Nobody is saying that traditional wind farm operations and maintenance (O&M) is easy. It often involves working at height in remote, exposed environments. The industry has rightly identified safety as a major priority for engineers and technicians.

But from a logistical point of view, there are perhaps certain benefits to the traditional wind farm setup. Having turbines all located in a single area means travel time between them is minimised. Assets, such as control rooms or component stores, can be located on site. Cabling is simplified.

There are no such advantages, however, in the distributed wind market, which typically caters for residential or small commercial or community customers looking to install a single turbine of up to 500kW.

In countries such as the UK, the distributed wind market is being encouraged by feed-in tariff (FiTs) regimes targeting particular turbine dimensions. UK FiTs, for example, offer incentives for users to install 500kW machines and those between 1.5kW and 100kW.

Such turbines can face similar permitting challenges as much bigger machines, says Colin Morgan, regional advisory division manager for the certification and consultancy business DNV GL. “The impact in terms of planning and community rejection is just the same,” he says.

“You get as much outcry around a 50kW machine as around a 2MW or 3MW machine, and by comparison they generate next to nothing.”

Technical maturity

Furthermore, he continues, O&M, which is already challenging because turbines are sited alone in a variety of locations, is not helped by a lack of technical maturity in the products. “The technology is not as well developed as in larger turbines,” he says.

“This sector has not had the same investment in development.”

George Pooley, the head of Renewable Energy Loss Adjustors, a wind sector loss adjusting company, adds: “I have found that these sorts of individual units have always been a worse risk than the larger farms.

“I have dealt with small units going wrong for a whole number of reasons, which often are related to maintenance or lack of it.”

It appears at least some of the vendors in the distributed wind sector are rising up to meet these challenges, however. Norvento Enerxia, a Spanish manufacturer targeting the UK market with a 100kW machine, is working hard to make sure O&M will not be an issue for its turbines.

“By installing single sticks you are incurring more maintenance costs or less economies of scale,” accepts Ivo Arnús Montsalvatge, Norvento UK business development director. “But the UK is building a significant portfolio of single sticks, so there is certain scale.

New technology

“Within a few miles you can service a few different turbines. Here is where the new technology has a certain advantage. New turbines like ours can be monitored to a very, very deep extent. We can remote-monitor our machines extensively and that saves a lot of travelling.”

Norvento’s remote monitoring centre is based in Spain and uses technology developed for grid-scale wind farms.

It enables the company to restart a turbine remotely in the event of a shutdown, and provides diagnostics that ensure a technician will always arrive on site with the right tools and spares to carry out the repairs needed.

In Norvento’s case, the technician will usually be from a third-party O&M provider. The company currently has two technical experts based in Avonmouth, southwest England, and is in the process of building a distributor channel that will be responsible for turbine maintenance.

Distributors, says Arnús, may themselves build extended networks of maintenance partners, which could range from electricians to farmers with appropriate turbine experience.

“We will provide backup support to their O&M teams,” Arnús says. “On those sites that we develop for our own balance sheets, we will service them ourselves because they will serve as showcases.”

Maintenance plans

Norvento turbines, which are small enough to use a low-voltage connection and big enough to take best advantage of the UK FiT regime, come with a choice of two maintenance plans.

A basic option, which owners have to contract in order to meet the manufacturer’s warranty conditions, involves one scheduled maintenance visit a year and a round-the-clock remote monitoring service.

The company also offers a more extensive package including scheduled maintenance, warranty and monitoring, along with coverage of all unforeseen call outs. “It is a product more for an investor who wants to have a pool of sites,” Arnús explains.

Although final pricing will depend on the distributor, Norvento has a guide price of between GBP£2,500 and £3,000 a year per turbine for the basic maintenance package, and £7,000 a year for the full service pack.

“That would be less than 10% of what the turbine generates,” Arnús points out. He adds that the company’s oldest turbine has been spinning for three years. “We are seeing 98% or 99% availability,” he says.