PV buttress at Locust Hill

A general prefatory note is needed. It is important to know that the tall towers with their requisite large buttressed bases are not intrinsically necessary in most photovoltaic installations. Their use at Raven Rocks is a specific consequence of their location within a project that is deeply committed to the restoration and long-term protection of native forest. With tracking that uses state-of-the-art technology that can add 40% to a PV cell's production, we felt our demonstration should include it. At the same time we felt that we would not compromise another message that we feel is at least equal to the issue of energy supply and a benign source for that energy. That issue is, of course, the protection and enlargement of forersted areas. These, after all, are the lungs of this Earth. Seen in this light -- which is most certainly a factual light -- we have no sense whatsoever that we are undertaking an expense that is unwarranted. With the sun having reached a significant energy output at 15 degrees altitude, it is easy to see that without some significant elevation above the ground, trees of any significant height would have to be kept clear for hundreds of feet on all but the north sides. Moreover, as is true throughout the Locust Hill project, further significant amelioration of the cost is won with care about the engineering design, and with proper placement and curing of the concrete for these towers. They should have a remarkably long and hence a very economical life.

Following are photographs of the construction of our first (the western) of four towers. Again, because of the shading issues that tracking introduces, this particular tower, located downhill from the others, required a taller and hence a heftier base.

In most circumstances, neither the array elevations nor the extra construction of this west tower would be required. Recommended elevation on any particular site would vary according to such considerations as shading from any source, snowfall, pedestrian or other traffic under the array or aesthetics.

01-3947-South_aerial 02-Big_and_Bigger_tracker 03-4057-PV_with_Pavel 04-Steelbending
1. South aerial view 2. Big and bigger tracker 3. PV with Pavel Stary of the Czech Republic 4. Steelbending
05-C_ties_steel 06-Don_on_wall,evening 12-3392-Don_ties_steel
5. Chris ties steel
6. Concrete Mobile
7. Don on wall 8. Don tying steel
07-ringwall-1 09-blasting 10-applying_Heydi 11-forming_begins
9. Ringwall complete 10. Sandblasting 11. Applying Hey'di 12. Forming of buttress begins
15-4501-WS_at_controls 13-4484-pour_overview 14-4473-Ted_up_ramp 16-4521-Herb_waiting
13. Warren at controls
14. Pour overview

15. Ted wheeeling up ramp
16. Herb waiting
19-4522-John_Herb_dump 17-4494-barrow_action 18-4513-Don_vibrates 20-4531-evening_work
17. Herb and John, dump and scrape
18. Wheelbarrow action 19.Don on the vibrator 20. Evening work
22-4673-night,board 21-1024-tower_galvanized 23-4735-setting_tower
21. Working through the night
22. Expert welds 23. Tower galvanized 24. Setting tower
26-4780-detail,welds_grout 24-4768-tower_from_north 25-4789-tada_tower!  
25. Welds, bolts grout
26. Tower from north
27. Tada, a tower!