Ethanol from Lake Kivu's CO2 can Double Clean Energy Output?

Introduction

Can we produce ethanol or methanol from Lake Kivu as an additional product to methane? If so, how? Methane is the primary energy form in the lake, which contains four times as much unusable CO₂ in the reservoir. Academic research news offers a challenge and an opportunity to do much more for energy production options.

A research team led by scientists from Argonne National Laboratory, the University of Chicago’s Pritzker School of Molecular Engineering, and Northern Illinois University has discovered a new electrocatalyst that can consistently convert carbon dioxide and water into ethanol with very high energy efficiency and low cost.

Argonne’s Laboratory Directed Research and Development (U.S. Department of Energy Office of Science).

Hydragas Energy worked for a decade to prove the leading gas extraction method from Lake Kivu. It gets tens of billions worth of methane out cheaply and effectively. But what if the waste product is worth even more?

Ethanol Production Potential

Can we now achieve this with another innovation? The lake is already a hugely important case for carbon reduction through the production of renewable natural gas (RNG). But we do return gigatons of carbon dioxide to the lake – a huge carbon sink. It is essentially a low-value, unwanted product that continues to accumulate. Carbon dioxide is a by-product of the natural digestion process producing methane. It is scrubbed out during methane extraction to upgrade the product gas. We currently return it to the lake.

Panoramic of Mt Nyiragongo from Lake Kivu in wet season

What if we continue to take the methane out but recover a CO2 stream to shore? With the right process, can we also recover ethanol from Lake Kivu’s CO₂? Could this be a cheap supplement to regional gasoline supply, in the form of a carbon-negative fuel? The market is there as a 15% blendstock to imported gasoline from the Arabian Gulf. If so, we can do this by using a newly developed catalyst from the University of Chicago’s Pritzker School. In addition, all one needs is CO₂, water, and electrical power – all abundant from the lake. So how big is the potential?

The numbers can add up to a massive economic injection for the region. Q1 2021 prices in the USA are $540 per ton ethanol. With the production potential of one million tons per annum, that is a $25 B market over 50 years. Ethanol sales potential is half the Kivu methane potential, which is already $50 billion over 50 years. How would the economics look for ethanol?

Cheaper fuel – Ethanol from Lake Kivu

Gasoline has a vast, still growing market internationally. Many markets promote the use of up to 15% ethanol blended in gasoline. A subsidy is usually needed to make production economic as ethanol is mostly derived from corn (maize) or sugar cane. These substrates are expensive to produce – hence their subsidy needs. But where the CO₂substrate is available for this alternative production process at virtually no cost, the fuel produced can be much cheaper.

One would expect that it reduces the cost of fuel and the quantity of fuel imports. Ethanol from Lake Kivu can also be sold competitively within the region for fuel blending as gasoline prices inland are close to global highs.

The contribution to a circular regional economy for East Africa is a real contribution to reducing reliance on imports. It enhances the use of the lake for CCUS, or carbon capture, usage, and storage. It is already a vast opportunity, but further enhanced.

“The process resulting from our catalyst would contribute to the circular carbon economy, which entails the reuse of carbon dioxide.” — Di-Jia Liu, senior chemist in Argonne’s Chemical Sciences and Engineering division and a UChicago CASE scientist

Advancing a Clean Economy in Africa

We are looking to build onto an established energy case for a cleaner regional economy. Methane from Lake Kivu can eliminate diesel fuel imports for power generation while replacing charcoal as a domestic fuel. With a power production potential of 600 MW, the produced power can supply power at half the region’s marginal cost of power. However, the use of gasoline as the primary transport fuel in Rwanda, DRC, and other regional users was a complex opportunity. Ethanol from Lake Kivu’s production is an important alternative to supplement imports at a lower cost.

According to the USAID data in 2014, Rwanda’s GHG emissions had a net total of 7.6 Mt per year. With 100 MW of installed Hydragas-powered gas extraction and power generation, Rwanda becomes net-zero. The path to making the DRC net-zero is steeper, with 207 Mt per year of GHG emissions. However, the Eastern provinces of DRC, including Kivu Nord and Kivu Sud, may well transition to net zero within 10-15 years.

Ethanol production can use some of the vast store of accumulated CO₂ gas in Lake Kivu. We currently need to wash this CO₂ out of raw gas produced, to make 80% pure renewable natural gas (RNG) as pipeline natural gas.

But now instead of returning the washed-out CO₂ to the lake, we can process the wash water to make ethanol. If testing shows that the process is successful and economical, we can hugely enhance ethanol from Lake Kivu as part of a clean energy production phenomenon. Rwanda can, with the Kivu gas project, become 100% supplied with clean non-transport energy. With this added gasoline substitution it can commence the displacement of a significant percentage of transport fuel too.