidies, political will, a clear environment for subsidies, and it was decentralized, with a lot of smaller engines.”
But he cautioned that “around the world it is difficult to get subsidies or financing” and the technology challenge of cleaning waste gas is very costly. However he is “mildly optimistic – there is a lot of waste – we’re still developing technologies to make it commercially feasible – but it will take a lot of time.”
Frank Grewe, Managing Director at 2G Energietechnik, said that “currently we see that it’s getting more and more important for us to be flexible with our CHP and power generation”.
2G Energietechnik specializes in heat, not just power generation, especially in the small power range, and here Grewe said “that flexibility becomes more important”.
He listed three main requirements for today’s gas engines: “To be reliable so they’re there if needed, low maintenance costs, and to fit the emissions regulations.”
|Hamm: “flexible energy presents unique challenges”|
Thorsten Hamm, Field Testing Co-ordinator for Europe, Africa and Middle East at ExxonMobil, said that “flexible energy supply presents unique challenges” in terms of the lubricant. The stop-start nature of flexible operations puts more pressure on the lubricant to protect the engine during startup. As the engine starts up, it takes time for the lubricant to be pumped through the system, which can leave moving parts operating without suitable protection. It’s therefore important to select a lubricant that can enable quick start-ups, while offering optimum protection, even when aggressive gases are being used.”
A key issue for all the panellists was the quality of gas from differing sources.
Andreas Görtz, Director of Sales for Power Generation at Rolls-Royce Power Systems, believes it makes no sense to use farmland to grow plants for producing biogas or biofuel. “I spoke to a farmer a couple of days ago and he’s invested in a biogas power station. His price for corn was €70 ($81) – now it’s €36.”
However, he said gas from waste makes sense: “In Asia there’s a huge amount of waste, so use it.” But he does not believe that in Germany you can use biogas as backup for renewables – “it’s not sufficient, you have to use natural gas.”
Paul Jordan, Global Market Sector Head of Clean Energy & Power Generation at Ricardo, said that landfill feedstock is changing as well, as recycling and composting is improved. “Feedstock is going into scrubbers pre-pipeline, so there will be challenges around how you standardize that – it’s difficult. Industry will have to be aware that what we set today may not be the same as in 20 years’ time.”
He said it will require flexibility in whatever process, whether pre-pipeline or with a gas engine”.
Jarmo Vihersalo, Europe, Africa and Middle East Industrial Marketing Advisor for Energy at ExxonMobil, said the fluctuation of gas quality has an effect on engine maintenance.
“Variable gas quality puts more pressure on engine performance. You could have one batch that is relatively clean and then the next batch could have high levels of impurities such as siloxanes and sulphides. It’s important to protect engines against these impurities and lubricants are now available which can help mitigate the negative effects to reduce scuffing and wear and keep engines running for longer.
“It’s also important to make regular maintenance checks – used oil analysis is even more important for engines running on aggressive gases such as those from landfill or farming waste where engine wear can be accelerated. Developing products that have the potential to offer energy efficiencies can also help extend oil drain intervals and reduce waste. With a thorough process it is possible to improve the productivity of gas engines running on biogas.”
Klimstra said that gas quality “has to be determined by customers and not by suppliers. By now gas companies have completely changed their position. If the gas quality is variable, you can’t guarantee flexibility.
“With poor quality you have to start the engine very slowly; with good gas quality, engines perform very well. With poor quality they can’t respond so quickly, so the engine can’t deliver ancillary services.”
I asked the panel what is the biggest constraint to the growth of gas engines fuelled by alternative gas – policy or technology?
“Both,” said Gunjan, while Rick Boom, Director of Product Marketing of Large Engines at Woodward Nederland, said that while the technology has to deal with different gas qualities, “that can be done. Most engines today are tuned for a certain gas quality, but with direct feedback from the combustion chamber you can adapt that, so the technology is available – but not on every engine installed today. But it should not be a hurdle.”
Hamm noted that “it’s a question of investment on the customer side. Flexibility is a cost driver, but from a lubricant perspective it’s challenging. Regular start-stops of a gas engine can result in greater scuffing and wear from impurities, which ultimately compromises engine longevity and productivity.
“But that doesn’t mean it’s impossible – it’s about working with our customers to develop lubricants that match their requirements. We’re aware of the challenges in producing power from waste and landfill gas and develop our lubricants accordingly.”
Jordan raised the potential of energy storage. “There is a role for energy storage with gas engines. If you have variability on renewable energy and there’s variability on demand, I’m sure there’ll be hybrid situations where you can run engines at higher capacity to maintain optimum efficiency, using the excess into storage. Storage then will have faster response in certain applications as well, which again can help the grid. We’re starting to look at this in our field, and it’s one of the areas we think will develop over time.”
Görtz said there is an interesting concept in Germany: “Engines for district heating – thermal boiler capacity for storing heat. You can use the electricity to heat up the boiler, and can get money from the green energy ministry and no need for CHP for heating demand – it can feed into the thermal boiler. It’s a very innovative and interesting concept.”
Grewe added that power-to-heat is also happening in the smart power range. “It can be very quick and can go down with the engine a bit slower. It doesn’t destroy energy, it makes heat.”
|Vihersalo: “We need to keep corrosion out of the engine”|
Vihersalo said that, for the most part, these types of biogases are being used to make up the gap at peak energy levels. “We therefore need to find a way to keep corrosion out of the engine, so that when energy is required, it can be delivered quickly and efficiently. This all comes down to maintenance – when the engine is running the in-service lubricant is protecting components.
“However, when the engine is not in operation, the aggressive elements are left in the engine, increasing the risk of corrosion. So we really need to find a solution to optimize operations and reduce this risk. If we’re only using biogas for peak energy demand, it’s making it much more difficult to protect the engine. We have to work closely with our customers and OEMs to find the best solution to this problem.”
Klimstra added that you also see this with heat changes. “With a condensing system there can be sulphur in the exhaust gases. Even with stainless steel you see a lot of heavy metals in the water stream coming from the plant, because of standstill and corrosivity of liquids from condensation.”
I then asked the panel what changes we can expect to see in engine design.
Tütken said that, for low calorific value gases, “I might foresee more capacity in fuel pumps and fuel injectors, but not a big change”.
|Boom: highlighted increasing maintenance costs|
Boom said: “When you have nasty gases you have to apply coatings, but the coatings cost money. Even with the coating it has an impact on lifetime, so there are higher maintenance costs. The technology is there to do it. You can adapt to different fuel quality cycle-to-cycle.”
Görtz added: “One trend is to use more flare gas that’s available that’s of poorer quality – this is a trend for the future.”
In terms of the potential of alternative gas engines, I asked, which countries offer the most scope for development?
Jordan said that the UK “has done a lot of study on this, and at the moment about half of the methane is used out of landfill sites in the UK. That’s almost all of the economically attractive methane from landfill sites, so this has peaked and is in decline. “
He said “the big opportunities will definitely be in developing countries – but it’s a question of how quickly they get their waste streams developed.”
Tütken noted that “Europe is difficult. It’s difficult to assess because the regulations are not stable, so every company is making a feasibility model based on the availability of feedstock and the FiT you will get. It’s a complex evaluation. We have to see other waste conversion – there is a lot of talk about syngas but we will see if it gets to a significant business.”
|Tütken: highlighted the “German success story of biogas”|
He added that “if there is support from the political system” then growth could be EU-wide, “but in the past it was always Germany running in the front and the others not following. We will see if the EC will look on technology targets or other targets.”
Hamm said that in Europe “we’re driving the technology. Engine builders are leading the market and exporting to other countries. We need to continue investing in technology so we can overcome barriers to market and create reliable power generation models.”
|Görtz: spoke about trends for the future|
Görtz predicted that biogas won’t be a big trend in Europe – “There is a small market for island use but not a big market” – and Boom and Grewe also conceded that it is a niche market.
Gunjan said that the problem with landfill “is that nobody wants it in their back yard. Waste-to-energy, if that can be sent out to consumers at the same cost, there would be support for it. Whether utilities are able to meet that kind of cost demand is something else.”
But even the developing countries have their own barriers to growth. Gunjan said India “is too diverse, too decentralized”. She said the key drivers for the sector to grow are proper grid infrastructure and support mechanisms, not the fact that there is a lot of waste available.
Hamm explained how ExxonMobil keeps pace with, and even anticipates, future demand and challenges.
“We keep in close contact with major OEMs, keep our ear on the rail to find out what’s going on – what is the next trend or challenge, and this feeds into the next product development we’d like to do.
“Our design department comes up with a new formulation, and then it goes to lab testing. The variation in gas quality is sometimes challenging – you need 6000-10,000 hours before you can say the oil has been proven, so it can take 18 months. Product development is three years, so we have to be really early on the market.”
He said that “now everybody is crazy about the efficiency rate, so we have to manage the oxidation challenge”.
“Mechanical oil consumption is something everybody is trying to get down. Making sure the heat exchanger does not receive too much ash; we have to find a really good solution, that’s what’s really driving development.”
Finally, I asked the panellists what would be the best and the worst thing that could happen to the sector in the near future.
Hamm said the best thing would be having “a solid gas standard and quality so that we know what we can expect for the engine”.
Görtz said a real boost would be “if there is a solution for power-to-gas. I’m not sure it’s really feasible, but this would change it a lot and would be a real economic way of having power – with storage to overcome wind and solar variability.
“Backup power fired by gas is a solution at the moment, but a booster would be if there was a decent concept for power-to-gas, to use green energy to produce gas which can then be fired. Maybe hydrogen, but this is a big question – what is the right gas – can we feed it into a normal gas line? This would change the whole world for us.”
Tilmen said that “we have power-to-gas – for methanization we need CO2 – that is an existing technology: the plants are running.
“But,” he continued, “under the legal framework operators are seen as consumers and they have to pay EEG fees, so the legal framework would have to support this concept. We need mid-term storage, more than pumped storage – this would help everybody.”
Jordan said that the worst thing would be uncertainty over regulation, subsidy, and gas quality variability. “The best thing would be more opportunity in terms of big markets – China and India – opening up, and whether those countries start to accelerate and stimulate those markets in a much bigger way, because they’re learning from what Europe can transfer across.
“The best thing,” he concluded, “is opportunity.”