Inventor wants to slow climate change with modern steam engine
A Canterbury man has invented a better steam engine and believes it can help to relieve climate change. Will Harvie reports. Sam Mackwell wants to get diesel out of food production. Some New Zealand farmers are burning 200,000 to 300,000 litres of the dirty fuel a year, he says, and every drop contributes to the warming planet. Mackwell insists he has a better alternative a steam engine. Burning wood chip. His steam tractor matches the weight, speed and performance of the equivalent diesel tractor . Most farmers have more than enough trees to power a steam tractor all day, every day. And theyd save all that diesel cost. To him, it adds up. READ MORE: * Orapota!!! Auckland iwi launch 111-year-old steam train for Matariki * Century-old steam train rescued from ruin and back on track * Could steam bring back commuter rail in Christchurch? Mackwell claims to have improved the steam engine. His model burns fuel at about 900C compared to about 400C in conventional steam engines. This means all the fuel is consumed. Theres no smoke and no sparks. Its zero-carbon, he says. How he achieves this is a company secret but involves an advanced combustion system and a heat exchange system that uses just 3% of the water that a conventional steam engine does. The result is high-pressure superheated steam . In a brochure, he calls it very pure steam. It powers an engine, which turns the wheels. Its all been independently peer-reviewed and a patent applied for. Convincing farmers that a 150 horsepower steam tractor is practical has not been possible. Its surely unhelpful that the first steam tractors would cost about double what equivalent diesel tractors cost. So hes turned to trains. Or rather, hes returned to trains because hes been in that market before. Indeed, he almost had a deal to build a steam engine for Dunedin Railways, best known for operating heritage trains through the Taieri River Gorge . Alas, the pandemic collapsed Dunedins heritage train market and the sale was shunted aside. Still, there are hundreds of heritage trains operating around the world and the cost of maintaining old and very old steam boilers can be huge. Mackwells new, improved steam engine could be a better alternative. Especially considering that lots of heritage steam engines are burning cursed coal. Climate change is my entire motivation, Mackwell says in a company video. He got that motivation at a young age. While still in high school in Christchurch, he was experimenting with hydrogen as a fuel not an average teenage interest. But he did set off numerous explosions on his parents lifestyle block west of Christchurch. He moved on to liquid and gaseous biofuels and at age 18 devised a turbine engine and mounted it on a go-kart contraption. Theres video of him driving it on a Canterbury back road, but little evidence that it met vehicle safety standards. Mackwell soon concluded that liquid and gas biofuels burn almost as much energy to produce as they contain, which is inefficient and unhelpful to the changing climate. So in 2015, at age 21, he switched to solid biofuels trees. They are natures solar panels and batteries, he says on the video. Hes been on the project ever since. Mackwell, now 28, doesnt have formal qualifications. He enrolled in engineering at Canterbury University but dropped out six weeks later because it was eating into his steam-engine time. He had already taught himself to weld on his parents lifestyle block. Hed acquired a big lathe, later a milling machine and other manufacturing gear and taught himself to work them. And he was deep into learning how conventional steam engines work and how to improve them. There are maybe 50 people working on modern steam around the world Argentina is a hotspot and Mackwell tapped into their expertise and adopted some of their technology. He also found private investors willing to fund this quest. One is Philip Royds, a co-founder of Christchurch-based Link Engine Management , which develops and manufactures motorsport electronics and performance technology thats sold in 65 countries. Royds is chief executive of Mackwells two companies, Mackwell Locomotive and AgLoco. The pair have now identified a new niche that combines food production and trains sugar cane farmers in Australia and Fiji. Sugar cane grows tall and bulky. Many of Queenslands 4000 cane farmers already transport harvested cane on narrow gauge railways instead of trucks. Anybody who has driven through cane country in Queensland will have seen these operations. In the state, train infrastructure and train expertise already exists. The biofuel would be the bulky chaff left over after harvesting and processing the cane. Indeed the chaff, or bagasse , was burned in steam locomotives that historically served the cane industry in Queensland, before being replaced by diesel. The industry also burns bagasse in its sugar processing plants to generate power and sells the excess electricity into the grid. Clearly, Mackwells steam engine can burn different solid biofuels. He selected wood in New Zealand because its widely available and wood chip because its easy to handle and store. But he could burn a sawn-up picnic table (and probably has). And in case anyone pictures a farmer madly shovelling wood chip into a firebox, Mackwell has an answer: mechanise it. Lots of coal-fired locomotives have these systems that replace manual labour. Mackwell has yet to sell one of his steam engines. Hes fighting perception barriers that steam is not relevant any more. His investors dont seem to mind. Mackwells companies have been hiring there are now seven employees. And the atmospheres carbon count is still climbing. In the middle of August, the atmospheric CO2 reading at Baring Head, Wellington was 415.4 parts per million, up from up from 400ppm in 2016 . We need to move away from fossil fuels as fast as we can and current technology ... isnt letting us do that, Mackwell says.