ENERGY SAVING
results of the other two technologies are explained below.
PV panels
’t Voske was one of the first mushroom farms in the Netherlands to install an array of PV solar panels. For comparison purposes, two types were chosen: monocrystalline PV panels and thin film PV panels. Monocrystalline PV panels are more expensive, but have a higher effici- ency and perform better in direct sunlight. Thin film solar panels are cheaper, but offer lower efficiency. However, they perform better in diffuse sunlight and at higher temperatures. The table below shows the figures as an average of both types of panel.
Heat pump connected to geothermal energy storage.
Monitor for the Dutch Mushroom Sector, 2013, revealed that chestnut mushroom cultivation uses on average 88% more electricity and 32% more gas per kilo of mushrooms than white mushrooms. The total energy-efficiency of 9.4 MJ/kg product with chestnut mushrooms is on average 54% higher than that of white mushrooms (6.1 MJ/kg).
The long-term aim of ’t Voske is to become an energy neutral mushroom farm that produces its own, renewable energy. Three types of technology are used: PV solar panels, geothermal energy with a heat pump and absorption refrigerator and an innovative, small-scale, on-farm ‘power station’ based around a spent mushroom compost burner with a steam generator (that can generate electricity, heat and steam). The innovative spent mushroom compost burner needs improvement, and is currently undergoing further development so the results are still unknown at present. The
Voske PV panels
Annual consumption electricity kwh price
Annual costs electricity PV solar panels (averages) Panel surface
Peak output per panel Peak output per m2
Conversion factor annual production Annual production per m2 panel Number m2 panels
Annual production PV panels Savings on buying electricity SSE subsidy
Annual saving (excl. VAT) 34 MUSHROOM BUSINESS
466.363 KWh/ year € 0,11 per kWh
€ 51.300 Mix monocrystalline/thin fi lm 1,65 m2/panel
198 Wpeak/panel 120 Wpeak/m2 0,9
111 kWh/m2/year 1.218 m2
134.976 kWh/year = 29 % € 0,11 per kWh € 0,035 per kWh € 19.572 -38%
At the farm, the output of the PV panels was measured and amounted to 134,976 kWh. This equates to 29% of the total electrical energy requirement. Savings on the amount of electri- city purchased, and a SSE subsidy for renewably produced energy, resulted in total savings of € 19,572, which converts to a cost saving of 38% on electricity.
Geothermal energy
’t Voske uses a geothermal energy storage installation for heating and cooling (+/- 500 kW max.) combined with a heat pump (+/- 200 kW max.). The geothermal energy installation is connected to a central duct, so the incoming air can be conditioned using low-level heat or cold taken from the stored geothermal energy. The heat pump supplies any extra heat or cooling required for the central duct or the climate units in the growing rooms. An absorption refrigerator is available to maintain the energy balance of the sources and to supply any addition cooling capacity. The intention is to power this absorption refrigerator using the high-level heat surplus from the spent mushroom compost burner. However, as
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
