Imperilled tortoise prompts solar farm rethink

The continuing tension between conservationists and the renewable energy sector reared its head again last week, when US solar energy giant BrightSource Energy announced it would scale back a proposed solar thermal plant in California in order to protect the local tortoise population.

Conservation groups have claimed that the desert tortoise, a native species in the southwest's Mojave region that is officially on the endangered species list, is seeing its habitat threatened by huge thermal solar projects in the area.

One such project is BrightSource's Ivanpah solar array, which is due to become fully operational in 2012. The original plans for the project, which called for it to begin construction late last year, featured three large arrays – two producing 100MW each, and the third phase (Ivanpah 3) producing 200MW. The plans call for the units to cover a total surface area of 5.3 square miles.

However, last week the company submitted a proposal to the Californian Energy Commission (CEC) to reduce the overall area for the facility by 12 per cent, scaling back the size of the third phase of the project by 23 per cent, and replacing the five planned towers with just one.

The company said the changes would mean the facility avoids the area that would have required the most grading and rock removal in the solar fields, while leaving the largest natural stormwater features in the northern portion of the site intact.

The proposal will reduce the electricity-producing capacity of the project by 11 per cent to 392MW.

According to Defenders of Wildlife, the population of the desert tortoise has dropped by 90 per cent in the past 50 years, leaving as little as 100,000 of the animals in the south western desert region. Threats include human disturbance, to which the tortoises are extremely sensitive. The animals also rely heavily on local flora for their water supply.

This is not the first time that BrightSource Energy has had to adjust its plans for solar plants in California due to concerns from conservation lobby groups.

The company cancelled a solar project in the Broadwell Lake area of the Mojave desert in September following concerns about the proposed development's impact on local wildlife.

The firm's expansion plans could also be hindered by the introduction in December of a new bill from Californian senator Diane Feinstein that would protect areas of the Mojave desert, turning some parts of it into a national monument.

However, the proposed protected areas do not appear to overlap with the area to be used for the Ivanpah project.

California renewable energy standards previously dictated that the state draw 20 per cent of its energy from renewable sources by this year. The state has now been instructed to extend that renewable portfolio standard, requiring a third of the state's power to come from renewable sources by 2020.