Biogas plants: varying gas yield, engines that must follow price
Why biogas plants struggle with varying digester yield and with running to power prices, and how to check feeding and gas storage planning first.
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Gas yield from the digester varies
What happens. The digester is fed with manure, silage or waste, and the bacteria need time to respond. Gas production rises and falls from day to day without a clear reason, and the engine receives a mixture of gas of changing amount and quality.
What it costs. Energy that could have been produced, engine stops and starts when gas runs short, and operators who feed by experience and sometimes overfeed and acidify the digester.
Why the usual fix fails. Lab samples arrive too late and are infrequent. Feeding to a fixed table ignores what the digester contains right now. A gas meter shows the result, not the state of the biology.
How a fixed-price remote diagnosis checks it. From feeding records, gas flow and composition, temperatures and the occasional lab values I look at how the digester responds to feed changes. The fixed-price remote diagnosis tells you whether a computed digester state can steer the feeding, and what data it takes.
Background: Computed measurements
Plants must run to the power price, with gas storage and engine starts
What happens. Support rules now reward flexible operation: producing when power is expensive and holding back when it is cheap. That needs gas storage, engines that start and stop often, and a feeding that supports it. Plants built to run flat out are asked to behave differently.
What it costs. Missed price peaks, extra engine starts with wear, a gas store that is full at the wrong time, and flexibility premiums that are not fully earned.
Why the usual fix fails. Larger engines and storage cost capital. A fixed daily schedule ignores prices and weather. Operators deciding by phone and by feel cannot plan the gas level for tomorrow.
How a fixed-price remote diagnosis checks it. From gas production, storage level, engine records and price histories I look at how much of the possible revenue current operation reaches. The fixed-price remote diagnosis tells you whether an optimised schedule of gas storage and engine starts, together with feeding, is worth it for your plant.
Background: Economic predictive control
After the first support period a plant has to earn from heat and flexible power
What happens. Plants whose first support period has ended must win a follow-on place in tenders, and many do not. Without it they stand idle or have to live from heat sales and flexible power on the market.
What it costs. Plants with ageing engines and heat customers but no secure income, and operators who must decide on running hours with prices they cannot foresee.
Why the usual fix fails. Running the engine as before ignores that heat and power prices now move apart. Adding storage without a plan for using it does not pay. Manual dispatch cannot weigh heat demand, prices and fuel together.
How a fixed-price remote diagnosis checks it. From heat demand profiles, price series, engine and storage data I look at what a heat- and price-led operation could earn compared with today. The fixed-price remote diagnosis tells you whether an optimised dispatch with storage is realistic for your plant.
Background: Economic predictive control
More problems that concern this industry
These problems are described on the page of the industry where they matter most:
- Boilers and engines face tighter nitrogen oxide and dust limits (Power and heat plant operators)
- Biomethane injection is limited by local demand (Gas grid operators)
- Engine plants run by heat demand only (Power and heat plant operators)
- Delivering reserve power to the grid brings penalties for missing it (Power and heat plant operators)
- Gas engines follow the gas level (Wastewater plants and associations)
- Moisture and temperature in compost heaps are unknown (Recycling, sorting and composting plant)
- Biowaste for digestion changes from load to load (Recycling, sorting and composting plant)
Check it on your plant first: a fixed-price remote diagnosis
EUR 4,500 net · 5 working days · remote · availability on request · freelance or through temporary agency work
Within a fixed scope and at a fixed price, I review your data, control structure and measurements remotely and tell you whether the problem on this page is behind your symptoms and what fixing it would take. You get a short summary for decision-makers and a technical report for your engineers.