Wednesday, 15 December 2010

Energy - Nuclear prospects - Nuclear Option Unclear

Nuclear Option Unclear -

Costing doubts and technical controversy bedevil SA’s nuclear future

Nuclear energy could contribute 13,4% of SA’s electricity generation needs by 2030, according to the department of energy’s draft integrated resource plan (IRP). The proposal has drawn both criticism and praise during this month’s public hearings.

SA’s total electrical generation capacity is projected to reach 85241MW by 2030, of which 9600MW will be from nuclear power (on top of Koeberg’s current 1840MW capacity) as envisaged in the department’s revised balanced scenario. The types of nuclear power plants being looked at range from 1000MW to 1600MW in size, which means six to 10 reactors could be constructed.

Energy minister Dipuo Peters told the media recently that nuclear was becoming a preferred solution to SA’s energy needs. “The acute need to secure reliable energy supplies and the urgent requirement to reduce carbon emissions has put nuclear energy firmly on the agenda as a viable choice to be pursued in order to achieve a suitable energy mix for our country,” she said.

But the technology is controversial, to say the least. Debates cluster around four main issues.

The first is cost. The capital expenditure required to build a nuclear plant is high. Using a reference price of R26575/kW, the 9600MW fleet would cost R342bn, and would be built between 2016 to 2030. But while the initial investment is high, nuclear plants have low operating and fuel costs .

SA Nuclear Energy Corp CEO Rob Adam says examples in the US and France show that once a nuclear power plant is amortised (in 15-20 years), with low operating costs, it can generate large returns. “With the new generation of plants having an initial licensed life of 60 years, the return can be substantial,” says Adam.

But criticisms focus more on the uncertainty of costs. Looking at the fleet as a whole and not the life of the individual plant, costs may actually increase over time as the technology develops — firstly because it’s a seller’s market globally (at least for now) and secondly because of design changes and increased safety mechanisms.

“The IRP numbers based on the nuclear industry are proven to be underestimates,” says Rianne Teule of Greenpeace. Teule argues that global examples show a downward-sloping learning curve, and says the capital costs of France’s 58 reactors have increased with each new addition.

The size and capital costs of nuclear plants introduce a second concern cited by critics — their inflexibility, and the likelihood of excess capacity.

Given the fact that demand projections are estimates at best, such large centralised plants do not allow the industry to flexibly respond to changes in demand or technology, unlike renewable options, says Ruth Rabinowitz, chair of MamaEarth and a former IFP MP. The lead time of a nuclear plant, including commissioning and construction, is a minimum of 10 years, and they are seldom built on time or within budget. Then there is the commitment to a plant lifetime of 30-60 years (depending on the plant). If available renewables are given priority on the grid in the future, as is the case in Germany today, excess capacity from the nuclear plant could remain unsold. “That’s one of the concerns for investors,” says Teule, “what is the chance you can sell excess capacity in the future?”

Adam argues that this is not a concern, and that the same can be said of the coal- fired power stations Medupi or Kusile. The concerns underpin Greenpeace’s argument of an inherently uncertain net present value of nuclear plants.

The third danger of nuclear power, say critics, is the legacy of its waste. The spent fuel is highly radioactive. Simply put, uranium is transmuted into other elements that are radioactive, some of which take seconds to decay and others which take millions of years. It would take about 100000 years for the waste to reach natural levels of radioactivity. The waste also needs to be stored in deep underground containers to remain stable for this amount of time. “Nowhere in the world has the issue of storage been solved,” says Rabinowitz.

SA’s waste is temporarily stored under water at Koeberg.

“While there is no doubt that this waste is dangerous, it is compact and manageable,” says Peet du Plooy, sustainable growth programme manager at Trade & Industrial Policy Strategies, an economic research institution. For comparison purposes, a 1000MW coal- powered plant would require around 3Mt/year of coal and produce around 1Mt /year of ash; a nuclear power plant of the same size would use 17t/year of nuclear fuel and produce 17t of spent fuel, with a volume of less than 20m³ for long-term storage, according to Adam.

There’s also the option of reprocessing the spent fuel by extracting the uranium and plutonium to be (re)used , leaving smaller quantities for long-term storage. France, England and Russia are already reprocessing waste, but aren’t using the fuel because it’s more expensive.

Adam says the technology exists to take this one step further by breaking down the waste into shorter-lived products that would remain radioactive for only a couple of hundred years, but that the costs of these technologies are the problem. “It doesn’t reflect well on [the industry] to not have a complete business plan,” he says. “It’s an R&D challenge, but it’s a question of engineering and economics — the science is there.”

Opponents also raise a concern — the fourth — about safety. While an accident like the 1986 Chernobyl disaster (which caused an estimated 4000 deaths after technical mishaps brought about a series of explosions) is unlikely to happen today, given current safety standards, incidences in France are increasing, according to Teule. “They are not all serious, but they are showing that things can and do go wrong.”

But modern science allows us to rely on passive safety, says Tony Stott, nuclear assurance manager at Eskom. The physics of generation 3 plants make them inherently safe, but more expensive to build. Generation2 plants like Koeberg still rely on engineered safety and backup systems, but with added modifications they are deemed as safe as the newer technologies. Around R1bn has been spent over the past 20 years on modifications to ensure Koeberg’s safety. This has improved its safety by a factor of 10 (the probability of the fuel melting should be less than one in 10000/year; now it is one in 100000). Future plants would likely be either modified generation 2 or generation 3 plants.

Du Plooy argues that the only real safety issue is ensuring that enriched uranium doesn’t reach the hands of rogue regimes. Connotations with Hiroshima and Nagasaki illustrate the potential destructive power of the technology, though nuclear weapons require uranium to be enriched to a higher level than for power generation. SA dismantled its nuclear weaponry programme in the 1990s.

There is a need to ask what the best trade-off is between costs, megawatts of electricity produced, and the reduction of carbon emissions .

Both WWF and Greenpeace argue that an energy mix that excludes nuclear, and introduces renewables while phasing out coal, is both optimal and possible.

The prevailing view is, however, that given the high cost of renewable energy (which may decrease as the technology develops), a plan that excludes nuclear would be too costly, and that renewable energy doesn’t make for a sufficiently reliable supply.

But with dual challenges of climate change and energy security, the solution lies in finding the most efficient way to meet future energy demands in a way that is sustainable and clean — and a balanced mix of technologies may be the best way to do this.

No comments:

Post a Comment

LinkedIn Group
Xing Group
Ecademy Club
Google Coop
Search Engine