It is accepted that nuclear electricity is a low-carbon and well understood energy source. In the zerocarbonbritain2030 strategy, existing plants will continue to generate until the end of their designed operational lives. It has nevertheless been decided to exclude new nuclear capacity from the scenario.
Nuclear power poses a significant risk to human and environmental health. The problems of long-lived high-level waste remain unresolved and there is a risk, albeit low, of extremely serious accidents. Water-consumption is also high per unit of output.
It is also important to consider the international dimension. If the UK and other “developed” nations make new nuclear power a core component of their electricity supply, other countries with rapidly developing economies will want to follow suit. There are doubts about the continued availability of uranium given a world-wide nuclear renaissance. But more significantly, this raises concerns about nuclear weapons proliferation and an increased risk of and vulnerability to very serious forms of terrorism.
The development of Carbon Capture & Storage (CCS) technology should continue. However, the zerocarbonbritain2030 scenario excludes the use of CCS technology for a range of reasons:
- it is a very new technology which is unlikely to be deployed within the next couple of decades;
- CCS is unable to capture all the CO2 emissions produced by a power station. The greenhouse gas emissions from a power station with CCS, while lower than from one without CCS, are not negligible and are significantly higher than those associated with renewables.
CCS is also not likely to be a cheap technology. In all, it is likely to be more cost effective, safer and greener to support the deployment of renewables.
Britain’s renewable energy resources include wind, hydro, biogas, biomass, landfill gas, solar, wave and tidal.
Wind is perhaps Britain’s greatest strategic renewable resource, and the UK has been described as the “Saudi Arabia of wind”. Onshore wind is an established renewable energy technology, and is already a rapidly expanding sector. Onshore wind farms are also compatible with multiple uses of the land, such as agriculture. However it is offshore wind which represents the UK’s most significant renewable resource. The UK benefits from a large marine territory and thus the potential site area for offshore wind generators is enormous.
In the zerocarbonbritain2030 scenario, there is 615TWh of offshore wind power, generated from 195GW of installed capacity, and 75TWh of onshore wind power, generated from 28.5GW of installed capacity.
The large marine territory also suggests that wave power can be an important renewable resource for Britain. At present, wave power generating technology is not fully developed, but is an exciting area of development.
There are a number of resources which can add useful diversity to the generation mix. This includes biomass, biogas and landfill gas, which currently are underexploited, and hydro, tidal and solar.
There is scope for the development of further tidal power, including at the Severn Estuary. There is little scope for a large expansion of hydroelectric generation but some potential for small scale hydro which can be useful for small local generation schemes.
The scope for solar to contribute greatly to the generation mix in Britain is limited, although it will be a key technology in countries located further south. The limitations in Britain are due to our lack of sun, and lack of sun at the right times. Nonetheless, a key advantage of solar photovoltaics is that they can be installed at a domestic scale and the scenario includes a small amount of solar PV.
Wind turbines are now a mature technology and power outputs are steadily increasing. This means that the financial cost is falling. This is true for wind turbines developed for both the onshore and offshore environment. Significant improvements in the capacity of offshore wind turbines in particular are expected in the next few years.
Offshore wind is more expensive than onshore wind, but presents a number of advantages. Firstly, offshore wind turbines tend to have higher capacity factors than onshore wind turbines. This is because, at turbine height, wind speeds tend to be higher and steadier offshore. Secondly, offshore wind turbines can be larger. Thirdly, offshore wind farms are not subject to as high a planning scrutiny from the public – as they are located away from populations, design aesthetics and noise are not significant issues.
If we take a long-term view of power generation, wind in general, and offshore wind in particular, is not necessarily more expensive than fossil fuel power generation. Analysis by the European Commission demonstrates that onshore wind has similar capital costs to coal and that the development of offshore wind has similar capital costs to coal with CCS. However, it is not just the cost of building the infrastructure that is important. The generation potential, cost of maintenance and fuel supply costs also have to be taken into account.
Taking generation potential (capacity factors) into account renewables have higher investment costs compared to fossil fuel generating infrastructure but the marginal cost of electricity produced is extremely low for renewable infrastructure whereas it is high and variable for fossil fuel infrastructure. In other words, whilst it costs a more to build sufficient wind capacity, the cost of the wind itself is free.
The UK Energy Research Centre has estimated that decarbonisation of the UK energy supply only increases the cost of the electricity system by about 10% (over a system based solely on coal – the cheapest form of production if you ignore the costs of carbon).
The cost of each MW unit of power will fall significantly as offshore wind technology is deployed and learning occurs. We estimate that the cost per MW of capacity between 2010 and 2030 can fall from £3.1 million to £1.2 million. In order to decrease offshore wind costs, more suppliers are needed and it would be highly beneficial for the UK to strengthen the domestic supply chain.
Any policy which aims to integrate the cost of carbon into the financial price of a product or service will have the effect of reducing the financial cost of renewable power generation compared to fossil fuel power generation. This would drive investment into these technologies, reducing their price overall as well greatly increasing installed capacity. Specific policy measures can also be introduced which more directly subsidise the development and deployment of renewable power generation technology, including onshore and offshore wind farms.
North Africa and Southern Europe benefit from an enormous solar resource, just as Britain benefits from wind. The development of “concentrated solar power” in this region is very exciting and we strongly support its rapid development. Indeed researchers have projected that it is likely to become one of the cheapest forms of renewable electricity to generate in the future.
However, this does not mean that we should rely on it to the exclusion of developing our own resources.
Firstly, buying electricity from North Africa and Southern Europe will not necessarily be cheaper than producing our own. In particular, the cost of transmitting power over extremely long distances will add to the financial cost of the electricity received. Losses can be minimised by using modern High Voltage Direct Current (HVDC) cables in place of traditional cables running alternating current (AC). Such cables can transport electricity over huge distances with low losses (under 10%), making long distance transfer of electricity a viable option. The development of an effective HVDC network across Europe should be encouraged.
There are other very important reasons, beyond the financial cost of energy from North Africa, why we shouldn’t simply rely on this region for our power. Within the zerocarbonbritain2030 scenario, security of supply is important. We will be energy insecure if the majority of our power comes from one source in a single foreign country, being transmitted through other countries. It is also necessary to consider how a high demand for energy from countries such as Britain may affect the energy supply of citizens in other nations, and how the lack of development of our own renewable resources will undermine a valuable economic sector in Britain.
One of the disadvantages associated with many types of renewable sources of power is that they are not constant. In any one place, the sun is not always shining; the wind is not always blowing; the waves are not always crashing. And certainly, the periods of peak supply of renewable power may not coincide with the periods of peak demand. In the UK, electricity demand is greatest in the evening and in the winter.
The zerocarbonbritain2030 report clearly demonstrates that renewables can nonetheless provide a secure energy system which responds to daily and seasonal variability and is robust enough to respond to unanticipated spikes in demand as well. The zerocarbonbritain2030 scenario has successfully been tested by the “Future Energy Scenario Assessment” (FESA) software. This combines weather and demand data to test several aspects, including if there is enough dispatchable generation to manage the variable base supply of renewable electricity with the variable demand.
Locating wind farms in multiple locations across Britain makes the overall power output smoother. Back-up generation is provided from biogas, biomass, and hydro. Britain is also connected to the electricity grids of other European nations and can import electricity during periods of heavy demand, and export it to other countries during their peaks.
At the same time, we can also make the demand profile smoother. Electric cars, appliances such as rechargers, washing machines and dishwashers as well as heat stores can be programmed to turn on during the night or at other times when the demand is lower (and the electricity price cheaper for the consumer).