Aquamarine Power, the wave energy pioneer whose Oyster 800 device was hailed as the future of marine energy, has shelved plans to build Scotland's first wave energy farm for at least five years.

The struggling Edinburgh-based firm has attracted around £93 million of (70 per cent private) investment since its foundation in 2005 but laid off more than half its staff last year after making a £15.7m loss in 2013-14. The firm also won planning consent for a 40MW wave power site 500m off the west coast of Lewis, where it planned to install "the world's first ever" fully consented array of up to 50 wave devices in 10m of "some of the wildest seas in the world".

A spokesman for the firm told the Sunday Herald that the firm was now in "explorative discussions" with other parties regarding the potential future of the Lewis site, and a smaller site in Orkney. He added that future plans "could include developing the Lewis site as a multi-technology pre-commercial test zone, or co-developing the site with other interested parties".

Despite investment of around £1m in preparation and the obtaining of planning consent, the Lewis plan foundered as the firm's prototype device, installed at the European Marine Energy Centre (EMEC), a testing facility in Orkney, suffered repeated technical failures, proving unable to generate electricity for a sustained period of more than about 24 hours. The Outer Hebrides also lack a grid connection to the mainland, with the company seeing no prospect of one being installed before 2020.

Having reduced its work force from 50 to 18 last year, and seen the departure of its £286,000-a-year chief executive Martin McAdam, Aquamarine has now changed its business plan to concentrate on the development of separate component technologies that can be shared across the industry. Its priority is now the "take off" systems - the so-far elusive device capable of transmitting wave-generated kinetic power from seaborne to shore connectors. However a spokesman stressed that the firm hopes to resurrect the now mothballed Oyster 800, and its proposed streamlined successor Oyster 801 in the future.

A spokesman for the firm added: "After more than three full winters at sea the Oyster 800 machine has now completed its test programme. In that time our second full-scale machine has demonstrated its survivability in all seas including waves over eight metres high. Our machine has successfully generated electrical power into the Orkney grid network and has yielded incredibly valuable operating data which confirms the Oyster wave energy converter performs in line with tank test and numerical modelling predictions."

"We have therefore decided to draw our Oyster 800 test programme to an end. Aquamarine Power is now focussed on the development of the next-generation Oyster in parallel with critical sub-systems such as WavePOD, a pan-industry power take off system being developed in partnership with Bosch Rexroth and Carnegie Wave Energy.

"As well as offering improved performance and reliability at lower cost, WavePOD will be capable of generic application across a range of wave energy technologies, and we hope this innovative approach will accelerate learning and cost reduction in the industry."

Aquamarine's shift to component development coincides with the creation of a new public body under Highlands and Islands Enterprise, Wave Energy Scotland, announced by energy minister Fergus Ewing last November in the wake of the collapse of rival wave technology developer Pelamis.

Projected as a ten-year project, WES will provide public funding for wave energy device development "until the technical and commercial risks are low enough for the private sector to re-enter". A HIE spokeswoman said that the recruitment process for 10-12 staff with appropriate technical and commercial expertise will begin "later this month", with appointees expected to be in place by the autumn. The infant quango is also set to issue its first industry-wide "call for proposals for wave energy technology development projects" as early as next week.

The establishment of WES, and the "uncommercial" management of tens of millions of public investment by Scotland's wave power pioneers have beencriticised by the Inverness-based economist and energy expert Tony Mackay, who said:

"Scotland's public bodies have provided a lot of support for the industry over the last few years but there has been increasing evidence that some of it has been poor value for money."

"It is characteristic that the Scottish Government's main reaction to [the difficulties of] Pelamis and Aquamarine was to set up another quango and I am sceptical that such a body will do any better than the plethora of existing public bodies involved, including the Offshore Renewable Energy Captapult, the European Centre for Marine Energy , HIE, Scottish Enterprise, the Carbon Trust and Scottish Renewables."

"The Offshore Energy Catapult's economic and financial publications have been very poor, showing little understanding of the economics of the industry. They are basically demands for more public money without any realistic assessment of the benefits and costs involved."

Mackay also criticised the "far too high" salary paid to Martin McAdam saying it was "indicative of the non-commercial attitude in the marine energy industry".

Dr Paddy O'Kane, Aquamarine Power's chief technical officer said: "Data gathered from the operation of Oyster 800 enables us to validate the numerical models we have developed through years of tank testing. In simple terms, Oyster does what is says on the tin".