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Low Carbon Technologies for Greenhouse Horticulture What are the options for Growers in the UK?. Chris Plackett FEC Services Ltd. Topics. Results from two recent HDC projects PC256 A review of closed greenhouse technology PC265 Biomass heating systems. Closed Greenhouse Technologies.
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Low Carbon Technologies for Greenhouse HorticultureWhat are the options for Growers in the UK? Chris Plackett FEC Services Ltd
Topics • Results from two recent HDC projects • PC256 • A review of closed greenhouse technology • PC265 • Biomass heating systems
Closed Greenhouse Technologies • Interesting concepts • Complex engineering solutions • Impressive headlines • Commercially, where are they now? • Do they offer anything to growers in the UK?
Where is the technology now? • Themato project has been a flagship • Successfully grown tomatoes • Moved to other crops - strawberry • Commercial focus now on ‘semi-closed’ greenhouses • Similar advantages • Reduced investment • Lower risk?
What about the UK? • Aquifer thermal energy storage is not viable • No other commercially attractive energy storage options currently exist • But! • Air handling / heating technology has good potential
Air Movement Technology • The Benefits • Uniform greenhouse conditions • temperature, humidity & CO2 • More efficient heating? • Better response • Use low grade heat • Increased opportunities to use alternative heat supplies
New HDC Project – PC278 • Adapting the Dutch approach …… • And doing it better! • Meeting the needs of the UK grower • R&D with a commercial installation • 1Ha Tomato Nursery • Side by side comparison with conventional system • Partnership between • HDC • Mill Nursery Ltd • Industry suppliers
Project Objectives • Reduce energy use & cost • Reduce CO2 emissions • Expand the opportunities to use alternative heat sources • Improve yield & quality • Reduce disease incidence & the use of crop protection chemicals
Project Status • Installation complete • Work ongoing • 4 year project • Look out for results • All of the normal HDC communications routes • Website for HDC members
Summary – Sealed Greenhouses • Not likely to be economic in the UK • Aquifer thermal storage not widely available • Long paybacks • ‘Semi-sealed’ offers better opportunities • Air movement technology • Opportunities for ‘low grade’ heat • A new HDC Project is investigating the potential • PC 278
What about biomass heating? • Options? • Wood pellets • Miscanthus • Wood chip • Straw
One Potential Problem • CO2 enrichment • not currently commercially available • What impact does this have on boiler utilisation? • What are the alternatives?
Options for CO2 enrichment • Pure CO2 • Not currently economic • Biomass for winter heating only? • Heat with biomass when CO2 demand is low • Use mains gas to produce CO2 in summer
What size boiler? • Choose the biggest possible? • Satisfy peak winter heat demand • Low output most of the year • Smaller boiler? • Won’t meet all of the heat demand but… • Lower capital cost • Higher utilisation
Heat Storage • Helps to maximise boiler use • Connect as ‘open buffer’ • What size?
Finding the answers • Data from commercial nurseries • CO2 demand • 5 minute data • complete cropping season • Scenarios • Low CO2 demand, moderate heat use • High CO2 demand, high heat use
Scenario 1 • 1 Hectare • Energy efficient • Thermal screen etc. • Low CO2 user • Ignoring the need for CO2
No CO2 demand 500kW, 200m3 – 84% biomass Scenario 1
CO2 demand – 423 tonnes/Ha p.a. Nursery 1
CO2 demand satisfied by mains gas 500kW, 200m3 – 42% biomass Scenario 1
Scenario 2 • Higher energy & CO2 user • 697 tonnes CO2 /Ha p.a. • Biomass heat = 31%
Some simple economics • Assumptions • 600kWh/m2/year heat use • ‘Low’ CO2 demand • 42% heat provided by biomass • Comparative fuel costs • Mains gas 2p/kWh (60p/therm) • Wood chip 0.7p/kWh (£25/t) • Fuel cost saving = £32,760/Ha/year.
Simple economics • 3Ha nursery • Total fuel cost saving = £98,280/year. • Cost of 1.5MW boiler & infrastructure • £200k - £300k • 2 - 3 year pay back, ignoring O&M costs • Economies of scale & fuel cost sensitivity are high • Gas price 1.5p/kWh, payback up to 6 yrs • Lower capital cost /MW for bigger boiler
Also consider • Boiler selection • Fuel flexibility • Ease of use • Fuel • Cost now & in the future • Reliability of supply • Ease of storage & handling • Operation & maintenance • Labour • Rules & regulations
Summary - Biomass • Lack of CO2 enrichment is a barrier to uptake • But not a complete ‘lock out’ • The technology is not fit & forget • There are opportunities • Do your homework • The economics are very site specific