Swedish wood combustion technology has pinnacled with the floating sauna (refer pictures - sorry for size, working on how to upload bigger ones). Instructions for use: 

1. Gather a heat engineer or two, preferably one you feel comfortable naked with (if this is too big an ask, just find a friend and work out the technical issues as you go).
2. Ensure a good supply of dry firewood, say moisture content less than 25%
3. Stoke up wood stove to ensure temperature inside floating sauna at least 45 degrees C.
4. Cast floating sauna off from shore (ensure you have a small outboard or at least a paddle, otherwise you will need a good supply of wood to stay warm until the wind returns to whence you came).
5. Strip. Take care not to enjoy the 'naked' thing too much - after all, this is primarily in the interests of wood energy research. Swedes have a different attitude to this stuff than us of uptight Anglo-Saxon heritage. They are nature bunnies and dance around maypoles for real, not some pansy morris dancing sort of stuff.
6. Enjoy sauna. When too hot, dive into icy lake. Repeat for as long as you want.
7. When ready,  come back to shore for pickled herrings and akvavit (alcohol 40% by volume).

WARNING: Ensure the akvavit is consumed after the above, not before. Optional for teetotallers if you must but the nudity is mandatory - true woody types are heavily into nature. Are you game enough to take the real woody biomass inititation? P.S. Renewable energy is more fun than energy efficiency. Throw another log on the fire and pass the pickled herring.........

Drove to Karlskrona with Rebecca Heap, who was my local guide to woody biomass. En route we stopped to investigate residential wood energy use in Småland. Outside his rural house Lars was cutting firewood for his home boiler. Over the course of a winter Lars would use 40-50 m³.  However his house has little insulation and on the top floor has only 5 cm boards with no insulation, so he estimates the average modern rural Swedish house would use 20-30 m³ a year. He pays SEK 250 per m³ (for birch - see below). There are three main types of firewood:

1. Björk (birch)
2. Ål (beech)
3. Gron (spruce)

Of these, beech is the best as it has the highest calorific value. Energy logs sold for such residential purposes are sold in either three or four metre lengths according to the supplier. Enso sell in four metre lengths and Södra sell in three metre lengths. Lars cuts it up himself like any good Swedish homeowner - here, chopping wood is a national pastime. However, like any good Swede, he uses good equipment. His aging Volvo tractor had its PTO rigged to an automatic cutter and feeder. He is also, like me, going to the Elmia Woods fair near Jönköping to ogle 150 ha of forestry equipment. I suspect every rural male Swede capable of walking or crawling will be there.

New Zealand residue harvesting snippets:

• A landing site is used for an average of three weeks.
• An average harvesting crew will harvest 200-400 tonnes/day of biomass.
• Residue to log ratio is 1:10.
• Therefore 20-40 tonnes/day x 3 weeks gives say 630 tonnes of residue per landing site.
• Suggest 375-625 tonnes/site.
• At a bulk density of 100 kg/m³ this suggests 15-25 trucks could remove uncomminuted residues.
• Suggest $33-44/tonne for consolidated, cominuted residue on a superskid or old landing site, transported an average 50km to heat plant.

Swedish forestry snippets:

• 60% of Swedish land area is forest. Is 1% of world forests.
• Predominant species spruce, most important for wood processing industry.
• 355,000 small landowners own 50% of all commercial forest estate in Sweden. Often been ion the family for several generations and passed on.

 On 20 May Met Hans Gulliksson of Energikontor Sydost at Evedal. Hans wanted to show me a small district heating plant near Ljunby west of Växjö that was having an open day. We drove though pleasant spring fields, in a rather open agricultural environment as contrasted with the more densly forested areas in Småland. So the parallels with the New Zealand countryside were greater. In fact, three farmers are behind this plant. One has been the driving force and it has been five years on the drawing board. The whole community ‘owns' the plant as consultantion has been high. Prior to design starting everyone in the village was consulted. An EU grant of NZ$100k was obtained. The whole plant cost NZ$500K so far but there is a lot of work in kind, as of the three farmers who own it one is a plumber, one an electrician and the third is the school caretaket too and pretty handy. Farming does not appear to be a full time occupation in Småland. When the community was canvassed, seven parties put their hand up and said they would become customers if it was built, and all seven have. The plant started with a second hand 1984 vintage pellet boiler which will remain as a peaker and back-up (required by law). It ran last winter, and went into service one week after the date scheduled for commencement of service. I wish all our projects ran that late! Anyway, the new boiler will handle chips at 50% moisture. The fuel feed will have a moving floor and auger feed, still under construction. The fuel store was impressive, entirely covered with enough height and space for tipping, drying and a tractor with loader to move about. The plant is 500KW and there is 1.9 km of reticulation. The local farmers will chip in forest and supply, which will give them yet another income stream apart from (beef cattle, plumbing and caretaking!) It seemed in fact the whole village was involved in some way. Ingela proudly told me she had spent a year on agricultural student exchange at a table pigeon farm near Melbourne in the early 1980s.

After leaving the village plant we drove to something at the other end of the scale in Ljungby town.  As we drove Hans told me that chip is about 3 cents NZ a KWh, ranging up to 6. Pellets for residential can be 9 cents/kWh. Anyway, Ljungsjöverket is a waste to energy plant. They no longer talk about incineration round here, and don't have landfills. It's all W2E. Municipal waste (residential and commercial) is delivered at 19 SEK?? a tonne - but the plant is PAID to take it so for a start, they are making money before they even sell the energy. What about the environmental issues? Bo, the plant manager who showed Hans and me around, showed some pretty impressive emission performance statistics. Dioxin, for example, is below the error of measurement, effectively zero. Well, he would say that. However there is some pretty strict monitoring to back it up. Also, by law, evey particle in the combustion chamber must have at least 2 seconds at 850 degrees C. If sensors detect that is not achieved, then two standby oil burners automatically swing into the chamber and inject additional heat. They have only been used in test so far. If they fail to get the required combustion, then the waste boiler starts to shut down.

The plant statistics:

• Waste boiler 18 MW, 25 m high (needed for height of waste combustion chamber) step grate.
• Automated crane 10 m3 per load feed, energy content ??
• Second boiler biomass (chip and peat) 6 MW currently burning 100 percent peat due to economics even with carbon tax on peat.
• 1 MW flue gas condenser. Backup gas and oil boiler 2x6.3 MW.
• Heat use - district industrial and residential process and space heating
• Network 100 km peaking 30 MW Shifts 7 - unmanned most of the time.

 

The bioenergy adventures just don't stop! Went to Sandviksverket to see a 104 MW circulating fluid bed biomass boiler on a CHP plant that can chew through up to 50 tonnes of fuel per hour. 50% moisture (which seems to be standard). Right now it's running at 20 MW, because of recent warm weather. Much warmer and they will have to take it offline and start up a smaller, older one.

Lotta, the VEAB (check out http://www.veab.se/) chemical engineer who showed me around told me that they can keep it a constant 50% because the flora and fauna that make their home in the 6m pile of fuel compensate for the rain by using water. Sounds pretty technical. Well how's this for complicated then? Biomass boiler NO_x emissions across Sweden have been dropping, because the Swedish government say that those that have below average NOx emissions can get tax credits, paid for by those who have above average NOx emissions. The result - everyone races to be below the median, and total emissions drift down. Very Swedish policy. Last year VEAB earned SEK 3 million from the NOx they DIDN'T emit! Wonder who paid? They do this by using a catalyst.

Lotta posed for me in front of not one but two generators! Of the 104 MW capacity, 38 can be used for electricity. So they can sell when they want. The tax system is so strange (green certification) that sometimes it is even economic to burn wood to generate electricity to heat the water for the district scheme! Strange but true.....

  19/5/09

This morning I visited  JGA Wood, a sustainable sawmill.  The JGA plant is 30km from Växjö. Clas, a fourth generation member of JGA's family owners, met us.

The first thing that struck me was the huge area of logs, awaiting processing. Mainly spruce, with some pine. These log stacks look black from a distance - almost as though they have been creosoted! However, then you see the sprinklers over the top, spraying 24x7. By keeping the logs saturated, they can prevent decomposition and store them up to five years prior to milling. Clas said that it is only recently that they have processed the last of the Hurricane Gudrun windthrow. Gudrun, was the biggest storm in living Swedish memory and occurred in 2004. When I was here in 2007 there were still large areas of devastated forest visible all around.

 I arrived in Sweden last night but unfortunately my luggage didn't! With a 40 min connection in Frankfurt something had to give, I suppose. Never mind, after four hours sleep in Stockholm (thanks Michael and Paul) I was on the 05:20 a.m. to Växjö where I was greeted by my gracious guide Suzana from Växjö Kommun (council). First up we visited a district heating plant using 100% wood processing residue from a local sawmill.

Silve Piejko showed me around the plant. Silve is VP of the plant's manufacturer, Järnforsen Energi System AB, www.jf-energi.se.

Key facts about the plant:

One thing that strikes me is how the Nordic countries especially Sweden and Finland have their heads around innovation in bioenergy. Anyone wondering about how this works should take a look at http://www.biofuelregion.se/dokument/43_120.pdf  because it is a great example of many stakeholders co-operating for innovation and economic growth. Shaun