Renewable Energy in Agriculture Brief technology overview AgriSETA Annual Seminar Ulrich Terblanche 17 September 2015 AgriSETA 2015/09/16 1
The Centre for Renewable and Sustainable Energy Studies was established in 2007 to facilitate and stimulate activities in renewable energy study and research at Stellenbosch University. The Department of Science and Technology has been funding the Renewable and Sustainable Energy (RSE) Hub at Stellenbosch University since its establishment in August 2006. The aims of the RSE Hub are to develop human capital, deepen knowledge, and stimulate innovation and enterprise in the field of RSE. Currently the DST is still sponsoring the work of the Centre with an annual grant administrated by the National Research Foundation. Stellenbosch University was designated as the Specialisation Centre in Renewable Energy Technology as part of the Eskom Power Plant Engineering Institute (EPPEI). The research and teaching activities sponsored by Eskom focus on concentrating solar power (CSP) and wind energy and also includes the Eskom Chair in Concentrating Solar Power. The Sasol Technology group sponsored the new facilities for the Centre for Renewable and Sustainable Energy Studies as well as the work and facilities of the Solar Thermal Energy Research Group at Stellenbosch University.
Index • Introduction • Electricity in South Africa • Renewable Energy Technology – Hydro – Solar – Wind – Biomass – Other • Way forward • Incentives • Conclusion 2015/09/16 3
Introduction • Ulrich Terblanche – B.Eng Mechanical Engineer at Stellenbosch University – M.Sc Sustainable Energy Engineering at the Royal Institute of Technology, Sweden Former work experience includes project engineering in the oil and gas refining sector, analyses on using excess heat for district heating and electricity generation in the cement manufacturing industry as well as PV-hybrid systems and energy efficient design in the renewable energy sector. I currently works as a research engineer and project coordinator at the Centre for Renewable and Sustainable Energy Studies at Stellenbosch University. • Centre for Renewable Energy Studies – Post graduate studies in Renewable Energy – Short courses in various Renewable Energy fields for students and industry – Contract research for industry, focus on feasibility studies for solar energy – Technology transfer through policy and decision briefs and assisting the public – Public awareness through schools programs, conferences and events 2015/09/16 4
South African electricity landscape 5
South African electricity landscape 2015/09/16 6
Factors affecting supply The useful life of the ESKOM generation fleet is at 60% on average (design life of 50 years) The required Maintenance duration (corrective or preventive) of the power plants is growing Age of Eskom generation fleet (source: RE Policy mapping Study of RSA) 7
Factors affecting Supply: SA power situation beyond 2030 Since thermal power stations last around 40-50 years, most of SA’s existing thermal power stations must be replaced by 2030 8
Electrical Energy Demand (250 TWh) 9
Integrated Resource Plan (IRP2010) Wind: 800 MW (2010-2013) * 2 400 MW (Total to 2019) CSP: 200 MW (2014-2015) * 400 MW (Total to 2019) Solar PV: 2 400 MW (2012 – 2019) * Pevious IRP 10
Updated IRP for Comment (Nov 2013) 11
REIPPP - Costs 2015/09/16 12
REIPPP Source: www.energy.org.za 2015/09/16 13
SA Renewable Energy Power plants Photovoltaic Letsedi 64MW Postmasburg Jeffreysbaai Letsatsi 64MW Windfarm Bloemfontein 138MW Khi Solar One Central Receiver 50MW Upington
Cookhouse De Aar Wind Farm Photovoltaic 135MW 50MW Upington KaXu Solar One Parabolic Trough 100MW
Droogfontein Kalkbult Photovoltaic Photovoltaic 50MW 75 MW Kimberley De Aar Hopefield Windfarm 65.4MW Hopefield Windfarm 66MW
Renewable Energy Resources • Energy is required for any work being done • Energy can be obtained from various sources: – Gas for heating – Electricity for electrical machines – Diesel for vehicles – Chemical reactions in body for manual labour • Renewable Energy (RE) resources has the ability to replenish itself, whereas non-renewable energy sources do not • No single RE resource is the solution, a combination of systems most often required 2015/09/16 17
Hydro Power • Mature technology • Efficient technology (~90%) • Available in large and small scale • Suitable for base load • Suitable for energy storage (pumped hydro) 2015/09/16 18
Hydro Power 2015/09/16 19
Hydro Power 2015/09/16 20
Pumped Storage • Pumped storage (Hydro energy as storage) • Life cycle efficiency between 73% and 78% 2015/09/16 21
Pumped Storage • Pump storage usage – Turbine activated during peak demand periods which is in line with highest tariffs – Pump activated during low demand periods which is in line with lowest tariffs Pump Generate 2015/09/16 22
Hydro Power • The power of water dependent on the following: – How far the water falls (vertical head) – Amount of water falling (volume flow) • Power = Eff . ρ . Q . H . g Eff – Efficiency ρ – Density of water Q – Volume flow H – Head (height) g – Gravitational constant 2015/09/16 23
Hydro Power • Seasonal Variation 2015/09/16 24
Micro Hydro • Small scale hydro applicable to farms with rivers: www.powerspout.com www.zmsa.co.za 2015/09/16 25
Micro Hydro Source: www.hydro4africa.net 2015/09/16 26
Micro Hydro • Maintenance skills requirements: – Mechanical workshop skills: • Servicing of turbines, shafts, motors, piping, etc. – Electrical skills: • Installation and maintenance of switches, cables, electrical motors, etc. • Qualified electrician for issuing a Certificate of Compliance (COC) – Civil engineering: • Building of dam, understanding hydrology, concrete structures, etc. 2015/09/16 27
Pico Hydro • Example: Driekoppen Turbine head: 30 m Flow rate: 4 L/s Power output: 1.6 kWp (690 W) Storage capacity: 100 000 L System cost: R 88 000 Monthly saving: R 450 Payback: 20 years 2015/09/16 28
Solar Energy • The energy from the sun can be captured in multiple ways, the two best known technologies are: – Concentrated solar power (CSP) – Solar thermal technology – Photovoltaic (PV) technology 2015/09/16 29
Concentrated Solar Power • Focus direct sunlight onto a central receiver using heliostats, troughs or dishes (variations of mirrors) • “Old” technology being improved, some existing plants over 30 years old • Applicable for large scale power plants and some industrial processes • Can be combined with thermal storage to extend operation beyond sunset • Resource ideal in desert like areas (areas with no or little agricultural activity) 2015/09/16 30
Oldest CSP Plants in the USA SEGs plants built in 1984, still operational. 31
Latest CSP Plants in the USA Solana (Abengoa) now in operation 250 MWe, 6 hours storage (molten salt), Solar field 2.2 km 2 , Area 1 200 ha, Annual energy production of 980 GWh . 32
Latest CSP Plants in the USA Ivanpah, Bright- Source, 377MWe, No Storage Crescent Dune, Solar Reserve, 110MWe, 10 Hour Storage 33
Solar Thermal Solar thermal: • Uses the heat from the sun to heat up a gas or fluid, cook food or dry produce • E.g. Solar water heaters, solar cookers, solar ovens and solar dryers 2015/09/16 34
Solar Thermal • Solar Water Heaters – High and low pressure systems – Reduce electricity consumption by replacing element geysers or provide hot water where there were none 2015/09/16 35
Solar Thermal • Solar Water Heater types: – Flat plate collector – Evacuated tube collector 2015/09/16 36
Types of swh - HP
Types of swh – LP (Kuyasa)
Solar Thermal • Solar Water Heaters for Industrial Processes – Textile industry Hangtshou, Chinea (13 000m²) 2015/09/16 39
Solar Thermal • Solar Ovens & Cookers – Used for food preparation – DIY or available off the shelf – Uses concentrated solar energy principles 2015/09/16 40
Solar Thermal • Solar Drying – Food processing through dehydration – Industrial and small scale potential – System design dependent on the food being processed www.muktienergy.com www.pen.solar www.solarfooddryer.com 2015/09/16 41
Solar Thermal • Maintenance skills requirement: – Mechanical workshop skills • Manufacturing of parts for solar dryers such as wooden structures, steel drawers, fittings, etc. – Plumbing • Copper piping, geyser installation, hot water systems, etc. • Qualified plumbers to issue Certificate of Compliance (COC) – Electrical skills • Mostly for disconnecting existing systems – Basic understanding of solar physics • System orientation, shading effects and mounting 2015/09/16 42
Solar PV Photovoltaic panels: • Absorbs light (photons) from the sun and releases electrons, thus direct electricity generation • Electricity generation only when the sun shines • Used to offset electricity from the grid or for off-grid systems if used in conjunction with batteries 2015/09/16 43
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