Monthly Archives: September 2014


Replies are very much welcome, but please try to stay on topic. If the topic is “global warming and ice melts”, let’s talk about just that and not “solar PV”! I will in the future try to moderate replies by deleting off-topic comments.

Another point; don’t waste yours and my time with offers for commercial services. This site is meant to be informative and we don’t need any third parties to promote it. Let the site promote itself!

Thank you for the feed-back so far. – Mogens Lauritzen

Hydro Power; the end or here to stay?

With resent efforts to promote the tear-down of Hetch Hetchy dam and restore the flooded valley, one must ask why, and not only in the sense of resurrection of the lost valley.

With the approach of global warming, we can expect a continued decrease in snow pack levels. Future precipitation levels are as of yet unknown. If decreased, we need all available storage to last through dry seasons. If increased, we need storage to prevent catastrophic flooding. Above all, with global warming, the snow pack will be replaced by rain, effectively removing our snow pack water storage, and increasing our need for alternative storage.

From the electricity grid point of view, Hetch Hetchy, when water is available, provides a robust predictable and dispatchable power source with no greenhouse gas emission. In addition, the system can also be used to store electricity/energy on a short-term basis through “pump-up” technology. Pump-up is equivalent to having access to a gigantic battery, and is a key component in stabilizing the electric grid. This is especially needed as we introduce alternative and unpredictable power sources such as wind and to some extend solar power.

There’s no question that California hydro power dams have caused severe environmental harm. Almost 3000 miles worth of upset creek/river habitat. But if you compare that to the added safety of flood control, predictable water supply, and reliable and clean energy supply, the end result should favor our dams. We have seen experimentation with fish ladders, and forced water release to preserve smelt populations. Surely there must be more mitigating ideas we can study and introduce.

The bottom line must be this; we need dams and water storage systems. They are a cornerstone of our future survival. Removing dams to restore ecosystems amounts to nothing but a utopian notion.

Solar Trackers & Reliability

Looking at a solar tracker, and one sees a simple mechanical structure. Probably something anybody could build? Now add to that a requirement for it to operate over a 20 year lifespan, and the picture has quickly changed. Try to think of a electrical/mechanical structure which has operated non-stop, during all types of weather, for the last 20 years.

When designing and building a solar tracker, a goal of 20 year operational life must be considered because the additional performance gain can quickly erode with unexpected maintenance costs. Baring lightning or other extreme power surges, the electronics and software will easily last 20 years when designed correctly. The main problems are mechanical, gears, motors and bearings.

If you are about to venture out and design a new solar tracker, please give us a call to discuss your options. With our remote managed controllers, we see the day-to-day operational troubles, and have helped many tracker manufacturers improve their designs. There’s no need to retry paths leading to troublesome designs.

A Local Content Perspective; why Solar Trackers?

We often hear solar PV systems promote job growth, but conveniently overlook where the bulk of capital is flowing. Solar PV modules, inverters, and racking systems all consume the lion’s share of a solar system’s capital investment. Adding a solar tracking system, can increase a solar system’s energy yield by as much as 45% or higher, while also benefiting the local economy. Most solar trackers can be designed by local machine or steel fabrication shops – thereby increasing local content. The additional Operational & Maintenance effort, usually reduced to an annual lubrication visit, also increases the local labor component.

A Grid Perspective; why Solar Trackers?

Dual Axis Tracking vs. Stationary

Despite the continued downward solar PV module price pressure, Solar trackers will remain an important component in tomorrow’s energy systems because of the sustained daily power curve.

With stationary solar PV systems, a daily bell shaped power curve is produced with maximum power produced at noon. As a result, a the power grid will have to be engineered to distribute the momentary noon time power production. A poor cost/benefit proposition.

Solar tracking systems will, because of the sustained power curve, provide the grid with a sustained power curve throughout the day. As a result, possibly little to no additional engineering efforts will have to be made to the grid.

It is the cost/benefit proposition from the grid’s perspective which will drive the need for future tracking systems, and this is something we will see in the way Power Purchase Agreements are about to be negotiated.