Making It Work In KenyaCharlene Maina

MD, Plexus Energy Limited

HIGH CONCENTRATION PHOTOVOLTAIC (HCPV) TECHNOLOGY

• What is it• Why talk About

it• Case Study –

current project• Some analytics

Concentrated Photovoltaic (CPV):

Uses optics such as lenses or curved mirrors to concentrate a large amountof sunlight onto a small area of solar photovoltaic (PV) cells to generate electricity.

High Concentration Photovoltaic (HCPV):

Systems employ concentrating optics consisting of dish reflectors or fresnel lenses that concentrate sunlight to intensities of 1000 suns or more.

• Customer with singular objective

– Reduction of power bills

• Multiple challenges in approaching the solution

– MW power required– Both lighting and

Thermal solutions– Space Restrictions – Financial Viability

Address the most pressing concern

- Biggest expense - Boiler ( heating

the transfer fluid in the boiler system)

Linear Fresnel Solar Collector

THE PRINCIPAL

Flat Mirrors concentrate sunlight on absorber tubeMirrors track the sun over the dayHeat transfer fluid circulates to transfer energy to process

– Large temperature range 100 – 400°C– Easy to integrate (thermal & structural)– Easy to operate– Space Economics

THE REASONING

THE INTEGRATION

ATTRACTIVE RETURNS

THE MONEY QUESTION

CLIENT ANALYTICS

EVEN BETTER

• Carbon Credits – Initial assessment showed that client is in a

position to claim carbon credits based on reduction of emissions further reducing time to break even point

THANK YOU

Contact me: charlene.maina@plexus-energy.co.keTelephone: 0754-405-552 or 0754-405-055

WHERE CAN YOU USE IT?

MULTIPLE USES

Solar process heatSolar coolingSolar thermal power generationSolar desalinationSolar poly-generation

Length: modular in steps of 4m Total width: 7.5mAperture width: 5.5m

Height: 4mWeight: 27 kg/m²Peak power: 560 W/m²

approx. 100 m

approx. 135 m

One collector unit (approx. 65 x 8 m)352 m² / 176 kW peak

Collector field layout with 7040 m² aperture area for a thermal peak power of 4 MW

Typical industrial roof top layout

Facts & Figures

• Heat transfer fluid– Pressurized water– Steam– Thermal oil

• Receiver SCHOTT PTR® 70 – Maximum pressure

up to 120 bar (different versions 40, 60, 120 bar)– Maximum temperature

up to 380 °C with thermal oilup to 330 °C with saturated steam or pressurized

water– Thermal loss per m² of primary reflector

u1 = 0.00043 W/(m²K²) (according to DLR)

Thermal Fresnel PTC Fresnel vs. PTC

Peak Power GroundArea

Ground Area Ground Usage Factor Ratio

88 kWth 264 m2 458 m2 1,73

176 kWth 528 m2 869 m2 1,65

500 kWth 1.500 m2 2.462 m2 1,64

1.0 MWth 3.000 m2 4.923 m2 1,64

10.0 MWth 30.000 m2 48.574 m2 1,62

Advantages I

• Low wind load• Good weight-spread• High ground usage factor• No north-south alignment necessary

• Stationary receiver, no flexible connections• Concentrated sunlight hits absorber

tube always from below

Rooftopinstallation

Industry

Steam

Summary Advantages

• Easy cleaning (flat glass / good access)• Low water demand for cleaning• Reliable components (mirror/tube/drives)

Low O&M

• Primary mirrors made of flat glass vs. aluminum (durability, reflectivity)

• Precise temperature and power control• Less absorber tube per m² allows high quality

70 mm vacuum absorber tube (industrial standard)• Remote control and monitoring via

LAN and internet