Transcript Bild 1
Ruralisation with Eco-Units Folke Günther http://www.holon.se/folke [email protected] Nutrients To produce food, you need nutrients Folke Günther http://www.holon.se/folke [email protected] Nutrients What are ’nutrients’? In principle, ’nutrients’ are the constituents of the animal or plant body Folke Günther http://www.holon.se/folke [email protected] FG Nutrients The constituents of an animal (or plant) body: All nutrients are not the same H O C N S P Na K Ca …64 Folke Günther With gaseous phases — can be transported by the air Without gaseous phases — must be transported as solids or liquids http://www.holon.se/folke [email protected] Nutrients H O C N S 10 times more common in the P body than in the Earth's crust Na More common in the Earth's => phosphorus isKthe most important nutrient ! Ca crust than in All nutrients are not the same …64 the body Folke Günther http://www.holon.se/folke [email protected] Extraction horizons of phosphorus Peak phosphorus At higher energy price: At current energy price: Folke Günther http://www.holon.se/folke ?? years 100 – 150 years [email protected] We are in trouble Cheap energy will soon be a memory of forlorn times 1. Without cheap energy, phosphorus needs to be recycled 2. Without cheap energy, supply lines need to be short (Clausewitz) 3. Without cheap energy, we have to rely on ecosystem services Folke Günther http://www.holon.se/folke [email protected] Therefore, we need a lifeboat Folke Günther http://www.holon.se/folke [email protected] Peak phosphorus = Exploration = Possible consumption Folke Günther http://www.holon.se/folke [email protected] Scenario analysis for phosphorus recycling A. Current practice, sludge P on landfills etc, concentration to1/60 of the food producing area. B. Efficiency, all the P collected in the sludge is placed on agriculture C. Substitution, source separating toilets recycling all P entering the town to an appropriate area D. Rethinking, The city is distributed over the food producing area Folke Günther http://www.holon.se/folke [email protected] Scenario * Energy P to req'd for agricul- handling ture (index) (tons) Max theoretical circulation A (Current) 183 154 1,7 % B (Efficiency) 761 235 76 % C (Substitution) 958 319 96 % D (Rethinking) 986 1 100 % *) calculations for a city with a population of 1 millon Folke Günther http://www.holon.se/folke [email protected] Peak phosphorus is not a problem in an eco-unit • Phosphorus molecules do not wear out ! • The eco-unit is designed for recycling of phosphorus! • The main thing is to avoid losses Folke Günther http://www.holon.se/folke [email protected] Safe and secure food supply with nutrient recycling requires: • a diverse, balanced agriculture • a limited group of people • a local recycling system Folke Günther http://www.holon.se/folke [email protected] One hectare: Balanced agriculture Balanced agriculture: Animals are fed with plants growing from their manure = about 80% recycling of nutrients Feed Urine PO 4 Folke Günther http://www.holon.se/folke [email protected] One hectare: Limited group of people Feed Urine Food PO 4 .. but 3-4 kg of the phosphorus (20%) is exported as food 3-4 kg P is the P content in the excrement from appr. 5 people ≈ 0,2 ha/pers Urine Folke Günther http://www.holon.se/folke [email protected] One hectare: Local recycling system Feed .. these nutrients must be returned to close the cycle With sourceseparating toilets, these nutrients can be recycled Urine Food PO 4 PO 4 Urine = 0,2 ha/pers Folke Günther http://www.holon.se/folke [email protected] The eco-unit, a small population maintained Small by permaculture agriculture population, about 200, Balanced agriculture supported by the Providing most of theagriculture human food Balanced and all of the animal fodder agriculture, Nutrients from the settlement are aimed at the recycled to agricultural land support ofOpen the ditches •Nutrient reclamation local population •Landscape diversity •Predator habitat •Windbreak trees •Biomass production Area: 50 ha for 200 inhabitants Folke Günther http://www.holon.se/folke [email protected] The eco-unit PO4 Food PO 4 Feed • High diversity • Perennial plants • Co-operation • Mutualism • Nutrient circulation • On-site consumption • Water export by evaporation Biological greywater treatment plant (wetpark) Clean water is returned to households Folke Günther http://www.holon.se/folke [email protected] Economy Folke Günther http://www.holon.se/folke [email protected] The energy economy of conventional food production Food energy delivered to household: about 4.000 kWh/ 4 p. Energy invested by middlemen: about 36.000 kWh/ 4 p. Total energy investment: about 40.000 kWh / 4 pers Energy invested in agriculture: about 4.000 kWh/ 4 p. Folke Günther http://www.holon.se/folke [email protected] The economy of conventional food production in Sweden 60 000 kr Annual consumer cost for food (four person Swedish family) 60.000 kr Trade, distribution and processing about 75% of the total price 30 000 kr 15 000 kr Folke Günther 0 kr Producer salary, about 3.000 kr Payment to producer, less than 25% (5% of consumer cost) Producer cost (fuel, interests etc.) 80% of producer payment http://www.holon.se/folke [email protected] The economy of eco-unit food production 60.000 No middlemen means consumer cost for food decreases by 50% 60 000 45 000 30 000 ..but the rest is the farmer's Distribution trade salary,and which may increase 400% 30.000 12.000 15 000 Folke Günther 0 Because of increased 18.000 3.000 Salary 13.000 diversity in production, the farmer’s expenses are Expenses assumed to increase by 50% [email protected] http://www.holon.se/folke conventional eco-unit Assume a group of consumers subscribe for food from a local farmer Folke Günther http://www.holon.se/folke [email protected] They will drive the industry out of the market by paying double the industrial price (≈half of the consumer price) Folke Günther http://www.holon.se/folke [email protected] The energy economy of eco-unit food production Total energy investment in food : about 8.000 kWh / 4 pers Energy invested local management: about 4.000 kWh/ 4 p. Energy invested in (conventional) agriculture: about 4.000 kWh/ 4 p. Folke Günther http://www.holon.se/folke [email protected] Saved money Let’s hope that the consumers will use their saved money to invest in the agriculture… Cheaper food Less energy price vulnerability Folke Günther http://www.holon.se/folke [email protected] The ruralisation scenario # A scenario is an imagination made by a scientist # The rules are: You can imagine the most ridiculous things But you have to render a statement of the effects Folke Günther http://www.holon.se/folke [email protected] The ruralisation scenario – start point At startscenario, point, thethe centre of theismunicipality In this following assumed: has a population of 33 000 The 3 000 1. Theperiphery: city is inhabited by decision-makers who have the capacity to make far-sighted and strategic decisions 2. They have the same knowledge of limiting resources, ecology and the rules for long-term survival as you. 3. Furthermore, they understand that the city is not static, but dynamic. Old houses are torn down and new are built. (The average life-time for a house is assumed to be 60 years, which gives the city a rate of change of 1,6%) 4. They decide that, instead of building new houses in the same place as the old ones torn down, they will build ecounits around the periphery of the town. Folke Günther http://www.holon.se/folke [email protected] Ruralisation – after 12 years The town center : 24 000 The periphery : 12 000 Groups of four Eco-units Each group is inhabited by 800 people Local parks replace the old houses Folke Günther http://www.holon.se/folke [email protected] Ruralisation – after 25 years The town : 12 000 The periphery : 24 000 Reversed ditching: Cleaner waterstreams are Underground brought to the surface Folke Günther http://www.holon.se/folke [email protected] Ruralisation – after 50 years The endpoint of the ruralisation process: The municipality : 3 000 The periphery : 36 000 Area with 5,600 inhabitants in eco-units Population density closing to 500/km2 By changing into a more resilient and less fueldependent state, the ecological maturity of the area increases considerably Folke Günther http://www.holon.se/folke • High diversity • Perennial plants • Co-operation • Mutualism • Nutrient circulation • On-site consumption • Slow change • Water export by evaporation The human impact has changed from parasitic to possibly supportive [email protected]