Story by Nicola Heath Many have come to rely on coffee for a kick-start when they need it, so it may not come as too much of a surprise that what’s in our cup is now being touted as a renewable energy source. In 2008 a University of Nevada study showed that spent coffee grounds are an effective feedstock in the production of biofuels: liquid fuels derived from organic matter. The recent global push for business and governments to address climate change has sparked a fresh glance at these renewable sources, and using spent coffee grounds for energy is becoming an increasingly less ridiculous reality. One aspect of this drive is growing investment in renewable energy, including bioethanol and biodiesel. According to the United States Environmental Protection Agency, one litre of cellulosic ethanol will save 2.11 kilograms of carbon dioxide, while one litre of biodiesel saves 1.8 kilograms of CO2. Biofuel is not a climate change cure-all, however. First-generation biofuels such as corn-derived ethanol and biodiesel produced from palm oil have proven to be environmental liabilities. The boom in the biodiesel industry has led to large-scale deforestation in South East Asia as huge swathes of forest have been removed to make way for palm oil plantations. In Indonesia, by 2015 another 4 million hectares of palm oil plantations are expected to be added to the 6 million already established. Clearing forests and burning peatland adds more greenhouse gases to the atmosphere than what is saved by using the palm oil-derived biodiesel. Government subsidies in America, currently under review due to the ongoing debt crisis, have created a massive corn-ethanol industry that last year saw nearly 40 per cent of the American corn crop turned into ethanol. Corn farmers in Kansas are growing, for the first time, a genetically modified strain of corn that has been designed for ethanol production and is unsuitable for use in the food industry. Corn-derived ethanol centres have been criticised for increasing food prices and global food security fears, tragically realised in the current famine in the Horn of Africa. Second-generation biofuels – those made from non-food sources and waste products – are in development but are still five to 10 years off commercially viable industrial production. Promising biofuel feedstocks include algae, grown in brackish water on non-arable land and agave, the primary ingredient in tequila, which has proven very water efficient. Waste that would normally be sent to landfill is another second-generation biomass that has a much smaller carbon footprint than food-crop feedstocks.
The University of Nevada study investigating the potential for coffee as a biofuel feedstock suggests that each year 340 million litres of biofuel could be produced from waste coffee. The researchers collected spent coffee grounds from their local Starbucks, which otherwise would have been disposed of via the ‘Grounds for Your Garden’ program. The grounds are dried and treated with a solvent to remove the oil, then free fatty acids are converted to a soap and separated from the oil. The next step of the process is transesterification, where the oil is reacted with alcohol to create biodiesel. While it’s unlikely that we’ll see refineries built expressly to produce coffee-derived biofuel, it is a possibility that operators currently producing biofuel could incorporate coffee as a feedstock. Since 2007, thousands of London’s black cabs have been running on biodiesel, produced by the city’s only licensed biodiesel producer, Uptown Oil. Every day in Southwark, not far from the Thames, cabbies queue to fill up on fuel made from used cooking oil (UCO) collected from hundreds of London pubs and restaurants. Every year Uptown Oil collects around 2 million litres of UCO to make 1 million litres of biodiesel. It currently sells at 125 pence per litre. Stuart Buckingham from Uptown Oil says their fuel is more or less carbon neutral, rated by the UK Renewable Fuels Agency as containing 84 per cent less carbon dioxide than fossil diesel. Taking into account lifecycle carbon dioxide emissions, Buckingham says fossil diesel produces some three times as much CO2 than Uptown Oil’s biodiesel. Biodiesel is free of sulphur dioxide (the cause of acid rain), contains 60 per cent less PM10 diesel particulates (which form health damaging smog), and in the case of Uptown Oil, uses a waste that can damage the environment. Buckingham has been exploring other potential feedstocks for Uptown Oil’s biodiesel production due to a lack of UCO, even though there is plenty of oil
in the city. “It’s just not collected,” says Buckingham, “or it’s exported for other nations’ benefit or wasted through poor management. We can’t get enough oil, but it’s not because it doesn’t exist. It is the unregulated free-for-all that chases this resource around that fails the system and the pursuit of environmental benefit.” In 2009 Uptown Oil ran a study into the use of sewer sludge as a fuel source. Each year 3000 tonnes of sewer fat ends up in UK landfills, where it decomposes, releasing methane into the atmosphere. “It made good biodiesel but a terrible smell,” says Buckingham. Buckingham has also investigated using spent coffee grounds as a feedstock. He calculated that 1000 tonnes of coffee grounds would produce 11,500 litres of biodiesel each month – a viable output. “Once up and running the system looked sustainable, providing sufficient raw coffee grounds could be acquired and subsequently composted after oil extraction.”
Prohibitively high capital expenditure, including the cost of solvent and infrastructure investment, put the plan on hold. “We would need funding to install the equipment and an outlet for the waste grounds, such as composting,” says Buckingham. “But apart from that we would love to use waste coffee to make biodiesel.” UK-based coffee chain Costa Coffee is trialling a program that sees 46 of its sites across the UK send all food and coffee waste to a biofuel plant in Lincoln. At the plant, the waste is treated to extract water and oil; on average the treated waste breaks down to 60 per cent water, 35 per cent biofuel and 5 per cent tallow, which is used as fuel at the plant. Each week stores send an average of 9.29 tonnes of food and coffee waste to the plant, saving on landfill taxes and improving the company’s carbon footprint. Coffee grounds can also be used as a fuel for gasification, a process that turns carbon-based matter – both organic and fossil – into syngas by heating it to temperatures above 700 degrees celsius. When organic matter is used to power gasification the process is considered a renewable energy source, and its by-product, biochar, has many uses including the ability to improve soil fertility. In 2010 Martin Bacon of the Teesdale Conservation Volunteers in the UK built the Coffee Car Mark One, a modified 1988 Volkswagon Sirocco, for BBC television program ‘Bang Goes the Theory’. Bacon and his team added a gasifier fuelled by spent coffee grounds to the car, with cooling pipes rising from the boot. The challenge was to drive the car from the BBC studios in London to Manchester, which the team did successfully despite being delayed by traffic. Having proved a car can run on waste coffee, Bacon and TCV have started a new project, Coffee Car Mark 2. This time the stakes are much higher; the challenge is to break the world land speed record for a coffee-fuelled car at Elvington race track near York this September. There are a number of differences between the two cars. The cooling system is contained within the converted Rover SD1 to improve aerodynamics, and the engine is built for speed, making it much bigger than the first car’s engine.
In August the team took the car out for a practice run, and despite encountering bad weather clocked 104 kilometres per hour on the racetrack. “You have to think that this has not been done before and gasifiers in the past had a bad reputation for being very slow. We’re looking at around 128 kilometres per hour for the record,” says Bacon. A local coffee shop in Teesdale supplies the coffee grounds, which are dried and then mixed with sawdust to make pellets. Bacon says around 10 kilograms of wet grounds will fuel the car for around 160 kilometres. “If you take into account using the biochar that is left in the gasifier at the end of a run, it would make a neutral carbon footprint,” he says. The next project in the pipeline is to develop a large community-scale gasifier fuelled by waste that would put around 50 kilowatts of power into the grid – enough to run six to 10 houses. The group has about half the funding it needs to finance the project, which will include studies into biochar, labour costs and converting waste tonnage to gas and then to power. As governments move to address the growing problem of climate change, strategies such as carbon taxes and emission trading schemes will become more and more common. Biofuels are guaranteed to become major players in the global energy industry as fossil fuel production and consumption becomes increasingly expensive.
In July, the Australian Government led by Prime Minister Julia Gillard introduced a carbon tax that will require 500 of Australia’s biggest polluters to pay a set carbon price starting at around US$24 per tonne from 1 July 2012. In 2015 the tax will switch to an emissions trading scheme, meaning the market will set the carbon price. The Australian government has committed to cutting emissions by 5 per cent, or 160 million tonnes by 2020, while the Renewable Energy Target aims to have 20 per cent of Australia’s electricity generated by renewable sources by the same year. Carbon tax modelling forecasts that 75 per cent of fuel used in Australia by 2050 will be biofuel. The carbon tax figures on an enthusiastic and widespread conversion to biofuel by the transport sector, which is responsible for 85 per cent of the total transport emissions in Australia. Heather Brodie, CEO of Biofuels Association of Australia is optimistic this target can be achieved. “It is a very bullish figure,” she says, “and one that I think the industry will certainly be striving to achieve. It will rely on a lot of different things coming together – the right feedstocks, the right yields, the right technology, then a good take-up.” The right feedstocks are those that offer the best net benefit in terms of yield, efficiency and lowering greenhouse gas emissions. With research and investment into waste and cellulosic feedstocks on the rise there are plenty of reasons to be optimistic about the future of biofuels. US President Barack Obama has announced a US$510 million plan to invest in biofuel feedstocks other than heavily subsidised corn, which will see the government match funding to private operators who plan to build new biofuel refineries or retrofit existing ones. The focus will be on cellulosic feedstocks (inedible plant material like wood chips and grasses) and the navy is touted as being a potential customer. Innovative groups and individuals – and forward-thinking businesses seeking to lessen their carbon footprint – will be instrumental in driving second-generation biofuel development forward. Increasingly, it is in everyone’s interest to dispose of waste in an environmentally responsible way, and this means more and more spent coffee grounds could be turned into biofuel or fed into gasifiers, fuelling our lives as well as our minds.
Technology
Coffee as biofuel: The fuel of the future?
