Southland extends lead in biomass energy research and use
IF THREE YEARS RESEARCH BY VENTURE SOUTHLAND IN partnership with Energy Efficiency Conservation Authority (EECA) comes to fruition, the province will extend its lead in New Zealand in the conversion of wood biomass for heat energy in place of fossil fuels.
And that’s a very good thing for the forestry industry, as it provides another revenue stream.
The research has focused on processing wood biomass from forest harvest and mill residue with other waste sources into heat energy for boiler fuel, which has the added benefit of cutting greenhouse gas emissions under the Emissions Trading Scheme, as well as being an environmentally sustainable resource.
At a symposium in Invercargill, some 150 delegates were told research data indicated that more than 200,000 tonnes of residue will soon be available from the 194 commercial forestry operations in Southland. This is expected to balloon out to 600,000 tonnes within the next 30 years.
If this was processed into chip fuel at a reasonable cost it would be capable of heating 65 boilers within the 1 megaWatt range for heating schools, businesses and a variety of institutions, such as aquatic centres and sports facilities.
Currently, 17 new wood energy sites have been installed in Southland, which, according to Wood Energy South, will reduce in excess of 201,300 tonnes of CO2 in the atmosphere over their lifetime, with annual emissions projected to be down by 8050 tonnes per year. This includes two new wood chip boilers projects – the Parata rest homes in Gore and Mossburn – that were completed within the last few weeks.
Also, a major regional college is evaluating the installation of a wood biomass boiler. Further planned conversions to wood energy boilers include a dry cleaning plant and additional primary schools in Southland.
These efforts by Venture Southland have won it the Deloitte Award for Large Energy User Initiative, and its Methane Recovery Project was nominated as a finalist for the Energy Technology of the Year category.
Stephen Canny, CEO of Venture Southland, reports that Invercargillbased dry cleaning company McCallums Group is saving $323,000 pa in fuel and rising, as heat recovery efficiencies are achieved. A further $14,000 saving pa in boiler maintenance from using chip fuel has led to carbon emissions reducing by approximately 1,426 tonnes/pa or $24,242 based on carbon credits at @ $17/tonne. The results as a competitive business model equate to $361,740 less costs pa, which minimises exposure to further carbon costs.
While those achievements are excellent for the fledgling woody biomass energy industry down south, there are still concerns among some people about the consistency of fuel supply on top of an expensive boiler installation. However, the $1.5 million research programme indicates there will be a sustainable local resource to chip for at least the next 50 years. Most forest owners are Forest Stewardship Council certified, meaning they are committed to rotational plantings with a continuous supply of residue at both skid site and mill.
Whilst the local lignite coal is far cheaper delivered to bunkers than chip, there are additional costs related to coal, which work in wood’s favour.
The Invercargill City Council’s aqua centre, popularly known as Splash Palace, recently replaced its coal boiler for a 750kW Binder chip boiler. Centre supervisor, Stephen Cook, explains the difference in heat energy from coal was only 69% compared with chip at 87%. Added costs for coal include attendance and maintenance of at least two hours per day, clearing dross and clinker, and paying to have it
dumped at the landfill, up to $1,500 p/a. The chip boiler’s automatic electronic control system means that just a couple of hours per week are needed and the small quantity of wood ash is used in a compost mix. Based on this scenario, the end cost in kiloWatt hours is far cheaper with chip.
Questioned about the costs and logistics of salvaging and processing chip on harvest skid sites, Kent Chalmers, of Dunedin City Forests, says costings with recovery of suitable round wood could be marginal.
The company supplies chip log to Pioneer Energy, which processes chip wood for a number of boilers around Dunedin and Otago. The chip needs to be uniform in size for the smaller boilers used mainly at the Otago University and Polytechnic. That virtually eliminates branch wood, cut-over slash, heads, slovens and undersize off-cuts, but there’s still plenty of resource left.
Mr Chalmers estimates only about 10% of chip size logs is carted to the Pioneer’s Three Mile Hill processing yard above Dunedin, where a mobile chipper processes the chip, which then has to be partially dried before fed into boilers.
The extra handling costs from contractors does mount up, though. How the skid site or in-bush residue is handled around Southland’s forests will be part of the final peer review on the research findings by Venture Southland consultants.
Currently two local sawmills, Niagara at Kennington and Finlater’s Mills at Tussock Creek, supply existing boilers. Both Wayne Findlater and Ross Richardson of Niagara were sceptical on how skid site material was to be recovered economically. But they did not discount innovation and new technology to solve this problem.
Also, recent large boilers, such as Politechnik’s 6 megaWatt pair that supply wood fuel to Burwood Hospital are able to take the full range of residue from stems, slovens, off-cuts and slash in hogged form. It is cheaper to process and can be landed at the bunkers wet, where excess heat from these boilers is used to dry the material before it’s fed into furnaces. These boilers would be suitable for large scale business and district schemes, or Fonterra’s powder milk factories.
Monitoring biomass progress in the south is Spark Energy’s Eduard Ebbinge, who markets Austrian-made Eta boilers and German Viessnann boilers capable of up to 3.5mgW. Some 50 of these have been installed around New Zealand.
A subsidiary of the company, LUMBR, operates a mobile Jenz chipper supplying these boilers. Its southern central processing yard (CPY) is in Dunedin, where it takes mostly binned off-cuts and chip log carted from nearby skid sites. The company runs a chip boiler at Wakari Hospital and Mr Ebbinge sees possibilities of skid site recovery from large corporate forests where a continual harvest operation occurs and a CPY could be established.
Other promising possibilities include the establishment of a food technology hub in Invercargill, a council district heating scheme and the planned Denone milk treatment plant at Clydevale.
EECA Chief Executive, Andrew Caseley, says the next step for Southland is to establish how the process can be repeated elsewhere.
Steve Canny labels the research as “new thinking” for New Zealand, adding: “The peer review would be the ‘true litmus test’ for the project.”
NZL