Bergey Windpower: When does wind power makes sense?

In the 1970’s, Karl Bergey, an aircraft designer-turned Professor of Aeronautical Engineering at the University of Oklahoma, was conducting feasibility studies looking at wind power. When the oil embargo hit the US, Karl was tagged as an alternate energy expert. Meanwhile, son Mike Bergey was studying Mechanical Engineering and leading a team that won the wind energy portion of an international design competition. When Mike graduated in 1977, father and son launched Bergey Windpower, now the world’s leading manufacturer of small wind turbines, which are in use at over a thousand cell sites worldwide.

TowerXchange: Please introduce Bergey Windpower and in particular your experiences in telecom energy.

We were under-capitalised when we launched back in 1977 - I remember my father asked me what was the smallest amount I could live on - I wish I hadn’t answered that question so honestly! After three years of product development, we shipped our first 1 kW turbine in 1980, our first for telecom in 1981, our first 10 kW turbine for telecom in 1984, and have been active in telecom energy ever since.

Bergey Windpower is now an established and stable supplier. Of Bergey’s nine to ten thousand installations worldwide, around a third are telecom. The telecom industry represents the largest customer base for our 1 kW units, for the 10 kW units the grid-tie segment is much larger.

TowerXchange: The first question our readers always ask is ‘how proven is the solution in the field’, so please tell us about your deployment experiences, particularly in Africa, Latin America and Asia.

The use of our wind turbines in telecom is concentrated in emerging markets because we’re a well-matched solution for off-grid sites where, alone or alongside solar, wind power is able to save a lot of opex compared with diesel. Bergey Windpower turbines have been installed in over 50 countries.

The highest concentration of our telecom sites are in Asia. For 16 years we had an operation in China, where we built all our 1 kW turbines. Our largest customer was China Mobile, and there are around 300-400 cell sites with our turbines in China, where it is common practice to use multiple 1 kW solutions, rather than larger turbines, as there is less concern about land usage. Smart Communications in The Philippines also uses 1 kW turbines at around 100 remote sites, for which they won the first GSMA Green Power for Mobile award in 2008.

Bergey Windpower’s dealer in Nairobi, WinAfrique Technologies, were the first to introduce small wind for remote cell sites in Africa. In 2007-8 Safaricom undertook a three site pilot leading to the installation of Bergey’s 10 kW turbines at 55 sites in Kenya. Wind was the primary power source at each of those sites, leading to a DG runtime saving of better than 80%. WinAfrique also installed Bergey 7.5 kW turbines for Orange in Kenya and documented similar KPI’s at six trial sites (see Figure 1). In Africa we also have 7.5 kW turbines installed in South Africa, Angola and Tanzania.

TowerXchange: How much wind is enough wind to provide power to a cell site?

As a rule of thumb for site selection, we recommend wind power at sites with average wind speeds of 5.5-6mp/s (13mph) at a height in the 80-100ft range, assuming the turbines will be mounted on a separate tower.

If we can put wind turbine on top of an existing 40m telecom tower, we can be competitive with a lower average wind speed. However, while our turbines create no antenna interference issues or deflection problems for microwave backhaul, we find that very few existing telecom towers have the structural headroom to hold a wind turbine large enough to significantly lower the opex. One of our R&D objectives is to develop the technology to control the thrust load, enabling us to retrofit wind power turbines on more telecom towers.

TowerXchange: It’s a common misconception that wind is an oversized energy solution for cell sites given their typical load. What’s the range of load your turbines can support? And what’s the turbine size to output ratio?

If you’re talking about micro cell sites with a 100W load, then yes wind power is oversized. But as you get to 1-3 kW of telecom equipment load, with air conditioning on top, a wind system can make a lot of sense. Most of the cell sites we’re powering with our 7.5/10 kW turbines are in the 1.5-4.5 kW range, often with some solar involved (although with wind often the larger component). Seasonal issues mean that in some months you’ll have excess energy, but we’re good at sizing systems for lowest lifecycle cost of energy.

At a typical wind resource site we run at a 20-25% capacity factor. With controls, storage and conversion losses, the power available to support the telecom load is in the 1-2 kW range from a 10kW wind turbine – similar to solar. At a site with a better wind resource, a capacity factor or 30-35% enables 2-3 kW load range.

The best lifecycle cost of energy is often achieved when you’re providing 75% from renewables, and 25% from backup diesel generators – if you go higher than that you get into diminishing returns as you waste more high capex wind and solar generating capacity.

TowerXchange: How can carriers and towercos quickly assess whether a particular site might be a viable option for wind power?

Just send us the co-ordinates and we’ll tell you!

Finding out the wind resource available at a given location used to be a big challenge – data was very poor quality in emerging markets as a result of meteorological equipment that was mounted too low, or was poorly maintained. Therefore the wind resources in many emerging markets have been underestimated.

We have access to better wind maps now, with subscription services from companies who offer worldwide modeling combining balloon data with GIS and flow modeling. Bergey Windpower subscribes to a wind database from 3Tier and we’ve integrated that data into our online design tool called WindCAD. We provide our dealers and partners free access – all we have to do is enter a longtitude, latitude and the height of the tower, and we get an instant performance prediction.

Sometimes I think the telecom industry has no idea how easy it is to evaluate a list of sites for potential use of wind power – if a network planner or towerco sends us an NDA and a site list, we can tell them quickly which sites have sufficient wind resources to be candidates for wind power.

TowerXchange: Can you give an idea of the typical payback for installing wind power at cell sites? And what’s the longevity of your telecom wind power solutions?

Bergey have a few systems that have been in situ for over 30 years, and a lot that have been operating for over 20 years, all with minimal maintenance and replacement component costs. The longevity of our turbines means many of our systems that have paid for themselves four to six times over!

We used to say that we designed solutions for a 30-year lifespan, but they’re lasting longer than that so we have no idea how long they’ll last!

The key point is that this is not an experimental technology; our turbines have a substantial track record, supported by documented KPI studies and boat loads of data about fuel savings. When other renewable energy solution providers claim a hypothetical 90% DG runtime reduction, we have the data to prove that our solutions work and they work over time.

TowerXchange: How do you sell, directly or through dealers?

We prefer the dealership model, where we partner with a local dealer for installation and after sales support. 90% of our sales come through dealers, including WinAfrique Tecnologies in East Africa, Tricom Structures in South Africa, Wireless Chile in South America, Mast-Och in Scandinavia, and AJ Telecom in the Caribbean.

TowerXchange: How does the TCO of wind compare with solar?

The typical payback in our telecom applications is in the two to five year range, depending on the wind resource and delivered cost of fuel.

Wind power isn’t really in competition with solar – there are sites suitable for wind, sites suitable for solar and sites where, even if solar panels were free, it would make sense  to exploit both complimentary energy resources. After all, wind speeds increase at night, during inclement weather and during winter seasons when there are less hours of sunshine per day.

The declining cost in solar is a near term challenge, but in the long term it builds the market for our wind turbines. The lower price of solar encourages MNOs and towercos to put in solar instead of dual diesel gensets and more aggressively pursue retrofits. But, if the site is at a higher or lower latitude then there’s not enough solar resource in the winter to carry the load.  And there are sites with rainy or cloudy or foggy seasons where the solar resource is much reduced for months at a time.  Every spring we start getting calls from MNO’s in the northern hemisphere who had site reliability problems over the winter.  In the fall we get the calls for the southern hemisphere!

Also as the load grows with new technologies and new tenants on towers, in many places it will be more cost effective to add capacity with wind rather than more solar, given the availability of more hours of green energy supply and the smaller footprint of wind solutions (on a retrofit you can install a 10kW system with a foundation footprint of around of 10m², and with a monopole you could need as little as 4m²).  And of course wind power has no theft issues whatsoever!

The economics of wind power are very sensitive to the wind resource. Performance goes up essentially as the square of the available wind resource – where solar is linear. A small difference in wind speed makes an exponential difference in energy output for us. Good wind sites, with wind speeds of 6mp/s or more at the top of the tower, have a cost advantage due to superior capacity factors. BTS sites often have the best wind resources in the area because the sites are elevated and well exposed.

The challenge facing Bergey Windpower and our competitors is to reduce the cost of wind to become competitive at lower wind resource sites.

TowerXchange: Tell us about your “Affordable Green Site Program”.

The Affordable Green Site Program is our in-house R&D effort. We’re trying to reduce the total cost of wind power to match the capital cost of dual diesel solutions for new rollouts, and to come up with an affordable retrofit solution.

Bergey Windpower is working with some significant radio, battery and electronics system vendors to better integrate monitoring and control, taking different approaches to energy storage management, with a significant improvement in battery longevity and TCO.

Our Affordable Green Site initiative also includes a community power effort. This involves installing a more powerful wind turbine to enable rural electrification, using a guyed tower which is safeguarded by the community because it also provides power to the school, water pump, or a health clinic. We’re trying to reduce equipment costs and provide some value to the local community, and trying to escape the fortress approach to site security.

TowerXchange: Which financial model works best in telecoms, an up-front capex or a lease model?

From our dialogue with the telecom industry, it’s become clear that capex and opex budgets are often separate – saving opex doesn’t necessarily unlock additional money on the capex side. As things stand, for a given annual capex budget, operators can put in twice as many brown power as green power sites, so we need to move toward a leasing or financing approach and take away the initial capex burden.

Bergey was the first company to have the lease model available for grid-tie small wind, where we’re working with United Wind to lease 10kW turbines to farmers and home owners. Leasing has been game-changer in the grid-tie market, and it will bleed over to off grid telecom.  It will be interesting to see how this business model fits into the telco market.

TowerXchange: Where would the capital come from to enable a lease model for telecom wind power?

Bergey’s core competency is wind power technology, so we’d prefer to supply to a company that has the experience, resources and access to capital.

Third party leasing will have an impact, but an alternate model would be for towercos and MNOs to use export finance institutions, many of which are willing to make low interest, long term loans at a lower cost than the savings renewable energy yields – so a deployment could be cash flow positive from the get-go.

TowerXchange: Finally, what differentiates a premium wind solution like Bergey’s from some of the lower cost solutions in the market?

In the wind business more than anywhere else, you get what you pay for. The initial capital outlay is important of course, but reliability and ruggedness are critical to ensuring your capital is invested wisely. It’s clearly better to invest in slightly more expensive solutions like Bergey’s, which last 30 or more years, than cheap wind power solutions that might last two years. Interestingly, a significant segment of our telecom market is retrofits to replace failed wind turbines from other suppliers.  The original towers and wiring is often reusable.

Lots of new entrants have come and gone in the small wind power business – many became highly leveraged, manufactured products that were not always reliable, and went under. I’d urge buyers to look for the track record of their potential supplier. It’s rare that a CTO or his staff would understand wind technology deeply enough to sort the wheat from chaff, so seek reliable third party references. I would advise MNO’s and towercos to only work with companies with five years or more history – that’s the best due diligence.

Bergey Windpower have the longest and most successful track record, the highest reliability and the most robust designs. We welcome comparisons.