by Anthony Harrington
One of the perennial issues for owners of grid-connected renewable power generation assets is the obligation to comply with National Grid’s instructions to stop pumping electricity into the grid when there is over-supply. Of course, this is just one of any number of maintenance tasks that come with ownership of renewable power generating assets.
However, as Pieter D’haen, Commercial Director at the renewables consultancy, Natural Power, explains, perhaps the easiest way of responding to instructions from National Grid is to outsource the management and maintenance of the asset to a specialist provider. Natural Power runs a grid ControlCentre at its offices near Castle Douglas where it manages some 30 per cent of the UK’s installed wind power.
“The UK has very strict wind turbine safety rules. Any activity on a wind farm site has to be monitored to ensure the highest standards of safety for any staff. Above all, you want to make sure that the turbine is not restarted while staff are still in the vicinity,” D’haen notes. All the client has to do is to call Natural Power’s ControlCentre for permission for maintenance staff to go onsite and the company can then shut down the turbine and log the visit and the reason. This provides a clear safety record for all visits to any of the sites monitored by the Centre.
“Our ControlCentre is manned round the clock, we also look after a number of high voltage lines and grid infrastructure items from the Centre,” he comments.
Natural Power has a very close relationship with National Grid and will act on all instructions from them, stopping wind farms and turning them back on as capacity dictates. While a large number of clients are onshore, the Centre also looks after a number of offshore assets. 
“The infrastructure that runs from the wind farm to the shore, along with the shore based station, is owned by the offshore transmission operator, and they generally look to outsource the management of those assets. We already look after these types of asset for some seven offshore operators and we are the biggest caretaker of offshore assets,” he notes. 
It might seem as if undersea cabling would require little intervention, but it can require a surprising number of resets over time to cure minor faults.
“We have expanded our capacity in the sector and we will be opening our new ControlCentre. We carried out an upgrade of our systems so that we can respond to hundreds of instructions from National Grid. We have some 35 monitors and 10 control desks where operators monitor client networks day and night,” he notes.
The operational control and monitoring of wind farms is just a part of the portfolio of services that Natural Power provides. It has a well established maintenance section where engineers carry out maintenance work on windfarms. “When turbines come out of warranty or the existing maintenance contracts come to an end, we’ll bid for the contracts. This is a very competitive business now,” he notes.
He points out that one of the advantages the company has in bidding for such contracts is that the depth of experience in the company means it can work on a range of turbine types and can respond very quickly to faults across the UK. “We did a study recently which showed we were able to help clients reduce energy output losses through the winter. This helps the operator to drive the cost of energy production down and helps to increase the performance of the asset.”
It is hard to overstate the importance of driving down generation costs for onshore wind. The sector has been knocked back by the UK Government’s decision to withdraw subsidies from onshore wind. “The onshore wind sector is something of a victim of its own success. For the last 10 to 15 years it has been very successful at driving down the cost per kilowatt hour. We have had bigger turbines and better optimized turbines and there have been real cost reductions. However, it remains a struggle to get new onshore wind farm projects funded without investors being able to see some underwriting of future revenues by Government,” he notes.
It is not the difficulties of competing in a zero-subsidy generation environment that is causing the problem for new projects. D’haen points out that there is now a feeling in the sector that onshore wind has matured to the point where it can compete without subsidy. But onshore wind farms are capital-intensive projects, with the bulk of the cost being borne upfront in the construction phase.
“Upfront capital costs are a real disincentive. Instead of withdrawing subsidies totally, government would perhaps have been better advised to have worked out some kind of initial capital grant. The lack of new projects is a problem that will need to be addressed,” he notes.
The alternative for the owners of a proposed new onshore wind farm would be to secure a long-term purchase contract for their power from a large corporate. However, as D’haen observes, such deals are few and far between.
“What we are suggesting to government is that they offer to provide contracts for difference (CfDs) guaranteeing, say, £40 a kilowatt hour. Investors are less risk averse than banks so even that low level of guarantee would be enough to give them sufficient confidence to back projects. It is very unlikely that the market price would fall below that level so the whole thing would more than likely be cost-free to government,” he comments.
What the onshore wind sector needs is a framework from government that enables projects to go forward, once again. “This is how companies in Germany and elsewhere are able to get new projects and these countries are seeing reductions in the generating costs,” he notes.
Despite the difficulties, D’haen says that Natural Power is advising on a number of proposed projects that are looking at the viability of operating purely on market pricing or by securing long term corporate power purchasing agreements in advance of construction.